Dichotomiini

Key to genera and subgenera of the tribe Dichotomiini View in CoL

(*subgenus with a second key to determine the species group)

1. Antenna with eight antennomeres ( Fig. 1a View Figure 1 ) .....................................…2

1’. Antenna with nine antennomeres ( Figs. 1c, d View Figure 1 ) ................................…3

2. Posterior margin of pronotum bordered ( Figs.1e, g View Figure 1 ; 2a, c View Figure 2 ; 3a, c, e, g View Figure 3 ). Seventh elytral interstria flat. Color black, at most with weak blue iridescent sheen. Northern Argentina, Brazil, Peru........... Isocopris Pereira & Martínez, 1960 (see: Rossini and Vaz-de-Mello, 2017; Arias-Buriticá et al., 2023)

2’. Posterior margin of pronotum not bordered ( Fig. 1b View Figure 1 ). Seventh elytral interstria basally convex. Color shiny black or brownish to green metallic. Argentina, Brazil, Paraguay..................... Chalcocopris Burmeister, 1846 (see: Rossini and Vaz-de-Mello (2015))

3. Antennal club more or less spherical ( Fig.1c View Figure 1 ). Second labial palpomere very large,flattened, oval,concealing smaller third palpomere in ventral view. Brazil, Paraguay..................................... Holocephalus Hope, 1838 View in CoL (See: Smith and Génier (2001); Nunes and Vaz-de-Mello (2016a))

3’. Antennal club elongate ( Fig. 1d View Figure 1 ). Second labial palpomere triangular, not covering the third palpomere in ventral view. United States to Argentina... Dichotomius Hope, 1838 View in CoL .....................................................4