Eucinetus zhenhuai Li & Cai, 2024

Li, Yan-Da, Engel, Michael S., Huang, Di-Ying & Cai, Chen-Yang, 2024, Three new species of the extant genus Eucinetus from mid-Cretaceous amber of northern Myanmar (Coleoptera: Eucinetidae), Zootaxa 5492 (2), pp. 214-230 : 223-224

Eucinetus zhenhuai Li & Cai sp. nov.

( Figs 9–12 )

Material. Holotype, NIGP203941 , female.

Etymology. The species is named after the coleopterist Dr. Zhenhua Liu.

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. Labrum weakly biemarginate ( Fig. 11A ). Apical maxillary palpomere asymmetrical ( Fig. 11A ). Basal antennomeres relatively elongate (especially antennomeres 3–5); antennomere 3 about 0.85 times as long as 4 ( Fig. 11A ); antennomere 11 about 2.1 times as long as wide ( Fig. 11B ). Scutellar shield acute at apex ( Fig. 11 GA). Elytra about 2.1 times as long as combined width. Hind wings present. Metanepisternum at least twice as long as wide. Meso- and metatibiae with relatively dense spines along outer edge ( Fig. 11D,E ). Mesotibial spurs large; both distinctly stouter than spines along apical fringe of mesotibia ( Fig. 11D ). Metatibial spurs unequal ( Fig. 11D ).

Description. Body fusiform and slender, about 2.5 mm long, 1.0 mm wide; surface with fine short setae.

Head deflexed against ventral side of prothorax; entirely concealed from above by pronotum. Compound eyes weakly emarginate anteriorly, with interfacetal setae. Antennae 11-segmented, filiform; basal antennomeres distinctly elongate (especially antennomeres 2–5); distal antennomeres somewhat shortened; antennomere 3 about 0.85 times as long as 4; antennomere 11 about 2.1 times as long as wide. Frontoclypeal suture straight anteriorly and with distinct anterolateral angles. Labrum transverse, apically very weakly biemarginate. Mouthparts non-suctorial. Apical maxillary palpomere asymmetrical.

Prothorax widest at base. Lateral pronotal carinae complete, simple. Pronotal disc simple. Procoxae obliquely oriented, well-projecting, narrowly separated. Scutellar shield triangular, acute at apex. Elytra about 2.1 times as long as combined width; transversely strigulate; sutural stria present; epipleuron narrow, incomplete. Hind wings present. Metaventral posterior process without externally discernable discrimen. Metanepisternum at least twice as long as wide. Metacoxae contiguous; metacoxal plates well-developed and greatly enlarged.

Mid and hind legs with fringe of spines at apices of tibiae and tarsomeres; fore legs without apical fringes of spines. Meso- and metatibiae with relatively dense spines along outer edge. Mesotibial spurs large; both distinctly stouter than spines along apical fringe of mesotibia. Metatibial spurs unequal. Tarsi 5-5-5, simple. Meso- and metapretarsal claws with accessory lobes ( Fig. 11F ).

Abdomen with five ventrites. Ovipositor simple, with gonocoxites and gonostyli ( Fig. 11H,I ).

Figures

FIGURE 9. General habitus of Eucinetus zhenhuai Li & Cai sp. nov., holotype, NIGP203941, under incident light. A, Dorsal view. B, Ventral view. Scale bars: 500 μm.

FIGURE 10. General habitus of Eucinetus zhenhuai Li & Cai sp. nov., holotype, NIGP203941, under confocal microscopy. A, Dorsal view. B, Ventral view. Scale bars: 500 μm.

FIGURE 11. Details of Eucinetus zhenhuai Li & Cai sp. nov., holotype, NIGP203941, under confocal microscopy. A, Head, dorsal view. B, Antenna. C, Fore legs. D, Mid leg. E, Hind legs. F, Hind legs. G, Scutellar shield, dorsal view. H, Abdominal apex, dorsal view. I, Abdominal apex, ventral view. Abbreviations: a2–11, antennomeres 2–11; gc, gonocoxite; gs, gonostylus; lb, labrum; mstb, mesotibia; mttb, metatibia; mtts, metatarsus; mxp, maxillary palp; pts, protarsus; sc, scutellar shield. Scale bars: 100 μm.

FIGURE 12. X-ray microtomographic reconstruction of Eucinetus zhenhuai Li & Cai sp. nov., holotype, NIGP203941. A, Dorsal view. B, Ventral view. C, Lateral view. Scale bar: 500 μm.