A southern species of the tropical catfish genus Phractocephalus (Teleostei: Siluriformes) in the Miocene of South America

摘要

Catfish bones from Tortonian (Miocene) freshwater beds of central Argentina are here identified as pertaining to a new species of the tropical pimelodid genus Phractocephalus. The new species differs from the other recent and fossil species of the genus in skull, pectoral girdle and spine characters. The material was found in different localities near the city of Parana, Entre Rios Province. The bearing horizon is the so-called "Conglomerado osifero" which constitutes the lowermost beds of the fluvial Ituzaingo Formation. The aquatic vertebrate fauna occurring in the bearing bed shows a similar generic composition to several northern South American Miocene units where Phractocephalus remains were found. This report extends the range of Phractocephalus more than 2000 km to the South. The record is in agreement with higher global temperatures and putative ample hydrographic connections of the river basins in the Parana area with the Amazon basin until at least the early late Miocene. (C) 2016 Elsevier Ltd. All rights reserved.