Species delimitation based on integrative approach suggests reallocation of genus in Hypostomini catfish (Siluriformes, Loricariidae)

Integrative approaches are particularly useful to resolve taxonomic uncertainties in species-rich groups that have undergone explosive radiation, such as Hypostomini (suckermouth armored catfishes). This tribe encompasses the genera Hypostomus and Pterygoplichthys, but the actual number of species in each genus and the intergeneric interrelationships are confusing or unknown for some ecoregions in the Neotropics. Here, we analyzed three endemic species Hypostomus chrysostiktos, H. jaguar and H. unae from Northeastern Mata Atlantica in northeastern Brazil based on meristic characters, geometric morphometrics, chromosomal data, DNA barcode and species delimitation algorithms. The current taxonomic status of these catfishes is challenged. While H. unae and H. jaguar revealed a close evolutionary relationship similar to those observed within Hypostomus from other basins, H. chrysostiktos was herein more closely related to Pterygoplichthys, being invariably recovered as a highly distinctive taxonomic unit than to Hypostomus. Therefore, we recommend the reallocation of H. chrysostiktos as Pterygoplichthys chrysostiktos and a thorough systematic review of Pterygoplichthys, particularly focusing on putative convergence traits in relation to Hypostomus.