<mods:affiliationid="956960D926EB38A3C79F86123FD09A37">The Hokkaido University Museum, Hokkaido University, Kita 10 - jo, Nishi 8 - chome, Kita-ku, Sapporo 060 - 0810, Japan</mods:affiliation>
<figureCitationid="6A1334F01DE8FF3E5018D78E800E70AD"captionStart="Figure 1"captionStartId="F1"captionText="Figure 1. General view of amber pieces with lucanid inclusions. A, B. Protonicagus mandibularis sp. nov., holotype, SEHU- 0000121205, showing dorsal (A) or lateral (B) views of the holotype; C. Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206; D. Ceratognathini gen. et sp. indet. 1, SEHU- 0000121207; E. Ceratognathini gen. et sp. indet. 2, SEHU- 0000121208. Scale bars: 3.0 mm (A, B); 1.0 cm (C); 5.0 mm (D, E)."httpUri="https://binary.pensoft.net/fig/868859"pageId="0"pageNumber="211">Figs 1C</figureCitation>
<figureCitationid="FC787F6367350FFDE3319F1EC819497B"captionStart="Figure 6"captionStartId="F6"captionText="Figure 6. General habitus of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Dorsal view; B. Ventral view. Scale bars: 1.0 mm."httpUri="https://binary.pensoft.net/fig/868864"pageId="0"pageNumber="211">, 6</figureCitation>
<figureCitationid="8DFBBC42F2E528C79057D8CCE4DAD23A"captionStart="Figure 7"captionStartId="F7"captionText="Figure 7. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Head with right antenna, dorsal view; B. Head with right antenna, ventral view; C. Enlargement of A; D. Right antenna, ventral view. Abbreviations: a 1 - 10, antennomeres 1 - 10; ey, compound eye; lp 3, labial palpomere 3; md, mandible; mp 3 - 4, maxillary palpomeres 3 - 4; pn, pronotum; pom, preocular margin of head; prt, protarsus. Scale bars: 0.3 mm (A, B); 0.2 mm (C, D)."httpUri="https://binary.pensoft.net/fig/868865"pageId="0"pageNumber="211">, 7</figureCitation>
<figureCitationid="940E51CCAC374E5B09EA9A984F8AEF59"captionStart="Figure 8"captionStartId="F8"captionText="Figure 8. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Pronotum and elytral base, dorsal view; B. Left elytron, dorsolateral view; C. Punctation on elytra, pronotum, and scutellar shield; D. Left lateral margin of pronotum, dorsal view; E. Left elytral margin with elytral shoulder, dorsal view. Abbreviations: epg, epipleural gutter along outer margin of elytron; pg, gutter along outer margin of pronotum; pn, pronotum; sc, scutellar shield. Scale bars: 0.5 mm (A, B, E); 0.3 mm (D)."httpUri="https://binary.pensoft.net/fig/868866"pageId="0"pageNumber="211">, 8</figureCitation>
<figureCitationid="D50E490884C54548A894A24F4392BDF3"captionStart="Figure 9"captionStartId="F9"captionText="Figure 9. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Right protibia and protarsus with arrow showing row of small teeth between large spines along outer edge of protibia, dorsal view; B. Right protibia with arrow showing row of small teeth between large spines along outer edge of protibia, ventral view; C. Left mesotibia and mesotarsus, dorsolateral view; D. Left metatibia and metatarsus, dorsolateral view; E. Left mesotarsus, ventrolateral view; F. Left mesotarsus, dorsolateral view; G. Left metatarsus, dorsolateral view; H. Left metatarsus, ventrolateral view. Abbreviations: as, apical spur; at, apical tooth of protibia; cl, claw; el, elytron epg, epipleural gutter along outer margin of elytron; mds, mid-dorsal spines of meso- and metatibia; mdt 1 - 2, mid-dorsal teeth 1 - 2 of protibia; mst 1 - 5, mesotarsomeres 1 - 5; msti, mesotibia; mtt 1 - 5, metatarsomeres 1 - 5; mtti, metatibia; pt 1 - 5, protarsomeres 1 - 5; pti, protibia; ra, rod of arolium; sa, setae on rod of arolium. Scale bars: 0.3 mm (A, C, D); 0.2 mm (B, E - H)."httpUri="https://binary.pensoft.net/fig/868867"pageId="0"pageNumber="211">, 9</figureCitation>
<figureCitationid="2B02705B803F91CBB227410E62CA3615"captionStart="Figure 10"captionStartId="F10"captionText="Figure 10. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Prosternum with arrow showing subcontiguous procoxae, ventral view; B. Meso- and metathorax, ventral view; C. Abdomen, ventral view; D. Meso- and metathorax with arrow showing discrimen (median longitudinal sulcus) on metaventrite, ventral view. Abbreviations: msf, mesofemur; msv, mesoventrite; mtc, metacoxal cavity; mtf, metafemur; mtti, metatibia; mtv, metaventrite; pf, profemur; ps, prosternum; v 1 - 5, ventrites 1 - 5. Scale bars: 0.3 mm (A); 0.2 mm (B); 0.5 mm (C, D)."httpUri="https://binary.pensoft.net/fig/868868"pageId="0"pageNumber="211">, 10</figureCitation>
(Holloway), by the complete lack of modified scales on the dorsal surface (Figs
<figureCitationid="7A7738244047BFBB40017F138D09AD16"captionStart="Figure 6"captionStartId="F6"captionText="Figure 6. General habitus of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Dorsal view; B. Ventral view. Scale bars: 1.0 mm."httpUri="https://binary.pensoft.net/fig/868864"pageId="0"pageNumber="211">6A</figureCitation>
,
<figureCitationid="5F4B1F45E5F7A20B97765CB54A84D602"captionStart="Figure 8"captionStartId="F8"captionText="Figure 8. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Pronotum and elytral base, dorsal view; B. Left elytron, dorsolateral view; C. Punctation on elytra, pronotum, and scutellar shield; D. Left lateral margin of pronotum, dorsal view; E. Left elytral margin with elytral shoulder, dorsal view. Abbreviations: epg, epipleural gutter along outer margin of elytron; pg, gutter along outer margin of pronotum; pn, pronotum; sc, scutellar shield. Scale bars: 0.5 mm (A, B, E); 0.3 mm (D)."httpUri="https://binary.pensoft.net/fig/868866"pageId="0"pageNumber="211">8</figureCitation>
<taxonomicNameid="8C889EE39328A13F94AB174A7A9835FC"authorityName="Li & Cai"authorityYear="2023"class="Insecta"family="Lucanidae"genus="Oncelytris"higherTaxonomySource="CoL"kingdom="Animalia"lsidName="Oncelytris"order="Coleoptera"pageId="0"pageNumber="211"phylum="Arthropoda"rank="genus">
Li & Cai, 2023 (in Li Y-D et al. 2023) from Kachin amber in the absence of dosal scales (Li Y-D et al. 2023). However, the distinctly tuberculate elytra of
<taxonomicNameid="87EB96A7BE6003A4860DBF03D903FC56"authorityName="Li & Cai"authorityYear="2023"class="Insecta"family="Lucanidae"genus="Oncelytris"higherTaxonomySource="CoL"kingdom="Animalia"lsidName="Oncelytris"order="Coleoptera"pageId="0"pageNumber="211"phylum="Arthropoda"rank="genus">
Body very small, moderately elongate oval, rather flattened; body length well below 3.0 mm. Dorsal surface lacks neither modified scales nor setae (Figs
<figureCitationid="8F87A0290F19C5FA6CDBC110ADD8E615"captionStart="Figure 6"captionStartId="F6"captionText="Figure 6. General habitus of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Dorsal view; B. Ventral view. Scale bars: 1.0 mm."httpUri="https://binary.pensoft.net/fig/868864"pageId="0"pageNumber="211">6A</figureCitation>
,
<figureCitationid="D10A48FE9BE255B85E1C0EAA1E23357D"captionStart="Figure 8"captionStartId="F8"captionText="Figure 8. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Pronotum and elytral base, dorsal view; B. Left elytron, dorsolateral view; C. Punctation on elytra, pronotum, and scutellar shield; D. Left lateral margin of pronotum, dorsal view; E. Left elytral margin with elytral shoulder, dorsal view. Abbreviations: epg, epipleural gutter along outer margin of elytron; pg, gutter along outer margin of pronotum; pn, pronotum; sc, scutellar shield. Scale bars: 0.5 mm (A, B, E); 0.3 mm (D)."httpUri="https://binary.pensoft.net/fig/868866"pageId="0"pageNumber="211">8</figureCitation>
). Head with broadly rounded anterior margin (Fig.
<figureCitationid="56606199E0845A3842243D9417461C2F"captionStart="Figure 7"captionStartId="F7"captionText="Figure 7. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Head with right antenna, dorsal view; B. Head with right antenna, ventral view; C. Enlargement of A; D. Right antenna, ventral view. Abbreviations: a 1 - 10, antennomeres 1 - 10; ey, compound eye; lp 3, labial palpomere 3; md, mandible; mp 3 - 4, maxillary palpomeres 3 - 4; pn, pronotum; pom, preocular margin of head; prt, protarsus. Scale bars: 0.3 mm (A, B); 0.2 mm (C, D)."httpUri="https://binary.pensoft.net/fig/868865"pageId="0"pageNumber="211">7A</figureCitation>
); vertex simple, without a pair of protuberances (Fig.
<figureCitationid="BD99F90718A6DE13558EE172AB81ED93"captionStart="Figure 7"captionStartId="F7"captionText="Figure 7. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Head with right antenna, dorsal view; B. Head with right antenna, ventral view; C. Enlargement of A; D. Right antenna, ventral view. Abbreviations: a 1 - 10, antennomeres 1 - 10; ey, compound eye; lp 3, labial palpomere 3; md, mandible; mp 3 - 4, maxillary palpomeres 3 - 4; pn, pronotum; pom, preocular margin of head; prt, protarsus. Scale bars: 0.3 mm (A, B); 0.2 mm (C, D)."httpUri="https://binary.pensoft.net/fig/868865"pageId="0"pageNumber="211">7A</figureCitation>
). Antenna non-geniculate, with three-segmented, rather strong club (Fig.
<figureCitationid="0099264852B579EF929CA50B16D1E225"captionStart="Figure 7"captionStartId="F7"captionText="Figure 7. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Head with right antenna, dorsal view; B. Head with right antenna, ventral view; C. Enlargement of A; D. Right antenna, ventral view. Abbreviations: a 1 - 10, antennomeres 1 - 10; ey, compound eye; lp 3, labial palpomere 3; md, mandible; mp 3 - 4, maxillary palpomeres 3 - 4; pn, pronotum; pom, preocular margin of head; prt, protarsus. Scale bars: 0.3 mm (A, B); 0.2 mm (C, D)."httpUri="https://binary.pensoft.net/fig/868865"pageId="0"pageNumber="211">7A, B, D</figureCitation>
<figureCitationid="16C3408407145CD4E038BB68D1C69D70"captionStart="Figure 7"captionStartId="F7"captionText="Figure 7. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Head with right antenna, dorsal view; B. Head with right antenna, ventral view; C. Enlargement of A; D. Right antenna, ventral view. Abbreviations: a 1 - 10, antennomeres 1 - 10; ey, compound eye; lp 3, labial palpomere 3; md, mandible; mp 3 - 4, maxillary palpomeres 3 - 4; pn, pronotum; pom, preocular margin of head; prt, protarsus. Scale bars: 0.3 mm (A, B); 0.2 mm (C, D)."httpUri="https://binary.pensoft.net/fig/868865"pageId="0"pageNumber="211">7A-C</figureCitation>
). Pronotum densely strongly punctate (Fig.
<figureCitationid="382DDC8C40BE560038F16A5D14205755"captionStart="Figure 8"captionStartId="F8"captionText="Figure 8. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Pronotum and elytral base, dorsal view; B. Left elytron, dorsolateral view; C. Punctation on elytra, pronotum, and scutellar shield; D. Left lateral margin of pronotum, dorsal view; E. Left elytral margin with elytral shoulder, dorsal view. Abbreviations: epg, epipleural gutter along outer margin of elytron; pg, gutter along outer margin of pronotum; pn, pronotum; sc, scutellar shield. Scale bars: 0.5 mm (A, B, E); 0.3 mm (D)."httpUri="https://binary.pensoft.net/fig/868866"pageId="0"pageNumber="211">8A</figureCitation>
); lateral pronotal margins smooth, with very narrow gutter along whole margins (Fig.
<figureCitationid="C5453CBB00983D3FCA03E22E82977D72"captionStart="Figure 8"captionStartId="F8"captionText="Figure 8. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Pronotum and elytral base, dorsal view; B. Left elytron, dorsolateral view; C. Punctation on elytra, pronotum, and scutellar shield; D. Left lateral margin of pronotum, dorsal view; E. Left elytral margin with elytral shoulder, dorsal view. Abbreviations: epg, epipleural gutter along outer margin of elytron; pg, gutter along outer margin of pronotum; pn, pronotum; sc, scutellar shield. Scale bars: 0.5 mm (A, B, E); 0.3 mm (D)."httpUri="https://binary.pensoft.net/fig/868866"pageId="0"pageNumber="211">8A, D</figureCitation>
). Prosternum biconcaved; prosternal process strongly narrowed and laminate between procoxae, resulting in subcontiguous procoxae (Fig.
<figureCitationid="822BB76CAAF3E0333AB8A1260D6ABE8D"captionStart="Figure 10"captionStartId="F10"captionText="Figure 10. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Prosternum with arrow showing subcontiguous procoxae, ventral view; B. Meso- and metathorax, ventral view; C. Abdomen, ventral view; D. Meso- and metathorax with arrow showing discrimen (median longitudinal sulcus) on metaventrite, ventral view. Abbreviations: msf, mesofemur; msv, mesoventrite; mtc, metacoxal cavity; mtf, metafemur; mtti, metatibia; mtv, metaventrite; pf, profemur; ps, prosternum; v 1 - 5, ventrites 1 - 5. Scale bars: 0.3 mm (A); 0.2 mm (B); 0.5 mm (C, D)."httpUri="https://binary.pensoft.net/fig/868868"pageId="0"pageNumber="211">10A</figureCitation>
). Elytra smooth without distinct tubercles and evident rows of punctures (Fig.
<figureCitationid="C92917B1FD094C1344BBD56B57A2F745"captionStart="Figure 8"captionStartId="F8"captionText="Figure 8. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Pronotum and elytral base, dorsal view; B. Left elytron, dorsolateral view; C. Punctation on elytra, pronotum, and scutellar shield; D. Left lateral margin of pronotum, dorsal view; E. Left elytral margin with elytral shoulder, dorsal view. Abbreviations: epg, epipleural gutter along outer margin of elytron; pg, gutter along outer margin of pronotum; pn, pronotum; sc, scutellar shield. Scale bars: 0.5 mm (A, B, E); 0.3 mm (D)."httpUri="https://binary.pensoft.net/fig/868866"pageId="0"pageNumber="211">8B, C, E</figureCitation>
); lateral margin with narrow epipleural gutter. Outer protibial margin with one large, curved, and slender apical tooth (
<figureCitationid="E941AAF333A9BB0635079652ACE8DF6D"captionStart="Figure 9"captionStartId="F9"captionText="Figure 9. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Right protibia and protarsus with arrow showing row of small teeth between large spines along outer edge of protibia, dorsal view; B. Right protibia with arrow showing row of small teeth between large spines along outer edge of protibia, ventral view; C. Left mesotibia and mesotarsus, dorsolateral view; D. Left metatibia and metatarsus, dorsolateral view; E. Left mesotarsus, ventrolateral view; F. Left mesotarsus, dorsolateral view; G. Left metatarsus, dorsolateral view; H. Left metatarsus, ventrolateral view. Abbreviations: as, apical spur; at, apical tooth of protibia; cl, claw; el, elytron epg, epipleural gutter along outer margin of elytron; mds, mid-dorsal spines of meso- and metatibia; mdt 1 - 2, mid-dorsal teeth 1 - 2 of protibia; mst 1 - 5, mesotarsomeres 1 - 5; msti, mesotibia; mtt 1 - 5, metatarsomeres 1 - 5; mtti, metatibia; pt 1 - 5, protarsomeres 1 - 5; pti, protibia; ra, rod of arolium; sa, setae on rod of arolium. Scale bars: 0.3 mm (A, C, D); 0.2 mm (B, E - H)."httpUri="https://binary.pensoft.net/fig/868867"pageId="0"pageNumber="211">9A, B</figureCitation>
Left elytral margin with elytral shoulder, dorsal view. Abbreviations: epg, epipleural gutter along outer margin of elytron; pg, gutter along outer margin of pronotum; pn, pronotum; sc, scutellar shield. Scale bars: 0.5 mm (
Left metatarsus, ventrolateral view. Abbreviations: as, apical spur; at, apical tooth of protibia; cl, claw; el, elytron epg, epipleural gutter along outer margin of elytron; mds, mid-dorsal spines of meso- and metatibia; mdt1-2, mid-dorsal teeth 1-2 of protibia; mst1-5, mesotarsomeres 1-5; msti, mesotibia; mtt1-5, metatarsomeres 1-5; mtti, metatibia; pt1-5, protarsomeres 1-5; pti, protibia; ra, rod of arolium; sa, setae on rod of arolium. Scale bars: 0.3 mm (
based on the moderately elongate and rather dorsoventrally flattened body shape, 10-segmented antennae with a relatively long antennomere 1 and three-segmented, non-coherent and lamellate apical club, 5-5-5 tarsal formula, protibial structures with characteristic outer teeth, strongly developed bisetose arolium between the pretarsal claws, and five visible abdominal ventrites (e.g.,
<bibRefCitationid="91059A3E96E86DC292BEA112167B449C"author="Holloway, BA"journalOrPublisher="Fauna of New Zealand"pageId="0"pageNumber="211"pagination="1 - 254"refId="B22"refString="Holloway, BA, 2007. Lucanidae (Insecta: Coleoptera). Fauna of New Zealand 61: 1 - 254"title="Lucanidae (Insecta: Coleoptera)."volume="61"year="2007">Holloway 2007</bibRefCitation>
;
<bibRefCitationid="F4A4977F885B459F10390FC346967F90"DOI="https://doi.org/10.1016/j.cretres.2017.06.008"author="Cai, C"journalOrPublisher="Cretaceous Research"pageId="0"pageNumber="211"pagination="109 - 112"refId="B9"refString="Cai, C, Yin, Z, Liu, Y, Huang, D, 2017. Protonicagus tani gen. et sp. nov., the first stag beetles from Upper Cretaceous Burmese amber (Coleoptera: Lucanidae: Aesalinae: Nicagini). Cretaceous Research 78: 109 - 112, DOI: https://doi.org/10.1016/j.cretres.2017.06.008"title="Protonicagus tani gen. et sp. nov., the first stag beetles from Upper Cretaceous Burmese amber (Coleoptera: Lucanidae: Aesalinae: Nicagini)."url="https://doi.org/10.1016/j.cretres.2017.06.008"volume="78"year="2017">Cai et al. 2017</bibRefCitation>
based on its non-geniculate antennae with a three-segmented club, complete eyes (not divided by ocular canthus), small mandibles, non-striate elytra, and strongly narrowed prosternal process with subcontiguous procoxae (e.g.,
<bibRefCitationid="2C3F73B1946DB4C100DD743E3169481D"author="Holloway, BA"journalOrPublisher="Fauna of New Zealand"pageId="0"pageNumber="211"pagination="1 - 254"refId="B22"refString="Holloway, BA, 2007. Lucanidae (Insecta: Coleoptera). Fauna of New Zealand 61: 1 - 254"title="Lucanidae (Insecta: Coleoptera)."volume="61"year="2007">Holloway 2007</bibRefCitation>
by a combination of the following character states (Paulsen 2005): complete absence of evident ground scales (setae) on the dorsum, much longer setae of the arolium, and particularly the features of the outer protibial edge (i.e., apical tooth (
) narrower with acute apex, and the presence of subequal smaller teeth between apical tooth and mid-dorsal tooth 2) (see Fig.
<figureCitationid="C4AD5D53ADB1F07F87D39138E04D5B43"captionStart="Figure 15"captionStartId="F15"captionText="Figure 15. Details of extant species of Aesalinae. A, D, G, K. Nicagus japonicus (tribe Nicagini), male, showing head with left antenna in dorsal view (A), prosternal process (intercoxal process of procoxae) with subcontiguous procoxae in ventral view (D), right protibia in dorsal view (G), or right metatarsus in ventral view (K) based on two specimens; B, E, H, J, L. Ceratognathus cf. niger (tribe Ceratognathini), female, showing head with left antenna in dorsal view (B), prosternal process (intercoxal process of procoxae) with subcontiguous procoxae in ventral view (E), right protibia in dorsal view (H), pronotum and left elytron with scales (J), or left metatarsus in ventral view (L) based on same specimen; C, F, I. Aesalus asiaticus asiaticus (tribe Aesalini), female, showing left antenna in dorsal view (C), prosternal process (intercoxal process of procoxae) with separated procoxae in ventral view (F), or right protibia in dorsal view (I) based on two specimens. Arrows show either smooth (G) or serrate outer edge (H) between mid-dorsal tooth 1 and mid-dorsal tooth 2 of each protibia. Abbreviations: a 1, a 2, a 8 - 10, antennomeres 1, 2, 8 - 10; as, apical spur; at, apical tooth of protibia; cl, claw; ey, compound eye; md, mandible; mdt 1 - 2, mid-dorsal teeth 1 - 2 of protibia; mtt 5, metatarsomere 5; psp, prosternal process between procoxae; ra, rod of arolium; scl, scales on head, pronotum, and elytra; sa, setae on rod of arolium."httpUri="https://binary.pensoft.net/fig/868873"pageId="0"pageNumber="211">15</figureCitation>
for the comparison). Furthermore, the new genus is easily distinguished from
in having a strongly narrowed prosternal process and subcontiguous procoxae (see
<bibRefCitationid="1AD66BEB32D1F002A96E5A423B631895"DOI="https://doi.org/10.11646/zootaxa.2069.1.2"author="Huang, H"journalOrPublisher="Zootaxa"pageId="0"pageNumber="211"pagination="18 - 42"refId="B28"refString="Huang, H, Bi, W-X, Li, L-Z, 2009. Discovery of a second species of Aesalini from continental China, with description of the new species and its third instar larva (Coleoptera: Scarabaeoidea: Lucanidae). Zootaxa 2069 (1): 18 - 42, DOI: https://doi.org/10.11646/zootaxa.2069.1.2"title="Discovery of a second species of Aesalini from continental China, with description of the new species and its third instar larva (Coleoptera: Scarabaeoidea: Lucanidae)."url="https://doi.org/10.11646/zootaxa.2069.1.2"volume="2069"year="2009">Huang et al. 2009</bibRefCitation>
, particularly based on the structures of the protibial edges. In fact, the new genus has the typical pattern of protibial spines. Consequently, it is best placed within
is a small tribe with only four extant genera (Table
<tableCitationid="455EC4A296D1F762DACDB7E35331BE91"captionStart="Table 1"captionStartId="T1"captionText="Table 1. General overview of Aesalinae based on Schoolmeesters (2023), Li Y-D et al. (2023), and this study."httpUri="http://table.plazi.org/id/58609FC0C8857E9C424565BE269CBB23"pageId="0"pageNumber="211"tableUuid="58609FC0C8857E9C424565BE269CBB23">1</tableCitation>
<taxonomicNameid="B334D6AE85B9EF3DC2ECCAA1B793B17C"authorityName="Paulsen & Mondaca"authorityYear="2006"class="Insecta"family="Lucanidae"genus="Hilophyllus"higherTaxonomySource="CoL"kingdom="Animalia"lsidName="Hilophyllus"order="Coleoptera"pageId="0"pageNumber="211"phylum="Arthropoda"rank="genus">
<bibRefCitationid="4902DB7FCC2089B8F6D9A36D37D6EC77"DOI="https://doi.org/10.1080/03014223.1998.9517578"author="Holloway, BA"journalOrPublisher="Journal of the Royal Society of New Zealand"pageId="0"pageNumber="211"pagination="641 - 656"refId="B21"refString="Holloway, BA, 1998. A re-evaluation of the genera of New Zealand aesaline stag beetles (Coleoptera: Lucanidae). Journal of the Royal Society of New Zealand 28 (4): 641 - 656, DOI: https://doi.org/10.1080/03014223.1998.9517578"title="A re-evaluation of the genera of New Zealand aesaline stag beetles (Coleoptera: Lucanidae)."url="https://doi.org/10.1080/03014223.1998.9517578"volume="28"year="1998">Holloway 1998</bibRefCitation>
,
<bibRefCitationid="AD483866C541B512D1CBD54099BBEBBE"author="Holloway, BA"journalOrPublisher="Fauna of New Zealand"pageId="0"pageNumber="211"pagination="1 - 254"refId="B22"refString="Holloway, BA, 2007. Lucanidae (Insecta: Coleoptera). Fauna of New Zealand 61: 1 - 254"title="Lucanidae (Insecta: Coleoptera)."volume="61"year="2007">2007</bibRefCitation>
;
<bibRefCitationid="EFD0282462BE05F0069530106DB05207"DOI="https://doi.org/10.11646/zootaxa.1191.1.1"author="Paulsen, MJ"journalOrPublisher="Zootaxa"pageId="0"pageNumber="211"pagination="1 - 19"refId="B61"refString="Paulsen, MJ, Mondaca, J, 2006. Revision of the South American Ceratognathini (Coleoptera: Lucanidae: Aesalinae) with the description of a new genus and a new species. Zootaxa 1191 (1): 1 - 19, DOI: https://doi.org/10.11646/zootaxa.1191.1.1"title="Revision of the South American Ceratognathini (Coleoptera: Lucanidae: Aesalinae) with the description of a new genus and a new species."url="https://doi.org/10.11646/zootaxa.1191.1.1"volume="1191"year="2006">Paulsen and Mondaca 2006</bibRefCitation>
;
<bibRefCitationid="84C668DF6E3F22E1BD0FE97222CD5215"author="Paulsen, MJ"journalOrPublisher="Insecta Mundi"pageId="0"pageNumber="211"pagination="1 - 25"refId="B59"refString="Paulsen, MJ, 2013. A new genus for the Neotropical species of Aesalus Fabricius, with descriptions of eight new species (Coleoptera: Lucanidae: Aesalinae). Insecta Mundi 0325: 1 - 25"title="A new genus for the Neotropical species of Aesalus Fabricius, with descriptions of eight new species (Coleoptera: Lucanidae: Aesalinae)."volume="0325"year="2013">Paulsen 2013</bibRefCitation>
<taxonomicNameid="B6E40A7C599C233D80AC05D621025222"authorityName="Li & Cai"authorityYear="2023"class="Insecta"family="Lucanidae"genus="Oncelytris"higherTaxonomySource="CoL"kingdom="Animalia"lsidName="Oncelytris"order="Coleoptera"pageId="0"pageNumber="211"phylum="Arthropoda"rank="genus">
from Kachin amber was very recently described (Li Y-D et al. 2023). Although these extant genera share externally similar habitus and body parts, they are mainly identified by the different structures and arrangements of the smaller protibial outer teeth-like spines (
<bibRefCitationid="7C8E685E016A1282646299883089F551"DOI="https://doi.org/10.1080/03014223.1998.9517578"author="Holloway, BA"journalOrPublisher="Journal of the Royal Society of New Zealand"pageId="0"pageNumber="211"pagination="641 - 656"refId="B21"refString="Holloway, BA, 1998. A re-evaluation of the genera of New Zealand aesaline stag beetles (Coleoptera: Lucanidae). Journal of the Royal Society of New Zealand 28 (4): 641 - 656, DOI: https://doi.org/10.1080/03014223.1998.9517578"title="A re-evaluation of the genera of New Zealand aesaline stag beetles (Coleoptera: Lucanidae)."url="https://doi.org/10.1080/03014223.1998.9517578"volume="28"year="1998">Holloway 1998</bibRefCitation>
,
<bibRefCitationid="8D44011328B44341A8550206DB31FD1A"author="Holloway, BA"journalOrPublisher="Fauna of New Zealand"pageId="0"pageNumber="211"pagination="1 - 254"refId="B22"refString="Holloway, BA, 2007. Lucanidae (Insecta: Coleoptera). Fauna of New Zealand 61: 1 - 254"title="Lucanidae (Insecta: Coleoptera)."volume="61"year="2007">2007</bibRefCitation>
;
<bibRefCitationid="9B0473562465D93BCADDDA234329DE44"DOI="https://doi.org/10.11646/zootaxa.1191.1.1"author="Paulsen, MJ"journalOrPublisher="Zootaxa"pageId="0"pageNumber="211"pagination="1 - 19"refId="B61"refString="Paulsen, MJ, Mondaca, J, 2006. Revision of the South American Ceratognathini (Coleoptera: Lucanidae: Aesalinae) with the description of a new genus and a new species. Zootaxa 1191 (1): 1 - 19, DOI: https://doi.org/10.11646/zootaxa.1191.1.1"title="Revision of the South American Ceratognathini (Coleoptera: Lucanidae: Aesalinae) with the description of a new genus and a new species."url="https://doi.org/10.11646/zootaxa.1191.1.1"volume="1191"year="2006">Paulsen and Mondaca 2006</bibRefCitation>
which has numerous variably sized small spines, the new genus has numerous small, equal spines elsewhere along the outer edges of the protibiae (cf.
<bibRefCitationid="27AA0FA473C787A403F2DCE0881B4928"DOI="https://doi.org/10.1080/03014223.1998.9517578"author="Holloway, BA"journalOrPublisher="Journal of the Royal Society of New Zealand"pageId="0"pageNumber="211"pagination="641 - 656"refId="B21"refString="Holloway, BA, 1998. A re-evaluation of the genera of New Zealand aesaline stag beetles (Coleoptera: Lucanidae). Journal of the Royal Society of New Zealand 28 (4): 641 - 656, DOI: https://doi.org/10.1080/03014223.1998.9517578"title="A re-evaluation of the genera of New Zealand aesaline stag beetles (Coleoptera: Lucanidae)."url="https://doi.org/10.1080/03014223.1998.9517578"volume="28"year="1998">Holloway 1998</bibRefCitation>
,
<bibRefCitationid="694B7E64E99421EB92526210F8C1A2C0"author="Holloway, BA"journalOrPublisher="Fauna of New Zealand"pageId="0"pageNumber="211"pagination="1 - 254"refId="B22"refString="Holloway, BA, 2007. Lucanidae (Insecta: Coleoptera). Fauna of New Zealand 61: 1 - 254"title="Lucanidae (Insecta: Coleoptera)."volume="61"year="2007">2007</bibRefCitation>
;
<bibRefCitationid="50AF1C9A59A1F105BFB7E05F010487EF"DOI="https://doi.org/10.11646/zootaxa.1191.1.1"author="Paulsen, MJ"journalOrPublisher="Zootaxa"pageId="0"pageNumber="211"pagination="1 - 19"refId="B61"refString="Paulsen, MJ, Mondaca, J, 2006. Revision of the South American Ceratognathini (Coleoptera: Lucanidae: Aesalinae) with the description of a new genus and a new species. Zootaxa 1191 (1): 1 - 19, DOI: https://doi.org/10.11646/zootaxa.1191.1.1"title="Revision of the South American Ceratognathini (Coleoptera: Lucanidae: Aesalinae) with the description of a new genus and a new species."url="https://doi.org/10.11646/zootaxa.1191.1.1"volume="1191"year="2006">Paulsen and Mondaca 2006</bibRefCitation>
). It is somewhat difficult to compare the new taxon with the three other extant ceratognathinin genera in further detail based on the structures and arrangements of the protibial teeth, but
<figureCitationid="4FBEB4A4777022168081ED78103E2B6F"captionStart="Figure 8"captionStartId="F8"captionText="Figure 8. Details of Cretognathus minutissimus gen. et sp. nov., holotype, SEHU- 0000121206. A. Pronotum and elytral base, dorsal view; B. Left elytron, dorsolateral view; C. Punctation on elytra, pronotum, and scutellar shield; D. Left lateral margin of pronotum, dorsal view; E. Left elytral margin with elytral shoulder, dorsal view. Abbreviations: epg, epipleural gutter along outer margin of elytron; pg, gutter along outer margin of pronotum; pn, pronotum; sc, scutellar shield. Scale bars: 0.5 mm (A, B, E); 0.3 mm (D)."httpUri="https://binary.pensoft.net/fig/868866"pageId="0"pageNumber="211">8</figureCitation>
). This condition has never been observed in any recent ceratognathinin (Fig.
<figureCitationid="38CC3416CE1C63074D96E31FA8956F49"captionStart="Figure 15"captionStartId="F15"captionText="Figure 15. Details of extant species of Aesalinae. A, D, G, K. Nicagus japonicus (tribe Nicagini), male, showing head with left antenna in dorsal view (A), prosternal process (intercoxal process of procoxae) with subcontiguous procoxae in ventral view (D), right protibia in dorsal view (G), or right metatarsus in ventral view (K) based on two specimens; B, E, H, J, L. Ceratognathus cf. niger (tribe Ceratognathini), female, showing head with left antenna in dorsal view (B), prosternal process (intercoxal process of procoxae) with subcontiguous procoxae in ventral view (E), right protibia in dorsal view (H), pronotum and left elytron with scales (J), or left metatarsus in ventral view (L) based on same specimen; C, F, I. Aesalus asiaticus asiaticus (tribe Aesalini), female, showing left antenna in dorsal view (C), prosternal process (intercoxal process of procoxae) with separated procoxae in ventral view (F), or right protibia in dorsal view (I) based on two specimens. Arrows show either smooth (G) or serrate outer edge (H) between mid-dorsal tooth 1 and mid-dorsal tooth 2 of each protibia. Abbreviations: a 1, a 2, a 8 - 10, antennomeres 1, 2, 8 - 10; as, apical spur; at, apical tooth of protibia; cl, claw; ey, compound eye; md, mandible; mdt 1 - 2, mid-dorsal teeth 1 - 2 of protibia; mtt 5, metatarsomere 5; psp, prosternal process between procoxae; ra, rod of arolium; scl, scales on head, pronotum, and elytra; sa, setae on rod of arolium."httpUri="https://binary.pensoft.net/fig/868873"pageId="0"pageNumber="211">15</figureCitation>
<bibRefCitationid="F0D6BC226B19FA88AF30BA212AC0C6D1"author="Bartolozzi, L"journalOrPublisher="Taita Publishers, Hradec Kralove"pageId="0"pageNumber="211"refId="B2"refString="Bartolozzi, L, Zilioli, M, de Keyzer, R, 2017. The Stag Beetles of Australia, New Zealand, New Caledonia and Fiji (Coleoptera: Lucanidae). Taita Publishers, Hradec Kralove"title="The Stag Beetles of Australia, New Zealand, New Caledonia and Fiji (Coleoptera: Lucanidae)."year="2017">Bartolozzi et al. 2017</bibRefCitation>
). Interestingly, however, the other Kachin amber ceratognathinin
<taxonomicNameid="D5DFC5114DB655BAF4B64F26486F9B04"authorityName="Li & Cai"authorityYear="2023"class="Insecta"family="Lucanidae"genus="Oncelytris"higherTaxonomySource="CoL"kingdom="Animalia"lsidName="Oncelytris"order="Coleoptera"pageId="0"pageNumber="211"phylum="Arthropoda"rank="genus">
<bibRefCitationid="F279AF32A6E6202ABF9B425FFE46540A"DOI="https://doi.org/10.1016/j.cretres.2022.105208"author="Wu, L"journalOrPublisher="Insecta Mundi"pageId="0"pageNumber="211"refId="B87"refString="Wu, L, Tang, H, Peng, L, Zhang, H, Tong, H, 2022. The first representatives of Lucaninae from mid-Cretaceous Burmese amber based on two new species of Anisoodontus gen. nov. (Coleoptera: Scarabaeoidea: Lucanidae). Cretaceous Research 135: e105208. https://doi.org/10.1016/j.cretres.2022.105208"title="The first representatives of Lucaninae from mid-Cretaceous Burmese amber based on two new species of Anisoodontus gen. nov. (Coleoptera: Scarabaeoidea: Lucanidae). Cretaceous Research 135: e 105208."url="https://doi.org/10.1016/j.cretres.2022.105208"year="2022">Wu et al. 2022</bibRefCitation>
), non-geniculate antennae, and short, inconspicuous mandibles (cf.
<bibRefCitationid="D577A5697965DAFF19AAB3A3F1E6406C"DOI="https://doi.org/10.1016/j.cretres.2022.105208"author="Wu, L"journalOrPublisher="Insecta Mundi"pageId="0"pageNumber="211"refId="B87"refString="Wu, L, Tang, H, Peng, L, Zhang, H, Tong, H, 2022. The first representatives of Lucaninae from mid-Cretaceous Burmese amber based on two new species of Anisoodontus gen. nov. (Coleoptera: Scarabaeoidea: Lucanidae). Cretaceous Research 135: e105208. https://doi.org/10.1016/j.cretres.2022.105208"title="The first representatives of Lucaninae from mid-Cretaceous Burmese amber based on two new species of Anisoodontus gen. nov. (Coleoptera: Scarabaeoidea: Lucanidae). Cretaceous Research 135: e 105208."url="https://doi.org/10.1016/j.cretres.2022.105208"year="2022">Wu et al. 2022</bibRefCitation>
); from
<taxonomicNameid="0E28920D97DAC700B110C1D790FF5B2B"authorityName="Cai, Yin, Liu & Huang"authorityYear="2017"class="Insecta"family="Lucanidae"genus="Protonicagus"higherTaxonomySource="CoL"kingdom="Animalia"lsidName="Protonicagus"order="Hymenoptera"pageId="0"pageNumber="211"phylum="Arthropoda"rank="genus">
) by non-crenulate pronotal lateral margins without a row of setae, larger head with non-enlarged preocular margin of the eyes, absence of any dorsal scales or ground setae, and presence of small subcontiguous teeth-like spines between the apical tooth and mid-dorsal tooth 2 (cf.
<bibRefCitationid="AC5985917C248207C3254B843C552C58"DOI="https://doi.org/10.1016/j.cretres.2017.06.008"author="Cai, C"journalOrPublisher="Cretaceous Research"pageId="0"pageNumber="211"pagination="109 - 112"refId="B9"refString="Cai, C, Yin, Z, Liu, Y, Huang, D, 2017. Protonicagus tani gen. et sp. nov., the first stag beetles from Upper Cretaceous Burmese amber (Coleoptera: Lucanidae: Aesalinae: Nicagini). Cretaceous Research 78: 109 - 112, DOI: https://doi.org/10.1016/j.cretres.2017.06.008"title="Protonicagus tani gen. et sp. nov., the first stag beetles from Upper Cretaceous Burmese amber (Coleoptera: Lucanidae: Aesalinae: Nicagini)."url="https://doi.org/10.1016/j.cretres.2017.06.008"volume="78"year="2017">Cai et al. 2017</bibRefCitation>
; this study); from
<taxonomicNameid="2A07744B461DA5B01FD0E7793B1F075C"authorityName="Bai, Zhang & Qiu"authorityYear="2017"class="Insecta"family="Lucanidae"genus="Electraesalopsis"higherTaxonomySource="CoL"kingdom="Animalia"lsidName="Electraesalopsis"order="Coleoptera"pageId="0"pageNumber="211"phylum="Arthropoda"rank="genus">
<bibRefCitationid="661F97FAAC5D35EAFD3781DF900851E7"DOI="https://doi.org/10.11865/zs.201717"author="Qiu, T"journalOrPublisher="Zoological Systematics"pageId="0"pageNumber="211"pagination="390 - 394"refId="B66"refString="Qiu, T, Lu, Y, Zhang, W, Wang, S, Yang, Y, Bai, M, 2017. Electraesalopsis beuteli gen. & sp. nov., the first lucanid beetle from the Cretaceous Burmese amber (Coleoptera: Scarabaeoidea). Zoological Systematics 42 (3): 390 - 394, DOI: https://doi.org/10.11865/zs.201717"title="Electraesalopsis beuteli gen. & sp. nov., the first lucanid beetle from the Cretaceous Burmese amber (Coleoptera: Scarabaeoidea)."url="https://doi.org/10.11865/zs.201717"volume="42"year="2017">Qiu et al. 2017</bibRefCitation>
) by the presence of much shorter, unmodified mandibles, much strongly developed antennal club, broadly rounded clypeal margin, distinctly shorter metatarsi, smaller body (5.6 mm, including mandibles, in
<taxonomicNameid="E862C866543738BF377A28AFC8558382"authorityName="Bai, Zhang & Qiu"authorityYear="2017"class="Insecta"family="Lucanidae"genus="Electraesalopsis"higherTaxonomySource="CoL"kingdom="Animalia"lsidName="Electraesalopsis"order="Coleoptera"pageId="0"pageNumber="211"phylum="Arthropoda"rank="genus">
), and structures of the protibiae with their strongly developed apical teeth (cf.
<bibRefCitationid="C89A6832F9B3BF817A8FDAD704BEAE70"DOI="https://doi.org/10.11865/zs.201717"author="Qiu, T"journalOrPublisher="Zoological Systematics"pageId="0"pageNumber="211"pagination="390 - 394"refId="B66"refString="Qiu, T, Lu, Y, Zhang, W, Wang, S, Yang, Y, Bai, M, 2017. Electraesalopsis beuteli gen. & sp. nov., the first lucanid beetle from the Cretaceous Burmese amber (Coleoptera: Scarabaeoidea). Zoological Systematics 42 (3): 390 - 394, DOI: https://doi.org/10.11865/zs.201717"title="Electraesalopsis beuteli gen. & sp. nov., the first lucanid beetle from the Cretaceous Burmese amber (Coleoptera: Scarabaeoidea)."url="https://doi.org/10.11865/zs.201717"volume="42"year="2017">Qiu et al. 2017</bibRefCitation>
<taxonomicNameid="954E83688A702855E60A735F0446600E"authorityName="Li & Cai"authorityYear="2023"class="Insecta"family="Lucanidae"genus="Oncelytris"higherTaxonomySource="CoL"kingdom="Animalia"lsidName="Oncelytris"order="Coleoptera"pageId="0"pageNumber="211"phylum="Arthropoda"rank="genus">
by the lack of a pair of not well-separated protuberances and tuberculate elytra. Consequently, the new genus can easily be distinguished from any fossil genera described from Kachin amber. Furthermore,
gen. nov. is separated from the two undetermined provisional ceratognathins reported below, mainly by the shape of the protibiae and antennae (the latter can be applied only for
