Comparative brain gross morphology of the Neotropical catfish family Pseudopimelodidae (Osteichthyes, Ostariophysi, Siluriformes), with phylogenetic implications

The Neotropical catfish family Pseudopimelodidae includes seven genera and 50 valid species, widely distributed in South America. To address the lack of comparative information on siluriform brains, the gross morphology of the major brain subdivisions of Pseudopimelodidae is described, illustrated and interpreted. A comprehensive comparison based on the shape, relative size and position of main brain subdivisions is presented for representative species of all valid genera in the family. Comparisons with species of other phylogenetically related families, Pimelodidae and Heptapteridae, and non-related species provide a broader context for understanding transformations in the pseudopimelodid brain. The phylogenetic implications of the observed modifications in the brain are discussed and new possible synapomorphies proposed. Using this new information, almost all genera were recovered as monophyletic using neuroanatomical characters. Additional morphological modification was hierarchically interpreted against previously proposed phylogenetic hypotheses. The results of this study provide further information with phylogenetic implications within Pseudopimelodidae and their position with respect to closely related families.