Pelotius hesselae, gen. et sp. nov. (Teleostei: Holocentridae) from the Cretaceous (Turonian) of Pelotas Basin, Brazil

Abstract

ABSTRACT The first holocentroid fish from South America, Pelotius hesselae gen. et sp. nov., is described from the Turonian of the Atlântida Formation, Pelotas Basin, southern Brazil. It is a small fish preserved in a dark gray neritic shale from a drill-core sample collected at a depth of around 4,000 m. The inclusion of P. hesselae in the Holocentroidei is supported by the presence of four spines in the anal fin, the penultimate one being the longer, and an expanded neural spine of the fourth preural centrum. Although preservation is insufficient to permit detailed morphological description of the skull and caudal skeleton, the high number of dorsal spines (10), the median suture in the posterior portion of the pelvic bone, and the presence of seven rays in the pelvic fin exclude Pelotius from the Trachichthyoidei, Stichocentridae and Pycnosteroididae and suggest its inclusion in the Holocentridae. On the other hand, it shares with the clade Erygocentrus + Tenuicentrinae + Myripristinae + Holocentrinae the apomorphic presence of two predorsals. Pelotius hesselae is distinguished from all other known holocentroids by having unusual coarse ornamentation in the anterior edge of preopercular and opercular, and lateral portion of the maxilla.