Systematics of the genus Cnesterodon Garman, 1895 (Cyprinodontiformes: Poeciliidae: Poeciliinae)

a phylogenetic hypothesis of relationships is proposed for the species of cnesterodon. a series of derived features supports the monophyly of the genus and infrageneric clades. the genus cnesterodon is revised, with gulapinnus considered a junior synonym. a lectotype is designated for poecilia decemmaculata jenyns. nine species of cnesterodon are recognized: c. decemmaculatus, c. carnegiei, c. brevirostratus, c. septentrionalis, c. omorgmatos, c. hypselurus, c. raddai, a new species from the rio ribeira de iguape, described herein, and a new species from the rio grande do sul, being described by in a separate paper. diagnoses and distribution ranges are provided for each species as well as a key to identification of the species.