Coslonatus rasnitsyni Li & Cai, 2021

Li, Yan-Da, Huang, Di-Ying & Cai, Chen-Yang, 2021, An aberrant colydiine-like tenebrionoid beetle from mid-Cretaceous Burmese amber (Coleoptera: Tenebrionoidea: Zopheridae), Palaeoentomology 4 (6), pp. 614-619 : 615-618

Coslonatus rasnitsyni Li & Cai sp. nov.

( Figs 1–4 )

Material. Holotype, NIGP177330 , crazed and probably wrinkled during fossilisation.

Etymology. The species is named for Prof.Alexander P. Rasnitsyn, a well-known Russian palaeoentomologist.

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 elongate, parallel-sided, 1.93 mm long, 0.54 mm wide, covered with distinct setae.

Head ( Fig. 4A, B ) prognathous, without distinct neck; dorsal surface with a pair of longitudinal protuberances. Compound eyes lateral, entire, with short interfacetal setae. Antennal insertions dorsally located ( Fig. 4A ), separated by less than twice diameter of antennomere 1. Antennae 11-segmented, long, almost reaching elytral apex when posteriorly directed; antennomere 1 long and wide; antennomere 2 shorter; antennomere 3–8 elongate; antennomeres 9–11 short, asymmetrical (serrate in 9– 10), forming a club ( Fig. 4E ). Mandibles apically with two vertically arranged teeth ( Fig. 4B ). Maxillary palps relatively long; apical palpomere fusiform. Labial palps present; apical palpomere cylindrical.

Pronotal disc quadrate; lateral margins straight, denticulate; anterior and posterior angles right- angled; surface with a pair of longitudinal elevated platforms. Hypomera without antennal grooves or impressions. Notosternal sutures not evident, probably absent. Prosternal process raised. Procoxae seemingly countersunk, concealed by prosternal process.

Scutellar shield( Fig. 4C ) with anterior margin slightly emarginate; posterior margin rounded. Elytra elongate, parallel-sided; each with five subtle carinae (including sutural carina); scutellar striole present. Mesocoxae longer than wide; separated by approximately width of mesocoxae. Mesocoxal cavities not evident, probably closed laterally. Metacoxae separated by intercoxal process.

Tibiae with two spurs. Tarsi 4-4-4 ( Fig. 4F–H ); tarsomeres 1–3 similar in form, together shorter than tarsomere 4. Pretarsal claws simple.

Abdomen with five ventrites, separated by wide and deeply impressed sutures.

Figures

FIGURE 1. General habitus of Coslonatus rasnitsyni gen. et sp. nov., holotype, NIGP177330, under incident light. A, Dorsal view. B, Ventral view. Scale bars: 500 μm.

FIGURE 2. General habitus of Coslonatus rasnitsyni gen. et sp. nov., holotype, NIGP177330, under widefield fluorescence. A, Dorsal view. B, Ventral view. Scale bars: 500 μm.

FIGURE 3. General habitus of Coslonatus rasnitsyni gen. et sp. nov., holotype, NIGP177330, under confocal microscopy. A, Dorsal view. B, Ventral view. Scale bars: 400 μm.

FIGURE 4. Details of Coslonatus rasnitsyni gen. et sp. nov., holotype, NIGP177330, under confocal microscopy. A, Head, dorsal view. B, Mouthparts, ventral view. C, Elytral base, dorsal view. D, Middle portion of elytra, dorsal view. E, Antennal club, ventral view. F, Protarsus, ventral view. G, Mesotarsus, ventral view. H, Metatarsus, ventral view. Abbreviations: an1,9–11, antennomeres 1,9–11; es, elytral suture; ey, compound eye; lbp, labial palp; md, mandible; mst1–4, mesotarsomeres 1–4; mstb, mesotibia; mtt1–4, metatarsomeres 1–4; mttb, metatibia; mxp, maxillary palp; pt1–4, protarsomeres1–4;ptb, protibia; sc, scutellum.Scale bars:100 μm.