The genus Rhodocanthopus Kaup was originally proposed to include five species; after that, more species were added and different criteria were adopted to delimit it, generating great taxonomic confusion. At present, Rhodocanthopus Kaup is considered as a synonym of Passalus and is currently named as the group Rhodocanthopus without formal taxonomic circumscription. To clarify this, phylogenetic analyses (Bayesian inference and parsimony) were performed using morphological and molecular data with genes 12S, 16S and COI. In both analyses, the group Rhodocanthopus resulted monophyletic inside Passalus and included seven previously described species, plus Passalus chocoensis sp.n. and Passalus rufiventris sp.n. Morphologically, the group can be recognized by the presence of secondary internal tubercles over the frontal edge, reduced compound eyes and strong spines on the external edge of the meso- and metatibiae.

Bess beetles, Mesoamerica, phylogenetic systematics, taxonomy