Oryctini, LeConte & Horn, 1883

Alvarez, Héctor Jaime Gasca, da, Claudio Ruy Vasconcelos, Fonseca & Ratcliffe, Brett C., 2008, Synopsis of the Oryctini (Coleoptera: Scarabaeidae: Dynastinae) from the Brazilian Amazon, Insecta Mundi 2008 (61), pp. 1-62 : 4-5

Key to the genera of adult Oryctini of Brazilian Amazonia

1. Protibia tridentate ....................................................................................................................... 2

— Protibia quadridentate ................................................................................................................. 3

2(1). Elytra smooth, black, shiny. Clypeus emarginate or truncate (bidentate in M. philoctetes ). Mandibles bidentate ...................................................................................... Megaceras Hope

— Elytra with 5 distinct rows of punctures on relatively smooth surface. Clypeus with apex sharply bidentate. Mandibles tridentate ........................................................................ Coelosis Hope

3(1). Elytra with deeply furrowed rows of punctures. Mandibles broad, with 2 lobes, strongly projecting from beneath clypeus. Clypeus with a conical tubercle on dorsal surface. Pronotal fovea of males broadly triangular, extending almost to posterior margin of pronotum ..................................... ................................................................................................................ Gibboryctes Endrödi

— Elytra smooth, rugose, or with punctures, never with deeply furrowed rows of punctures. Mandibles variably toothed, never with 2 large lobes. Head with 1-2 conical tubercles in frontoclypeal region, never with 1 on top of clypeus. Males with pronotal fovea variable in form ............... 4

4(3). Body form elongate, subparallel. Protibia with teeth projecting almost at right angles. Apex of metatibia with 2 strong teeth. Males with anterior half of pronotum nearly smooth and with single, median horn or tubercle. Females without fovea on pronotum .. Podischnus Burmeister

— Body form broader, sides rounded (not subparallel). Protibia with teeth projecting obliquely. Apex of metatibia crenulate or with 1, 3, or 4 teeth. Males with anterior half of pronotum densely punctate or rugose or, if nearly smooth, then with lateral horns or tubercles. Females with or without fovea on pronotum ....................................................................................................... 5

5(4). Both males and females with head horn. Prosternal process short. Pronotum with anterior margin distinctly emarginate at center ........................................................................... Enema Hope

— Males with or without head horn; females never with head horn, instead tuberculate at most. Prosternal process long or subconical. Anterior margin of pronotum lacking emargination at center ........................................................................................................................................ 6

6(5). Frons in males and females unarmed or with 2 tubercles, never with horn on the head. Mandibles tridentate. Pronotum in males with subapical horn and usually with lateral horn or elevated, triangular ridge on each side; females with fovea in anterior third of pronotum ...................... ....................................................................................................................... Strategus Kirby

— Males usually with distinct head horn; females with single tubercle. Mandibles without teeth, or with 1-2 rounded teeth. Pronotum in males with horn or prominence arising from posterior half and with or without lateral horns; females usually lacking pronotal fovea ............................... .................................................................................................. Heterogomphus Burmeister