A new deep bodied ray-finned fish (Osteichthyes/Actinopterygii) from the Permian Pedra de Fogo Formation (Northeastern Brazil) and its phylogenetic and paleogeographic affinities

Abstract

A deep bodied ray-finned fish is reported from Cisuralian lacustrine deposits of the Parnaíba Basin. Its ecological niche and systematic affinities are discussed, considering the paleogeographic distribution of selected Permo-Carboniferous deep bodied fishes from several separate sedimentary successions of western Gondwana. The occurrence of deep bodied fishes in the Parnaíba Basin mirrors the presence of a similarly shaped but less derived and distantly related taxon, Paranaichthys longianalis from the late Permian of the Paraná Basin of southern Brazil. The new taxon’s unique combination of characters includes an elongated pectoral fin; posteriorly inclined suspensorium; deep flank scales ornamented with fine vertical striae, tiny mandibular teeth and palatal crushing dental plates. It shares with Guildayichthys and Discoserra two preopercular bones, a supraorbital, and marginal teeth on the lower jaw. Phylogenetic analyses were performed based on two datasets. Dataset 1 included 53 characters coded for 26 deep bodied and fusiform fish fossils from Brazil, North America, China, South Africa, and Australia, with results indicating that is most closely related to the North American order Guildayichthyformes, known from marine rocks of Pennsylvanian age. Dataset 2 included 119 taxa coded for 293 characters. The two analyses place the new taxon as the sister group of a clade comprised of Blourugia and Paranaichthys. However, the results of the study of both datasets show a high degree of uncertainty about the interrelationships between the new taxon and other deep bodied Paleozoic fish species.