A New Species of Psalidodon (Characiformes: Acestrorhamphidae) from the Upper Rio São Francisco Basin, Brazil, with Comments on Hasemania

Abstract

A new species of Psalidodon without an adipose fin and with an interrupted lateral line and scaleless caudal fin isdescribed from a marshland area in headwater tributaries of Rio Paraopeba, Rio Sa˜o Francisco basin, Minas Gerais,Brazil. The new species can be promptly distinguished from all members of the Acestrorhamphidae by the presence ofan ossified canal segment on the dorsal portion of the preopercular laterosensory canal running across the posterodorsal tip of the fourth infraorbital and posterior portion of the fifth infraorbital (vs. preopercular laterosensorycanal lacking an ossified canal segment in the fourth and fifth infraorbitals). The new species fits the classical definition of the genus Hasemania; however, a comprehensive phylogenetic analysis carried out herein to assess its phylogenetic relationships revealed it as the sister group of Psalidodon crenuchoides, new combination. Further, both speciesare deeply nested within the genus Psalidodon, as recently redefined, which led to the generic reallocation of the latter. Comments on the phylogenetic position of the new species, as well as its conservation status, are presented.