Alveoderes yamamotoi Li & Cai, 2024

Li, Yan-Da & Cai, Chen-Yang, 2024, AlveOderes gen. nov., the earliest fossil of Bothrideridae from mid-Cretaceous Burmese amber (Coleoptera: Coccinelloidea), Zoologia (e 23084) 41, pp. 1-10 : 3-4

Alveoderes yamamotoi Li & Cai sp. nov.

Figs 1–13

https://zoobank.org/ 76A6CB73-4A51-4939-AE5C-A97BF5AE411B

Material. Holotype, NIGP203385 .

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 ( Shi et al. 2012, Mao et al. 2018).

Diagnosis. As for the genus.

Description. Body elongate, about 1.5 mm long, 0.4 mm wide; surface with scattered setae.

Head declined at base. Compound eyes with short interfacetal setae. Antennae likely 11-segmented; antennomere 1 robust; antennomere 2 wider than 3; antennomeres 3–8 submoniliform to subfiliform; antennomeres 9–11 forming loose club; antennomere 11 conical.

Pronotal disc about 1.1 times as long as wide, widest anteriorly; surface with median longitudinal groove, about 0.8 times as long as pronotal length, anteriorly acute, gradually widened backwards, posteriorly open, posterolaterally bordered by distinct posteriorly directed projections; anteri- or pronotal angles each with a distinct oval cavity (possibly a glandular opening). Procoxae subcontiguous (status of coxal cavities unknown).

Scutellar shield elongated oval, anteriorly emarginate. Elytra elongate; surface with indistinct rows of fine punctures; one distinct longitudinal ridge present at base of elytron, anteriorly opposite to respective projection on pronotum, shorter than 1/4 elytral length, gradually weakened posteriorly; elytral humeri distinctly ridged; epipleura narrow. Mesoventrite with median carina and paired parallel carinae continuous with edges of mesoventral process. Mesocoxal cavities narrowly separated. Metaventrite anteromedially slightly tumid, without clear median discrimen; katepisternal suture absent. Metacoxae suboval, moderately separated, laterally separated from elytra by metanepisternum.

Legs well-developed, slender. Trochanters relatively reduced and somewhat concealed. Tibiae with two or three weak spines along outer margin; protibiae with strongly unequal spurs; one being enlarged and strongly curved; meso- and metatibiae with paired equal spurs. Tarsi all 4-segmented; tarsomeres simple, unlobed. Pretarsal claws simple.

Abdomen with five ventrites. Ratio of ventrite lengths along middle: 5.2:2.0:1.0:1.1:2.0. Ventrite 1 with intercoxal process apically broadly angulate; postcoxal lines absent.

Etymology. The species is named after the coleopterist Dr. Shûhei Yamamoto.

Remarks. The antennomere 11 of the left antenna is not preserved in the specimen. The prosternal process cannot be observed, and the state of procoxal cavities cannot be confidently determined.

Figures

Figures 1–2. General habitus of Alveoderes yamamotoi Li & Cai gen. et sp. nov., holotype, NIGP203385, under incident light: (1) dorsal view; (2) ventral view. Scale bars: 500 Μm.

Figures 3–4. General habitus of Alveoderes yamamotoi Li & Cai gen. et sp. nov., holotype, NIGP203385, under confocal microscopy: (3) dorsal view; (4) ventral view. Scale bars: 500 Μm.

Figures 5–13. Details of Alveoderes yamamotoi Li & Cai gen. et sp. nov., holotype, NIGP203385, under confocal microscopy: (5) prothorax, dorsal view, with the cavity at anterior pronotal angle indicated (arrowhead); (6) elytral base, dorsal view; (7) elytral apex, dorsal view; (8) head and prothorax, ventral view; (9) mesothorax, ventral view; (10) abdominal base, ventral view; (11) fore leg, showing strongly unequal protibial spurs; (12) mid leg; (13) abdominal apex and hind legs, ventral view. (a1–11) antennomeres 1–11, (mstb) mesotibia, (mstc) mesotrochanter, (msts) mesotarsus, (mtc) metacoxa, (mttb) metatibia, (mttc) metatrochanter, (mtv) metaventrite, (pc) procoxa, (pf) profemur, (ps) prosternum, (ptb) protibia, (ptc) protrochanter, (pts) protarsus, (sc) scutellum, (v1–5) ventrites 1–5. Scale bars: 100 Μm.