Archaenosodendron angulare 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 : 234-236

Archaenosodendron angulare Li & Cai sp. nov.

( Figs 12–14 )

Material. Holotype, NIGP177615 .

Etymology. The specific name refers to anterolaterally produced anterior angles of mentum.

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 slightly longer than wide ( Fig. 14C ). Lateral regions of mentum without longitudinally arranged larger punctures ( Fig. 14B ). Anterior angles of mentum produced anterolaterally ( Fig. 14B ). Outer edge of protibia with about 20 denticles/stout setae ( Fig. 14F–H ). Medial and lateral portions of prosternum separated by an incomplete ridge ( Fig. 14D ).

Description. Body elongated oval, about 3.1 mm long, 1.4 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; antennomeres 3–8 progressively shorter and wider; antennomeres 9–11 enlarged, forming a relatively loose club. Mandibles unidentate. Maxillary palps 4-segmented; palpomere 4 longer than others. Mentum with lateral edges subparallel in the basal third, then converging anteriorly; surface with similar-sized punctures in lateral and anterior portions; anterior angles produced anterolaterally. Ligula bilobed. 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 separated by an incomplete ridge; 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; anterolateral portion with curved line delimiting the impression. Metacoxae narrowly separated.

Femora with groove for receiving tibia. Tibiae expanded distally, with two apical spurs; outer edge of protibia with about 20 denticles/stout setae. Tarsi 5-5-5; tarsomeres slender, not distinctly lobed; tarsomeres 1–4 ventrally with a cluster of long hairs at apex. Pretarsal claws simple.

Figures

FIGURE 12. General habitus of Archaenosodendron angulare Li & Cai sp. nov., holotype, NIGP177615, under incident light. A, Dorsal view. B, Ventral view. Scale bars: 1 mm.

FIGURE 13. General habitus of Archaenosodendron angulare Li & Cai sp. nov., holotype, NIGP177615, under widefield fluorescence. A, Dorsal view. B, Ventral view. Scale bars: 1 mm.

FIGURE 14. Details of Archaenosodendron angulare Li & Cai sp. nov., holotype, NIGP177615, under confocal microscopy. A, Head, dorsal view. B, Mouthparts, ventral view. C, Antenna, ventral view. D, Prothorax, ventral view. E, Anterolateral depression of metaventrite, ventral view. F, G, Protibia and -tarsus. H, Fore and mid legs. I, Metatibia and -tarsus. Abbreviations: an9–11, antennomeres 9–11; lbp, labial palp; msc, mesocoxa; mstb, mesotibia; msv, mesoventrite; mt, mentum; mttb, metatibia; mtts, metatarsus; mtv, metaventrite; mxp, maxillary palp; pc, procoxa; pf, profemur; pn, pronotum; ps, prosternum; ptb, protibia. Scale bars: 200 μm.