Key to males of Bothynus entellus species group

Males have pronotal horns, pronounced pronotal excavations, and enlarged anterior claws.

1. Pronotum with 2–3 horns (Figs. 1A, 3A), or only with a small (Fig. 5A) to moderate (Fig. 2A) apical tubercle; if moderate, apical tubercle with rounded apex; mesofemora with setae confine on disc (Fig. 5F); tergite VII with 2 bands of weakly marked carinae (Fig. 7A); parameres without laterovental contraction at apical half (Fig. 9A)............................... 2

- Pronotal tubercle strong, horn shaped, acute on apex (Fig. 4A); mesofemora completely setose (Fig. 4B); tergite VII with 1 band of well-marked carinae (Fig. 7C); parameres with lateroventral contraction at apical half in lateral view (Fig.9D)................................................................................ Bothynus lancifer Dechambre, 1981

2. Pronotum strongly convex posteriorly in lateral view (Fig. 2B); pronotum only with an apical tubercle moderate in size; protarsomere IV with elongate ventral apex nearly reaching the apex of the ventro-basal tooth of tarsomere V (Fig. 2E)......... 3

- Pronotum moderately convex (Fig. 5B), or with a horn (Figs. 1A, 3A) or tubercle (Figs. 1C, 3C) on each side); protarsomere IV with short ventral apex, not reaching the base of the ventro-basal tooth of tarsomere V (Fig. 5E).................... 4

3. Metatrochanter with rounded apex (Fig. 2F); parameres with subparallel outer margins (Fig. 8B)............................................................................................ Bothynus stenelus (Burmeister, 1847)

- Metatrochanter with acute apex (Fig. 6B); parameres with rounded lateral flaps (Fig. 8F)........................................................................................ Bothynus condacki Duarte & Grossi, new species

4. Pronotum with moderate (Fig. 1A) or shallow (Fig. 5A) concavity; hypomeron not emarginate in ventral view (Fig. 5D)... 5

- Pronotal concavity extremely deep (Fig. 3A); hypomeron strongly emarginate in ventral view (Fig. 3E)............................................................................................ Bothynus tricornis Arrow, 1937

5. Stridulatory apparatus with well-marked carinae near to basal margin (Fig. 7B); apical half of parameres with subparallel lateral flaps, narrower than basal half (Fig. 8E).............................. Bothynus araya Duarte & Grossi, new species

- Stridulatory apparatus with weakly marked carinae near to basal margin (Fig. 7A); apical half of parameres with rounded lateral flaps, broader than basal half (Fig. 8A).............................. Bothynus entellus (LePeletier & Serville, 1828)