Anomocephalobus liuhaoi Li, Jäch & Cai, 2022

Li, Yan-Da, Yu, Ya-Li, Jäch, Manfred A., Huang, Di-Ying & Cai, Chen-Yang, 2022, Anomocephalobus, a new genus of minute marsh-loving beetles from mid-Cretaceous Burmese amber (Coleoptera: Limnichidae), Zoologia (e 21030) 39, pp. 1-8 : 3-5

Anomocephalobus liuhaoi Li, Jäch & Cai , sp. nov.

Figs 1–13

http://zoobank.org/ 45F69AF5-4EE7-4E94-9ACE-B04A82CA2D22

Type material. Holotype, NIGP177044 , female.

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. Adult female. Body relatively wide, oval, 2.6 mm long, 1.7 mm wide.

Head hypognathous ( Fig. 5 ), largely covered by pronotum, with anterior pronotal edges reaching compound eyes ( Fig. 7 ). Frontoclypeal suture seemingly present ( Fig. 5 ). Eyes separated by more than twice the width of single eye, without interfacetal setae ( Figs 7, 8 ). Antennal insertion capsule closed. Antennae 11-segmented; antennomeres 1–3 slender and elongate; antennomeres 4–11 serrate ( Fig. 6 ), with gradually increasing asymmetry from antennomeres 4 to 7.

Pronotum with sharp lateral edges; posterior pronotal angles rounded ( Fig. 9 ); posterior pronotal margin bisinuate, crenulate ( Fig. 9 ). Prosternum in front of procoxae transverse; prosternal process parallel-sided, broad, distinctly wider than one third of maximum width of prosternum, apically rounded, fitting well into mesoventral cavity ( Fig. 11 ). Hypomera without ridges and associated grooves for reception of fore legs ( Fig. 10 ).

Scutellar shield triangular. Elytra widest near middle, gently arcuate in lateral margins; basal elytral margin crenulate ( Fig. 9 ). Mesocoxal cavities circular, widely separated ( Fig. 11 ). Metaventrite with transverse suture; excavation for reception of mid legs absent ( Fig. 12H ). Metacoxae narrowly separated, transverse, without large metacoxal plates ( Fig. 12 ).

Legs slender. Femora obliquely attached to trochanters; profemur excavated to receive protibia ( Fig. 10 ). Tibiae as long as femora, without stout spines. Tarsal formula 5-5-5; tarsomeres 1–4 together longer than tarsomere 5. Pretarsal claws simple; empodium absent.

Abdomen with five ventrites. Excavation for reception of hind legs absent. Ratio of ventrite lengths along middle: 1.8:1.4:1.2:1.0:1.7. Ventrite 5 apically broadly rounded.

Etymology. The species is named after Hao Liu, who kindly shared with us helpful information about Burmese amber.

Remarks. The fossil was partially transparentized during the fossilization process ( Figs 1, 2 ), making the ovipositor inside the body visible even under optical methods ( Fig. 13 ), which is kind of unusual in Mesozoic fossils. The placement of the fossil in Dryopoidea (sensu Cai et al. 2022) seems to be well corroborated by this ovipositor, which, in fact, agrees remarkably well with that of Cephallobyrrhus ( Yoshitomi 2019b).

Figures

Figures 1–2. General habitus of Anomocephalobus liuhaoi gen. et sp. nov., holotype, NIGP177044, under incident light: (1) dorsal view; (2) ventral view. Scale bars: 1 mm.

Figures 3–4. General habitus of Anomocephalobus liuhaoi gen. et sp. nov., holotype, NIGP177044, under widefield fluorescence: (3) dorsal view; (4) ventral view. Scale bars: 1 mm.

Figures 5–13. Details ofAnomocephalobus liuhaoi gen. et sp. nov., holotype,NIGP177044, under confocal microscopy: (5) mouthparts,ventral view;(6) antenna,dorsal view; (7) compound eye,dorsal view;(8) compound eye,ventral view;(9) crenulate posterior pronotal margin (arrowhead), dorsal view; (10) pronotal hypomeron, ventral view; (11) mesothorax,ventral view;(12) metacoxa, ventral view; (13) ovipositor, ventral view. (an1–11) antennomeres 1–11, (cl) clypeus, (el) elytron, (ey) compound eye, (hy) hypomeron, (lb) labrum, (msv) mesoventrite, (mtc) metacoxa, (mttc) metatrochanter, (mtv) metaventrite, (ov) ovipositor, (pn) pronotum, (ps) prosternum, (v5) ventrite 5. Scale bars: 200 Μm.