Austronausibius Halstead, 1980

Alekseev, Vitalii I. & Bukejs, Andris, 2022, Extant genus of flat bark beetle (Coleoptera: Silvanidae) with a present-day Australian-southern South American disjunction discovered in Eocene Rovno amber, Zootaxa 5129 (1), pp. 137-144 : 138

Genus Austronausibius Halstead, 1980

Type species: Silvanus congener Olliff, 1886

Note. Morphological characters of the inclusion under study convincingly place it among Silvanidae (antenna with 11 antennomeres, not moniliform; open mesocoxal cavities; subparallel body form; pentamerous tarsi; head and pronotum without sublateral carinae or grooves) and namely within Silvaninae (antennae clubbed; antennal scape comparatively short, about as long as wide; frons laterally without longitudinal sulcus; frontoclypeal suture absent; scutellary striole absent; tarsomere 4 smallest). The specimen under consideration is assigned to the genus Austronausibius based on the combination of the following characters, which distinguish the specimen from other similar silvanine genera having six teeth or undulations on the pronotal lateral sides: (1) antenna with 11 antennomeres and a club composed of 3 antennomeres (gradually developed club of 4 antennomeres in Nausibius ; club of 2 antennomeres in Afronausibius Halstead, 1980 and Acorimus Halstead, 1980 ); (2) dorsal pubescence weakly curved, pronotal and elytral margins not widely explanate (in contrast to dorsal pubescence composed of strongly curved setae and pronotal and elytral margins explanate in Acorimus and Afrocorimus ); (3) head without antennal grooves (head with antennal grooves ventrally in Afronausibius and Eunausibius Grouvelle, 1912 ); (4) antennomere 10 about as wide as antennomere 9 (distinctly wider than antennomere 9 in Silvanopsis Grouvelle, 1892 ); (5) tarsomere 3 simple (incrassate in Oryzaephilus and Silvanopsis ); (6) pronotum without crescentic depression (with crescentic depression towards base in Nausibius ); (7) short temples present; and (8) inner interstriae of elytra flat (convex in Pseudonausibius Halstead, 1980 ).