Oncelytris esquamatus Li & Cai, 2023

Li, Yan-Da, Huang, Di-Ying & Cai, Chen-Yang, 2023, Oncelytris esquamatus gen. et sp. nov. from mid-Cretaceous amber of northern Myanmar (Coleoptera: Lucanidae), Zootaxa 5284 (1), pp. 192-198 : 196-197

Oncelytris esquamatus Li & Cai sp. nov.

( Figs 1–3 )

Type material. Holotype, NIGP200820 , possibly male (as the emarginate abdominal ventrite 5 is present in only some of the males of the presumably closely-related Holloceratognathus and Mitophyllus ; Holloway 1998).

Etymology. The specific name refers to the absence of scales on its dorsal surface.

Locality and horizon. Amber mine located near Noije Bum Village, Tanai Township, Myitkyina District, Kachin State, Myanmar; unnamed horizon, mid-Cretaceous, Upper Albian to Lower Cenomanian.

Diagnosis. As for the genus.

Description. Body moderately elongate, about 4.0 mm long, 1.7 mm wide; surface without scales.

Head small, shorter than half pronotal length and narrower than half pronotal width; vertex with a pair of not well-separated protuberances. Eyes moderately protuberant; ocular canthus probably absent. Anteocular process moderately developed, weakly pointed laterally (rather than anteriorly). Antennae 10-segmented, with 3-segmented club; antennomere 1 more than three times as long as wide, curved, with almost constant width; antennomeres 4–7 short, each wider than length, successively widened; antennomeres 8–10 moderately lamellate. Mandibles short, not extending beyond labial palps. Maxillary palp 4-segmented; apical palpomere elongate.

Pronotal disc widest basally, slightly wider than elytra combined; surface simple; lateral sides smooth, subparallel in posterior half and converging anteriorly in anterior half; anterior angles slightly produced; posterior angles right-angled. Prosternum with median longitudinal carina; prosternal process narrow, with procoxae subcontiguous.

Elytra 1.6 times as long as combined width, nearly parallel-sided in anterior three-fifths; lateral sides serrulate (at least in posterior half); punctures on surface likely not forming distinct rows; distinct tubercles present in posterior half of elytral surface. Mesocoxal cavities likely narrowly separated. Posterior intercoxal process of metaventrite apically with two acute points. Metacoxae transverse, subcontiguous.

Protibia with one large apical spur; outer protibial edge with one large apical spine, one large postmedial spine, one moderately enlarged premedial spine, and numerous equal-sized small tooth-like spines. Mesotibia with paired apical spurs. Tarsi 5-segmented. Pretarsal claws simple; empodium well developed and bisetose.

Abdomen with five ventrites; ventrite 5 apically emarginate.

Figures

FIGURE 1. General habitus of Oncelytris esquamatus Li & Cai gen. et sp. nov., holotype, NIGP200820, under incident light. A, Dorsal view. B, Ventral view. Scale bars: 1 mm.

FIGURE 2. General habitus of Oncelytris esquamatus Li & Cai gen. et sp. nov., holotype, NIGP200820, under widefield fluorescence. A, Dorsal view. B, Ventral view. Scale bars: 1 mm.

FIGURE 3. Details of Oncelytris esquamatus Li & Cai gen. et sp. nov., holotype, NIGP200820, under confocal microscopy. A, Mouthparts, ventral view. B, Prothorax, ventral view. C, Abdominal base, ventral view. D, Abdominal apex, ventral view. E, Antenna, ventral view. F, Protibia. G, Mid leg. H, Head, dorsal view. I, Elytral apex, dorsal view. Abbreviations: a1–10, antennomeres 1–10; lbp, labial palp; md, mandible; mstb, mesotibia; msts, mesotarsus; mxp, maxillary palp; pc, procoxa; ps, prosternum; ptb, protibia; v1–5, ventrites 1–5. Scale bars: 200 μm.