Trogidae, MacLeay, 1819

Costa-Silva, Vinícius, Strümpher, Werner P., Thyssen, Patricia J. & Vaz-de-Mello, Fernando Z., 2024, Taxonomic revision of the South American genus Polynoncus Burmeister, 1876 (Coleoptera: Scarabaeoidea: Trogidae), Journal of Natural History 58 (1 - 4), pp. 14-166 : 22

Key to South American Trogidae genera:

1 Antennae with round scape ( Figure 1c ); margin of head evenly rounded, not angled at clypeogenal junction; lateral and posterior margins of pronotum with distinctive spatulate setae ............................................................................................................ genus Trox Fabricius

1’ Antennae with elongate scape ( Figure 1a,b ); margin of head usually angled at junction of clypeus and gena; lateral and posterior margins of pronotum with small filiform setae .......................................................................................................................................... 2

2 Antennae with pedicel attached subapically in the scape ( Figure 1b ); scutellum constricted at base ( Figure 1e ) or oval ( Figure 1f ); sixth antennomere without any seta ventrally; apex of clypeus reflexed or straight ........................ genus Omorgus Erichson

2’ Antennae with pedicel attached apically in the scape ( Figure 1a ); elongate scutellum ( Figure 1d ) or reduced (for species without humeral callus); sixth antennomere with a single seta ventrally ( Figure 1a ); apex of clypeus bent downwards, forming a right angle with the front ................................................................ genus Polynoncus Burmeister 3

Figures

Figure 1. Schematic drawing of the Trogidae antennae showing the relation between scape and pedicel for a, Polynoncus and b, Omorgus (Omorginae); and c, Trox genera (Troginae). Scutellum form for d, Polynoncus; e, Omorgus; and f, Trox genera (also found in some exceptions in Omorgus).