diff --git a/data/03/B1/87/03B187978D486459FE5BF8ABFA81F928.xml b/data/03/B1/87/03B187978D486459FE5BF8ABFA81F928.xml new file mode 100644 index 00000000000..27977574dd8 --- /dev/null +++ b/data/03/B1/87/03B187978D486459FE5BF8ABFA81F928.xml @@ -0,0 +1,851 @@ +<document id="C25CAB8F230EB60EC8A8674A0F438B37" ID-DOI="10.1093/zoolinnean/zlae058" ID-ISSN="0024-4082" ID-Zenodo-Dep="14971765" IM.bibliography_approvedBy="felipe" IM.illustrations_approvedBy="juliana" IM.materialsCitations_approvedBy="juliana" IM.metadata_approvedBy="felipe" IM.taxonomicNames_approvedBy="juliana" IM.treatments_approvedBy="juliana" checkinTime="1741163808392" checkinUser="plazi" docAuthor="Dearden, Richard P., Herrel, Anthony & Pradel, Alan" docDate="2025" docId="03B187978D486459FE5BF8ABFA81F928" docLanguage="en" docName="zlae058.pdf" docOrigin="Zoological Journal of the Linnean Society (Statistics in Society) 203 (2)" docSource="https://doi.org/10.1093/zoolinnean/zlae058" docStyle="DocumentStyle:4F230B9370E98E256D973D6DFB57F36C.10:ZoolJLinnSoc.2023-.journal_article" docStyleId="4F230B9370E98E256D973D6DFB57F36C" docStyleName="ZoolJLinnSoc.2023-.journal_article" docStyleVersion="10" docTitle="Acanthodes Agassiz 1833" docType="treatment" docVersion="1" lastPageNumber="15" masterDocId="FF88FFEF8D4C6457FFDCFF9CFFBEFF9B" masterDocTitle="Te pharynx of the iconic stem-group chondrichthyan Acanthodes Agassiz, 1833 revisited with micro-computed tomography" masterLastPageNumber="19" masterPageNumber="1" pageNumber="5" updateTime="1741357023066" updateUser="juliana"> +<mods:mods id="1BF78F9FB8EC55FE905A57DFC1CC6C5F" xmlns:mods="http://www.loc.gov/mods/v3"> +<mods:titleInfo id="A9FB3B474D7126539A9873C35B3A6AF2"> +<mods:title id="4C5CA478B902B51D4A0AC8380B68A539">Te pharynx of the iconic stem-group chondrichthyan Acanthodes Agassiz, 1833 revisited with micro-computed tomography</mods:title> +</mods:titleInfo> +<mods:name id="0D68D9052279A09B216E29D78CB83F2F" type="personal"> +<mods:role id="49E34E5F84F9CD083E74A0D6038F3596"> +<mods:roleTerm id="77C3E312DF80A28292233993A2669D94">Author</mods:roleTerm> +</mods:role> +<mods:namePart id="275C63FD786ADD24FFCDE22F9EC72284">Dearden, Richard P.</mods:namePart> +<mods:affiliation id="A751DE93E575E2B1DBEAA8FE6DDF5103">Naturalis Biodiversity Center, Darwinweg 2, 2333 CR, Leiden, Te Netherlands & CR 2 P, Centre de Recherche en Paléontologie-Paris, Muséum national d’Histoire naturelle, Sorbonne Université, Centre National de la Recherche Scientifique, 75005 Paris cedex 05, France</mods:affiliation> +<mods:nameIdentifier id="C7A028B956F9E2695C688319B1896363" type="email">richard.dearden@naturalis.nl</mods:nameIdentifier> +</mods:name> +<mods:name id="948ACDF9FB693CDE6C46BD5FB8EDD107" type="personal"> +<mods:role id="864501252E4AD2EEFC895DA7FA15D76B"> +<mods:roleTerm id="8EA648A98C3AE4285CDF04F7742990BD">Author</mods:roleTerm> +</mods:role> +<mods:namePart id="A2445B1CF3A9164D5E7F57017C1DF150">Herrel, Anthony</mods:namePart> +<mods:affiliation id="D6AD08D7F06C18BA041C863510033262">UMR 7179 (MNHN-CNRS) MECADEV, Département Adaptations du Vivant, Muséum National d’Histoire Naturelle, 75005 Paris, France & Department of Biology, Evolutionary Morphology of Vertebrates, Ghent University, K. L. Ledeganckstraat 35, 9000 Ghent, Belgium & Department of Biology, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium & Naturhistorisches Museum Bern, Bernastrasse 15, 3005 Bern, Switzerland</mods:affiliation> +</mods:name> +<mods:name id="F3B51E9A0E4C17D349FD672F6F62C5EB" type="personal"> +<mods:role id="620BE4931522DDD2218359546129EC6D"> +<mods:roleTerm id="B57E3C413F410F8C13C065D3422D6B07">Author</mods:roleTerm> +</mods:role> +<mods:namePart id="ADAF670C11336D0E1EDB3174B151AD3F">Pradel, Alan</mods:namePart> +<mods:affiliation id="6C182E9697F95F1F4A6EC0DB70AED339">CR 2 P, Centre de Recherche en Paléontologie-Paris, Muséum national d’Histoire naturelle, Sorbonne Université, Centre National de la Recherche Scientifique, 75005 Paris cedex 05, France</mods:affiliation> +</mods:name> +<mods:typeOfResource id="CAA47F08797164151F119A29DD72CA66">text</mods:typeOfResource> +<mods:relatedItem id="324582F3707C1F7FA5C3822A324093CC" type="host"> +<mods:titleInfo id="0D34F788850CE994D3E6EE74A2504876"> +<mods:title id="F4DCBF2A8E3DBC7050FB492A3D8E41C2">Zoological Journal of the Linnean Society</mods:title> +</mods:titleInfo> +<mods:part id="078EAFB053164687535A4E3C787C0876"> +<mods:date id="668A38DDEC97BADDE9841D6224A052F0">2025</mods:date> +<mods:detail id="B8EFC6D1E233B0E265E11730A0AE67DA" type="series"> +<mods:title id="B4A3B38BD7E6070ACAF13EF009CBB020">Statistics in Society</mods:title> +</mods:detail> +<mods:detail id="1A4F31B48B6944830657A6284187201F" type="pubDate"> +<mods:number id="45EDDA4F4C51679181345A02AE7F6554">2024-05-30</mods:number> +</mods:detail> +<mods:detail id="71936E10111167810CBF65F0B7B372ED" type="volume"> +<mods:number id="0C75EA58C928F2387A19C2401D051D15">203</mods:number> +</mods:detail> +<mods:detail id="1444493E92F216C83CBC708C7978EFD5" type="issue"> +<mods:number id="336A230C09F29F9A4F099B266E1653DD">2</mods:number> +</mods:detail> +<mods:extent id="82C7EF17F87DD80C30D947F32E9E60A0" unit="page"> +<mods:start id="31F2D0E9561D5AA1400D12596B597089">1</mods:start> +<mods:end id="051AB60EA2294E11DB8A6B33DDC1A933">19</mods:end> +</mods:extent> +</mods:part> +</mods:relatedItem> +<mods:location id="8C0F0812584B28DDB91510E80FCA2EEF"> +<mods:url id="32175D7372FEAC4496FCCD195008A808">https://doi.org/10.1093/zoolinnean/zlae058</mods:url> +</mods:location> +<mods:classification id="CA826395AE4B48A4FA88088B26FD097D">journal article</mods:classification> +<mods:identifier id="0A39B2FC833686AEFC9F713D0C3E6438" type="DOI">10.1093/zoolinnean/zlae058</mods:identifier> +<mods:identifier id="72AE5E63A2B462093E12C1CB8C4C8EEB" type="ISSN">0024-4082</mods:identifier> +<mods:identifier id="8EE6D46D0D0FBB30FD7DB48E8A4B161C" type="Zenodo-Dep">14971765</mods:identifier> +</mods:mods> +<treatment id="03B187978D486459FE5BF8ABFA81F928" LSID="urn:lsid:plazi:treatment:03B187978D486459FE5BF8ABFA81F928" httpUri="http://treatment.plazi.org/id/03B187978D486459FE5BF8ABFA81F928" lastPageId="14" lastPageNumber="15" pageId="4" pageNumber="5"> +<subSubSection id="C302650A8D486453FE5BF8ABFDBCF8CA" box="[391,514,1847,1873]" pageId="4" pageNumber="5" type="nomenclature"> +<paragraph id="8BA736818D486453FE5BF8ABFDBCF8CA" blockId="4.[391,514,1847,1873]" box="[391,514,1847,1873]" pageId="4" pageNumber="5"> +<heading id="D0EF81ED8D486453FE5BF8ABFDBCF8CA" allCaps="true" bold="true" box="[391,514,1847,1873]" centered="true" fontSize="11" level="1" pageId="4" pageNumber="5" reason="1"> +<taxonomicName id="4C184D028D486453FE5BF8ABFDBCF8CA" ID-CoL="M6L" authority="Agassiz, 1833" authorityName="Agassiz" authorityYear="1833" box="[391,514,1847,1873]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="4" pageNumber="5" phylum="Arthropoda" rank="genus"> +<emphasis id="B96CEA938D486453FE5BF8ABFDBCF8CA" bold="true" box="[391,514,1847,1873]" pageId="4" pageNumber="5">RESULTS</emphasis> +</taxonomicName> +</heading> +</paragraph> +</subSubSection> +<subSubSection id="C302650A8D486459FF5DF8FFFA81F928" lastPageId="14" lastPageNumber="15" pageId="4" pageNumber="5" type="description"> +<paragraph id="8BA736818D486453FF5DF8FFFB84F822" blockId="4.[129,778,1891,1978]" lastBlockId="4.[825,1475,1641,1978]" pageId="4" pageNumber="5"> +All +<specimenCount id="9D1EFD088D486453FF78F8FFFEF7F8E0" box="[164,329,1891,1915]" count="3" pageId="4" pageNumber="5" type="generic">three specimens</specimenCount> +have collapsed laterally, but the 3D shape of individual pharyngeal elements is retained and is consistent on either side of specimens. Between the +<specimenCount id="9D1EFD088D486453FDD1F83EFD0AF821" box="[525,692,1954,1978]" count="3" pageId="4" pageNumber="5" type="generic">three specimens</specimenCount> +most of the known endoskeleton of +<taxonomicName id="4C184D028D486453FB87F9F5FB75F91A" authorityName="Agassiz" authorityYear="1833" box="[1115,1227,1641,1665]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="4" pageNumber="5" phylum="Arthropoda" rank="genus"> +<emphasis id="B96CEA938D486453FB87F9F5FB75F91A" box="[1115,1227,1641,1665]" italics="true" pageId="4" pageNumber="5">Acanthodes</emphasis> +</taxonomicName> +is preserved ( +<figureCitation id="13232A048D486453FA83F9F5FA09F91A" box="[1375,1463,1641,1665]" captionStart-0="Figure 2" captionStart-1="Figure 3" captionStart-2="Figure 4" captionStartId-0="3.[113,178,1621,1645]" captionStartId-1="4.[129,194,1343,1367]" captionStartId-2="5.[113,178,1539,1563]" captionTargetBox-0="[117,1455,147,1591]" captionTargetBox-1="[132,1470,147,1313]" captionTargetBox-2="[116,1456,146,1509]" captionTargetId-0="figure-68@3.[114,1458,144,1594]" captionTargetId-1="figure-210@4.[129,1473,144,1316]" captionTargetId-2="figure-106@5.[114,1458,144,1511]" captionTargetPageId-0="3" captionTargetPageId-1="4" captionTargetPageId-2="5" captionText-0="Figure 2. The head skeleton of Acanthodes confusus MNHN-F-SAA21, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pq. autop., palatoquadrate autopalatine; pq. metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." captionText-1="Figure 3. The head skeleton of Acanthodes confusus MNHN-F-SAA20, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; hypobr., hypobranchials; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scapcor., scapulocoracoids; scler., sclerotic ring. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bar = 20 mm." captionText-2="Figure 4. The head skeleton of Acanthodes confusus MNHN-F-SAA24, visualized using computed tomography. A, in right lateral view. B, in left lateral view. Abbreviations: basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; interhy., interhyal; L., left; mand.sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; scapcor., scapulocoracoids; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi-0="http://doi.org/10.5281/zenodo.14971769" figureDoi-1="http://doi.org/10.5281/zenodo.14971771" figureDoi-2="http://doi.org/10.5281/zenodo.14971773" httpUri-0="https://zenodo.org/record/14971769/files/figure.png" httpUri-1="https://zenodo.org/record/14971771/files/figure.png" httpUri-2="https://zenodo.org/record/14971773/files/figure.png" pageId="4" pageNumber="5">Figs 2–4</figureCitation> +) including the jaws, hyoid arch, branchial skeleton, braincase, and shoulder girdle. Here we concentrate on the visceral skeleton: the braincase and shoulder girdle will be the focus of future descriptions. Generally speaking the details of the visceral skeleton of +<taxonomicName id="4C184D028D486453FC6FF899FB9DF886" authorityName="Agassiz" authorityYear="1833" box="[947,1059,1797,1821]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="4" pageNumber="5" phylum="Arthropoda" rank="genus"> +<emphasis id="B96CEA938D486453FC6FF899FB9DF886" box="[947,1059,1797,1821]" italics="true" pageId="4" pageNumber="5">Acanthodes</emphasis> +</taxonomicName> +matches the detailed accounts of +<bibRefCitation id="EF894B708D486453FA55F899FCC6F8A6" author="Miles RS" pageId="4" pageNumber="5" pagination="457 - 9" refId="ref12336" refString="Miles RS. A reinterpretation of the visceral skeleton of Acanthodes. Nature 1964; 204: 457-9. htps: // doi. org / 10.1038/204457a0" type="journal article" year="1964">Miles (1964</bibRefCitation> +, +<bibRefCitation id="EF894B708D486453FC58F8B9FC06F8A6" author="Miles RS" box="[900,952,1829,1853]" pageId="4" pageNumber="5" pagination="233 - 55" refId="ref12369" refString="Miles RS. Some features in the cranial morphology of acanthodians and the relationships of the Acanthodii. Acta Zoologica 1965; 46: 233-55. htps: // doi. org / 10.1111/j.1463-6395.1965.tb00733.x" type="journal article" year="1965">1965</bibRefCitation> +, +<bibRefCitation id="EF894B708D486453FC18F8B9FC46F8A6" author="Miles RS" box="[964,1016,1829,1853]" pageId="4" pageNumber="5" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">1968</bibRefCitation> +, +<bibRefCitation id="EF894B708D486453FBDFF8B9FB89F8A6" author="Miles RS" box="[1027,1079,1829,1853]" pageId="4" pageNumber="5" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">1973</bibRefCitation> +; +<figureCitation id="13232A048D486453FB99F8B9FB17F8A6" box="[1093,1193,1829,1853]" captionStart-0="Figure 5" captionStart-1="Figure 6" captionStart-2="Figure 7" captionStart-3="Figure 8" captionStart-4="Figure 9" captionStart-5="Figure 10" captionStartId-0="6.[127,192,1032,1056]" captionStartId-1="7.[114,179,1408,1432]" captionStartId-2="8.[129,194,1539,1563]" captionStartId-3="9.[113,178,1758,1782]" captionStartId-4="10.[129,194,1644,1668]" captionStartId-5="11.[115,179,1285,1309]" captionTargetBox-0="[129,1473,144,1005]" captionTargetBox-1="[116,1456,146,1378]" captionTargetBox-2="[132,1470,147,1509]" captionTargetBox-3="[117,1455,147,1727]" captionTargetBox-4="[132,1470,146,1613]" captionTargetBox-5="[117,1455,147,1255]" captionTargetId-0="figure-459@6.[129,1473,144,1005]" captionTargetId-1="figure-205@7.[114,1458,144,1381]" captionTargetId-2="figure-129@8.[129,1473,144,1512]" captionTargetId-3="figure-6@9.[114,1458,144,1730]" captionTargetId-4="figure-6@10.[129,1473,144,1616]" captionTargetId-5="figure-331@11.[114,1458,144,1258]" captionTargetPageId-0="6" captionTargetPageId-1="7" captionTargetPageId-2="8" captionTargetPageId-3="9" captionTargetPageId-4="10" captionTargetPageId-5="11" captionText-0="Figure 5. Sections through tomograms from the scan data for MNHN-F-SAA21. A, sagittal section.B, transverse section. C, coronal section. Abbreviations:basisph., basisphenoid; rak.br., branchial rakers; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors.oss., dorsal ossification of neurocranium; epibr., epibranchial; hyomand., hyomandibula; rak.hy., hyoid rakers; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. pl., plinth for branchial raker.Red plane indicates plane of bisection.Scale bar = 10 mm. In tomograms lighter values represent more radiodense materials:light grey areas are the matrix, dark grey areas are skeletal tissues, and black areas are air spaces." captionText-1="Figure 6. The mandibular arch of Acanthodes confusus MNHN-F-SAA21. A, left Meckel’s cartilage and palatoquadrate in lateral view. B, left Meckel’s cartilage and palatoquadrate in medial view.C, D, left palatoquadrate in (C) ventral and (D) dorsal view. E, F, left Meckel’s cartilage in (E) dorsal and (F) ventral view.G, left Meckel’s cartilage and palatoquadrate in anterior view. Abbreviations: add. foss., fossa for the adductor muscle; art. cot., articular cotylus; art. pr., articular process; bas. proc., basal process; extrapal. rid., extrapalatoquadrate ridge; Meck.ant., anterior mineralization of Meckel’s cartilage; Meck.post., posterior mineralization of Meckel’s cartilage; obl. rid., oblique ridge; ot. cot., cotylus for articulation with otic region; otic. proc., otic process; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; prart. pr., prearticular process; preg.pr., preglenoid process; sp. gr., mandibular splint groove; sym., expanded mandibular symphysis; trigem. for., foramen for the mandibular ramus of the trigeminal nerve (V3). Scale bar = 20 mm." captionText-2="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." captionText-3="Figure 8. The hyoid skeleton of Acanthodes confusus. A, B, the hyoid skeleton of MNHN-F-SAA24 in (A) left lateral and (B) right lateral view. C–E, the hyoid skeleton of MNHN-F-SAA21 in (C) right lateral, (D) left lateral, and (E) dorsal view. F, the posterior mineralization of the left hyomandibula in MNHN-F-SAA21.G, H, the left interhyal of MNHN-F-SAA24 in (G) lateral and (H) medial view.I, J, the left ceratohyal of MNHN-F-SAA21 in (I) lateral and (J) medial view.K–M, the basibranchial of MNHN-F-SAA21 in (K) ventral, (L) dorsal, and (M) right lateral view.Abbreviations: ant., anterior ossification; artic., articulation; basibr., basibranchial; basisph., basisphenoid; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; L., left; hyomand., hyomandibula; hypobr., hypobranchials; med.gr., medial groove; med.rid., medial ridge; post., posterior ossification; R., right.; I–II, branchial arches I–II. Scale bar = 10 mm." captionText-4="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." captionText-5="Figure 10. The gular rays, hyoid rakers, and branchial rakers of Acanthodes confusus. A, right lateral view of jaws of MNHN-F-SAA21 showing relationship of gular rays and mandibular splint to Meckel’s cartilage.B, right lateral view of jaws of MNHN-F-SAA20 with mandibular splints removed showing gular rays and relationship of hyoid rakers to ceratobranchial. C, left lateral view of MNHN-F-SAA20 showing hyomandibular rakers.D, branchial rakers in articulation with the epibranchial of SAA21.E, branchial rakers in articulation with the ceratobranchial of SAA21. F, hyoid rakers from the ceratohyal of SAA20.G, branchial rakers from the epibranchial of SAA20. Abbreviations: ceratobr., ceratobranchials; epibr., epibranchial; gul. ray., gular rays; rak.br., branchial rakers; rak.hy., hyoid rakers; rak.pl., plinth for branchial raker; I–V, branchial arches I–V.Scale bar = 10 mm except in C where scale bar = 2.5 mm. Note in D and E the shape of the rakers is poorly captured by the scan." figureDoi-0="http://doi.org/10.5281/zenodo.14971775" figureDoi-1="http://doi.org/10.5281/zenodo.14971777" figureDoi-2="http://doi.org/10.5281/zenodo.14971779" figureDoi-3="http://doi.org/10.5281/zenodo.14972026" figureDoi-4="http://doi.org/10.5281/zenodo.14972030" figureDoi-5="http://doi.org/10.5281/zenodo.14972032" httpUri-0="https://zenodo.org/record/14971775/files/figure.png" httpUri-1="https://zenodo.org/record/14971777/files/figure.png" httpUri-2="https://zenodo.org/record/14971779/files/figure.png" httpUri-3="https://zenodo.org/record/14972026/files/figure.png" httpUri-4="https://zenodo.org/record/14972030/files/figure.png" httpUri-5="https://zenodo.org/record/14972032/files/figure.png" pageId="4" pageNumber="5">Figs 5–10</figureCitation> +). In this account we generally follow Miles’ terminology; a comparison of the terminology we use to that used by previous authors is given in Supporting Information, Table S1. A drawing of our pharyngeal reconstruction is given in +<figureCitation id="13232A048D486453FC0FF83EFB8AF821" box="[979,1076,1954,1978]" captionStart="Figure 11" captionStartId="12.[129,192,1120,1144]" captionTargetBox="[292,1310,147,1090]" captionTargetId="figure-500@12.[289,1313,144,1093]" captionTargetPageId="12" captionText="Figure 11.Reconstruction of the pharyngeal skeleton of Acanthodes confusus as described here.Abbreviations:basibr.,basibranchial;ceratobr., ceratobranchials;ceratohy., ceratohyal;epibr., epibranchial; hyomand., hyomandibula; hypobr., hypobranchial; interhy., interhyal; pharbr., pharyngobranchials.Matching colours denote serially homologous elements.Reconstruction shown as if spread horizontally,with anterior above." figureDoi="http://doi.org/10.5281/zenodo.14972036" httpUri="https://zenodo.org/record/14972036/files/figure.png" pageId="4" pageNumber="5">Figure 11</figureCitation> +. +</paragraph> +<caption id="DF6766098D496452FFADF99FFDE1F945" ID-DOI="http://doi.org/10.5281/zenodo.14971773" ID-Zenodo-Dep="14971773" httpUri="https://zenodo.org/record/14971773/files/figure.png" pageId="5" pageNumber="6" startId="5.[113,178,1539,1563]" targetBox="[116,1456,146,1509]" targetPageId="5" targetType="figure"> +<paragraph id="8BA736818D496452FFADF99FFDE1F945" blockId="5.[113,1408,1539,1759]" pageId="5" pageNumber="6"> +<emphasis id="B96CEA938D496452FFADF99FFF77F980" bold="true" box="[113,201,1539,1563]" pageId="5" pageNumber="6">Figure 4.</emphasis> +The head skeleton of +<taxonomicName id="4C184D028D496452FE49F99FFDF3F980" authorityName="Heidtke" authorityYear="2011" box="[405,589,1539,1563]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="5" pageNumber="6" phylum="Arthropoda" rank="species" species="confusus"> +<emphasis id="B96CEA938D496452FE49F99FFDF3F980" box="[405,589,1539,1563]" italics="true" pageId="5" pageNumber="6">Acanthodes confusus</emphasis> +</taxonomicName> +MNHN-F-SAA24, visualized using computed tomography. A, in right lateral view. B, in left lateral view. Abbreviations: basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; interhy., interhyal; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq. metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; scapcor., scapulocoracoids; scler., sclerotic ring. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm. +</paragraph> +</caption> +<paragraph id="8BA736818D496451FF51F893FDF0FA74" blockId="5.[113,763,1807,1956]" lastBlockId="6.[128,778,1244,1519]" lastPageId="6" lastPageNumber="7" pageId="5" pageNumber="6"> +All endoskeletal elements in +<taxonomicName id="4C184D028D496452FE37F893FDD6F8BC" authorityName="Heidtke" authorityYear="2011" box="[491,616,1807,1831]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="5" pageNumber="6" phylum="Arthropoda" rank="species" species="confusus"> +<emphasis id="B96CEA938D496452FE37F893FDD6F8BC" box="[491,616,1807,1831]" italics="true" pageId="5" pageNumber="6">A. confusus</emphasis> +</taxonomicName> +comprise a heavily mineralized outer shell surrounding an internal space ( +<figureCitation id="13232A048D496452FFA0F8D1FF0BF8FE" box="[124,181,1869,1893]" captionStart="Figure 5" captionStartId="6.[127,192,1032,1056]" captionTargetBox="[129,1473,144,1005]" captionTargetId="figure-459@6.[129,1473,144,1005]" captionTargetPageId="6" captionText="Figure 5. Sections through tomograms from the scan data for MNHN-F-SAA21. A, sagittal section.B, transverse section. C, coronal section. Abbreviations:basisph., basisphenoid; rak.br., branchial rakers; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors.oss., dorsal ossification of neurocranium; epibr., epibranchial; hyomand., hyomandibula; rak.hy., hyoid rakers; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. pl., plinth for branchial raker.Red plane indicates plane of bisection.Scale bar = 10 mm. In tomograms lighter values represent more radiodense materials:light grey areas are the matrix, dark grey areas are skeletal tissues, and black areas are air spaces." figureDoi="http://doi.org/10.5281/zenodo.14971775" httpUri="https://zenodo.org/record/14971775/files/figure.png" pageId="5" pageNumber="6">Fig. 5</figureCitation> +) that was presumably filled with unmineralized cartilage in life. Our scan data is of insufficient high resolution to show the histology of the outer tissue, but +<bibRefCitation id="EF894B708D496452FE2EF817FD3EF83F" author="Orvig T" box="[498,640,1931,1956]" pageId="5" pageNumber="6" pagination="321 - 454" refId="ref12597" refString="Orvig T. Histologic studies of placoderms and fossil elasmobranchs. I: Te endoskeleton, with remarks on the hard tissues of lower vertebrates in general. Arkiv for Zoologi 1951; 2: 321-454." type="journal article" year="1951">Ørvig (1951)</bibRefCitation> +interpreted the same tissue as perichondral bone in thin sections of acanthodians including +<taxonomicName id="4C184D028D496452FC29F8B2FBDBF8DD" authorityName="Agassiz" authorityYear="1833" box="[1013,1125,1838,1862]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="5" pageNumber="6" phylum="Arthropoda" rank="genus"> +<emphasis id="B96CEA938D496452FC29F8B2FBDBF8DD" box="[1013,1125,1838,1862]" italics="true" pageId="5" pageNumber="6">Acanthodes</emphasis> +</taxonomicName> +specimens from Lebach on the basis of the tissue having fusiform cell spaces with canaliculi and Sharpey’s fibre attachments, albeit lacking lamination or vascular canals. This perichondral bony tissue is distinct from the varied cartilage tissues that have been described in other stemchondrichthyans ( +<bibRefCitation id="EF894B708D4A6451FEE2FB60FE42FA8F" author="Burrow CJ & Newman MJ & den Blaauwen J" box="[318,508,1276,1300]" pageId="6" pageNumber="7" pagination="335 - 62" refId="ref11010" refString="Burrow CJ, Newman MJ, den Blaauwen J et al. Te Early Devonian ischnacanthiform acanthodian Ischnacanthus gracilis (Egerton, 1861) from the Midland Valley of Scotland. Acta Geologica Polonica 2018; 68: 335-62." type="journal article" year="2018"> +Burrow +<emphasis id="B96CEA938D4A6451FE4EFB60FE7CFA8F" box="[402,450,1276,1300]" italics="true" pageId="6" pageNumber="7">et al.</emphasis> +2018 +</bibRefCitation> +, 2020, +<bibRefCitation id="EF894B708D4A6451FD95FB60FCBAFA8F" author="Maisey JG & Denton JSS & Burrow C" box="[585,772,1276,1300]" pageId="6" pageNumber="7" pagination="919 - 41" refId="ref12235" refString="Maisey JG, Denton JSS, Burrow C et al. Architectural and ultrastructural features of tessellated calcified cartilage in modern and extinct chondrichthyan fishes. Journal of Fish Biology 2020; 98: 919-41. htps: // doi. org / 10.1111/jf.14376" type="journal article" year="2020"> +Maisey +<emphasis id="B96CEA938D4A6451FD45FB60FD74FA8F" box="[665,714,1276,1300]" italics="true" pageId="6" pageNumber="7">et al.</emphasis> +2020 +</bibRefCitation> +, +<bibRefCitation id="EF894B708D4A6451FF5CFA80FE25FAA8" author="Burrow CJ & Blaauwen JLD" box="[128,411,1307,1331]" pageId="6" pageNumber="7" pagination="81 - 91" refId="ref10872" refString="Burrow CJ, Blaauwen JLD. Endoskeletal tissues of acanthodians (stem Chondrichthyes). In: Pradel A, Denton JSS, Janvier P (eds), Ancient Fishes and their Living Relatives: A Tribute to John G. Maisey. Munich, Germany: Verlag Dr. Friedrich Pfeil, 2021, 81-91." type="book chapter" year="2021">Burrow and Blaauwen 2021</bibRefCitation> +). The thickness of this tissue is variable through the skeleton, for example being thicker in the mandibular arches than in the branchial arches, particularly around the mandibular articulation ( +<figureCitation id="13232A048D4A6451FE65FAE5FDB6FA0A" box="[441,520,1401,1425]" captionStart="Figure 5" captionStartId="6.[127,192,1032,1056]" captionTargetBox="[129,1473,144,1005]" captionTargetId="figure-459@6.[129,1473,144,1005]" captionTargetPageId="6" captionText="Figure 5. Sections through tomograms from the scan data for MNHN-F-SAA21. A, sagittal section.B, transverse section. C, coronal section. Abbreviations:basisph., basisphenoid; rak.br., branchial rakers; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors.oss., dorsal ossification of neurocranium; epibr., epibranchial; hyomand., hyomandibula; rak.hy., hyoid rakers; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. pl., plinth for branchial raker.Red plane indicates plane of bisection.Scale bar = 10 mm. In tomograms lighter values represent more radiodense materials:light grey areas are the matrix, dark grey areas are skeletal tissues, and black areas are air spaces." figureDoi="http://doi.org/10.5281/zenodo.14971775" httpUri="https://zenodo.org/record/14971775/files/figure.png" pageId="6" pageNumber="7">Fig. 5C</figureCitation> +). This probably reflects the function of different elements analogously to varying thicknesses in the prismatic tesselate calcified cartilage in extant and extinct chondrichthyans ( +<bibRefCitation id="EF894B708D4A6451FE54FA4BFD80FA74" author="Maisey JG & Denton JSS & Burrow C" box="[392,574,1495,1519]" pageId="6" pageNumber="7" pagination="919 - 41" refId="ref12235" refString="Maisey JG, Denton JSS, Burrow C et al. Architectural and ultrastructural features of tessellated calcified cartilage in modern and extinct chondrichthyan fishes. Journal of Fish Biology 2020; 98: 919-41. htps: // doi. org / 10.1111/jf.14376" type="journal article" year="2020"> +Maisey +<emphasis id="B96CEA938D4A6451FE0BFA44FDB8FA74" box="[471,518,1495,1519]" italics="true" pageId="6" pageNumber="7">et al.</emphasis> +2020 +</bibRefCitation> +). +</paragraph> +<caption id="DF6766098D4A6451FFA3FB94FF7DFB37" ID-DOI="http://doi.org/10.5281/zenodo.14971775" ID-Zenodo-Dep="14971775" httpUri="https://zenodo.org/record/14971775/files/figure.png" pageId="6" pageNumber="7" startId="6.[127,192,1032,1056]" targetBox="[129,1473,144,1005]" targetPageId="6" targetType="figure"> +<paragraph id="8BA736818D4A6451FFA3FB94FF7DFB37" blockId="6.[127,1453,1032,1196]" pageId="6" pageNumber="7"> +<emphasis id="B96CEA938D4A6451FFA3FB94FF68FBBA" bold="true" box="[127,214,1032,1057]" pageId="6" pageNumber="7">Figure 5.</emphasis> +Sections through tomograms from the scan data for MNHN-F-SAA21. A, sagittal section. B, transverse section. C, coronal section. Abbreviations: basisph., basisphenoid; rak. br., branchial rakers; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; hyomand., hyomandibula; rak. hy., hyoid rakers; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. pl., plinth for branchial raker. Red plane indicates plane of bisection. Scale bar = 10 mm. In tomograms lighter values represent more radiodense materials: light grey areas are the matrix, dark grey areas are skeletal tissues, and black areas are air spaces. +</paragraph> +</caption> +<paragraph id="8BA736818D4A6451FEB0F992FDA0F9B2" blockId="6.[129,778,1550,1989]" box="[364,542,1550,1577]" pageId="6" pageNumber="7"> +<emphasis id="B96CEA938D4A6451FEB0F992FDA0F9B2" bold="true" box="[364,542,1550,1577]" pageId="6" pageNumber="7">Mandibular arch</emphasis> +</paragraph> +<paragraph id="8BA736818D4A6451FF5DF9AAFB36F9F7" blockId="6.[129,778,1550,1989]" lastBlockId="6.[825,1475,1244,1644]" pageId="6" pageNumber="7"> +The mandibular arch ( +<figureCitation id="13232A048D4A6451FEB3F9A9FE14F9D6" box="[367,426,1589,1613]" captionStart="Figure 6" captionStartId="7.[114,179,1408,1432]" captionTargetBox="[116,1456,146,1378]" captionTargetId="figure-205@7.[114,1458,144,1381]" captionTargetPageId="7" captionText="Figure 6. The mandibular arch of Acanthodes confusus MNHN-F-SAA21. A, left Meckel’s cartilage and palatoquadrate in lateral view. B, left Meckel’s cartilage and palatoquadrate in medial view.C, D, left palatoquadrate in (C) ventral and (D) dorsal view. E, F, left Meckel’s cartilage in (E) dorsal and (F) ventral view.G, left Meckel’s cartilage and palatoquadrate in anterior view. Abbreviations: add. foss., fossa for the adductor muscle; art. cot., articular cotylus; art. pr., articular process; bas. proc., basal process; extrapal. rid., extrapalatoquadrate ridge; Meck.ant., anterior mineralization of Meckel’s cartilage; Meck.post., posterior mineralization of Meckel’s cartilage; obl. rid., oblique ridge; ot. cot., cotylus for articulation with otic region; otic. proc., otic process; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; prart. pr., prearticular process; preg.pr., preglenoid process; sp. gr., mandibular splint groove; sym., expanded mandibular symphysis; trigem. for., foramen for the mandibular ramus of the trigeminal nerve (V3). Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971777" httpUri="https://zenodo.org/record/14971777/files/figure.png" pageId="6" pageNumber="7">Fig. 6</figureCitation> +) comprises a palatoquadrate and Meckel’s cartilage, the morphology of which largely confirm the description of +<bibRefCitation id="EF894B708D4A6451FE98F9E8FE78F917" author="Miles RS" box="[324,454,1652,1676]" pageId="6" pageNumber="7" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles (1968</bibRefCitation> +, +<bibRefCitation id="EF894B708D4A6451FE0EF9E8FDB8F917" author="Miles RS" box="[466,518,1652,1676]" pageId="6" pageNumber="7" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">1973</bibRefCitation> +). The three ossifications of the palatoquadrates are unfinished and have open margins where they would have been joined by uncalcified cartilage. When reconstructed they conform with Miles’ account of their articulations with the neurocranium ( +<bibRefCitation id="EF894B708D4A6451FDDEF96DFDCBF892" author="Miles RS" box="[514,629,1777,1801]" pageId="6" pageNumber="7" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles 1968</bibRefCitation> +). The anterior edge of the autopalatine is finished, with no evidence for an anteriorly extending palatine commissure ( +<bibRefCitation id="EF894B708D4A6451FDFAF8ACFD23F8D3" author="Jarvik E" box="[550,669,1840,1864]" pageId="6" pageNumber="7" pagination="199 - 225" refId="ref12006" refString="Jarvik E. Te systematic position of acanthodian fishes. In: Andrews SM, Miles RS, Walker A (eds), Problems in Vertebrate Evolution. London, UK: Academic Press, 1977, 199-225." type="book chapter" year="1977">Jarvik 1977</bibRefCitation> +). Like the palatoquadrate ossifications, the two ossifications of the Meckel’s cartilage are unfinished towards the centre of the element. The relationship between the Meckel’s cartilage and the dermal mandibular splint matches the description of +<bibRefCitation id="EF894B708D4A6451FD9CF831FC3DFB6F" author="Dearden RP & Giles S" box="[576,899,1244,1989]" pageId="6" pageNumber="7" refId="ref11396" refString="Dearden RP, Giles S. Diverse stem-chondrichthyan oral structures and evidence for an independently acquired acanthodid dentition. Royal Society Open Science 2021; 8: 210822. htps: // doi. org / 10.1098 / rsos. 210822" type="journal volume" year="2021">Dearden and Giles (2021)</bibRefCitation> +. The cup-like anterior tip to the Meckel’s cartilages suggests a well-developed but mobile connective-tissue attachment between them, and may be a character uniting a subset of stem-group chondrichthyans ( +<bibRefCitation id="EF894B708D4A6451FBEAFAA6FA92FAC9" author="Dearden RP & Giles S" box="[1078,1324,1338,1362]" pageId="6" pageNumber="7" refId="ref11396" refString="Dearden RP, Giles S. Diverse stem-chondrichthyan oral structures and evidence for an independently acquired acanthodid dentition. Royal Society Open Science 2021; 8: 210822. htps: // doi. org / 10.1098 / rsos. 210822" type="journal volume" year="2021">Dearden and Giles 2021</bibRefCitation> +). The articulation between the palatoquadrate and Meckel’s cartilage confirm the description of +<bibRefCitation id="EF894B708D4A6451FC27FAE5FB38FA0A" author="Miles RS" box="[1019,1158,1401,1425]" pageId="6" pageNumber="7" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles (1973)</bibRefCitation> +, although the preglenoid process is notably more rounded than in that reconstruction. There is no pronounced retroarticular flange as in +<taxonomicName id="4C184D028D4A6451FACDFA24FA2DFA4B" authorityName="Long, Burrow, Ginter, Maisey, Trinajstic, Coates, Young & Senden" authorityYear="2015" box="[1297,1427,1464,1488]" genus="Gogoselachus" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="6" pageNumber="7" rank="genus"> +<emphasis id="B96CEA938D4A6451FACDFA24FA2DFA4B" box="[1297,1427,1464,1488]" italics="true" pageId="6" pageNumber="7">Gogoselachus</emphasis> +</taxonomicName> +and +<taxonomicName id="4C184D028D4A6451FCE5FA4BFC1DFA74" authorityName="Agassiz" authorityYear="1837" box="[825,931,1495,1519]" class="Elasmobranchii" family="Tristychiidae" genus="Tristychius" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="6" pageNumber="7" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D4A6451FCE5FA4BFC1DFA74" box="[825,931,1495,1519]" italics="true" pageId="6" pageNumber="7">Tristychius</emphasis> +</taxonomicName> +( +<bibRefCitation id="EF894B708D4A6451FC6EFA4BFBEDFA74" author="Long JA & Burrow CJ & Ginter M" box="[946,1107,1495,1519]" pageId="6" pageNumber="7" refId="ref12082" refString="Long JA, Burrow CJ, Ginter M et al. First shark from the Late Devonian (Frasnian) Gogo Formation, Western Australia sheds new light on the development of tessellated calcified cartilage. PLoS One 2015; 10: e 0126066. htps: // doi. org / 10.1371/journal.pone.0126066" type="journal volume" year="2015"> +Long +<emphasis id="B96CEA938D4A6451FC31FA44FBA2FA74" box="[1005,1052,1495,1519]" italics="true" pageId="6" pageNumber="7">et al.</emphasis> +2015 +</bibRefCitation> +, +<bibRefCitation id="EF894B708D4A6451FB82FA4BFAB1FA74" author="Coates MI & Tietjen K & Olsen AM" box="[1118,1295,1495,1519]" pageId="6" pageNumber="7" refId="ref11211" refString="Coates MI, Tietjen K, Olsen AM et al. High-performance suction feeding in an early elasmobranch. Science Advances 2019; 5: eaax 2742. htps: // doi. org / 10.1126/sciadv.aax2742" type="journal volume" year="2019"> +Coates +<emphasis id="B96CEA938D4A6451FB75FA44FB69FA74" box="[1193,1239,1495,1519]" italics="true" pageId="6" pageNumber="7">et al.</emphasis> +2019 +</bibRefCitation> +, +<bibRefCitation id="EF894B708D4A6451FAC5FA4BFA0FFA74" author="Frey L & Coates MI & Tietjen K" box="[1305,1457,1495,1519]" pageId="6" pageNumber="7" pagination="1 - 10" refId="ref11680" refString="Frey L, Coates MI, Tietjen K et al. A symmoriiform from the Late Devonian of Morocco demonstrates a derived jaw function in ancient chondrichthyans. Communications Biology 2020; 3: 1-10." type="journal article" year="2020"> +Frey +<emphasis id="B96CEA938D4A6451FA97FA44FAC4FA74" box="[1355,1402,1495,1519]" italics="true" pageId="6" pageNumber="7">et al.</emphasis> +2020 +</bibRefCitation> +). When closed the mouth is tilted dorsally at its anterior end, as reconstructed by +<bibRefCitation id="EF894B708D4A6451FC2DF98AFA89F9B6" author="Brazeau MD & de Winter V" box="[1009,1335,1557,1581]" pageId="6" pageNumber="7" refId="ref10783" refString="Brazeau MD, de Winter V. Te hyoid arch and braincase anatomy of Acanthodes support chondrichthyan affinity of ' acanthodians'. Proceedings of the Royal Society B: Biological Sciences 2015; 282: 20152210. htps: // doi. org / 10.1098/rspb.2015.2210" type="journal volume" year="2015">Brazeau and de Winter (2015)</bibRefCitation> +and +<bibRefCitation id="EF894B708D4A6451FAB2F989FC1AF9D6" author="Davis SP & Finarelli JA & Coates MI" pageId="6" pageNumber="7" pagination="247 - 50" refId="ref11322" refString="Davis SP, Finarelli JA, Coates MI. Acanthodes and shark-like conditions in the last common ancestor of modern gnathostomes. Nature 2012; 486: 247-50. htps: // doi. org / 10.1038/nature11080" type="journal article" year="2012"> +Davis +<emphasis id="B96CEA938D4A6451FA6DF98AFCECF9D6" italics="true" pageId="6" pageNumber="7">et al.</emphasis> +(2012) +</bibRefCitation> +, to some extent by +<bibRefCitation id="EF894B708D4A6451FBA6F9A9FB43F9D6" author="Miles RS" box="[1146,1277,1589,1613]" pageId="6" pageNumber="7" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles (1968</bibRefCitation> +, +<bibRefCitation id="EF894B708D4A6451FAD5F9A9FA83F9D6" author="Miles RS" box="[1289,1341,1589,1613]" pageId="6" pageNumber="7" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">1973</bibRefCitation> +) but not by +<bibRefCitation id="EF894B708D4A6451FCE5F9C9FC68F9F7" author="Watson DMS" box="[825,982,1620,1644]" pageId="6" pageNumber="7" pagination="49 - 146" refId="ref13149" refString="Watson DMS. Te acanthodian fishes. Philosophical Transactions of the Royal Society of London, Series B: Biological Sciences 1937; 228: 49-146." type="journal article" year="1937">Watson (1937)</bibRefCitation> +or +<bibRefCitation id="EF894B708D4A6451FC2BF9C8FB3CF9F7" author="Jarvik E" box="[1015,1154,1620,1644]" pageId="6" pageNumber="7" pagination="199 - 225" refId="ref12006" refString="Jarvik E. Te systematic position of acanthodian fishes. In: Andrews SM, Miles RS, Walker A (eds), Problems in Vertebrate Evolution. London, UK: Academic Press, 1977, 199-225." type="book chapter" year="1977">Jarvik (1977)</bibRefCitation> +. +</paragraph> +<paragraph id="8BA736818D4A6451FB9FF910FB07F93D" blockId="6.[825,1474,1676,1989]" box="[1091,1209,1676,1702]" pageId="6" pageNumber="7"> +<emphasis id="B96CEA938D4A6451FB9FF910FB07F93D" bold="true" box="[1091,1209,1676,1702]" pageId="6" pageNumber="7">Hyoid arch</emphasis> +</paragraph> +<paragraph id="8BA736818D4A6450FCE5F92FFBBFF95F" blockId="6.[825,1474,1676,1989]" lastBlockId="7.[810,1459,1676,1982]" lastPageId="7" lastPageNumber="8" pageId="6" pageNumber="7"> +The hyoid arch comprises paired hyomandibulae, interhyals, and ceratohyals, which join directly to a median basibranchial ( +<figureCitation id="13232A048D4A6451FC98F96DFC1DF892" box="[836,931,1777,1801]" captionStart-0="Figure 2" captionStart-1="Figure 3" captionStart-2="Figure 4" captionStartId-0="3.[113,178,1621,1645]" captionStartId-1="4.[129,194,1343,1367]" captionStartId-2="5.[113,178,1539,1563]" captionTargetBox-0="[117,1455,147,1591]" captionTargetBox-1="[132,1470,147,1313]" captionTargetBox-2="[116,1456,146,1509]" captionTargetId-0="figure-68@3.[114,1458,144,1594]" captionTargetId-1="figure-210@4.[129,1473,144,1316]" captionTargetId-2="figure-106@5.[114,1458,144,1511]" captionTargetPageId-0="3" captionTargetPageId-1="4" captionTargetPageId-2="5" captionText-0="Figure 2. The head skeleton of Acanthodes confusus MNHN-F-SAA21, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pq. autop., palatoquadrate autopalatine; pq. metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." captionText-1="Figure 3. The head skeleton of Acanthodes confusus MNHN-F-SAA20, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; hypobr., hypobranchials; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scapcor., scapulocoracoids; scler., sclerotic ring. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bar = 20 mm." captionText-2="Figure 4. The head skeleton of Acanthodes confusus MNHN-F-SAA24, visualized using computed tomography. A, in right lateral view. B, in left lateral view. Abbreviations: basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; interhy., interhyal; L., left; mand.sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; scapcor., scapulocoracoids; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi-0="http://doi.org/10.5281/zenodo.14971769" figureDoi-1="http://doi.org/10.5281/zenodo.14971771" figureDoi-2="http://doi.org/10.5281/zenodo.14971773" httpUri-0="https://zenodo.org/record/14971769/files/figure.png" httpUri-1="https://zenodo.org/record/14971771/files/figure.png" httpUri-2="https://zenodo.org/record/14971773/files/figure.png" pageId="6" pageNumber="7">Figs 2–4</figureCitation> +, +<figureCitation id="13232A048D4A6451FC69F96EFC7CF892" box="[949,962,1778,1801]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="6" pageNumber="7">7</figureCitation> +, +<figureCitation id="13232A048D4A6451FC08F96DFC5FF892" box="[980,993,1777,1801]" captionStart="Figure 8" captionStartId="9.[113,178,1758,1782]" captionTargetBox="[117,1455,147,1727]" captionTargetId="figure-6@9.[114,1458,144,1730]" captionTargetPageId="9" captionText="Figure 8. The hyoid skeleton of Acanthodes confusus. A, B, the hyoid skeleton of MNHN-F-SAA24 in (A) left lateral and (B) right lateral view. C–E, the hyoid skeleton of MNHN-F-SAA21 in (C) right lateral, (D) left lateral, and (E) dorsal view. F, the posterior mineralization of the left hyomandibula in MNHN-F-SAA21.G, H, the left interhyal of MNHN-F-SAA24 in (G) lateral and (H) medial view.I, J, the left ceratohyal of MNHN-F-SAA21 in (I) lateral and (J) medial view.K–M, the basibranchial of MNHN-F-SAA21 in (K) ventral, (L) dorsal, and (M) right lateral view.Abbreviations: ant., anterior ossification; artic., articulation; basibr., basibranchial; basisph., basisphenoid; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; L., left; hyomand., hyomandibula; hypobr., hypobranchials; med.gr., medial groove; med.rid., medial ridge; post., posterior ossification; R., right.; I–II, branchial arches I–II. Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972026" httpUri="https://zenodo.org/record/14972026/files/figure.png" pageId="6" pageNumber="7">8</figureCitation> +). The hyomandibula comprises a posterior and poorly mineralized anterior ossification ( +<figureCitation id="13232A048D4A6451FA9CF88CFA04F8B3" box="[1344,1466,1808,1833]" captionStart="Figure 8" captionStartId="9.[113,178,1758,1782]" captionTargetBox="[117,1455,147,1727]" captionTargetId="figure-6@9.[114,1458,144,1730]" captionTargetPageId="9" captionText="Figure 8. The hyoid skeleton of Acanthodes confusus. A, B, the hyoid skeleton of MNHN-F-SAA24 in (A) left lateral and (B) right lateral view. C–E, the hyoid skeleton of MNHN-F-SAA21 in (C) right lateral, (D) left lateral, and (E) dorsal view. F, the posterior mineralization of the left hyomandibula in MNHN-F-SAA21.G, H, the left interhyal of MNHN-F-SAA24 in (G) lateral and (H) medial view.I, J, the left ceratohyal of MNHN-F-SAA21 in (I) lateral and (J) medial view.K–M, the basibranchial of MNHN-F-SAA21 in (K) ventral, (L) dorsal, and (M) right lateral view.Abbreviations: ant., anterior ossification; artic., articulation; basibr., basibranchial; basisph., basisphenoid; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; L., left; hyomand., hyomandibula; hypobr., hypobranchials; med.gr., medial groove; med.rid., medial ridge; post., posterior ossification; R., right.; I–II, branchial arches I–II. Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972026" httpUri="https://zenodo.org/record/14972026/files/figure.png" pageId="6" pageNumber="7">Fig. 8A, B</figureCitation> +; +<bibRefCitation id="EF894B708D4A6451FCE5F8ACFC0FF8D3" author="Miles RS" box="[825,945,1840,1864]" pageId="6" pageNumber="7" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles 1968</bibRefCitation> +, +<bibRefCitation id="EF894B708D4A6451FC63F8ACFC4AF8D3" author="Miles RS" box="[959,1012,1840,1864]" pageId="6" pageNumber="7" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">1973</bibRefCitation> +). The end of the hyomandibula contacting the neurocranium is laterally compressed in cross-section, meaning that overall the hyomandibula grades into a circular cross-section posteriorly, and the posterior part of the medial face of the hyomandibula is split by a marked, longitudinal ridge, which separates it into dorsomesial and ventromesial faces ( +<figureCitation id="13232A048D4B6450FD0FF910FF33F958" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="7" pageNumber="8">Fig. 7F</figureCitation> +; +<bibRefCitation id="EF894B708D4B6450FF45F930FEB2F95F" author="Miles RS" box="[153,268,1708,1732]" pageId="7" pageNumber="8" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles 1968</bibRefCitation> +). +<bibRefCitation id="EF894B708D4B6450FEFEF930FE15F95F" author="Miles RS" box="[290,427,1708,1732]" pageId="7" pageNumber="8" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles (1968)</bibRefCitation> +drew a comparison between this shape and the hyomandibula of hexanchiform sharks. Amongst Palaeozoic forms the laterally flattened, curved, and posteriorly tapered shape of the hyomandibula is more comparable to that of the actinopterygian +<taxonomicName id="4C184D028D4B6450FE77F8B6FD72F8DA" authority="(Gardiner 1984)" baseAuthorityName="Gardiner" baseAuthorityYear="1984" box="[427,716,1833,1857]" family="Stegotrachelidae" genus="Mimipiscis" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="7" pageNumber="8" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D4B6450FE77F8B6FDA8F8DA" box="[427,534,1834,1857]" italics="true" pageId="7" pageNumber="8">Mimipiscis</emphasis> +( +<bibRefCitation id="EF894B708D4B6450FDFBF8B5FD7FF8DA" author="Gardiner BG" box="[551,705,1833,1857]" pageId="7" pageNumber="8" pagination="175 - 418" refId="ref11748" refString="Gardiner BG. Te relationships of the palaeoniscid fishes, a review based on new specimens of Mimia and Moythomasia from the Upper Devonian of Western Australia. Bulletin of the British Museum (Natural History) Geology 1984; 37: 175-418." type="journal article" year="1984">Gardiner 1984</bibRefCitation> +) +</taxonomicName> +, the symmoriiforms +<taxonomicName id="4C184D028D4B6450FEC0F8D5FDF7F8FA" authority="(Pradel et al. 2014)" baseAuthorityName="Pradel" baseAuthorityYear="2014" box="[284,585,1864,1889]" class="Elasmobranchii" family="Falcatidae" genus="Ozarcus" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="7" pageNumber="8" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D4B6450FEC0F8D5FED1F8FB" box="[284,367,1865,1888]" italics="true" pageId="7" pageNumber="8">Ozarcus</emphasis> +( +<bibRefCitation id="EF894B708D4B6450FE5EF8D4FD80F8FB" author="Pradel A & Maisey JG & Tafforeau P" box="[386,574,1864,1888]" pageId="7" pageNumber="8" pagination="608 - 11" refId="ref12686" refString="Pradel A, Maisey JG, Tafforeau P et al. A Palaeozoic shark with osteichthyan-like branchial arches. Nature 2014; 509: 608-11. htps: // doi. org / 10.1038/nature13195" type="journal article" year="2014"> +Pradel +<emphasis id="B96CEA938D4B6450FE12F8D5FDBFF8FB" box="[462,513,1864,1888]" italics="true" pageId="7" pageNumber="8">et al.</emphasis> +2014 +</bibRefCitation> +) +</taxonomicName> +and +<taxonomicName id="4C184D028D4B6450FD5EF8D5FE8DF81B" authority="(Frey et al. 2020)" baseAuthorityName="Frey" baseAuthorityYear="2020" genus="Ferromirum" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="7" pageNumber="8" rank="genus"> +<emphasis id="B96CEA938D4B6450FD5EF8D5FD44F8FB" box="[642,762,1865,1888]" italics="true" pageId="7" pageNumber="8">Ferromirum</emphasis> +( +<bibRefCitation id="EF894B708D4B6450FFA0F8F4FE96F81B" author="Frey L & Coates MI & Tietjen K" box="[124,296,1896,1920]" pageId="7" pageNumber="8" pagination="1 - 10" refId="ref11680" refString="Frey L, Coates MI, Tietjen K et al. A symmoriiform from the Late Devonian of Morocco demonstrates a derived jaw function in ancient chondrichthyans. Communications Biology 2020; 3: 1-10." type="journal article" year="2020"> +Frey +<emphasis id="B96CEA938D4B6450FF69F8F4FF54F81B" box="[181,234,1896,1920]" italics="true" pageId="7" pageNumber="8">et al.</emphasis> +2020 +</bibRefCitation> +) +</taxonomicName> +, and cladoselachians ( +<bibRefCitation id="EF894B708D4B6450FDF0F8F4FD08F81B" author="Maisey JG" box="[556,694,1896,1920]" pageId="7" pageNumber="8" pagination="174 - 90" refId="ref12198" refString="Maisey JG. Visceral skeleton and musculature of a Late Devonian shark. Journal of Vertebrate Paleontology 1989; 9: 174-90. htps: // doi. org / 10. 1080 / 02724634.1989.10011751" type="journal article" year="1989">Maisey 1989</bibRefCitation> +) than to the stem-group chondrichthyan +<taxonomicName id="4C184D028D4B6450FDDFF81BFF6BF824" authority="(Coates et al. 2018)" baseAuthorityName="Coates" baseAuthorityYear="2018" genus="Gladbachus" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="7" pageNumber="8" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D4B6450FDDFF81BFDC7F804" box="[515,633,1927,1951]" italics="true" pageId="7" pageNumber="8">Gladbachus</emphasis> +( +<bibRefCitation id="EF894B708D4B6450FD4EF81BFF74F825" author="Coates MI & Finarelli JA & Sansom IJ" pageId="7" pageNumber="8" pagination="1 - 10" refId="ref11170" refString="Coates MI, Finarelli JA, Sansom IJ et al. An early chondrichthyan and the evolutionary assembly of a shark body plan. Proceedings of the Royal Society B: Biological Sciences 2018; 285: 1-10." type="journal article" year="2018"> +Coates +<emphasis id="B96CEA938D4B6450FD35F814FF34F825" italics="true" pageId="7" pageNumber="8">et al.</emphasis> +2018 +</bibRefCitation> +) +</taxonomicName> +or to the stouter hyomandibulae of crown-group chondrichthyans such as xenacanths or hybodonts ( +<bibRefCitation id="EF894B708D4B6450FABBF911FCE1F95F" author="Hoton N" pageId="7" pageNumber="8" pagination="489 - 500" refId="ref11946" refString="Hoton N. Jaws and teeth of American xenacanth sharks. Journal of Paleontology 1952; 26: 489-500." type="journal article" year="1952">Hotton 1952</bibRefCitation> +, +<bibRefCitation id="EF894B708D4B6450FCB7F930FC4EF95F" author="Maisey JG" box="[875,1008,1708,1732]" pageId="7" pageNumber="8" pagination="1 - 39" refId="ref12163" refString="Maisey JG. Cranial anatomy of the lower Jurassic Shark Hybodus reticulatus (Chondrichthyes: Elasmobranchii), with comments on hybodontid systematics. American Museum Novitates 1987; 2878: 1-39." type="journal article" year="1987">Maisey 1987</bibRefCitation> +). +</paragraph> +<caption id="DF6766098D4B6450FFAEFA1CFA88F9C7" ID-DOI="http://doi.org/10.5281/zenodo.14971777" ID-Zenodo-Dep="14971777" httpUri="https://zenodo.org/record/14971777/files/figure.png" pageId="7" pageNumber="8" startId="7.[114,179,1408,1432]" targetBox="[116,1456,146,1378]" targetPageId="7" targetType="figure"> +<paragraph id="8BA736818D4B6450FFAEFA1CFA88F9C7" blockId="7.[113,1456,1408,1634]" pageId="7" pageNumber="8"> +<emphasis id="B96CEA938D4B6450FFAEFA1CFF77FA03" bold="true" box="[114,201,1408,1432]" pageId="7" pageNumber="8">Figure 6.</emphasis> +The mandibular arch of +<taxonomicName id="4C184D028D4B6450FE73FA1DFDD6FA02" authorityName="Heidtke" authorityYear="2011" box="[431,616,1409,1433]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="7" pageNumber="8" phylum="Arthropoda" rank="species" species="confusus"> +<emphasis id="B96CEA938D4B6450FE73FA1DFDD6FA02" box="[431,616,1409,1433]" italics="true" pageId="7" pageNumber="8">Acanthodes confusus</emphasis> +</taxonomicName> +MNHN-F-SAA21. A, left Meckel’s cartilage and palatoquadrate in lateral view. B, left Meckel’s cartilage and palatoquadrate in medial view. C, D, left palatoquadrate in (C) ventral and (D) dorsal view. E, F, left Meckel’s cartilage in (E) dorsal and (F) ventral view. G, left Meckel’s cartilage and palatoquadrate in anterior view. Abbreviations: add. foss., fossa for the adductor muscle; art. cot., articular cotylus; art. pr., articular process; bas. proc., basal process; extrapal. rid., extrapalatoquadrate ridge; Meck. ant., anterior mineralization of Meckel’s cartilage; Meck. post., posterior mineralization of Meckel’s cartilage; obl. rid., oblique ridge; ot. cot., cotylus for articulation with otic region; otic. proc., otic process; pq. autop., palatoquadrate autopalatine; pq. metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; prart. pr., prearticular process; preg. pr., preglenoid process; sp. gr., mandibular splint groove; sym., expanded mandibular symphysis; trigem. for., foramen for the mandibular ramus of the trigeminal nerve (V +<subScript id="179C34C48D4B6450FBBEF9C8FBD7F9F9" attach="left" box="[1122,1129,1620,1634]" fontSize="6" pageId="7" pageNumber="8">3</subScript> +). Scale bar = 20 mm. +</paragraph> +</caption> +<paragraph id="8BA736818D4B645FFC9AF957FB2EF833" blockId="7.[810,1459,1676,1982]" lastBlockId="8.[825,1474,1780,1961]" lastPageId="8" lastPageNumber="9" pageId="7" pageNumber="8"> +An interhyal is present between the hyomandibula and ceratohyal of +<taxonomicName id="4C184D028D4B6450FC66F976FB95F899" authorityName="Agassiz" authorityYear="1833" box="[954,1067,1770,1794]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="7" pageNumber="8" phylum="Arthropoda" rank="genus"> +<emphasis id="B96CEA938D4B6450FC66F976FB95F899" box="[954,1067,1770,1794]" italics="true" pageId="7" pageNumber="8">Acanthodes</emphasis> +</taxonomicName> +( +<figureCitation id="13232A048D4B6450FBE3F976FBC0F899" box="[1087,1150,1770,1794]" captionStart="Figure 4" captionStartId="5.[113,178,1539,1563]" captionTargetBox="[116,1456,146,1509]" captionTargetId="figure-106@5.[114,1458,144,1511]" captionTargetPageId="5" captionText="Figure 4. The head skeleton of Acanthodes confusus MNHN-F-SAA24, visualized using computed tomography. A, in right lateral view. B, in left lateral view. Abbreviations: basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; interhy., interhyal; L., left; mand.sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; scapcor., scapulocoracoids; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971773" httpUri="https://zenodo.org/record/14971773/files/figure.png" pageId="7" pageNumber="8">Figs 4</figureCitation> +, +<figureCitation id="13232A048D4B6450FB51F977FB24F899" box="[1165,1178,1771,1794]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="7" pageNumber="8">7</figureCitation> +, +<figureCitation id="13232A048D4B6450FB74F976FA99F899" box="[1192,1319,1770,1794]" captionStart="Figure 8" captionStartId="9.[113,178,1758,1782]" captionTargetBox="[117,1455,147,1727]" captionTargetId="figure-6@9.[114,1458,144,1730]" captionTargetPageId="9" captionText="Figure 8. The hyoid skeleton of Acanthodes confusus. A, B, the hyoid skeleton of MNHN-F-SAA24 in (A) left lateral and (B) right lateral view. C–E, the hyoid skeleton of MNHN-F-SAA21 in (C) right lateral, (D) left lateral, and (E) dorsal view. F, the posterior mineralization of the left hyomandibula in MNHN-F-SAA21.G, H, the left interhyal of MNHN-F-SAA24 in (G) lateral and (H) medial view.I, J, the left ceratohyal of MNHN-F-SAA21 in (I) lateral and (J) medial view.K–M, the basibranchial of MNHN-F-SAA21 in (K) ventral, (L) dorsal, and (M) right lateral view.Abbreviations: ant., anterior ossification; artic., articulation; basibr., basibranchial; basisph., basisphenoid; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; L., left; hyomand., hyomandibula; hypobr., hypobranchials; med.gr., medial groove; med.rid., medial ridge; post., posterior ossification; R., right.; I–II, branchial arches I–II. Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972026" httpUri="https://zenodo.org/record/14972026/files/figure.png" pageId="7" pageNumber="8">8A, B, G, H</figureCitation> +), confirming the account of +<bibRefCitation id="EF894B708D4B6450FC12F896FBE2F8B9" author="Miles RS" box="[974,1116,1802,1826]" pageId="7" pageNumber="8" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles (1973)</bibRefCitation> +. The interhyal is subrectangular and laterally flattened, with gently convex dorsal and ventral surfaces. Of the +<specimenCount id="9D1EFD088D4B6450FC08F8D4FBC2F8FB" box="[980,1148,1864,1888]" count="3" pageId="7" pageNumber="8" type="generic">three specimens</specimenCount> +described here, interhyals are only preserved in MNHN-F-SAA24 ( +<figureCitation id="13232A048D4B6450FB62F8F4FB45F81B" box="[1214,1275,1896,1920]" captionStart="Figure 4" captionStartId="5.[113,178,1539,1563]" captionTargetBox="[116,1456,146,1509]" captionTargetId="figure-106@5.[114,1458,144,1511]" captionTargetPageId="5" captionText="Figure 4. The head skeleton of Acanthodes confusus MNHN-F-SAA24, visualized using computed tomography. A, in right lateral view. B, in left lateral view. Abbreviations: basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; interhy., interhyal; L., left; mand.sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; scapcor., scapulocoracoids; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971773" httpUri="https://zenodo.org/record/14971773/files/figure.png" pageId="7" pageNumber="8">Fig. 4</figureCitation> +) and before that were only known from a single mouldic specimen, MFN MB 23, now lost but from which casts are preserved (e.g. NHMUK PV P 49990, +<bibRefCitation id="EF894B708D44645FFEC6F968FE2DF897" author="Miles RS" box="[282,403,1780,1804]" pageId="8" pageNumber="9" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles 1973</bibRefCitation> +, plate 7). The proportions of the interhyal in MNHN-F-SAA24 relative to the hyomandibula approximately match those of the interhyal in NHM PV P 49990, which comparison suggests probably preserves a postero-lateral view of the element. As +<bibRefCitation id="EF894B708D44645FFE48F8EDFD9AF812" author="Miles RS" box="[404,548,1905,1929]" pageId="8" pageNumber="9" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles (1973)</bibRefCitation> +highlighted it is unclear whether this ‘interhyal’ is homologous to the interhyal, stylohyal, or symplectic in osteichthyans ( +<bibRefCitation id="EF894B708D44645FFAC4F968FA02F897" author="Paterson C" box="[1304,1468,1780,1804]" pageId="8" pageNumber="9" pagination="241 - 59" refId="ref12663" refString="Paterson C. Morphology and interrelationships of primitive actinopterygian fishes. Integrative and Comparative Biology 1982; 22: 241-59." type="journal article" year="1982">Patterson 1982</bibRefCitation> +, +<bibRefCitation id="EF894B708D44645FFCE5F88FFC10F8B0" author="Veran M" box="[825,942,1811,1835]" pageId="8" pageNumber="9" pagination="1 - 98" refId="ref13115" refString="Veran M. Les elements accessoires de l'arc hyoidendes poissons teleostomes (Acanthodiens et Osteichthyens) fossiles et actuels. Memoires du Museum national d'histoire naturelle 1988; 54: 1-98." type="journal article" year="1988">Véran 1988</bibRefCitation> +). Whether or not these are homologous, additional elements of the hyoid skeleton are not found in this position in +<taxonomicName id="4C184D028D44645FFC86F8CDFB04F8F1" authority="(Coates et al. 2018)" baseAuthorityName="Coates" baseAuthorityYear="2018" box="[858,1210,1873,1898]" genus="Gladbachus" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="8" pageNumber="9" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D44645FFC86F8CDFC71F8F2" box="[858,975,1873,1897]" italics="true" pageId="8" pageNumber="9">Gladbachus</emphasis> +( +<bibRefCitation id="EF894B708D44645FFC3AF8CEFB10F8F1" author="Coates MI & Finarelli JA & Sansom IJ" box="[998,1198,1873,1898]" pageId="8" pageNumber="9" pagination="1 - 10" refId="ref11170" refString="Coates MI, Finarelli JA, Sansom IJ et al. An early chondrichthyan and the evolutionary assembly of a shark body plan. Proceedings of the Royal Society B: Biological Sciences 2018; 285: 1-10." type="journal article" year="2018"> +Coates +<emphasis id="B96CEA938D44645FFBE5F8CEFBD1F8F2" box="[1081,1135,1873,1897]" italics="true" pageId="8" pageNumber="9">et al.</emphasis> +2018 +</bibRefCitation> +) +</taxonomicName> +, or in other articulated Palaeozoic chondrichthyan hyoid arches ( +<bibRefCitation id="EF894B708D44645FFB21F8EDFA02F812" author="Pradel A & Maisey JG & Tafforeau P" box="[1277,1468,1905,1929]" pageId="8" pageNumber="9" pagination="608 - 11" refId="ref12686" refString="Pradel A, Maisey JG, Tafforeau P et al. A Palaeozoic shark with osteichthyan-like branchial arches. Nature 2014; 509: 608-11. htps: // doi. org / 10.1038/nature13195" type="journal article" year="2014"> +Pradel +<emphasis id="B96CEA938D44645FFA96F8EEFAC0F812" box="[1354,1406,1905,1929]" italics="true" pageId="8" pageNumber="9">et al.</emphasis> +2014 +</bibRefCitation> +, +<bibRefCitation id="EF894B708D44645FFCE5F80DFC6AF833" author="Frey L & Coates MI & Tietjen K" box="[825,980,1936,1961]" pageId="8" pageNumber="9" pagination="1 - 10" refId="ref11680" refString="Frey L, Coates MI, Tietjen K et al. A symmoriiform from the Late Devonian of Morocco demonstrates a derived jaw function in ancient chondrichthyans. Communications Biology 2020; 3: 1-10." type="journal article" year="2020"> +Frey +<emphasis id="B96CEA938D44645FFCB1F80DFC22F833" box="[877,924,1936,1960]" italics="true" pageId="8" pageNumber="9">et al.</emphasis> +2020 +</bibRefCitation> +, +<bibRefCitation id="EF894B708D44645FFC3CF80CFBC1F833" author="Klug C & Coates M & Frey L" box="[992,1151,1936,1960]" pageId="8" pageNumber="9" refId="ref12048" refString="Klug C, Coates M, Frey L et al. Broad snouted cladoselachian with sensory specialization at the base of modern chondrichthyans. Swiss Journal of Palaeontology 2023; 142: 2." type="journal volume" year="2023"> +Klug +<emphasis id="B96CEA938D44645FFBCBF80DFBF9F833" box="[1047,1095,1936,1960]" italics="true" pageId="8" pageNumber="9">et al.</emphasis> +2023 +</bibRefCitation> +). +</paragraph> +<caption id="DF6766098D44645FFF5DF99FFAD0F958" ID-DOI="http://doi.org/10.5281/zenodo.14971779" ID-Zenodo-Dep="14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="8" pageNumber="9" startId="8.[129,194,1539,1563]" targetBox="[132,1470,147,1509]" targetPageId="8" targetType="figure"> +<paragraph id="8BA736818D44645FFF5DF99FFAD0F958" blockId="8.[129,1474,1539,1732]" pageId="8" pageNumber="9"> +<emphasis id="B96CEA938D44645FFF5DF99FFF66F987" bold="true" box="[129,216,1539,1564]" pageId="8" pageNumber="9">Figure 7.</emphasis> +Overview of +<taxonomicName id="4C184D028D44645FFE8BF998FDB1F987" authorityName="Heidtke" authorityYear="2011" box="[343,527,1540,1564]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="8" pageNumber="9" phylum="Arthropoda" rank="species" species="confusus"> +<emphasis id="B96CEA938D44645FFE8BF998FDB1F987" box="[343,527,1540,1564]" italics="true" pageId="8" pageNumber="9">Acanthodes confusus</emphasis> +</taxonomicName> +hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view. C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak. hy., hyoid rakers. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bars = 10 mm. +</paragraph> +</caption> +<caption id="DF6766098D45645EFFADF942FBB0F806" ID-DOI="http://doi.org/10.5281/zenodo.14972026" ID-Zenodo-Dep="14972026" httpUri="https://zenodo.org/record/14972026/files/figure.png" pageId="9" pageNumber="10" startId="9.[113,178,1758,1782]" targetBox="[117,1455,147,1727]" targetPageId="9" targetType="figure"> +<paragraph id="8BA736818D45645EFFADF942FBB0F806" blockId="9.[113,1448,1758,1950]" pageId="9" pageNumber="10"> +<emphasis id="B96CEA938D45645EFFADF942FF77F96D" bold="true" box="[113,201,1758,1782]" pageId="9" pageNumber="10">Figure 8.</emphasis> +The hyoid skeleton of +<taxonomicName id="4C184D028D45645EFE41F942FDE8F96D" authorityName="Heidtke" authorityYear="2011" box="[413,598,1758,1782]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="9" pageNumber="10" phylum="Arthropoda" rank="species" species="confusus"> +<emphasis id="B96CEA938D45645EFE41F942FDE8F96D" box="[413,598,1758,1782]" italics="true" pageId="9" pageNumber="10">Acanthodes confusus</emphasis> +</taxonomicName> +. A, B, the hyoid skeleton of MNHN-F-SAA24 in (A) left lateral and (B) right lateral view. C–E, the hyoid skeleton of MNHN-F-SAA21 in (C) right lateral, (D) left lateral, and (E) dorsal view. F, the posterior mineralization of the left hyomandibula in MNHN-F-SAA21. G, H, the left interhyal of MNHN-F-SAA24 in (G) lateral and (H) medial view. I, J, the left ceratohyal of MNHN-F-SAA21 in (I) lateral and (J) medial view. K–M, the basibranchial of MNHN-F-SAA21 in (K) ventral, (L) dorsal, and (M) right lateral view. Abbreviations: ant., anterior ossification; artic., articulation; basibr., basibranchial; basisph., basisphenoid; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; L., left; hyomand., hyomandibula; hypobr., hypobranchials; med. gr., medial groove; med. rid., medial ridge; post., posterior ossification; R., right.; I–II, branchial arches I–II. Scale bar = 10 mm. +</paragraph> +</caption> +<caption id="DF6766098D46645DFF5DF9F0FD76F8F8" ID-DOI="http://doi.org/10.5281/zenodo.14972030" ID-Zenodo-Dep="14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="10" pageNumber="11" startId="10.[129,194,1644,1668]" targetBox="[132,1470,146,1613]" targetPageId="10" targetType="figure"> +<paragraph id="8BA736818D46645DFF5DF9F0FD76F8F8" blockId="10.[129,1469,1644,1892]" pageId="10" pageNumber="11"> +<emphasis id="B96CEA938D46645DFF5DF9F0FF66F91F" bold="true" box="[129,216,1644,1668]" pageId="10" pageNumber="11">Figure 9.</emphasis> +The dorsal branchial skeleton of +<taxonomicName id="4C184D028D46645DFDD2F9F0FD78F91F" authorityName="Heidtke" authorityYear="2011" box="[526,710,1644,1668]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="10" pageNumber="11" phylum="Arthropoda" rank="species" species="confusus"> +<emphasis id="B96CEA938D46645DFDD2F9F0FD78F91F" box="[526,710,1644,1668]" italics="true" pageId="10" pageNumber="11">Acanthodes confusus</emphasis> +</taxonomicName> +. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view. F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view. K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view. Abbreviations: artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V. Scale bar = 10 mm. +</paragraph> +</caption> +<caption id="DF6766098D47645CFFAFFA99FAFDFA5E" ID-DOI="http://doi.org/10.5281/zenodo.14972032" ID-Zenodo-Dep="14972032" httpUri="https://zenodo.org/record/14972032/files/figure.png" pageId="11" pageNumber="12" startId="11.[115,179,1285,1309]" targetBox="[117,1455,147,1255]" targetPageId="11" targetType="figure"> +<paragraph id="8BA736818D47645CFFAFFA99FAFDFA5E" blockId="11.[113,1451,1285,1478]" pageId="11" pageNumber="12"> +<emphasis id="B96CEA938D47645CFFAFFA99FF68FA85" bold="true" box="[115,214,1285,1310]" pageId="11" pageNumber="12">Figure 10.</emphasis> +The gular rays, hyoid rakers, and branchial rakers of +<taxonomicName id="4C184D028D47645CFD65FA9AFCD1FA85" authorityName="Heidtke" authorityYear="2011" box="[697,879,1286,1310]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="11" pageNumber="12" phylum="Arthropoda" rank="species" species="confusus"> +<emphasis id="B96CEA938D47645CFD65FA9AFCD1FA85" box="[697,879,1286,1310]" italics="true" pageId="11" pageNumber="12">Acanthodes confusus</emphasis> +</taxonomicName> +. A, right lateral view of jaws of MNHN-F-SAA21 showing relationship of gular rays and mandibular splint to Meckel’s cartilage. B, right lateral view of jaws of MNHN-F-SAA20 with mandibular splints removed showing gular rays and relationship of hyoid rakers to ceratobranchial. C, left lateral view of MNHN-F-SAA20 showing hyomandibular rakers. D, branchial rakers in articulation with the epibranchial of SAA21. E, branchial rakers in articulation with the ceratobranchial of SAA21. F, hyoid rakers from the ceratohyal of SAA20. G, branchial rakers from the epibranchial of SAA20. Abbreviations: ceratobr., ceratobranchials; epibr., epibranchial; gul. ray., gular rays; rak. br., branchial rakers; rak. hy., hyoid rakers; rak. pl., plinth for branchial raker; I–V, branchial arches I–V. Scale bar = 10 mm except in C where scale bar = 2.5 mm. Note in D and E the shape of the rakers is poorly captured by the scan. +</paragraph> +</caption> +<paragraph id="8BA736818D47645CFF51FA6AFB28F9B6" blockId="11.[113,763,1526,1988]" lastBlockId="11.[810,1460,1525,1988]" pageId="11" pageNumber="12"> +The ceratohyal is ossified in two parts with no hypohyals present ( +<figureCitation id="13232A048D47645CFF71F989FEBBF9B6" box="[173,261,1557,1581]" captionStart-0="Figure 2" captionStart-1="Figure 3" captionStart-2="Figure 4" captionStartId-0="3.[113,178,1621,1645]" captionStartId-1="4.[129,194,1343,1367]" captionStartId-2="5.[113,178,1539,1563]" captionTargetBox-0="[117,1455,147,1591]" captionTargetBox-1="[132,1470,147,1313]" captionTargetBox-2="[116,1456,146,1509]" captionTargetId-0="figure-68@3.[114,1458,144,1594]" captionTargetId-1="figure-210@4.[129,1473,144,1316]" captionTargetId-2="figure-106@5.[114,1458,144,1511]" captionTargetPageId-0="3" captionTargetPageId-1="4" captionTargetPageId-2="5" captionText-0="Figure 2. The head skeleton of Acanthodes confusus MNHN-F-SAA21, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pq. autop., palatoquadrate autopalatine; pq. metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." captionText-1="Figure 3. The head skeleton of Acanthodes confusus MNHN-F-SAA20, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; hypobr., hypobranchials; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scapcor., scapulocoracoids; scler., sclerotic ring. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bar = 20 mm." captionText-2="Figure 4. The head skeleton of Acanthodes confusus MNHN-F-SAA24, visualized using computed tomography. A, in right lateral view. B, in left lateral view. Abbreviations: basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; interhy., interhyal; L., left; mand.sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; scapcor., scapulocoracoids; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi-0="http://doi.org/10.5281/zenodo.14971769" figureDoi-1="http://doi.org/10.5281/zenodo.14971771" figureDoi-2="http://doi.org/10.5281/zenodo.14971773" httpUri-0="https://zenodo.org/record/14971769/files/figure.png" httpUri-1="https://zenodo.org/record/14971771/files/figure.png" httpUri-2="https://zenodo.org/record/14971773/files/figure.png" pageId="11" pageNumber="12">Figs 2–4</figureCitation> +, +<figureCitation id="13232A048D47645CFECDF989FEA0F9B7" box="[273,286,1557,1580]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="11" pageNumber="12">7</figureCitation> +, +<figureCitation id="13232A048D47645CFEF7F989FE31F9B7" box="[299,399,1557,1581]" captionStart="Figure 8" captionStartId="9.[113,178,1758,1782]" captionTargetBox="[117,1455,147,1727]" captionTargetId="figure-6@9.[114,1458,144,1730]" captionTargetPageId="9" captionText="Figure 8. The hyoid skeleton of Acanthodes confusus. A, B, the hyoid skeleton of MNHN-F-SAA24 in (A) left lateral and (B) right lateral view. C–E, the hyoid skeleton of MNHN-F-SAA21 in (C) right lateral, (D) left lateral, and (E) dorsal view. F, the posterior mineralization of the left hyomandibula in MNHN-F-SAA21.G, H, the left interhyal of MNHN-F-SAA24 in (G) lateral and (H) medial view.I, J, the left ceratohyal of MNHN-F-SAA21 in (I) lateral and (J) medial view.K–M, the basibranchial of MNHN-F-SAA21 in (K) ventral, (L) dorsal, and (M) right lateral view.Abbreviations: ant., anterior ossification; artic., articulation; basibr., basibranchial; basisph., basisphenoid; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; L., left; hyomand., hyomandibula; hypobr., hypobranchials; med.gr., medial groove; med.rid., medial ridge; post., posterior ossification; R., right.; I–II, branchial arches I–II. Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972026" httpUri="https://zenodo.org/record/14972026/files/figure.png" pageId="11" pageNumber="12">8A–E, I, J</figureCitation> +; +<bibRefCitation id="EF894B708D47645CFE41F989FDAFF9B6" author="Miles RS" box="[413,529,1557,1581]" pageId="11" pageNumber="12" pagination="233 - 55" refId="ref12369" refString="Miles RS. Some features in the cranial morphology of acanthodians and the relationships of the Acanthodii. Acta Zoologica 1965; 46: 233-55. htps: // doi. org / 10.1111/j.1463-6395.1965.tb00733.x" type="journal article" year="1965">Miles 1965</bibRefCitation> +, +<bibRefCitation id="EF894B708D47645CFDC1F989FDEFF9B6" author="Miles RS" box="[541,593,1557,1581]" pageId="11" pageNumber="12" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">1968</bibRefCitation> +, +<bibRefCitation id="EF894B708D47645CFD81F989FD2FF9B6" author="Miles RS" box="[605,657,1557,1581]" pageId="11" pageNumber="12" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">1973</bibRefCitation> +, +<bibRefCitation id="EF894B708D47645CFD42F989FF1BF9D7" author="Gardiner BG" pageId="11" pageNumber="12" pagination="175 - 418" refId="ref11748" refString="Gardiner BG. Te relationships of the palaeoniscid fishes, a review based on new specimens of Mimia and Moythomasia from the Upper Devonian of Western Australia. Bulletin of the British Museum (Natural History) Geology 1984; 37: 175-418." type="journal article" year="1984">Gardiner 1984</bibRefCitation> +) and its morphology confirms the account of +<bibRefCitation id="EF894B708D47645CFD1DF9A8FF02F9F0" author="Miles RS" pageId="11" pageNumber="12" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles (1968)</bibRefCitation> +. The posterior end is laterally flattened and lacks the lateral fossa seen in some early chondrichthyans ( +<bibRefCitation id="EF894B708D47645CFDA7F9EFFF1BF931" author="Coates MI & Finarelli JA & Sansom IJ" pageId="11" pageNumber="12" pagination="1 - 10" refId="ref11170" refString="Coates MI, Finarelli JA, Sansom IJ et al. An early chondrichthyan and the evolutionary assembly of a shark body plan. Proceedings of the Royal Society B: Biological Sciences 2018; 285: 1-10." type="journal article" year="2018"> +Coates +<emphasis id="B96CEA938D47645CFD16F9E8FD45F910" box="[714,763,1651,1675]" italics="true" pageId="11" pageNumber="12">et al.</emphasis> +2018 +</bibRefCitation> +). It also lacks the sharp dorsal angle at the posterior end of the ceratohyals of +<taxonomicName id="4C184D028D47645CFE92F92EFD3AF951" authority="(Frey et al. 2020)" baseAuthorityName="Frey" baseAuthorityYear="2020" box="[334,644,1714,1738]" genus="Ferromirum" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="11" pageNumber="12" rank="genus"> +<emphasis id="B96CEA938D47645CFE92F92EFE7AF952" box="[334,452,1714,1737]" italics="true" pageId="11" pageNumber="12">Ferromirum</emphasis> +( +<bibRefCitation id="EF894B708D47645CFE0BF92EFDC7F951" author="Frey L & Coates MI & Tietjen K" box="[471,633,1714,1738]" pageId="11" pageNumber="12" pagination="1 - 10" refId="ref11680" refString="Frey L, Coates MI, Tietjen K et al. A symmoriiform from the Late Devonian of Morocco demonstrates a derived jaw function in ancient chondrichthyans. Communications Biology 2020; 3: 1-10." type="journal article" year="2020"> +Frey +<emphasis id="B96CEA938D47645CFDD0F92EFD80F951" box="[524,574,1714,1738]" italics="true" pageId="11" pageNumber="12">et al.</emphasis> +2020 +</bibRefCitation> +) +</taxonomicName> +, +<taxonomicName id="4C184D028D47645CFD4EF92EFE99F972" authority="(Frey et al. 2019)" baseAuthorityName="Frey" baseAuthorityYear="2019" class="Elasmobranchii" family="Phoebodontidae" genus="Phoebodus" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="11" pageNumber="12" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D47645CFD4EF92EFD45F951" box="[658,763,1714,1738]" italics="true" pageId="11" pageNumber="12">Phoebodus</emphasis> +( +<bibRefCitation id="EF894B708D47645CFFA0F94DFEA2F972" author="Frey L & Coates MI & Ginter M & of the Royal Society B" box="[124,284,1745,1769]" pageId="11" pageNumber="12" refId="ref11624" refString="Frey L, Coates MI, Ginter M, et al. Te early elasmobranch Phoebodus: phylogenetic relationships, ecomorphology and a new time-scale for shark evolution. Proceedings of the Royal Society B: Biological Sciences 2019; 286: 20191336. htps: // doi. org / 10.1098/rspb.2019.1336" type="journal volume" year="2019"> +Frey +<emphasis id="B96CEA938D47645CFF6DF94EFF5CF972" box="[177,226,1745,1769]" italics="true" pageId="11" pageNumber="12">et al.</emphasis> +2019 +</bibRefCitation> +) +</taxonomicName> +, and +<emphasis id="B96CEA938D47645CFEBEF94DFDBBF972" box="[354,517,1745,1769]" italics="true" pageId="11" pageNumber="12">Maghriboselache</emphasis> +( +<bibRefCitation id="EF894B708D47645CFDCBF94DFD05F972" author="Klug C & Coates M & Frey L" box="[535,699,1745,1769]" pageId="11" pageNumber="12" refId="ref12048" refString="Klug C, Coates M, Frey L et al. Broad snouted cladoselachian with sensory specialization at the base of modern chondrichthyans. Swiss Journal of Palaeontology 2023; 142: 2." type="journal volume" year="2023"> +Klug +<emphasis id="B96CEA938D47645CFD8CF94EFD3FF972" box="[592,641,1745,1769]" italics="true" pageId="11" pageNumber="12">et al.</emphasis> +2023 +</bibRefCitation> +). The anterior end of the ceratohyal is not spatulate anteriorly like some Palaeozoic chondrichthyans such as +<taxonomicName id="4C184D028D47645CFDFCF893FF0FF8DC" authority="(Frey et al. 2019)" baseAuthorityName="Frey" baseAuthorityYear="2019" class="Elasmobranchii" family="Phoebodontidae" genus="Phoebodus" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="11" pageNumber="12" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D47645CFDFCF893FD37F8BC" box="[544,649,1807,1831]" italics="true" pageId="11" pageNumber="12">Phoebodus</emphasis> +( +<bibRefCitation id="EF894B708D47645CFD45F88CFF18F8DC" author="Frey L & Coates MI & Ginter M & of the Royal Society B" pageId="11" pageNumber="12" refId="ref11624" refString="Frey L, Coates MI, Ginter M, et al. Te early elasmobranch Phoebodus: phylogenetic relationships, ecomorphology and a new time-scale for shark evolution. Proceedings of the Royal Society B: Biological Sciences 2019; 286: 20191336. htps: // doi. org / 10.1098/rspb.2019.1336" type="journal volume" year="2019"> +Frey +<emphasis id="B96CEA938D47645CFD10F88CFD45F8BC" box="[716,763,1807,1831]" italics="true" pageId="11" pageNumber="12">et al.</emphasis> +2019 +</bibRefCitation> +) +</taxonomicName> +, instead pinching in and expanding out to form the articulation with the basibranchial (the +<emphasis id="B96CEA938D47645CFE1BF8D2FDE7F8FD" box="[455,601,1870,1894]" italics="true" pageId="11" pageNumber="12">expanded knob</emphasis> +of +<bibRefCitation id="EF894B708D47645CFDA4F8D2FD54F8FD" author="Miles RS" box="[632,746,1870,1894]" pageId="11" pageNumber="12" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles 1968</bibRefCitation> +). The longitudinal groove runs along the mesial surface of the element which may be homologous to a similar groove on the ceratohyal of +<emphasis id="B96CEA938D47645CFF20F830FECAF85F" box="[252,372,1964,1988]" italics="true" pageId="11" pageNumber="12">Gydoselache</emphasis> +( +<bibRefCitation id="EF894B708D47645CFE59F830FD80F85F" author="Maisey JG & Janvier P & Pradel A & Cambridge, UK" box="[389,574,1964,1988]" pageId="11" pageNumber="12" pagination="87 - 109" refId="ref12285" refString="Maisey JG, Janvier P, Pradel A et al. Doliodus and pucapampellids: contrasting perspectives on stem chondrichthyan morphology. In: JohansonZ, UnderwoodC, RichterM (eds), EvolutionandDevelopment of Fishes. Cambridge, UK: Cambridge University Press, 2019, 87-109." type="book chapter" year="2019"> +Maisey +<emphasis id="B96CEA938D47645CFE09F831FDBBF85F" box="[469,517,1964,1988]" italics="true" pageId="11" pageNumber="12">et al.</emphasis> +2019 +</bibRefCitation> +) and which +<bibRefCitation id="EF894B708D47645CFD1DF830FCCAF996" author="Miles RS" box="[705,884,1525,1988]" pageId="11" pageNumber="12" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles (1968)</bibRefCitation> +suggested was for the insertion of muscles including the anterior interhyoideus musculature. +</paragraph> +<paragraph id="8BA736818D47645BFC9AF9A9FE41F8D7" blockId="11.[810,1460,1525,1988]" lastBlockId="12.[129,778,1248,1868]" lastPageId="12" lastPageNumber="13" pageId="11" pageNumber="12"> +The component forming the ventral floor of the pharyngeal skeleton is composed of two mineralized parts ( +<figureCitation id="13232A048D47645CFAE9F9CFFA2EF9F7" box="[1333,1424,1619,1644]" captionStart-0="Figure 2" captionStart-1="Figure 3" captionStart-2="Figure 4" captionStartId-0="3.[113,178,1621,1645]" captionStartId-1="4.[129,194,1343,1367]" captionStartId-2="5.[113,178,1539,1563]" captionTargetBox-0="[117,1455,147,1591]" captionTargetBox-1="[132,1470,147,1313]" captionTargetBox-2="[116,1456,146,1509]" captionTargetId-0="figure-68@3.[114,1458,144,1594]" captionTargetId-1="figure-210@4.[129,1473,144,1316]" captionTargetId-2="figure-106@5.[114,1458,144,1511]" captionTargetPageId-0="3" captionTargetPageId-1="4" captionTargetPageId-2="5" captionText-0="Figure 2. The head skeleton of Acanthodes confusus MNHN-F-SAA21, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pq. autop., palatoquadrate autopalatine; pq. metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." captionText-1="Figure 3. The head skeleton of Acanthodes confusus MNHN-F-SAA20, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; hypobr., hypobranchials; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scapcor., scapulocoracoids; scler., sclerotic ring. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bar = 20 mm." captionText-2="Figure 4. The head skeleton of Acanthodes confusus MNHN-F-SAA24, visualized using computed tomography. A, in right lateral view. B, in left lateral view. Abbreviations: basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; interhy., interhyal; L., left; mand.sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; scapcor., scapulocoracoids; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi-0="http://doi.org/10.5281/zenodo.14971769" figureDoi-1="http://doi.org/10.5281/zenodo.14971771" figureDoi-2="http://doi.org/10.5281/zenodo.14971773" httpUri-0="https://zenodo.org/record/14971769/files/figure.png" httpUri-1="https://zenodo.org/record/14971771/files/figure.png" httpUri-2="https://zenodo.org/record/14971773/files/figure.png" pageId="11" pageNumber="12">Figs 2–4</figureCitation> +, +<figureCitation id="13232A048D47645CFA7CF9C8FA13F9F0" box="[1440,1453,1620,1643]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="11" pageNumber="12">7</figureCitation> +, +<figureCitation id="13232A048D47645CFCF6F9EFFC1BF911" box="[810,933,1651,1675]" captionStart="Figure 8" captionStartId="9.[113,178,1758,1782]" captionTargetBox="[117,1455,147,1727]" captionTargetId="figure-6@9.[114,1458,144,1730]" captionTargetPageId="9" captionText="Figure 8. The hyoid skeleton of Acanthodes confusus. A, B, the hyoid skeleton of MNHN-F-SAA24 in (A) left lateral and (B) right lateral view. C–E, the hyoid skeleton of MNHN-F-SAA21 in (C) right lateral, (D) left lateral, and (E) dorsal view. F, the posterior mineralization of the left hyomandibula in MNHN-F-SAA21.G, H, the left interhyal of MNHN-F-SAA24 in (G) lateral and (H) medial view.I, J, the left ceratohyal of MNHN-F-SAA21 in (I) lateral and (J) medial view.K–M, the basibranchial of MNHN-F-SAA21 in (K) ventral, (L) dorsal, and (M) right lateral view.Abbreviations: ant., anterior ossification; artic., articulation; basibr., basibranchial; basisph., basisphenoid; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; L., left; hyomand., hyomandibula; hypobr., hypobranchials; med.gr., medial groove; med.rid., medial ridge; post., posterior ossification; R., right.; I–II, branchial arches I–II. Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972026" httpUri="https://zenodo.org/record/14972026/files/figure.png" pageId="11" pageNumber="12">8A–E, K–M</figureCitation> +). This has variously been termed a basibranchial or basihyal; here we use the former due to its extending considerably further posteriorly than most elasmobranch basihyals. The anterior mineralization has a hammerhead-shaped anterior end with ventrally-oriented articulation surfaces for the ceratohyals. In its posterior half this becomes taller with deep ventral attachment surfaces for the coracohyoid and coracobranchial musculature, with an unfinished posterior face (i.e. not covered by perichondral bone). The posterior basibranchial mineralization isflatwithaposteriortail, itsunfinishedanteriorfacesuggeststhat it was joined to the anterior mineralization of the basibranchial by cartilage. There are no obvious articulation surfaces on the posterior part of the basibranchial, but based on their preserved position it seems likely to have articulated with the first and second branchial arch as reconstructed by +<bibRefCitation id="EF894B708D40645BFDF8FAA2FD15FACD" author="Miles RS" box="[548,683,1342,1366]" pageId="12" pageNumber="13" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles (1973)</bibRefCitation> +. This tall, narrow basibranchial is dissimilar from the broad flat basihyals of other known stem-group chondrichthyans ( +<bibRefCitation id="EF894B708D40645BFDA8FAE1FCBAFA0E" author="Brazeau MD" box="[628,772,1405,1429]" pageId="12" pageNumber="13" pagination="355 - 67" refId="ref10740" refString="Brazeau MD. A revision of the anatomy of the Early Devonian jawed vertebrate Ptomacanthus anglicus Miles. Palaeontology 2012; 55: 355-67. htps: // doi. org / 10.1111/j.1475-4983.2012.01130.x" type="journal article" year="2012">Brazeau 2012</bibRefCitation> +, +<bibRefCitation id="EF894B708D40645BFF5DFA00FE86FA2F" author="Coates MI & Finarelli JA & Sansom IJ" box="[129,312,1436,1460]" pageId="12" pageNumber="13" pagination="1 - 10" refId="ref11170" refString="Coates MI, Finarelli JA, Sansom IJ et al. An early chondrichthyan and the evolutionary assembly of a shark body plan. Proceedings of the Royal Society B: Biological Sciences 2018; 285: 1-10." type="journal article" year="2018"> +Coates +<emphasis id="B96CEA938D40645BFF12FA01FF40FA2F" box="[206,254,1436,1460]" italics="true" pageId="12" pageNumber="13">et al.</emphasis> +2018 +</bibRefCitation> +); a possible exception is in +<taxonomicName id="4C184D028D40645BFD85FA00FCBDFA2F" authorityName="Burrow, Trinajstic & Long" authorityYear="2012" box="[601,771,1436,1460]" family="Howittacanthidae" genus="Halimacanthodes" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="12" pageNumber="13" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D40645BFD85FA00FCBDFA2F" box="[601,771,1436,1460]" italics="true" pageId="12" pageNumber="13">Halimacanthodes</emphasis> +</taxonomicName> +, where an element identified as an?autopalatine (or possibly a basibranchial) could be the front of the basibranchial in lateral profile ( +<bibRefCitation id="EF894B708D40645BFF0EFA67FE37F989" author="Burrow CJ & Trinajstic K & Long JA" box="[210,393,1530,1554]" pageId="12" pageNumber="13" pagination="349 - 57" refId="ref11052" refString="Burrow CJ, Trinajstic K, Long JA. First acanthodian from the Upper Devonian (Frasnian) Gogo Formation, Western Australia. Historical Biology 2012; 24: 349-57. htps: // doi. org / 10.1080/08912963.2012. 660150" type="journal article" year="2012"> +Burrow +<emphasis id="B96CEA938D40645BFEFFFA67FEEFF989" box="[291,337,1530,1554]" italics="true" pageId="12" pageNumber="13">et al.</emphasis> +2012 +</bibRefCitation> +). A tapering posterior end is common in basibranchial copulae in extant and extinct chondrichthyans ( +<bibRefCitation id="EF894B708D40645BFF57F9A5FEF6F9CA" author="Coates MI & Finarelli JA & Sansom IJ" box="[139,328,1593,1617]" pageId="12" pageNumber="13" pagination="1 - 10" refId="ref11170" refString="Coates MI, Finarelli JA, Sansom IJ et al. An early chondrichthyan and the evolutionary assembly of a shark body plan. Proceedings of the Royal Society B: Biological Sciences 2018; 285: 1-10." type="journal article" year="2018"> +Coates +<emphasis id="B96CEA938D40645BFF06F9A6FEB2F9CA" box="[218,268,1593,1617]" italics="true" pageId="12" pageNumber="13">et al.</emphasis> +2018 +</bibRefCitation> +, Dearden +<emphasis id="B96CEA938D40645BFE64F9A6FE54F9CA" box="[440,490,1593,1617]" italics="true" pageId="12" pageNumber="13">et al.</emphasis> +2021), although otherwise these are dissimilar from the basibranchial in +<taxonomicName id="4C184D028D40645BFD8DF9C4FD7FF9EB" authorityName="Agassiz" authorityYear="1833" box="[593,705,1624,1648]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="12" pageNumber="13" phylum="Arthropoda" rank="genus"> +<emphasis id="B96CEA938D40645BFD8DF9C4FD7FF9EB" box="[593,705,1624,1648]" italics="true" pageId="12" pageNumber="13">Acanthodes</emphasis> +</taxonomicName> +in that copulae extend considerably beyond the posterior-most branchial arch (e.g. Dearden +<emphasis id="B96CEA938D40645BFE5FF904FE0BF934" box="[387,437,1687,1711]" italics="true" pageId="12" pageNumber="13">et al.</emphasis> +2021). We find no evidence for a chain of basibranchial elements as given in some reconstructions ( +<figureCitation id="13232A048D40645BFF19F949FE8EF975" box="[197,304,1749,1774]" captionStart="Figure1" captionStartId="2.[129,190,1867,1891]" captionTargetBox="[257,1345,152,1836]" captionTargetId="figure-7@2.[254,1348,149,1839]" captionTargetPageId="2" captionText="Figure1.Previous reconstructionsofthe hyoidandbranchial archskeletoninAcanthodes.A,Reis(1896). B,Watson (1937).C, Nelson(1968) withboth alternatereconstructionsof pharyngobranchialorientation.D,Miles(1973).E,Jarvik(1977). F,Gardiner (1984).Terminologyhas beenstandardizedto matchtermsused inthisstudy.Abbreviations:basibr.,basibranchial;basihy.,basihyal;ceratobr.,ceratobranchials;ceratohy.,ceratohyal;epibr.,epibranchial; hyomand.,hyomandibula;hypohy.,hypohyal;interhy.,interhyal;pharbr.,pharyngobranchials;pharhy.,pharyngohyal.Matchingcoloursdenote serially homologouselements.Grey indicatesinferredareas ofcartilage.Blackdashedlines indicatehypotheticalelements.Vertical grey dashedline indicates junctionofdorsal andventralbranchialskeleton.Allreconstructionsareshownas ifspread horizontally,withanterior upwards." figureDoi="http://doi.org/10.5281/zenodo.14971767" httpUri="https://zenodo.org/record/14971767/files/figure.png" pageId="12" pageNumber="13">Fig. 1A–C</figureCitation> +): this aspect of the reconstruction appears to be based on the +<typeStatus id="54A388238D40645BFEF1F969FE37F896" box="[301,393,1781,1805]" pageId="12" pageNumber="13" type="holotype">holotype</typeStatus> +of +<taxonomicName id="4C184D028D40645BFE71F969FDA3F896" authorityName="Heidtke" authorityYear="2011" box="[429,541,1781,1805]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="12" pageNumber="13" phylum="Arthropoda" rank="species" species="confusus"> +<emphasis id="B96CEA938D40645BFE71F969FDA3F896" box="[429,541,1781,1805]" italics="true" pageId="12" pageNumber="13">A. confusus</emphasis> +</taxonomicName> +( +<bibRefCitation id="EF894B708D40645BFDF2F969FD03F896" author="Heidtke UHJ" box="[558,701,1781,1805]" pageId="12" pageNumber="13" pagination="1 - 14" refId="ref11850" refString="Heidtke UHJ. Neue Erkenntwisse uber Acanthodes bronni AGASSIZ 1833. Miteilungen der POLLICHIA 2011; 95: 1-14." type="journal article" year="2011">Heidtke 2011</bibRefCitation> +: fig. 8) in which preserved hypobranchials give the impression of there having been a chain of basibranchials. +</paragraph> +<caption id="DF6766098D40645BFF5DFBFCFA09FB2B" ID-DOI="http://doi.org/10.5281/zenodo.14972036" ID-Zenodo-Dep="14972036" httpUri="https://zenodo.org/record/14972036/files/figure.png" pageId="12" pageNumber="13" startId="12.[129,192,1120,1144]" targetBox="[292,1310,147,1090]" targetPageId="12" targetType="figure"> +<paragraph id="8BA736818D40645BFF5DFBFCFA09FB2B" blockId="12.[128,1463,1120,1200]" pageId="12" pageNumber="13"> +<emphasis id="B96CEA938D40645BFF5DFBFCFF5DFBE3" bold="true" box="[129,227,1120,1144]" pageId="12" pageNumber="13">Figure 11.</emphasis> +Reconstruction of the pharyngeal skeleton of +<taxonomicName id="4C184D028D40645BFD55FBFCFC82FBE2" authorityName="Heidtke" authorityYear="2011" box="[649,828,1120,1145]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="12" pageNumber="13" phylum="Arthropoda" rank="species" species="confusus"> +<emphasis id="B96CEA938D40645BFD55FBFCFC82FBE2" box="[649,828,1120,1145]" italics="true" pageId="12" pageNumber="13">Acanthodes confusus</emphasis> +</taxonomicName> +as described here. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; hypobr., hypobranchial; interhy., interhyal; pharbr., pharyngobranchials. Matching colours denote serially homologous elements. Reconstruction shown as if spread horizontally, with anterior above. +</paragraph> +</caption> +<paragraph id="8BA736818D40645BFEB1F8F7FDA2F81E" blockId="12.[365,540,1899,1925]" box="[365,540,1899,1925]" pageId="12" pageNumber="13"> +<emphasis id="B96CEA938D40645BFEB1F8F7FDA2F81E" bold="true" box="[365,540,1899,1925]" pageId="12" pageNumber="13">Branchial arches</emphasis> +</paragraph> +<paragraph id="8BA736818D40645BFF5DF80EFAA6FA68" blockId="12.[129,778,1938,1993]" lastBlockId="12.[824,1475,1248,1993]" pageId="12" pageNumber="13"> +Five branchial arches are preserved which extend well-posterior to the braincase ( +<figureCitation id="13232A048D40645BFEE2F82DFE27F852" box="[318,409,1969,1993]" captionStart-0="Figure 2" captionStart-1="Figure 3" captionStart-2="Figure 4" captionStartId-0="3.[113,178,1621,1645]" captionStartId-1="4.[129,194,1343,1367]" captionStartId-2="5.[113,178,1539,1563]" captionTargetBox-0="[117,1455,147,1591]" captionTargetBox-1="[132,1470,147,1313]" captionTargetBox-2="[116,1456,146,1509]" captionTargetId-0="figure-68@3.[114,1458,144,1594]" captionTargetId-1="figure-210@4.[129,1473,144,1316]" captionTargetId-2="figure-106@5.[114,1458,144,1511]" captionTargetPageId-0="3" captionTargetPageId-1="4" captionTargetPageId-2="5" captionText-0="Figure 2. The head skeleton of Acanthodes confusus MNHN-F-SAA21, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pq. autop., palatoquadrate autopalatine; pq. metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." captionText-1="Figure 3. The head skeleton of Acanthodes confusus MNHN-F-SAA20, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; hypobr., hypobranchials; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scapcor., scapulocoracoids; scler., sclerotic ring. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bar = 20 mm." captionText-2="Figure 4. The head skeleton of Acanthodes confusus MNHN-F-SAA24, visualized using computed tomography. A, in right lateral view. B, in left lateral view. Abbreviations: basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; interhy., interhyal; L., left; mand.sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; scapcor., scapulocoracoids; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi-0="http://doi.org/10.5281/zenodo.14971769" figureDoi-1="http://doi.org/10.5281/zenodo.14971771" figureDoi-2="http://doi.org/10.5281/zenodo.14971773" httpUri-0="https://zenodo.org/record/14971769/files/figure.png" httpUri-1="https://zenodo.org/record/14971771/files/figure.png" httpUri-2="https://zenodo.org/record/14971773/files/figure.png" pageId="12" pageNumber="13">Figs 2–4</figureCitation> +, +<figureCitation id="13232A048D40645BFE74F82EFE0BF852" box="[424,437,1970,1993]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="12" pageNumber="13">7</figureCitation> +, +<figureCitation id="13232A048D40645BFE18F82DFE6FF852" box="[452,465,1969,1993]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="12" pageNumber="13">9</figureCitation> +). It remains unclear whether they articulated with the basioccipital, as reconstructed by +<bibRefCitation id="EF894B708D40645BFA55FB7CFC3DFA83" author="Miles RS" pageId="12" pageNumber="13" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles (1973)</bibRefCitation> +. In MNHN-F-SAA21 they overlap with the underside of the braincase anteriorly( +<figureCitation id="13232A048D40645BFBEEFA83FBD9FAAC" box="[1074,1127,1311,1335]" captionStart="Figure 2" captionStartId="3.[113,178,1621,1645]" captionTargetBox="[117,1455,147,1591]" captionTargetId="figure-68@3.[114,1458,144,1594]" captionTargetPageId="3" captionText="Figure 2. The head skeleton of Acanthodes confusus MNHN-F-SAA21, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pq. autop., palatoquadrate autopalatine; pq. metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971769" httpUri="https://zenodo.org/record/14971769/files/figure.png" pageId="12" pageNumber="13">Fig.2</figureCitation> +) but this is not the case in MNHN-F-SAA24 and MNHN-F-SAA20 [ +<figureCitation id="13232A048D40645BFB4EFAA2FB73FACD" box="[1170,1229,1342,1366]" captionStart="Figure 3" captionStartId="4.[129,194,1343,1367]" captionTargetBox="[132,1470,147,1313]" captionTargetId="figure-210@4.[129,1473,144,1316]" captionTargetPageId="4" captionText="Figure 3. The head skeleton of Acanthodes confusus MNHN-F-SAA20, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; hypobr., hypobranchials; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scapcor., scapulocoracoids; scler., sclerotic ring. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971771" httpUri="https://zenodo.org/record/14971771/files/figure.png" pageId="12" pageNumber="13">Figs 3</figureCitation> +, +<figureCitation id="13232A048D40645BFB0BFAA2FB5AFACD" box="[1239,1252,1342,1366]" captionStart="Figure 4" captionStartId="5.[113,178,1539,1563]" captionTargetBox="[116,1456,146,1509]" captionTargetId="figure-106@5.[114,1458,144,1511]" captionTargetPageId="5" captionText="Figure 4. The head skeleton of Acanthodes confusus MNHN-F-SAA24, visualized using computed tomography. A, in right lateral view. B, in left lateral view. Abbreviations: basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; interhy., interhyal; L., left; mand.sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; scapcor., scapulocoracoids; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971773" httpUri="https://zenodo.org/record/14971773/files/figure.png" pageId="12" pageNumber="13">4</figureCitation> +; see discussion of this character state in +<bibRefCitation id="EF894B708D40645BFC3BFAC2FB01FAED" author="Dearden RP & Stockey C & Brazeau MD" box="[999,1215,1374,1398]" pageId="12" pageNumber="13" pagination="1 - 7" refId="ref11589" refString="Dearden RP, Stockey C, Brazeau MD. Te pharynx of the stem-chondrichthyan Ptomacanthus and the early evolution of the gnathostome gill skeleton. Nature Communications 2019; 10: 1-7." type="journal article" year="2019"> +Dearden +<emphasis id="B96CEA938D40645BFB98FAC2FBCFFAED" box="[1092,1137,1374,1398]" italics="true" pageId="12" pageNumber="13">et al.</emphasis> +(2019) +</bibRefCitation> +, Supplementary material, Character 50, of +<bibRefCitation id="EF894B708D40645BFC38FAE2FB24FA0E" author="Frey L & Coates MI & Tietjen K" box="[996,1178,1405,1430]" pageId="12" pageNumber="13" pagination="1 - 10" refId="ref11680" refString="Frey L, Coates MI, Tietjen K et al. A symmoriiform from the Late Devonian of Morocco demonstrates a derived jaw function in ancient chondrichthyans. Communications Biology 2020; 3: 1-10." type="journal article" year="2020"> +Frey +<emphasis id="B96CEA938D40645BFBC5FAE2FBF7FA0E" box="[1049,1097,1405,1429]" italics="true" pageId="12" pageNumber="13">et al.</emphasis> +(2020) +</bibRefCitation> +]. The branchial arches comprise hypo-, cerato-, +<typeStatus id="54A388238D40645BFBCEFA00FB85FA2F" box="[1042,1083,1436,1460]" pageId="12" pageNumber="13" type="epitype">epi-</typeStatus> +, and pharyngobranchials. We find no evidence for accessory elements as in some osteichthyans and in the symmoriiform +<taxonomicName id="4C184D028D40645BFC26FA47FAAAFA68" authority="(Pradel et al. 2014)" baseAuthorityName="Pradel" baseAuthorityYear="2014" box="[1018,1300,1499,1523]" class="Elasmobranchii" family="Falcatidae" genus="Ozarcus" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="12" pageNumber="13" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D40645BFC26FA47FBF5FA69" box="[1018,1099,1499,1522]" italics="true" pageId="12" pageNumber="13">Ozarcus</emphasis> +( +<bibRefCitation id="EF894B708D40645BFB86FA47FAB6FA68" author="Pradel A & Maisey JG & Tafforeau P" box="[1114,1288,1499,1523]" pageId="12" pageNumber="13" pagination="608 - 11" refId="ref12686" refString="Pradel A, Maisey JG, Tafforeau P et al. A Palaeozoic shark with osteichthyan-like branchial arches. Nature 2014; 509: 608-11. htps: // doi. org / 10.1038/nature13195" type="journal article" year="2014"> +Pradel +<emphasis id="B96CEA938D40645BFB7DFA40FB6EFA68" box="[1185,1232,1499,1523]" italics="true" pageId="12" pageNumber="13">et al.</emphasis> +2014 +</bibRefCitation> +) +</taxonomicName> +. +</paragraph> +<paragraph id="8BA736818D40645AFC89FA67FD5CFF5C" blockId="12.[824,1475,1248,1993]" lastBlockId="13.[113,763,144,1986]" lastPageId="13" lastPageNumber="14" pageId="12" pageNumber="13"> +Four pairs of ceratobranchials are preserved, a fifth ceratobranchial is absent although rakers on the ventral part of the fifth arch in MNHN-F-SAA20 ( +<figureCitation id="13232A048D40645BFB8EF9A5FB31F9CA" box="[1106,1167,1593,1617]" captionStart="Figure 3" captionStartId="4.[129,194,1343,1367]" captionTargetBox="[132,1470,147,1313]" captionTargetId="figure-210@4.[129,1473,144,1316]" captionTargetPageId="4" captionText="Figure 3. The head skeleton of Acanthodes confusus MNHN-F-SAA20, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; hypobr., hypobranchials; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scapcor., scapulocoracoids; scler., sclerotic ring. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971771" httpUri="https://zenodo.org/record/14971771/files/figure.png" pageId="12" pageNumber="13">Figs 3</figureCitation> +, +<figureCitation id="13232A048D40645BFB46F9A5FB07F9CA" box="[1178,1209,1593,1617]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="12" pageNumber="13">7C</figureCitation> +) indicate that there was a ventral component to the fifth branchial arch. The ceratobranchials all have a similar overall structure, with a ventral groove for the afferent branchial artery and plinths on their pharynx-facing surfaces for the branchial rakers ( +<figureCitation id="13232A048D40645BFB4DF92AFB74F955" box="[1169,1226,1718,1742]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="12" pageNumber="13">Fig. 7</figureCitation> +). Ceratobranchial I and II are segmented into anterior and posterior sections, and ceratobranchial I has a pronounced articular facet on its anterior end which must have articulated with the basibranchial, although there is no corresponding facet on that element. More posterior ceratobranchials become progressively shorter and more pronouncedly curved until the fourth pair is almost as broad as they are long ( +<figureCitation id="13232A048D40645BFC0CF80DFB8CF832" box="[976,1074,1937,1961]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="12" pageNumber="13">Fig. 7E, F</figureCitation> +). The posteriormost ceratobranchial is not enlarged as in +<taxonomicName id="4C184D028D40645BFC28F82DFBD6F852" box="[1012,1128,1969,1993]" genus="Gladbachus" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="12" pageNumber="13" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D40645BFC28F82DFBD6F852" box="[1012,1128,1969,1993]" italics="true" pageId="12" pageNumber="13">Gladbachus</emphasis> +</taxonomicName> +and the stem-group gnathostome +<taxonomicName id="4C184D028D41645AFFADFF0CFEBDFF33" authorityName="Broili" authorityYear="1933" box="[113,259,144,168]" family="Paraplesiobatidae" genus="Paraplesiobatis" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="13" pageNumber="14" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D41645AFFADFF0CFEBDFF33" box="[113,259,144,168]" italics="true" pageId="13" pageNumber="14">Paraplesiobatis</emphasis> +</taxonomicName> +( +<bibRefCitation id="EF894B708D41645AFECBFF0CFE60FF33" author="Brazeau MD & Friedman M & Jerve A" box="[279,478,144,168]" pageId="13" pageNumber="14" pagination="1 - 9" refId="ref10832" refString="Brazeau MD, Friedman M, Jerve A et al. A three-dimensional placoderm (stem-group gnathostome) pharyngeal skeleton and its implications for primitive gnathostome pharyngeal architecture. Journal of Morphology 2017; 278: 1-9." type="journal article" year="2017"> +Brazeau +<emphasis id="B96CEA938D41645AFEACFF0DFE1DFF33" box="[368,419,144,168]" italics="true" pageId="13" pageNumber="14">et al.</emphasis> +2017 +</bibRefCitation> +, +<bibRefCitation id="EF894B708D41645AFE30FF0CFD17FF33" author="Coates MI & Finarelli JA & Sansom IJ" box="[492,681,144,168]" pageId="13" pageNumber="14" pagination="1 - 10" refId="ref11170" refString="Coates MI, Finarelli JA, Sansom IJ et al. An early chondrichthyan and the evolutionary assembly of a shark body plan. Proceedings of the Royal Society B: Biological Sciences 2018; 285: 1-10." type="journal article" year="2018"> +Coates +<emphasis id="B96CEA938D41645AFDE7FF0DFDD3FF33" box="[571,621,144,168]" italics="true" pageId="13" pageNumber="14">et al.</emphasis> +2018 +</bibRefCitation> +), yet is more flattened relative to the others as observed in these taxa. +</paragraph> +<paragraph id="8BA736818D41645AFF51FF53FEB5FDE5" blockId="13.[113,763,144,1986]" pageId="13" pageNumber="14"> +Hypobranchials are present on at least the second and third branchial arches ( +<figureCitation id="13232A048D41645AFEACFF72FE10FE9E" box="[368,430,238,262]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="13" pageNumber="14">Fig. 7</figureCitation> +). No hypobranchial IV is visible in our datasets ( +<figureCitation id="13232A048D41645AFE95FE91FE3AFEBE" box="[329,388,269,293]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="13" pageNumber="14">Fig. 7</figureCitation> +), although a cast of a now lost specimen (NHMUK PV P 49990; +<bibRefCitation id="EF894B708D41645AFE1AFEB1FD82FEDE" author="Miles RS" box="[454,572,301,325]" pageId="13" pageNumber="14" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles 1973</bibRefCitation> +, plate 7) shows a hypobranchial in this position quite clearly that conforms with the anatomy of the more anterior hypobranchials so it may be either lost or unmineralized in the specimens studied here. The hypobranchials are short and curved, with a lateral groove, and are oriented anteriorly. Ceratobranchial I has a well-developed condyle at its anterior tip and is preserved in close association with the basibranchial in MNHN-F-SAA21 ( +<figureCitation id="13232A048D41645AFD7FFD94FF3AFDA4" captionStart="Figure 8" captionStartId="9.[113,178,1758,1782]" captionTargetBox="[117,1455,147,1727]" captionTargetId="figure-6@9.[114,1458,144,1730]" captionTargetPageId="9" captionText="Figure 8. The hyoid skeleton of Acanthodes confusus. A, B, the hyoid skeleton of MNHN-F-SAA24 in (A) left lateral and (B) right lateral view. C–E, the hyoid skeleton of MNHN-F-SAA21 in (C) right lateral, (D) left lateral, and (E) dorsal view. F, the posterior mineralization of the left hyomandibula in MNHN-F-SAA21.G, H, the left interhyal of MNHN-F-SAA24 in (G) lateral and (H) medial view.I, J, the left ceratohyal of MNHN-F-SAA21 in (I) lateral and (J) medial view.K–M, the basibranchial of MNHN-F-SAA21 in (K) ventral, (L) dorsal, and (M) right lateral view.Abbreviations: ant., anterior ossification; artic., articulation; basibr., basibranchial; basisph., basisphenoid; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; L., left; hyomand., hyomandibula; hypobr., hypobranchials; med.gr., medial groove; med.rid., medial ridge; post., posterior ossification; R., right.; I–II, branchial arches I–II. Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972026" httpUri="https://zenodo.org/record/14972026/files/figure.png" pageId="13" pageNumber="14">Fig. 8C, D</figureCitation> +), suggesting a direct connection between the two without an intervening hypobranchial. We find no evidence for a fifth hypobranchial. +</paragraph> +<paragraph id="8BA736818D41645AFF51FD19FE2DFBE8" blockId="13.[113,763,144,1986]" pageId="13" pageNumber="14"> +Five pairs of epibranchials are present, one in each arch ( +<figureCitation id="13232A048D41645AFD0CFD19FFC0FD27" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="13" pageNumber="14">Figs 7</figureCitation> +, +<figureCitation id="13232A048D41645AFF51FD39FF24FD26" box="[141,154,677,701]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="13" pageNumber="14">9</figureCitation> +). The epibranchials are gently curved, with a dorsolateral groove for the efferent branchial artery ( +<figureCitation id="13232A048D41645AFDD6FD58FDD3FD40" box="[522,621,708,732]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="13" pageNumber="14">Fig. 9A, B</figureCitation> +). This groove is bordered medially by a ridge corresponding to the posterior flange ( +<bibRefCitation id="EF894B708D41645AFF63FC9FFEC9FC80" author="Coates MI & Finarelli JA & Sansom IJ" box="[191,375,770,795]" pageId="13" pageNumber="14" pagination="1 - 10" refId="ref11170" refString="Coates MI, Finarelli JA, Sansom IJ et al. An early chondrichthyan and the evolutionary assembly of a shark body plan. Proceedings of the Royal Society B: Biological Sciences 2018; 285: 1-10." type="journal article" year="2018"> +Coates +<emphasis id="B96CEA938D41645AFED0FC9FFE83FC81" box="[268,317,770,794]" italics="true" pageId="13" pageNumber="14">et al.</emphasis> +2018 +</bibRefCitation> +). At the distal end of the ceratobranchial this develops into a dorsal process ( +<bibRefCitation id="EF894B708D41645AFDC6FCBEFD30FCA1" author="Miles RS" box="[538,654,802,826]" pageId="13" pageNumber="14" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles 1968</bibRefCitation> +). Like the ceratobranchials the surface facing into the branchial chamber is pitted forming a series of plinths to carry the gill rakers ( +<figureCitation id="13232A048D41645AFD08FCFCFF27FC03" captionStart="Figure 10" captionStartId="11.[115,179,1285,1309]" captionTargetBox="[117,1455,147,1255]" captionTargetId="figure-331@11.[114,1458,144,1258]" captionTargetPageId="11" captionText="Figure 10. The gular rays, hyoid rakers, and branchial rakers of Acanthodes confusus. A, right lateral view of jaws of MNHN-F-SAA21 showing relationship of gular rays and mandibular splint to Meckel’s cartilage.B, right lateral view of jaws of MNHN-F-SAA20 with mandibular splints removed showing gular rays and relationship of hyoid rakers to ceratobranchial. C, left lateral view of MNHN-F-SAA20 showing hyomandibular rakers.D, branchial rakers in articulation with the epibranchial of SAA21.E, branchial rakers in articulation with the ceratobranchial of SAA21. F, hyoid rakers from the ceratohyal of SAA20.G, branchial rakers from the epibranchial of SAA20. Abbreviations: ceratobr., ceratobranchials; epibr., epibranchial; gul. ray., gular rays; rak.br., branchial rakers; rak.hy., hyoid rakers; rak.pl., plinth for branchial raker; I–V, branchial arches I–V.Scale bar = 10 mm except in C where scale bar = 2.5 mm. Note in D and E the shape of the rakers is poorly captured by the scan." figureDoi="http://doi.org/10.5281/zenodo.14972032" httpUri="https://zenodo.org/record/14972032/files/figure.png" pageId="13" pageNumber="14">Fig. 10E</figureCitation> +). The proximal end of the epibranchials has an articular surface for the ceratobranchial ( +<figureCitation id="13232A048D41645AFE78FC03FE4FFC2C" box="[420,497,927,951]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="13" pageNumber="14">Fig. 9C</figureCitation> +). The epibranchials have the same overall form, but become progressively shorter posteriorly ( +<figureCitation id="13232A048D41645AFF68FC42FF4DFC6E" box="[180,243,990,1014]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="13" pageNumber="14">Figs 7</figureCitation> +, +<figureCitation id="13232A048D41645AFEDDFC42FE9CFC6D" box="[257,290,990,1014]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="13" pageNumber="14">9H</figureCitation> +). The posteriormost (fifth) epibranchials are different in shape, with broad heads ( +<figureCitation id="13232A048D41645AFE29FC61FD8CFB8E" box="[501,562,1021,1045]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="13" pageNumber="14"> +Figs +<geoCoordinate id="EE2C50468D41645AFDF9FC62FD8CFB8E" box="[549,562,1022,1045]" degrees="7, 9" direction="east" orientation="longitude" pageId="13" pageNumber="14" precision="5555" value="7.9">7</geoCoordinate> +</figureCitation> +, +<figureCitation id="13232A048D41645AFDE3FC61FDE4FB8E" box="[575,602,1021,1045]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="13" pageNumber="14">9E</figureCitation> +). Although the epibranchials in MNHN-F-SAA20 and MNHN-F-SAA21 appear to be segmented, in MNHN-F-SAA24 they are ossified into a single structure ( +<figureCitation id="13232A048D41645AFEF2FBC7FED4FBE8" box="[302,362,1115,1139]" captionStart="Figure 4" captionStartId="5.[113,178,1539,1563]" captionTargetBox="[116,1456,146,1509]" captionTargetId="figure-106@5.[114,1458,144,1511]" captionTargetPageId="5" captionText="Figure 4. The head skeleton of Acanthodes confusus MNHN-F-SAA24, visualized using computed tomography. A, in right lateral view. B, in left lateral view. Abbreviations: basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; interhy., interhyal; L., left; mand.sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; scapcor., scapulocoracoids; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971773" httpUri="https://zenodo.org/record/14971773/files/figure.png" pageId="13" pageNumber="14">Figs 4</figureCitation> +, +<figureCitation id="13232A048D41645AFEA9FBC7FE3CFBE8" box="[373,386,1115,1139]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="13" pageNumber="14">9</figureCitation> +). +</paragraph> +<paragraph id="8BA736818D41645AFF51FBE7FEB8F93C" blockId="13.[113,763,144,1986]" pageId="13" pageNumber="14"> +There are four pairs of pharyngobranchials, best preserved in MNHN-F-SAA24 ( +<figureCitation id="13232A048D41645AFE86FB06FE29FB29" box="[346,407,1178,1202]" captionStart="Figure 4" captionStartId="5.[113,178,1539,1563]" captionTargetBox="[116,1456,146,1509]" captionTargetId="figure-106@5.[114,1458,144,1511]" captionTargetPageId="5" captionText="Figure 4. The head skeleton of Acanthodes confusus MNHN-F-SAA24, visualized using computed tomography. A, in right lateral view. B, in left lateral view. Abbreviations: basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; interhy., interhyal; L., left; mand.sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; scapcor., scapulocoracoids; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971773" httpUri="https://zenodo.org/record/14971773/files/figure.png" pageId="13" pageNumber="14">Figs 4</figureCitation> +, +<figureCitation id="13232A048D41645AFE78FB06FE0FFB2A" box="[420,433,1178,1201]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="13" pageNumber="14">7</figureCitation> +, +<figureCitation id="13232A048D41645AFE61FB06FE74FB29" box="[445,458,1178,1202]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="13" pageNumber="14">9</figureCitation> +) where all four pairs are preserved in articulation with the epibranchials. The individual anatomy of these pharyngobranchials is consistent with the description of Miles and that observed in casts of mouldic specimens (e.g. NHMUK PV P 59959, +<bibRefCitation id="EF894B708D41645AFE08FA8BFDF6FAB4" author="Miles RS" box="[468,584,1303,1327]" pageId="13" pageNumber="14" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles 1973</bibRefCitation> +: pl. 2), and there is no evidence for separate supra- and infrapharyngobranchials as in +<taxonomicName id="4C184D028D41645AFF61FACAFEB0FAF6" box="[189,270,1366,1389]" class="Elasmobranchii" family="Falcatidae" genus="Ozarcus" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="13" pageNumber="14" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D41645AFF61FACAFEB0FAF6" box="[189,270,1366,1389]" italics="true" pageId="13" pageNumber="14">Ozarcus</emphasis> +</taxonomicName> +and osteichthyans ( +<bibRefCitation id="EF894B708D41645AFDDCFACAFD1CFAF5" author="Gardiner BG" box="[512,674,1366,1390]" pageId="13" pageNumber="14" pagination="175 - 418" refId="ref11748" refString="Gardiner BG. Te relationships of the palaeoniscid fishes, a review based on new specimens of Mimia and Moythomasia from the Upper Devonian of Western Australia. Bulletin of the British Museum (Natural History) Geology 1984; 37: 175-418." type="journal article" year="1984">Gardiner 1984</bibRefCitation> +, +<bibRefCitation id="EF894B708D41645AFD65FACAFF53FA16" author="Pradel A & Maisey JG & Tafforeau P" pageId="13" pageNumber="14" pagination="608 - 11" refId="ref12686" refString="Pradel A, Maisey JG, Tafforeau P et al. A Palaeozoic shark with osteichthyan-like branchial arches. Nature 2014; 509: 608-11. htps: // doi. org / 10.1038/nature13195" type="journal article" year="2014"> +Pradel +<emphasis id="B96CEA938D41645AFFADFAEAFF15FA16" box="[113,171,1397,1421]" italics="true" pageId="13" pageNumber="14">et al.</emphasis> +2014 +</bibRefCitation> +). The morphology of each successive pair of pharyngobranchials is serially consistent, although the more posterior pharyngobranchials are slightly smaller. Unlike living chondrichthyans, but like +<taxonomicName id="4C184D028D41645AFE19FA4FFD87FA70" box="[453,569,1491,1515]" genus="Gladbachus" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="13" pageNumber="14" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D41645AFE19FA4FFD87FA70" box="[453,569,1491,1515]" italics="true" pageId="13" pageNumber="14">Gladbachus</emphasis> +</taxonomicName> +and +<taxonomicName id="4C184D028D41645AFDB3FA4FFD44FA70" authorityName="Miles" authorityYear="1973" box="[623,762,1491,1515]" genus="Ptomacanthus" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="13" pageNumber="14" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D41645AFDB3FA4FFD44FA70" box="[623,762,1491,1515]" italics="true" pageId="13" pageNumber="14">Ptomacanthus</emphasis> +</taxonomicName> +( +<bibRefCitation id="EF894B708D41645AFFA0FA6EFEFEF991" author="Coates MI & Finarelli JA & Sansom IJ" box="[124,320,1522,1546]" pageId="13" pageNumber="14" pagination="1 - 10" refId="ref11170" refString="Coates MI, Finarelli JA, Sansom IJ et al. An early chondrichthyan and the evolutionary assembly of a shark body plan. Proceedings of the Royal Society B: Biological Sciences 2018; 285: 1-10." type="journal article" year="2018"> +Coates +<emphasis id="B96CEA938D41645AFF11FA6FFEBCF991" box="[205,258,1522,1546]" italics="true" pageId="13" pageNumber="14">et al.</emphasis> +2018 +</bibRefCitation> +, +<bibRefCitation id="EF894B708D41645AFE8DFA6EFD99F991" author="Dearden RP & Stockey C & Brazeau MD" box="[337,551,1522,1546]" pageId="13" pageNumber="14" pagination="1 - 7" refId="ref11589" refString="Dearden RP, Stockey C, Brazeau MD. Te pharynx of the stem-chondrichthyan Ptomacanthus and the early evolution of the gnathostome gill skeleton. Nature Communications 2019; 10: 1-7." type="journal article" year="2019"> +Dearden +<emphasis id="B96CEA938D41645AFE68FA6FFE57F991" box="[436,489,1522,1546]" italics="true" pageId="13" pageNumber="14">et al.</emphasis> +2019 +</bibRefCitation> +) the posteriormost epibranchials and pharyngobranchials are not fused into a single complex element. The only other acanthodiform in which pharyngobranchials have been figured is +<taxonomicName id="4C184D028D41645AFDF7F9CCFD6BF9F3" authorityName="Burrow, Trinajstic & Long" authorityYear="2012" box="[555,725,1616,1640]" family="Howittacanthidae" genus="Halimacanthodes" higherTaxonomySource="GBIF" kingdom="Animalia" pageId="13" pageNumber="14" phylum="Chordata" rank="genus"> +<emphasis id="B96CEA938D41645AFDF7F9CCFD6BF9F3" box="[555,725,1616,1640]" italics="true" pageId="13" pageNumber="14">Halimacanthodes</emphasis> +</taxonomicName> +, in which they appear broadly similar in shape ( +<bibRefCitation id="EF894B708D41645AFDE4F9ECFD4DF913" author="Burrow CJ & Trinajstic K & Long JA" box="[568,755,1648,1672]" pageId="13" pageNumber="14" pagination="349 - 57" refId="ref11052" refString="Burrow CJ, Trinajstic K, Long JA. First acanthodian from the Upper Devonian (Frasnian) Gogo Formation, Western Australia. Historical Biology 2012; 24: 349-57. htps: // doi. org / 10.1080/08912963.2012. 660150" type="journal article" year="2012"> +Burrow +<emphasis id="B96CEA938D41645AFD56F9EDFD04F913" box="[650,698,1648,1672]" italics="true" pageId="13" pageNumber="14">et al.</emphasis> +2012 +</bibRefCitation> +: fig. 2b, +<emphasis id="B96CEA938D41645AFF65F913FF48F93C" box="[185,246,1679,1703]" italics="true" pageId="13" pageNumber="14">ph. br.</emphasis> +). +</paragraph> +<paragraph id="8BA736818D41645AFF51F933FC00FDE5" blockId="13.[113,763,144,1986]" lastBlockId="13.[810,1459,144,638]" pageId="13" pageNumber="14"> +The articulation between each pharyngobranchial and the head of each epibranchial confirms the account of +<bibRefCitation id="EF894B708D41645AFDB1F952FD4AF97D" author="Miles RS" box="[621,756,1742,1766]" pageId="13" pageNumber="14" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles (1973)</bibRefCitation> +, with two cotyli on the anterior end of each pharyngobranchial fitting with two condyli on the head of each ceratobranchial. This articulation is preserved +<emphasis id="B96CEA938D41645AFE74F8B1FE59F8DF" box="[424,487,1837,1860]" italics="true" pageId="13" pageNumber="14">in situ</emphasis> +in the right, second branchial arch of MNHN-F-SAA24 ( +<figureCitation id="13232A048D41645AFE14F8D7FD93F8F8" box="[456,557,1867,1891]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="13" pageNumber="14">Fig. 9G–J</figureCitation> +), and the positions of the other pharyngobranchials in this specimen are consistent with the same articulation. +<bibRefCitation id="EF894B708D41645AFE4EF816FD91F839" author="Nelson GJ" box="[402,559,1930,1954]" pageId="13" pageNumber="14" pagination="129 - 43" refId="ref12555" refString="Nelson GJ. Gill-arch structure in Acanthodes. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proc. Fourth Nobel Symp. Stockholm: Armqvist and Wiksell, 1968, 129-43." type="book chapter" year="1968">Nelson (1968)</bibRefCitation> +outlined two alternative arrangements of the pharyngobranchials in +<taxonomicName id="4C184D028D41645AFD56F835FD44F85A" authorityName="Agassiz" authorityYear="1833" box="[650,762,1961,1985]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="13" pageNumber="14" phylum="Arthropoda" rank="genus"> +<emphasis id="B96CEA938D41645AFD56F835FD44F85A" box="[650,762,1961,1985]" italics="true" pageId="13" pageNumber="14">Acanthodes</emphasis> +</taxonomicName> +( +<figureCitation id="13232A048D41645AFCE9FF0CFC3EFF33" box="[821,896,144,168]" captionStart="Figure1" captionStartId="2.[129,190,1867,1891]" captionTargetBox="[257,1345,152,1836]" captionTargetId="figure-7@2.[254,1348,149,1839]" captionTargetPageId="2" captionText="Figure1.Previous reconstructionsofthe hyoidandbranchial archskeletoninAcanthodes.A,Reis(1896). B,Watson (1937).C, Nelson(1968) withboth alternatereconstructionsof pharyngobranchialorientation.D,Miles(1973).E,Jarvik(1977). F,Gardiner (1984).Terminologyhas beenstandardizedto matchtermsused inthisstudy.Abbreviations:basibr.,basibranchial;basihy.,basihyal;ceratobr.,ceratobranchials;ceratohy.,ceratohyal;epibr.,epibranchial; hyomand.,hyomandibula;hypohy.,hypohyal;interhy.,interhyal;pharbr.,pharyngobranchials;pharhy.,pharyngohyal.Matchingcoloursdenote serially homologouselements.Grey indicatesinferredareas ofcartilage.Blackdashedlines indicatehypotheticalelements.Vertical grey dashedline indicates junctionofdorsal andventralbranchialskeleton.Allreconstructionsareshownas ifspread horizontally,withanterior upwards." figureDoi="http://doi.org/10.5281/zenodo.14971767" httpUri="https://zenodo.org/record/14971767/files/figure.png" pageId="13" pageNumber="14">Fig. 1C</figureCitation> +): one where each pharyngobranchial was oriented anteriorly from the more posterior arch to meet the one in front, and another where pharyngobranchials were oriented posteromedially from the top of each arch. Reconstructing the articulation between this pharyngobranchial and epibranchial leads to an angle of about 90 ° between the two, suggesting that the latter of Nelson’s reconstructions is accurate ( +<figureCitation id="13232A048D41645AFACAFED0FAC6FEF8" box="[1302,1400,332,356]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="13" pageNumber="14">Figs 9I, J</figureCitation> +, +<figureCitation id="13232A048D41645AFA54FED0FA1CFEFF" box="[1416,1442,332,356]" captionStart="Figure 12" captionStartId="14.[129,194,1309,1333]" captionTargetBox="[132,1470,146,1278]" captionTargetId="figure-339@14.[129,1473,144,1281]" captionTargetPageId="14" captionText="Figure 12. Reconstruction of Acanthodes confusus based on a composite of the material described here, animated to show mouth opening from left to right.A, in right lateral view.B, in anterior view.C, in dorsal view. D, in ventral view." figureDoi="http://doi.org/10.5281/zenodo.14972040" httpUri="https://zenodo.org/record/14972040/files/figure.png" pageId="13" pageNumber="14">12</figureCitation> +). Moreover there is no visible articulatory surface on the posterior end of each pharyngobranchial ( +<figureCitation id="13232A048D41645AFB1CFE16FA91FE39" box="[1216,1327,394,419]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="13" pageNumber="14">Fig. 9K, N</figureCitation> +), with them instead being narrow and unfinished ( +<bibRefCitation id="EF894B708D41645AFB7BFE36FAA6FE59" author="Miles RS" box="[1191,1304,426,450]" pageId="13" pageNumber="14" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles 1973</bibRefCitation> +). Based on this we interpret these new data as confirming that +<taxonomicName id="4C184D028D41645AFACAFE55FA38FE7A" authorityName="Agassiz" authorityYear="1833" box="[1302,1414,457,481]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="13" pageNumber="14" phylum="Arthropoda" rank="genus"> +<emphasis id="B96CEA938D41645AFACAFE55FA38FE7A" box="[1302,1414,457,481]" italics="true" pageId="13" pageNumber="14">Acanthodes</emphasis> +</taxonomicName> +had postero-medially oriented pharyngobranchials. The effect of the posterior process and dorsal ridge on each pharyngobranchial ( +<figureCitation id="13232A048D41645AFCE9FDBBFCC7FDA4" box="[821,889,551,575]" captionStart="Figure 12" captionStartId="14.[129,194,1309,1333]" captionTargetBox="[132,1470,146,1278]" captionTargetId="figure-339@14.[129,1473,144,1281]" captionTargetPageId="14" captionText="Figure 12. Reconstruction of Acanthodes confusus based on a composite of the material described here, animated to show mouth opening from left to right.A, in right lateral view.B, in anterior view.C, in dorsal view. D, in ventral view." figureDoi="http://doi.org/10.5281/zenodo.14972040" httpUri="https://zenodo.org/record/14972040/files/figure.png" pageId="13" pageNumber="14">Fig. 12</figureCitation> +) is thus to form a concave surface on the dorsal face each serving as anchoring points for the m. interpharyngobranchialis ( +<bibRefCitation id="EF894B708D41645AFCE4FDFAFC13FDE5" author="Jarvik E" box="[824,941,614,638]" pageId="13" pageNumber="14" pagination="199 - 225" refId="ref12006" refString="Jarvik E. Te systematic position of acanthodian fishes. In: Andrews SM, Miles RS, Walker A (eds), Problems in Vertebrate Evolution. London, UK: Academic Press, 1977, 199-225." type="book chapter" year="1977">Jarvik 1977</bibRefCitation> +). +</paragraph> +<paragraph id="8BA736818D41645AFC58FD29FAE7FD54" blockId="13.[900,1369,693,719]" box="[900,1369,693,719]" pageId="13" pageNumber="14"> +<heading id="D0EF81ED8D41645AFC58FD29FAE7FD54" allCaps="true" bold="true" box="[900,1369,693,719]" centered="true" fontSize="11" level="1" pageId="13" pageNumber="14" reason="1"> +<emphasis id="B96CEA938D41645AFC58FD29FAE7FD54" bold="true" box="[900,1369,693,719]" pageId="13" pageNumber="14">HYOID AND BRANCHIAL RAKERS</emphasis> +</heading> +</paragraph> +<paragraph id="8BA736818D41645AFCF6FD7DFC52FA96" blockId="13.[810,1459,737,1669]" pageId="13" pageNumber="14"> +Branchial and hyoid arches carry rows of small rakers. Our data is insufficiently high resolution to show any histological detail, but these elements are separate from the endoskeletal arches, with distinct bases and crowns, and are ornamented ( +<bibRefCitation id="EF894B708D41645AFACAFCA3FA32FCCD" author="Zidek J" box="[1302,1420,830,855]" pageId="13" pageNumber="14" pagination="147 - 66" refId="ref13218" refString="Zidek J. Growth in Acanthodes (Acanthodii: Pisces) data and implications. Palaontologische Zeitschrif 1985; 59: 147-66." type="journal article" year="1985">Zidek 1985</bibRefCitation> +) so we consider it probable they are dermal rakers ( +<bibRefCitation id="EF894B708D41645AFACFFCC2FA38FCED" author="Miles RS" box="[1299,1414,862,886]" pageId="13" pageNumber="14" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles 1968</bibRefCitation> +) rather than endoskeletal projections from the pharyngeal arches ( +<bibRefCitation id="EF894B708D41645AFCE8FC07FC13FC2E" author="Orvig T" box="[820,941,923,949]" pageId="13" pageNumber="14" pagination="119 - 50" refId="ref12636" refString="Orvig T. Acanthodian dentition and its bearing on the relationships of the group. Palaeontographica, Abteilung A 1973; 143: 119-50." type="journal article" year="1973">Ørvig 1973</bibRefCitation> +, +<bibRefCitation id="EF894B708D41645AFC67FC01FB8AFC2E" author="Jarvik E" box="[955,1076,925,949]" pageId="13" pageNumber="14" pagination="199 - 225" refId="ref12006" refString="Jarvik E. Te systematic position of acanthodian fishes. In: Andrews SM, Miles RS, Walker A (eds), Problems in Vertebrate Evolution. London, UK: Academic Press, 1977, 199-225." type="book chapter" year="1977">Jarvik 1977</bibRefCitation> +). On the basis of MNHN-F-SAA21 and MNHN-F-SAA20 ( +<figureCitation id="13232A048D41645AFBFDFC20FBE2FC4F" box="[1057,1116,956,980]" captionStart="Figure 2" captionStartId="3.[113,178,1621,1645]" captionTargetBox="[117,1455,147,1591]" captionTargetId="figure-68@3.[114,1458,144,1594]" captionTargetPageId="3" captionText="Figure 2. The head skeleton of Acanthodes confusus MNHN-F-SAA21, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pq. autop., palatoquadrate autopalatine; pq. metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971769" httpUri="https://zenodo.org/record/14971769/files/figure.png" pageId="13" pageNumber="14">Figs 2</figureCitation> +, +<figureCitation id="13232A048D41645AFBBBFC20FBCAFC4F" box="[1127,1140,956,980]" captionStart="Figure 3" captionStartId="4.[129,194,1343,1367]" captionTargetBox="[132,1470,147,1313]" captionTargetId="figure-210@4.[129,1473,144,1316]" captionTargetPageId="4" captionText="Figure 3. The head skeleton of Acanthodes confusus MNHN-F-SAA20, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; hypobr., hypobranchials; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scapcor., scapulocoracoids; scler., sclerotic ring. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971771" httpUri="https://zenodo.org/record/14971771/files/figure.png" pageId="13" pageNumber="14">3</figureCitation> +) there is a single row of antero-medially directed rakers on each branchial arch, although more than one row on each arch has been reported, which may vary through ontogeny ( +<bibRefCitation id="EF894B708D41645AFC2DFB86FBE8FBA9" author="Reis OM" box="[1009,1110,1050,1074]" pageId="13" pageNumber="14" pagination="143 - 220" refId="ref12887" refString="Reis OM. Ueber Acanthodes Bronni Agassiz. Morphologische Arbeiten 1896; 6: 143-220." type="journal article" year="1896">Reis 1896</bibRefCitation> +, +<bibRefCitation id="EF894B708D41645AFBBDFB86FB59FBA9" author="Watson DMS" box="[1121,1255,1050,1074]" pageId="13" pageNumber="14" pagination="49 - 146" refId="ref13149" refString="Watson DMS. Te acanthodian fishes. Philosophical Transactions of the Royal Society of London, Series B: Biological Sciences 1937; 228: 49-146." type="journal article" year="1937">Watson 1937</bibRefCitation> +, +<bibRefCitation id="EF894B708D41645AFB2DFB86FADDFBA9" author="Miles RS" box="[1265,1379,1050,1074]" pageId="13" pageNumber="14" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles 1968</bibRefCitation> +). Some small rakers are present on the ventral part of the hyomandibula in MNHN-F-SAA20 ( +<bibRefCitation id="EF894B708D41645AFBC4FBC4FB3CFBEB" author="Reis OM" box="[1048,1154,1112,1136]" pageId="13" pageNumber="14" pagination="143 - 220" refId="ref12887" refString="Reis OM. Ueber Acanthodes Bronni Agassiz. Morphologische Arbeiten 1896; 6: 143-220." type="journal article" year="1896">Reis 1896</bibRefCitation> +, +<bibRefCitation id="EF894B708D41645AFB4DFBC5FAA2FBEA" author="Watson DMS" box="[1169,1308,1113,1137]" pageId="13" pageNumber="14" pagination="49 - 146" refId="ref13149" refString="Watson DMS. Te acanthodian fishes. Philosophical Transactions of the Royal Society of London, Series B: Biological Sciences 1937; 228: 49-146." type="journal article" year="1937">Watson 1937</bibRefCitation> +, +<bibRefCitation id="EF894B708D41645AFAF0FBC4FA1CFBEB" author="Miles RS" box="[1324,1442,1112,1136]" pageId="13" pageNumber="14" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles 1968</bibRefCitation> +), and the ceratohyals carry a single row of rakers ( +<figureCitation id="13232A048D41645AFAF1FBE4FAD2FB0B" box="[1325,1388,1144,1168]" captionStart="Figure 2" captionStartId="3.[113,178,1621,1645]" captionTargetBox="[117,1455,147,1591]" captionTargetId="figure-68@3.[114,1458,144,1594]" captionTargetPageId="3" captionText="Figure 2. The head skeleton of Acanthodes confusus MNHN-F-SAA21, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pq. autop., palatoquadrate autopalatine; pq. metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971769" httpUri="https://zenodo.org/record/14971769/files/figure.png" pageId="13" pageNumber="14">Figs 2</figureCitation> +, +<figureCitation id="13232A048D41645AFAA6FBE4FA39FB0B" box="[1402,1415,1144,1168]" captionStart="Figure 3" captionStartId="4.[129,194,1343,1367]" captionTargetBox="[132,1470,147,1313]" captionTargetId="figure-210@4.[129,1473,144,1316]" captionTargetPageId="4" captionText="Figure 3. The head skeleton of Acanthodes confusus MNHN-F-SAA20, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; hypobr., hypobranchials; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scapcor., scapulocoracoids; scler., sclerotic ring. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bar = 20 mm." figureDoi="http://doi.org/10.5281/zenodo.14971771" httpUri="https://zenodo.org/record/14971771/files/figure.png" pageId="13" pageNumber="14">3</figureCitation> +, +<figureCitation id="13232A048D41645AFA49FBE4FA1CFB14" box="[1429,1442,1144,1167]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="13" pageNumber="14">7</figureCitation> +). Rakers are present on the dorsal and ventral parts of all five branchial arches, as can be seen in MNHN-F-SAA20 ( +<figureCitation id="13232A048D41645AFAEAFB2AFA1DFB55" box="[1334,1443,1206,1231]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="13" pageNumber="14">Fig. 7C, D</figureCitation> +). They are positioned on plinths along the length of the branchial elements ( +<figureCitation id="13232A048D41645AFC4AFB69FC65FA96" box="[918,987,1269,1293]" captionStart="Figure 10" captionStartId="11.[115,179,1285,1309]" captionTargetBox="[117,1455,147,1255]" captionTargetId="figure-331@11.[114,1458,144,1258]" captionTargetPageId="11" captionText="Figure 10. The gular rays, hyoid rakers, and branchial rakers of Acanthodes confusus. A, right lateral view of jaws of MNHN-F-SAA21 showing relationship of gular rays and mandibular splint to Meckel’s cartilage.B, right lateral view of jaws of MNHN-F-SAA20 with mandibular splints removed showing gular rays and relationship of hyoid rakers to ceratobranchial. C, left lateral view of MNHN-F-SAA20 showing hyomandibular rakers.D, branchial rakers in articulation with the epibranchial of SAA21.E, branchial rakers in articulation with the ceratobranchial of SAA21. F, hyoid rakers from the ceratohyal of SAA20.G, branchial rakers from the epibranchial of SAA20. Abbreviations: ceratobr., ceratobranchials; epibr., epibranchial; gul. ray., gular rays; rak.br., branchial rakers; rak.hy., hyoid rakers; rak.pl., plinth for branchial raker; I–V, branchial arches I–V.Scale bar = 10 mm except in C where scale bar = 2.5 mm. Note in D and E the shape of the rakers is poorly captured by the scan." figureDoi="http://doi.org/10.5281/zenodo.14972032" httpUri="https://zenodo.org/record/14972032/files/figure.png" pageId="13" pageNumber="14">Fig. 10</figureCitation> +). +</paragraph> +<paragraph id="8BA736818D41645AFC9AFA89FAD9F91E" blockId="13.[810,1459,737,1669]" pageId="13" pageNumber="14"> +The morphology of the rakers is variable on different elements ( +<figureCitation id="13232A048D41645AFCBAFAA8FC13FAD7" box="[870,941,1332,1356]" captionStart="Figure 10" captionStartId="11.[115,179,1285,1309]" captionTargetBox="[117,1455,147,1255]" captionTargetId="figure-331@11.[114,1458,144,1258]" captionTargetPageId="11" captionText="Figure 10. The gular rays, hyoid rakers, and branchial rakers of Acanthodes confusus. A, right lateral view of jaws of MNHN-F-SAA21 showing relationship of gular rays and mandibular splint to Meckel’s cartilage.B, right lateral view of jaws of MNHN-F-SAA20 with mandibular splints removed showing gular rays and relationship of hyoid rakers to ceratobranchial. C, left lateral view of MNHN-F-SAA20 showing hyomandibular rakers.D, branchial rakers in articulation with the epibranchial of SAA21.E, branchial rakers in articulation with the ceratobranchial of SAA21. F, hyoid rakers from the ceratohyal of SAA20.G, branchial rakers from the epibranchial of SAA20. Abbreviations: ceratobr., ceratobranchials; epibr., epibranchial; gul. ray., gular rays; rak.br., branchial rakers; rak.hy., hyoid rakers; rak.pl., plinth for branchial raker; I–V, branchial arches I–V.Scale bar = 10 mm except in C where scale bar = 2.5 mm. Note in D and E the shape of the rakers is poorly captured by the scan." figureDoi="http://doi.org/10.5281/zenodo.14972032" httpUri="https://zenodo.org/record/14972032/files/figure.png" pageId="13" pageNumber="14">Fig. 10</figureCitation> +). On the ceratohyal and hyomandibula the rakers comprise simple prongs with a broad, flat base ( +<figureCitation id="13232A048D41645AFAC8FACFFAEBFAF0" box="[1300,1365,1363,1387]" captionStart="Figure 9" captionStartId="10.[129,194,1644,1668]" captionTargetBox="[132,1470,146,1613]" captionTargetId="figure-6@10.[129,1473,144,1616]" captionTargetPageId="10" captionText="Figure 9. The dorsal branchial skeleton of Acanthodes confusus. A, B, articulated dorsal branchial skeleton of MNHN-F-SAA24 in right lateral (A) and dorsal (B) view with pharyngobranchials labelled. C–D, the right epibranchial II of MNHN-F-SAA24 in (C) lateral and (D) dorsal. E, the left fifth epibranchial of MNHN-F-SAA24 in dorsal view.F, the right epibranchial II of MNHN-F-SAA24 in posterior view. G, H, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 as preserved in (G) dorsal and (H) posterior view. I, J, right epibranchial and pharyngobranchial II of MNHN-F-SAA24 repositioned into estimate of life position in (I) dorsal and (J) posterior view.K–M, the right pharyngobranchials II of MNHN-F-SAA24 in (K) dorsal, (L) ventral, and (M) lateral view. N, all pharyngobranchials from MNHN-F- SAA24 in dorsal view.Abbreviations:artic., articulation; art. cot., articular cotylus; cerbr., ceratobranchial; dors. proc., dorsal process; dors. rid., dorsal ridge; epibr., epibranchial; L., left; med. rid., medial ridge; pharbr., pharyngobranchial; post. proc., posterior process; R., right; vent. cond., ventral condyle; I–V, branchial arches I–V.Scale bar = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14972030" httpUri="https://zenodo.org/record/14972030/files/figure.png" pageId="13" pageNumber="14">Fig. 9I</figureCitation> +), and on the hyomandibula these are even simpler and smaller ( +<figureCitation id="13232A048D41645AFA90FAEFFA1CFA10" box="[1356,1442,1395,1419]" captionStart="Figure 10" captionStartId="11.[115,179,1285,1309]" captionTargetBox="[117,1455,147,1255]" captionTargetId="figure-331@11.[114,1458,144,1258]" captionTargetPageId="11" captionText="Figure 10. The gular rays, hyoid rakers, and branchial rakers of Acanthodes confusus. A, right lateral view of jaws of MNHN-F-SAA21 showing relationship of gular rays and mandibular splint to Meckel’s cartilage.B, right lateral view of jaws of MNHN-F-SAA20 with mandibular splints removed showing gular rays and relationship of hyoid rakers to ceratobranchial. C, left lateral view of MNHN-F-SAA20 showing hyomandibular rakers.D, branchial rakers in articulation with the epibranchial of SAA21.E, branchial rakers in articulation with the ceratobranchial of SAA21. F, hyoid rakers from the ceratohyal of SAA20.G, branchial rakers from the epibranchial of SAA20. Abbreviations: ceratobr., ceratobranchials; epibr., epibranchial; gul. ray., gular rays; rak.br., branchial rakers; rak.hy., hyoid rakers; rak.pl., plinth for branchial raker; I–V, branchial arches I–V.Scale bar = 10 mm except in C where scale bar = 2.5 mm. Note in D and E the shape of the rakers is poorly captured by the scan." figureDoi="http://doi.org/10.5281/zenodo.14972032" httpUri="https://zenodo.org/record/14972032/files/figure.png" pageId="13" pageNumber="14">Fig. 10C</figureCitation> +). Contrastingly, on the epibranchials and ceratobranchials the blade of each raker is considerably longer and developed into a flattened leaf shape slightly inflected away from the midline, and a base that is quite rounded and concave. These branchial rakers are larger on more anterior arches, and also decrease in size towards the top and bottom of either arch ( +<figureCitation id="13232A048D41645AFB08F9B3FA83F9DD" box="[1236,1341,1583,1607]" captionStart="Figure 7" captionStartId="8.[129,194,1539,1563]" captionTargetBox="[132,1470,147,1509]" captionTargetId="figure-129@8.[129,1473,144,1512]" captionTargetPageId="8" captionText="Figure 7. Overview of Acanthodes confusus hyoid and branchial skeleton. A, B, MNHN-F-SAA21 with mandibular skeleton removed in (A) left lateral and (B) right lateral view.C, D, MNHN-F-SAA20 with mandibular and pectoral skeleton removed in (C) left lateral and (D) right lateral view. E, F, MNHN-F-SAA24 with mandibular and pectoral skeleton removed in (E) left lateral and (F) right lateral view. Abbreviations: basibr., basibranchial; ceratobr., ceratobranchials; ceratohy., ceratohyal; epibr., epibranchial; hyomand., hyomandibula; interhy., interhyal; L., left; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; R., right; rak. br., branchial rakers; rak.hy., hyoid rakers.Colour scheme:blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bars = 10 mm." figureDoi="http://doi.org/10.5281/zenodo.14971779" httpUri="https://zenodo.org/record/14971779/files/figure.png" pageId="13" pageNumber="14">Fig. 7C, D</figureCitation> +). More detailed views of raker morphology can be seen in casts, notably NHMUK PV P 49973 and 49990 ( +<bibRefCitation id="EF894B708D41645AFB4DF9F1FABDF91E" author="Miles RS" box="[1169,1283,1645,1669]" pageId="13" pageNumber="14" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles 1973</bibRefCitation> +: pls 6, 7). +</paragraph> +<paragraph id="8BA736818D41645AFC01F95FFABFF946" blockId="13.[989,1281,1731,1757]" box="[989,1281,1731,1757]" pageId="13" pageNumber="14"> +<heading id="D0EF81ED8D41645AFC01F95FFABFF946" allCaps="true" bold="true" box="[989,1281,1731,1757]" centered="true" fontSize="11" level="1" pageId="13" pageNumber="14" reason="1"> +<emphasis id="B96CEA938D41645AFC01F95FFABFF946" bold="true" box="[989,1281,1731,1757]" pageId="13" pageNumber="14">HYOID/GULAR RAYS</emphasis> +</heading> +</paragraph> +<paragraph id="8BA736818D416459FCF6F973FE96FA6C" blockId="13.[810,1460,1775,1987]" lastBlockId="14.[129,778,1409,1527]" lastPageId="14" lastPageNumber="15" pageId="13" pageNumber="14"> +The hyoid/gular rays are preserved in all +<specimenCount id="9D1EFD088D41645AFB3EF973FA33F89C" box="[1250,1421,1775,1799]" count="3" pageId="13" pageNumber="14" type="generic">three specimens</specimenCount> +, although the lateral collapse of the skeleton in each case has disarticulated them to some extent ( +<figureCitation id="13232A048D41645AFB52F8B1FB56F8DE" box="[1166,1256,1837,1861]" captionStart-0="Figure1" captionStart-1="Figure 2" captionStart-2="Figure 3" captionStartId-0="2.[129,190,1867,1891]" captionStartId-1="3.[113,178,1621,1645]" captionStartId-2="4.[129,194,1343,1367]" captionTargetBox-0="[257,1345,152,1836]" captionTargetBox-1="[117,1455,147,1591]" captionTargetBox-2="[132,1470,147,1313]" captionTargetId-0="figure-7@2.[254,1348,149,1839]" captionTargetId-1="figure-68@3.[114,1458,144,1594]" captionTargetId-2="figure-210@4.[129,1473,144,1316]" captionTargetPageId-0="2" captionTargetPageId-1="3" captionTargetPageId-2="4" captionText-0="Figure1.Previous reconstructionsofthe hyoidandbranchial archskeletoninAcanthodes.A,Reis(1896). B,Watson (1937).C, Nelson(1968) withboth alternatereconstructionsof pharyngobranchialorientation.D,Miles(1973).E,Jarvik(1977). F,Gardiner (1984).Terminologyhas beenstandardizedto matchtermsused inthisstudy.Abbreviations:basibr.,basibranchial;basihy.,basihyal;ceratobr.,ceratobranchials;ceratohy.,ceratohyal;epibr.,epibranchial; hyomand.,hyomandibula;hypohy.,hypohyal;interhy.,interhyal;pharbr.,pharyngobranchials;pharhy.,pharyngohyal.Matchingcoloursdenote serially homologouselements.Grey indicatesinferredareas ofcartilage.Blackdashedlines indicatehypotheticalelements.Vertical grey dashedline indicates junctionofdorsal andventralbranchialskeleton.Allreconstructionsareshownas ifspread horizontally,withanterior upwards." captionText-1="Figure 2. The head skeleton of Acanthodes confusus MNHN-F-SAA21, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; occ. pl., occipital plate; pharbr., pharyngobranchials; pq. autop., palatoquadrate autopalatine; pq. metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scler., sclerotic ring.Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton. Scale bar = 20 mm." captionText-2="Figure 3. The head skeleton of Acanthodes confusus MNHN-F-SAA20, visualized using computed tomography. A, in right lateral view. B, in left lateral view.Abbreviations:basibr., basibranchial; basiocc., basioccipital; basisph., basisphenoid; ceratobr., ceratobranchials; ceratohy., ceratohyal; dors. oss., dorsal ossification of neurocranium; epibr., epibranchial; gul. ray., gular rays; hyomand., hyomandibula; hypobr., hypobranchials; L., left; mand. sp., mandibular splint; Meck., Meckel’s cartilage; pharbr., pharyngobranchials; pecsp., pectoral fin spine; pq. autop., palatoquadrate autopalatine; pq.metapt., palatoquadrate metapterygoid; pq. quad., palatoquadrate quadrate; R., right; rak.br., branchial rakers; rak. hy., hyoid rakers; scapcor., scapulocoracoids; scler., sclerotic ring. Colour scheme: blue-greens, elements of visceral endoskeleton with mandibular arch, hyoid arch, hypobranchials, ceratobranchials, epibranchials, and pharyngobranchials coloured independently; dark grey, cranial and pectoral endoskeleton; light grey, elements of the dermal skeleton.Scale bar = 20 mm." figureDoi-0="http://doi.org/10.5281/zenodo.14971767" figureDoi-1="http://doi.org/10.5281/zenodo.14971769" figureDoi-2="http://doi.org/10.5281/zenodo.14971771" httpUri-0="https://zenodo.org/record/14971767/files/figure.png" httpUri-1="https://zenodo.org/record/14971769/files/figure.png" httpUri-2="https://zenodo.org/record/14971771/files/figure.png" pageId="13" pageNumber="14">Figs 1–3</figureCitation> +, +<figureCitation id="13232A048D41645AFB2BF8B1FA81F8DE" box="[1271,1343,1837,1861]" captionStart="Figure 10" captionStartId="11.[115,179,1285,1309]" captionTargetBox="[117,1455,147,1255]" captionTargetId="figure-331@11.[114,1458,144,1258]" captionTargetPageId="11" captionText="Figure 10. The gular rays, hyoid rakers, and branchial rakers of Acanthodes confusus. A, right lateral view of jaws of MNHN-F-SAA21 showing relationship of gular rays and mandibular splint to Meckel’s cartilage.B, right lateral view of jaws of MNHN-F-SAA20 with mandibular splints removed showing gular rays and relationship of hyoid rakers to ceratobranchial. C, left lateral view of MNHN-F-SAA20 showing hyomandibular rakers.D, branchial rakers in articulation with the epibranchial of SAA21.E, branchial rakers in articulation with the ceratobranchial of SAA21. F, hyoid rakers from the ceratohyal of SAA20.G, branchial rakers from the epibranchial of SAA20. Abbreviations: ceratobr., ceratobranchials; epibr., epibranchial; gul. ray., gular rays; rak.br., branchial rakers; rak.hy., hyoid rakers; rak.pl., plinth for branchial raker; I–V, branchial arches I–V.Scale bar = 10 mm except in C where scale bar = 2.5 mm. Note in D and E the shape of the rakers is poorly captured by the scan." figureDoi="http://doi.org/10.5281/zenodo.14972032" httpUri="https://zenodo.org/record/14972032/files/figure.png" pageId="13" pageNumber="14">10A, B</figureCitation> +). They are short narrow elements, some of which having a slight sinusoidal inflection ( +<bibRefCitation id="EF894B708D41645AFC00F8F0FB61F81F" author="Dearden RP & Giles S" box="[988,1247,1900,1924]" pageId="13" pageNumber="14" refId="ref11396" refString="Dearden RP, Giles S. Diverse stem-chondrichthyan oral structures and evidence for an independently acquired acanthodid dentition. Royal Society Open Science 2021; 8: 210822. htps: // doi. org / 10.1098 / rsos. 210822" type="journal volume" year="2021">Dearden and Giles 2021</bibRefCitation> +). They are oriented posteromedially from the ventral margin of each mandible [this can be clearly seen in NHMUK PV P 49973 ( +<bibRefCitation id="EF894B708D41645AFAC9F837FA34F858" author="Miles RS" box="[1301,1418,1963,1987]" pageId="13" pageNumber="14" pagination="63 - 103" refId="ref12464" refString="Miles RS. Relationships of acanthodians. In: Greenwood P, Miles RS, Paterson C (eds), Interrelationships of Fishes. London, UK: Zoological Journal of the Linnean Society, 1973, 63-103." type="book chapter" year="1973">Miles 1973</bibRefCitation> +: pl. 6)], and appear to be absent from the first fifth of the mandible’s length and then be arranged into a row running just beyond the mandible’s posterior margin. In life they would have underlain the gular region. +</paragraph> +<caption id="DF6766098D426459FF5DFA81FC73FACA" ID-DOI="http://doi.org/10.5281/zenodo.14972040" ID-Zenodo-Dep="14972040" httpUri="https://zenodo.org/record/14972040/files/figure.png" pageId="14" pageNumber="15" startId="14.[129,194,1309,1333]" targetBox="[132,1470,146,1278]" targetPageId="14" targetType="figure"> +<paragraph id="8BA736818D426459FF5DFA81FC73FACA" blockId="14.[129,1465,1309,1361]" pageId="14" pageNumber="15"> +<emphasis id="B96CEA938D426459FF5DFA81FF5BFAAE" bold="true" box="[129,229,1309,1333]" pageId="14" pageNumber="15">Figure 12.</emphasis> +Reconstruction of +<taxonomicName id="4C184D028D426459FE46FA81FDECFAAE" authorityName="Heidtke" authorityYear="2011" box="[410,594,1309,1333]" class="Insecta" family="Chrysomelidae" genus="Acanthodes" kingdom="Animalia" order="Coleoptera" pageId="14" pageNumber="15" phylum="Arthropoda" rank="species" species="confusus"> +<emphasis id="B96CEA938D426459FE46FA81FDECFAAE" box="[410,594,1309,1333]" italics="true" pageId="14" pageNumber="15">Acanthodes confusus</emphasis> +</taxonomicName> +based on a composite of the material described here, animated to show mouth opening from left to right. A, in right lateral view. B, in anterior view. C, in dorsal view. D, in ventral view. +</paragraph> +</caption> +<paragraph id="8BA736818D426459FF28F981FD28F9AC" blockId="14.[244,662,1565,1591]" box="[244,662,1565,1591]" pageId="14" pageNumber="15"> +<heading id="D0EF81ED8D426459FF28F981FD28F9AC" allCaps="true" bold="true" box="[244,662,1565,1591]" centered="true" fontSize="11" level="1" pageId="14" pageNumber="15" reason="1"> +<emphasis id="B96CEA938D426459FF28F981FD28F9AC" bold="true" box="[244,662,1565,1591]" pageId="14" pageNumber="15">FUNCTIONAL MORPHOLOGY</emphasis> +</heading> +</paragraph> +<paragraph id="8BA736818D426459FF5DF9D6FA81F928" blockId="14.[129,778,1609,1978]" lastBlockId="14.[825,1475,1409,1715]" pageId="14" pageNumber="15"> +Our 3D reconstruction confirms that the reconstruction of +<bibRefCitation id="EF894B708D426459FD0CF9D5FF75F91A" author="Miles RS" pageId="14" pageNumber="15" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles (1968)</bibRefCitation> +with three points of articulation with the neurocranium is plausible ( +<figureCitation id="13232A048D426459FF36F914FE90F93B" box="[234,302,1672,1696]" captionStart="Figure 12" captionStartId="14.[129,194,1309,1333]" captionTargetBox="[132,1470,146,1278]" captionTargetId="figure-339@14.[129,1473,144,1281]" captionTargetPageId="14" captionText="Figure 12. Reconstruction of Acanthodes confusus based on a composite of the material described here, animated to show mouth opening from left to right.A, in right lateral view.B, in anterior view.C, in dorsal view. D, in ventral view." figureDoi="http://doi.org/10.5281/zenodo.14972040" httpUri="https://zenodo.org/record/14972040/files/figure.png" pageId="14" pageNumber="15">Fig. 12</figureCitation> +) and that the effect of swinging the jaw laterally from these articulatory points is that the palatoquadrates swing laterally as he predicted. The double articulation of the Meckel’s cartilage and the palatoquadrate means that the mandible could only lower vertically relative to the palatoquadrate ( +<bibRefCitation id="EF894B708D426459FD5AF899FD49F886" author="Miles RS" box="[646,759,1797,1821]" pageId="14" pageNumber="15" pagination="109 - 27" refId="ref12416" refString="Miles RS. Jaw articulation and suspension in Acanthodes and their significance. In: Orvig T (ed.), Current Problems of Lower Vertebrate Phylogeny. Proceedings of the Fourth Nobel Symposium. Stockholm: Armqvist and Wiksell, 1968, 109-27." type="book chapter" year="1968">Miles 1968</bibRefCitation> +); as such the relative angles of the left and right mandibles change during jaw opening. This is perhaps the reason for the expanded symphyseal tip on the mandible, to accommodate the connective tissue (ligaments, cartilage) that allows this movement. Another effect of this movement is that the symphysis of the mandible moves anteriorly during jaw opening ( +<figureCitation id="13232A048D426459FAEAFA1DFAC0FA02" box="[1334,1406,1409,1433]" captionStart="Figure 12" captionStartId="14.[129,194,1309,1333]" captionTargetBox="[132,1470,146,1278]" captionTargetId="figure-339@14.[129,1473,144,1281]" captionTargetPageId="14" captionText="Figure 12. Reconstruction of Acanthodes confusus based on a composite of the material described here, animated to show mouth opening from left to right.A, in right lateral view.B, in anterior view.C, in dorsal view. D, in ventral view." figureDoi="http://doi.org/10.5281/zenodo.14972040" httpUri="https://zenodo.org/record/14972040/files/figure.png" pageId="14" pageNumber="15">Fig. 12</figureCitation> +). Our reconstruction suggests the proximal end of the hyomandibula would have been capable of staying close to the jaw articulation even with major abduction of the palatoquadrate. We note that we did not place any constraints on movement beyond the direction of rotation, so this reconstruction should be interpreted as a plausible rather than a maximum gape. Moreover, it is likely that in life the unmineralized cartilaginous midsections of the jaws and hyoid arch would have given them some degree of flexibility, something that is not incorporated into our model. +</paragraph> +</subSubSection> +</treatment> +</document> \ No newline at end of file