Phylogenetic relationships of Paleotetra, a new characiform fish (Ostariophysi) with two new species from the Eocene-Oligocene of south-eastern Brazil

Abstract

Paleotetra, a new characiform genus with two new species (P. entrecorregos and P. aiuruoca) from Palaeogene deposits of south-eastern Brazil is described. The fossil material is made up of two articulated specimens preserved as impressions in lateral view and including some bones and teeth. The new genus is hypothesized to be deeply inserted within the Characidae based on the apomorphic lack of a supraorbital bone, the low number of vertebrae (35), and the presence of four teeth in the inner series of the premaxilla; however, the new species cannot be assigned to any modern genus. Relationships of the two new species are further tested in a phylogenetic analysis along with 160 other characiform species using 360 morphological characters (150 coded for Paleotetra entrecorregos and 123 for P. aiuruoca), further supporting their recognition as characid characiforms. These results document the evolution of these characid lineages as early as the Eocene-Oligocene.