Archaenosodendron remotidens Li & Cai, 2021

Li, Yan-Da, Tihelka, Erik, Dahan, Loïc, Huang, Di-Ying & Cai, Chen-Yang, 2021, On the Nosodendridae from mid-Cretaceous amber of northern Myanmar (Coleoptera: Nosodendroidea), Zootaxa 5082 (3), pp. 223-244 : 231-233

Archaenosodendron remotidens Li & Cai sp. nov.

( Figs 9–11 )

Material. Holotype, NIGP177614 .

Etymology. The specific name refers to the relatively sparsely arranged denticles/stout setae on the outer edge of its protibia.

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. Medial antennomeres longer than wide ( Fig. 11C ). Lateral regions of mentum without longitudinally arranged larger punctures ( Fig. 11B ). Anterior angles of mentum not obviously produced ( Fig. 11B ). Antennal grooves on prosternum shorter than half-length of prosternum in front of coxae ( Fig. 11D ). Outer edge of protibia with about 14–16 relatively sparsely arranged denticles/stout setae, with the apical two distinctly stouter and more closely situated ( Fig. 11G ). Medial and lateral portions of prosternum not separated by a ridge ( Fig. 11D ).

Description. Body elongated oval, about 3.6 mm long, 1.8 mm wide.

Head prognathous. Eyes not strongly protuberant. Antennal insertions widely separated and concealed from above. Antennal grooves on head well developed. Frontoclypeal suture absent. Antennae 11-segmented; antennomere 2 about twice as long as wide; antennomere 3 about as long as but slender than 2; antennomeres 3–8 progressively shorter and wider; antennomeres 9–11 enlarged, forming a relatively loose club. Mandibles broad, unidentate. Maxilla with setose galea and lacinia; maxillary palps 4-segmented; palpomeres 1 and 4 longer than 2 and 3. Mentum with lateral edges subparallel in the basal half, then converging anteriorly; surface without clearly visible punctures; anterior angles not produced. Apical labial palpomere seemingly enlarged.

Pronotal disc subtrapezoidal, widest at base; anterior margin with shallow emarginations laterally, slightly protruding medially. Prosternum in front coxae transverse, not extremely shortened; medial and lateral portions of prosternum not separated by a ridge; antennal grooves on prosternum shorter than half-length of prosternum in front of coxae; prosternal process relatively slender. Procoxae strongly transverse, well separated. Procoxal cavities broadly open posteriorly.

Scutellar shield triangular, posteriorly acute. Elytra widest at anterior third; anterior corners weakly obtuse. Mesoventrite short, anteriorly with well-developed mesoventral cavity and procoxal rests. Mesocoxal cavities widely separated. Metaventrite transverse, flattened. Metacoxae narrowly separated.

Femora with groove for receiving tibia. Tibiae expanded distally, with two apical spurs; outer edge of protibia with relatively sparsely arranged denticles/stout setae, with the apical two distinctly stouter and more closely situated. Tarsi 5-5-5; tarsomeres slender, not distinctly lobed; tarsomeres 1–4 ventrally with a cluster of long hairs at apex. Pretarsal claws simple.

Abdomen with five ventrites. Ventrites 1 and 2 with a pair of impressions for receiving hind legs. Anterior margin of ventrites smooth, without notches.

Figures

FIGURE 9. General habitus of Archaenosodendron remotidens Li & Cai sp. nov., holotype, NIGP177614, under incident light. A, Dorsal view. B, Ventral view. Scale bars: 1 mm.

FIGURE 10. General habitus of Archaenosodendron remotidens Li & Cai sp. nov., holotype, NIGP177614, under widefield fluorescence. A, Dorsal view. B, Ventral view. Scale bars: 1 mm.

FIGURE 11. Details of Archaenosodendron remotidens Li & Cai sp. nov., holotype, NIGP177614, under confocal microscopy. A, Head, dorsal view. B, Mouthparts, ventral view. C, Antenna, ventral view. D, Prothorax, ventral view, showing the incomplete antennal groove on prosternum (arrowhead). E, Abdominal base, ventral view. F, Scutellar shield, dorsal view. G, Fore leg. H, Mesotibia and -tarsus. I, Metatibia and -tarsus. Abbreviations: an9–11, antennomeres 9–11; el, elytron; gl, galea; lbp, labial palp; md, mandible; mstb, mesotibia; msts, mesotarsus; msv, mesoventrite; mt, mentum; mtc, metacoxa; mtf, metafemur; mttb, metatibia; mtts, metatarsus; mtv, metaventrite; mxp, maxillary palp; pf, profemur; pn, pronotum; ps, prosternum; ptb, protibia; pts, protarsus; sc, scutellum. Scale bars: 200 μm.