Vetuprostomis gaoi Li & Cai, 2022

Li, Yan-Da, Hsiao, Yun, Huang, Di-Ying & Cai, Chen-Yang, 2022, New species of Vetuprostomis from mid-Cretaceous amber of northern Myanmar (Coleoptera: Tenebrionoidea: Prostomidae), Zootaxa 5125 (5), pp. 563-574 : 569-572

Vetuprostomis gaoi Li & Cai sp. nov.

( Figs 5–7 )

Material. Holotype, NIGP177908 .

Etymology. The species is named after Mr. Yu-He Gao, who kindly donated many fossils for our research.

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. Lateral sides of clypeus subparallel in anterior half ( Fig. 7H ). Left mandible with three apical teeth and two narrowly separated and basally strongly jointed teeth on incisor edge ( Fig. 7H ). Penultimate maxillary palpomere about as long as apical one ( Fig. 7A ). Jugal processes asymmetrical, comparatively short; right process longer than left one; inner sides with a tooth ( Fig. 7A ). Median groove of pronotum weakly developed, shorter than half length of pronotum ( Fig. 5 ). Anterior angles of pronotum not pointed ( Fig. 5 ).

Description. Body elongate and flattened, about 4.7 mm long, 1.0 mm wide (maximum width across head).

Head prognathous, constricted posteriorly, with distinct neck region. Temples ( Fig. 7B ) distinctly projected posterolaterally. Eyes small, round and finely facetted, without interfacetal setae. Antennal insertions slightly concealed from above; subantennal grooves absent. Frontoclypeal suture not clearly discerned. Clypeus ( Fig. 7H ) with lateral sides subparallel (or weakly diverging) in anterior portion; anterior margin truncate. Labrum ( Fig. 7H ) narrowed anteriorly, apically truncate, with numerous elongate setae. Antennae 11-segmented, moniliform, with weak, 3-segmented club. Mandibles ( Fig. 7H ) tridentate apically; left mandible with two narrowly separated and basally strongly jointed teeth on incisor edge; right mandible with one blunt tooth on incisor edge. Maxillary palps ( Fig. 7A ) probably 4-segmented; palpomere 1 short; palpomere 2 elongate; palpomere 3 longer than wide, distinctly longer than half length of apical one. Labial palps 3-segmented; palpomere 1 short; palpomeres 2 and 3 elongate. Ligula ( Fig. 7A ) biemarginate apically. Mentum strongly transverse. Jugal processes ( Fig. 7A ) asymmetrical; inner sides with a tooth; right process longer than left one, strongly constricted above tooth; left process weakly constricted above tooth.

Pronotal disc longer than wide; anterior angles not pointed; lateral sides subparallel; median groove not clearly discerned. Prosternal process ( Fig. 7C ) wide, expanding beyond procoxae and meeting broad postcoxal projections, apically truncate. Procoxal cavities ( Fig. 7C ) circular, widely separated. Elytra about 2.6 times as long as width combined; surface with longitudinal carinae. Mesoventrite ( Fig. 7E ) relatively narrow. Mesocoxal cavities ( Fig. 7E ) moderately separated. Exposed portion of metanepisternum elongate and narrow. Metaventral discrimen ( Fig. 7F ) short, only visible near the posterior end. Metacoxae ( Fig. 7F ) not meeting elytra laterally.

Legs ( Fig. 7D,F ) short. Femora distally with groove on inner side. Tibiae shorter than femora, widened apically with spinose outer apical angle; spurs large and stout, paired on all legs. Tarsi 4-4-4; tarsomeres simple, without ventral lobes. Pretarsal claws simple.

Abdomen ( Fig. 7G ) with five ventrites. Ratio of ventrite lengths along middle: 2.4: 1.8: 1.4: 1.0: 1.4. Ventrite 5 apically broadly rounded.

Figures

FIGURE 5. General habitus of Vetuprostomis gaoi Li & Cai sp. nov., holotype, NIGP177908, under incident light. A, Dorsal view. B, Ventral view. Scale bars: 1.5 mm.

FIGURE 6. Vetuprostomis gaoi Li & Cai sp. nov., holotype, NIGP177908, under widefield fluorescence. A, Dorsal view. B, Ventral view. Abbreviations: an, antenna; el, elytron; jp, jugular process; md, mandible; msf, mesofemur; mstb, mesotibia; msts, mesotarsus; msv, mesoventrite; mtf, metafemur; mttb, metatibia; mtts, metatarsus; mtv, metaventrite; mxp, maxillary palp; pf, profemur; pn, pronotum; ps, prosternum; ptb, protibia; pts, protarsus; v1–5, ventrites 1–5. Scale bars: 1 mm.

FIGURE 7. Vetuprostomis gaoi Li & Cai sp. nov., holotype, NIGP177908, under confocal microscopy. A, Mouthparts, ventral view. B, Temporal projection (arrowhead), ventral view. C, Prothorax, ventral view. D, Fore leg. E, Mesothorax, dorsal view. F, Hind leg. G, Abdomen, ventral view. E, Mouthparts, dorsal view. F, Elytral apex, dorsal view. Abbreviations: cl, clypeus; el, elytron; ey, compound eye; jp, jugular process; lb, labrum; lbp, labial palp; md, mandible; msv, mesoventrite; mt, mentum; mtf, metafemur; mttb, metatibia; mtts, metatarsus; mxp, maxillary palp; pc, procoxa; pf, profemur; ps, prosternum; ptb, protibia; ptc, protrochanter; pts, protarsus; v1–5, ventrites 1–5. Scale bars: 200 μm.