Revision of the neotropical genus Ischyomius with a discussion on its systematic position (Insecta: Coleoptera: Tenebrionoidea: Pythidae)

The Neotropical genus Ischyomius Chevrolat is reviewed and comprises six species: I. singularis Chevrolat, I. denticollis Champion, I. chevrolati Champion, I. bicolor Champion, I. nevermanni, new species (Costa Pica, Limon Province), and I. championi, new species (Ecuador, Pichincha Province). The following new synonymies are proposed: Pseudoischyomius Pic 1923 = Ischyomius Chevrolat 1878; Pseudoischyomius rufipennis Pic 1923 = Ischyomius bicolor Champion 1916. Primary types were examined for all species, and lectotypes are designated for I. singularis and I. chevrolati. The systematic placement of Ischyomius is discussed, and based on structure of male and female genitalia, the genus is placed in the family Pythidae, provisionally near Sphalma Horn.