<documentid="10B09D496CB46D8B11FBE064A876E1A0"ID-CLB-Dataset="305499"ID-DOI="10.5852/cr-palevol2024v23a17"ID-GBIF-Dataset="8fc26efa-4ffb-4993-bf58-7fb38916b793"ID-ISSN="1777-571X"ID-Zenodo-Dep="11387624"ID-ZooBank="urn:lsid:zoobank.org:pub:C0E27E25-6719-40FD-A2B8-829B484D6C13"IM.bibliography_approvedBy="valdenar"IM.illustrations_approvedBy="felipe"IM.materialsCitations_approvedBy="valdenar"IM.metadata_approvedBy="valdenar"IM.taxonomicNames_approvedBy="valdenar"IM.treatmentCitations_approvedBy="felipe"IM.treatments_approvedBy="valdenar"checkinTime="1732639101882"checkinUser="felipe"docAuthor="Blake, Daniel B. & Lefebvre, Bertrand"docDate="2024"docId="267CF001793BFFF2A777FE059DE3F84D"docLanguage="en"docName="CRPalevol.23.17.217-239.pdf"docOrigin="Comptes Rendus Palevol 23 (17)"docSource="http://dx.doi.org/10.5852/cr-palevol2024v23a17"docStyle="DocumentStyle:DACF86F01658A8850E13A63D98C287FD.1:CRPalevol.2020-.journal_article"docStyleId="DACF86F01658A8850E13A63D98C287FD"docStyleName="CRPalevol.2020-.journal_article"docStyleVersion="1"docTitle="Petraster rigidus"docType="treatment"docVersion="6"lastPageNumber="222"masterDocId="DA458879793CFFF5A662FFF29C26FFA1"masterDocTitle="Ordovician Petraster Billings, 1858 (Asteroidea: Echinodermata) and early asteroid skeletal differentiation"masterLastPageNumber="239"masterPageNumber="217"pageNumber="222"updateTime="1734637752356"updateUser="ExternalLinkService"zenodo-license-document="CC-BY-4.0">
<mods:titleid="E698B757868CA3159159D63A8026662D">Ordovician Petraster Billings, 1858 (Asteroidea: Echinodermata) and early asteroid skeletal differentiation</mods:title>
<mods:namePartid="6D02B3D11419965994BD8CF2ED754CCF">Blake, Daniel B.</mods:namePart>
<mods:affiliationid="B57E28B2ACBB2B7A6759B1BCD2A10762">Departement of Earth Sciences and Environmental Change, University of Illinois, 3081 NHB, 1301 West Green Street, 61801 Urbana, IL (United States)</mods:affiliation>
<bibRefCitationid="CA443CE6793BFFF2A7B7FE059E49FDB3"author="BILLINGS E."box="[469,623,503,530]"pageId="7"pageNumber="222"pagination="256 - 345"refId="ref14229"refString="BILLINGS E. 1857. - New species of fossils from the Silurian rocks of Canada. Geological Survey of Canada, Report of Progress for 1853 - 1856: 256 - 345."type="book chapter"year="1857">Billings, 1857</bibRefCitation>
<figureCitationid="36EE5D92793BFFF2A7FCFDE59DC9FD90"box="[414,495,535,561]"captionStart="FIG"captionStartId="6.[134,144,1411,1428]"captionTargetBox="[132,1455,215,1367]"captionTargetId="figure-425@6.[698,1267,746,1280]"captionTargetPageId="6"captionText="FIG. 1. — Problematic species of Petraster Billings, 1858: A1, A2, Petraster rigidus (Billings, 1858), generic type species;Trenton Limestone, Late Ordovician (Sandbian-early Katian), 45°026’37”N, 75°026’9”W, Ottawa, Canada; original specimen, holotype GSC 1401; A1, specimen remnant, surfaces of disk ossicles to left appearing largely unaltered, those to right more abraded thereby obscuring original surface appearances; A2, specimen wetted, axillary of interbrachium to left is triangular, possible second axillary (lower left arrow) immediately distal of MAO pair at base of single actinal series. Ossicles to right interbrachium altered but appearance unlike those to left interbrachium, significance of diagenetic alteration uncertain; upper two arrows mark position of inferomarginal near apparent termini of actinal series. Ossicles edging adaxial at one arm margin (arrow to lower right) appearing somewhat enlarged as compared to traces at other arm margins, the nature of the skeleton aboral to inferomarginals obscure; B1-B3, Petraster? ramseyensis (Hicks, 1873); Early Ordovician (early Arenig); Ramsey Island, Wales; latex casts; B1, B2, NHM E13707 = Manchester L10038, abactinals are differentiated, carinals (B1, arrow) bordered by small rectangular adradials, two marginal series; aboral disk largely lost, madreporite? (B2, arrow) remains; B3, NHM E13703 = Manchester L10036a distended specimen in oral aspect, ambulacra variously flattened, inferomarginals, adaxials, and axials dominate; possible axillary (arrow). Scale bars: A1, A2, B2, B3, 5 mm; B1, 3 mm."figureDoi="http://doi.org/10.5281/zenodo.14531862"httpUri="https://zenodo.org/record/14531862/files/figure.png"pageId="7"pageNumber="222">Fig. 1A</figureCitation>
<bibRefCitationid="CA443CE6793BFFF2A75AFDA29DD0FDC9"author="BILLINGS E."box="[312,502,591,616]"pageId="7"pageNumber="222"pagination="256 - 345"refId="ref14229"refString="BILLINGS E. 1857. - New species of fossils from the Silurian rocks of Canada. Geological Survey of Canada, Report of Progress for 1853 - 1856: 256 - 345."type="book chapter"year="1857">Billings, 1857: 291</bibRefCitation>
<bibRefCitationid="CA443CE6793BFFF2A74FFD8D9DF1FD36"author="BILLINGS E."box="[301,471,639,663]"pageId="7"pageNumber="222"pagination="75 - 85"refId="ref14263"refString="BILLINGS E. 1858. - On the Asteriadae of the Lower Silurian rocks of Canada. Geological Survey of Canada, Separate Report 425: 75 - 85. https: // doi. org / 10.4095 / 222579"type="book chapter"year="1858">Billings 1858: 80</bibRefCitation>
</treatmentCitation>
, pl. 10, fig. 3. —
<treatmentCitationid="2F746706793BFFF2A419FD8D9C86FD13"author="SPENCER W. K."page="40"pageId="7"pageNumber="222"year="1914">
<bibRefCitationid="CA443CE6793BFFF2A419FD8D9C86FD13"author="SPENCER W. K."pageId="7"pageNumber="222"pagination="1 - 56"refId="ref17832"refString="SPENCER W. K. 1914. - A Monograph of the British Palaeozoic Asterozoa. Part I. Monographs of the Palaeontographical Society 67 (328): 1 - 56. https: // doi. org / 10.1080 / 02693445.1914.12035566"type="journal article"year="1914">Spencer 1914: 40</bibRefCitation>
<bibRefCitationid="CA443CE6793BFFF2A6A6FD689DA8FD13"author="SCHUCHERT C."box="[196,398,666,690]"pageId="7"pageNumber="222"pagination="1 - 311"refId="ref17666"refString="SCHUCHERT C. 1915. - Revision of Paleozoic Stelleroidea with special reference to North American Asteroidea. Bulletin of the U. S. National Museum 88: 1 - 311."type="journal article"year="1915">Schuchert 1915: 141</bibRefCitation>
</treatmentCitation>
, pl. 27, fig. 5. —
<treatmentCitationid="2F746706793BFFF2A44DFD689EC0FD13"author="SPENCER W. K."box="[559,742,666,690]"page="359"pageId="7"pageNumber="222"year="1927">
<bibRefCitationid="CA443CE6793BFFF2A44DFD689EC0FD13"author="SPENCER W. K."box="[559,742,666,690]"pageId="7"pageNumber="222"pagination="325 - 388"refId="ref18053"refString="SPENCER W. K. 1927. - A Monograph of the British Palaeozoic Asterozoa. Part VII. Monographs of the Palaeontographical Society 79 (366): 325 - 388. https: // doi. org / 10.1080 / 026934 45.1927. 12035601"type="journal article"year="1927">Spencer 1927: 359</bibRefCitation>
</treatmentCitation>
. —
<treatmentCitationid="2F746706793BFFF2A6E1FD469DBFFD6D"author="SPENCER W. K. & WRIGHT C. W."box="[131,409,692,716]"page="43"pageId="7"pageNumber="222"year="1966">
<bibRefCitationid="CA443CE6793BFFF2A6E1FD469DBFFD6D"author="SPENCER W. K. & WRIGHT C. W."box="[131,409,692,716]"pageId="7"pageNumber="222"refId="ref18139"refString="SPENCER W. K. & WRIGHT C. W. 1966. - Asterozoans, in MOORE R. C. (ed.), Treatise on Invertebrate Paleontology, Part U, Echinodermata 3. Vol. 1. The Geological Society of America and The University of Kansas, Lawrence: U 4 - U 107."type="journal volume"year="1966">Spencer & Wright 1966: 43</bibRefCitation>
</treatmentCitation>
. —
<treatmentCitationid="2F746706793BFFF2A7A0FD469E7FFD6D"author="BLAKE D. B."box="[450,601,692,716]"page="28"pageId="7"pageNumber="222"year="2018">
<bibRefCitationid="CA443CE6793BFFF2A7A0FD469E7FFD6D"author="BLAKE D. B."box="[450,601,692,716]"pageId="7"pageNumber="222"pagination="1 - 96"refId="ref14512"refString="BLAKE D. B. 2018. - A history of the Paleozoic Asteroidea (Echinodermata). Bulletins of American Paleontology 394: 1 - 96."type="journal article"year="2018">Blake 2018: 28</bibRefCitation>
<bibRefCitationid="CA443CE6793BFFF2A73AFD169DD4FD5D"author="HALL J."box="[344,498,740,764]"pageId="7"pageNumber="222"pagination="282 - 303"refId="ref16112"refString="HALL J. 1868. - Note on the genus Palaeaster and other fossil starfishes. Annual Report of the Regents of the University of the State of New York on the State Cabinet of Natural History and the Historical and Antiquarian collection annexed thereto 20: 282 - 303."type="journal article"year="1868">Hall 1868: 294</bibRefCitation>
<specimenCodeid="FE73E96C793BFFF2A47FFCE19EACFC8A"box="[541,650,787,811]"collectionCode="GSC"country="Canada"httpUri="http://grbio.org/cool/52gs-z31g"name="Geological Survey of Canada"pageId="7"pageNumber="222">GSC 1401</specimenCode>
<bibRefCitationid="CA443CE6793BFFF2A6AFFCDC9D7AFCE7"author="BILLINGS E."box="[205,348,814,838]"pageId="7"pageNumber="222"pagination="256 - 345"refId="ref14229"refString="BILLINGS E. 1857. - New species of fossils from the Silurian rocks of Canada. Geological Survey of Canada, Report of Progress for 1853 - 1856: 256 - 345."type="book chapter"year="1857">Billings, 1857</bibRefCitation>
</taxonomicName>
; an incomplete, weathered specimen, only the oral surface exposed.
thought to exhibit two axillaries, one triangular and reaching the lateral margin, the second embedded; a single series of robust actinals well developed, it limited to disk.
<taxonomicNameid="69D53A94793BFFF2A6E6FB879CFAFB2F"baseAuthorityName="Spencer & Wright"baseAuthorityYear="1966"box="[132,220,1141,1166]"class="Asteroidea"family="Palasterinidae"genus="Petraster"kingdom="Animalia"order="Euaxosida"pageId="7"pageNumber="222"phylum="Echinodermata"rank="genus">
. Inferomarginals robust, rectangular, relatively wide on disk, more nearly equidimensional on arm; some ossicles appear to bear accessory pustules.Two available interbrachia of the
differ, one with a well-defined triangular axillary and a possible second small axillary enclosed on disk adjacent to MAO. Actinals on disk in well-defined single series. Second interbrachium, ossicular arrangement poorly preserved and ill-defined. Axillary, actinals not clearly defined. Adaxials rectangular, transversely elongate.
species is similar to other species assigned to the genus based on overall form and the limited data available on oral-surface expression, including inferomarginal shape, disk configuration, axillary, and actinal expressions. The diagnosis focuses on expression of the better-preserved interbrachium. The skeleton aboral to inferomarginals is almost unknown, the madreporite, axials, and MAO unknown. Posited presence of two axillaries serves to separate
, with specificities of expression differing between these two. The more lateral axillary is similar to the single axillary of
<taxonomicNameid="69D53A94793BFFF2A6E4F8A19D28F8CD"authorityName="Blake, Guensburg & Lefebvre"authorityYear="2016"box="[134,270,1875,1900]"class="Asteroidea"family="Palasterinidae"genus="Petraster"kingdom="Animalia"order="Euaxosida"pageId="7"pageNumber="222"phylum="Echinodermata"rank="species"species="crozonensis">
, the adjacent inferomarginals differ in outline. A few small elongate ossicles lateral to the inferomarginals of one arm appear unlike expressions among other species, although these ossicles as preserved appear dissimilar from traces exposed on other arms.
