The fossil record of chimaeras (Chondrichthyes, Holocephali) in Argentina

Abstract

The aim of the present contribution is to review the fossil record of chimaeroids in Argentina. We review previous records from Argentina, including the presence of Cretaceous chimaeroids reported by Ameghino in the 19th century from the Cretaceous of Santa Cruz province. We re-analyse the species Callorhynchus crassus described from the Miocene of Patagonia by Smith Woodward and Withe in the early 20th century. It is here considered as a valid taxon within the genus Ischyodus as I. crassus nov. comb. Ichyodus dolloi is reported for the first time for the Palaeocene of Patagonia, Argentina. We report for the first time in Argentina fossils belonging to Callorhinchus from Holocene deposits in Buenos Aires province. The long temporal range of Holocephali in Argentina (from Late Cretaceous to Holocene) contrasts with the paucity of their fossil record. This indicates that the history of the clade in southern South America is far from well known.