Homalenchodes jarzembowskii Li, Hsiao, Yoshitomi & Cai, 2022

LI, YAN-DA, HSIAO, YUN, YOSHITOMI, HIROYUKI, HUANG, DI-YING & CAI, CHEN-YANG, 2022, Homalenchodes, a new genus of Serropalpini from mid-Cretaceous amber of northern Myanmar (Coleoptera: Tenebrionoidea: Melandryidae), Palaeoentomology 5 (3), pp. 246-253 : 247-248

Homalenchodes jarzembowskii Li, Hsiao, Yoshitomi & Cai sp. nov.

( Figs 1–3 )

Material. Holotype, NIGP180475 .

Etymology. The species is named in honor of the palaeoentomologist Dr Edmund A. Jarzembowski.

Diagnosis. As for the genus.

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

Description. Body strongly elongate, about 2.7 mm long, 0.6 mm wide. Surface finely punctate and with fine hairs.

Head well exposed from above. Compound eyes lateral, large, emarginate in front of antennal insertions, coarsely facetted on the surface, without interfacetal setae. Antennal insertions fully concealed from above, widely separated. Subantennal grooves absent. Antennae 11-segmented, long, filiform; antennomere 1 elongate, almost parallel-sided; antennomere 2 short, subquadrate; antennomeres 3–11 elongate, subequal. Clypeus with anterior margin convex. Mandibles bilobed apically. Maxillary palps 4-segmented, simple, not clearly serrate; palpomere 1 small; palpomere 4 possibly securiform. Mentum subtrapezoidal. Submentum relatively smooth, with hairs somewhat denser than other regions.

Pronotum widest posteriorly, with slightly produced posterior pronotal angles; disc without depression medially; posterior edge margined. Notosternal sutures distinct. Prosternum about as long as longitudinal procoxal diameter; prosternal process complete,gradually narrowed posteriorly, slightly extending beyond posterior procoxal margin, apically acute. Procoxal cavities narrowly separated, externally broadly open. Protrochantins well exposed.

Scutellar shield transverse, subtrapezoidal, widest posteriorly; posterior edge slightly rounded, without notch. Elytra long, about 3.1 times as long as width combined, at base almost as wide as pronotum, apically separately rounded; surface without longitudinal striae. Mesocoxal cavities narrowly separated. Metacoxae almost contiguous; coxal plates absent.

Legs slender. Protrochanter small, obliquely attached to profemur, with profemur abutting procoxa. All tibiae with 2 spurs, without transverse rows of bristles or spines. Metatibial spurs normal-sized. Tarsi 5-5-4; penultimate tarsomeres ventrally lobed in all three pairs of legs; metatarsomere 1 long, distinctly longer than metatarsomeres 2–4 combined. Pretarsal claws simple.

Abdomen with five ventrites. Ratio of ventrite lengths along middle: 3.2:2.4:2.1:1.7:2.4. Ventrite 5 apically rounded, without emargination.

Figures

FIGURE 1. General habitus of Homalenchodes jarzembowskii Li, Hsiao,Yoshitomi & Cai gen. et sp. nov., holotype, NIGP180475, under incident light. A, Dorsal view. B, Ventral view. Scale bars = 1 mm.

FIGURE 2. Details of Homalenchodes jarzembowskii Li, Hsiao, Yoshitomi & Cai gen. et sp. nov., holotype, NIGP180475, under confocal microscopy. A, Head and prothorax, ventral view. B, Head and prothorax, dorsal view. C, Abdominal base and fore leg. D, Abdominal apex and metatibia, ventral view. E, Elytral apex, dorsal view. Abbreviations: an1–9, antennomeres 1–9; el, elytron; ey, compound eye; lbp, labial palp; md, mandible; mstb, mesotibia; msts, mesotarsus; mtc, metacoxa; mttb, metatibia; mtv, metaventrite; mxp, maxillary palp; pc, procoxa; pf, profemur; pn, pronotum; ps, prosternum; ptb, protibia; ptcn, protrochantin; pts, protarsus; v1–5, ventrites 1–5. Scale bars: 200 μm.

FIGURE 3. Details of Homalenchodes jarzembowskii Li, Hsiao, Yoshitomi & Cai gen. et sp. nov., holotype, NIGP180475, under confocal microscopy. A, Mesotarsus, lateral view. B, Metatarsus, dorsal view. C, Metatarsus, ventral view. Abbreviations: mst1–5, mesotarsomeres 1–5; mtt1–4, metatarsomeres 1–4. Scale bars = 100 μm.