Helioctamenus Schauffuss, 1882

ALEKSEEV, VITALII, MCKELLAR, RYAN C. & BUKEJS, ANDRIS, 2024, A revision and addition to Zopheridae (Coleoptera: Tenebrionoidea) in Baltic amber: possible connections between modern Holarctic distributions and Eocene ‘ amber forests’, Zootaxa 5536 (2), pp. 201-247 : 217

Genus Helioctamenus Schauffuss, 1882

Type species: Helioctamenus hippopotamus Schaufuss, 1882

Taxonomic assignment. The specimen under consideration belongs to the tribe Sarrotriini based on the combination of the following characters: (1) dorsally concealed antennal insertions; (2) antennae setose, 10- or 11-segmented, without distinctly separated antennal club; (3) antennal insertions distant from eyes; (4) procoxal cavities open posteriorly; (5) all tarsi tetramerous, not dilated; (6) prosternal process wide, emarginate apically; and (7) metacoxae separated by intercoxal abdominal process with rounded apex. The tribe includes three genera from the Western Palearctic: monotypic Diplagia Reitter, 1882 ; Orthocerus Latreille, 1796 with two European species; and comparatively diverse Helioctamenus ( Ślipiński & Schuh 2008) . The new extinct species is assigned to the genus Helioctamenus based on: antennae sparsely and shortly setose (in contrast to Diplagia and Orthocerus ), not fusiform (in contrast to Orthocerus ); interfacetal setae absent; body sparsely setose dorsally; and pronotum distinctly narrower than elytral base (in contrast to Diplagia ).