Consideraciones sobre el registro de Hypolophodon (Chondrichthyes, Myliobatiformes) en el techo de la formación Jagüel (Maastrichtiense), provincia de Río negro, Argentina

Abstract

The fossil record of the extinct ray Hypolophodon is restricted to the Paleogene marine sediments of Northern Hemisphere (in America and Europe) and North Africa. In this paper, a new tooth material from the higher level of Jagüel Formation, at Bajo Trapalcó Río Negro Province, Argentina, is described. This tooth is referable to H. silvestris based both in morphological and histological reliable evidence. This record also allows the reassignment of MML 228 to this genera and species, instead the original assignation to the genus Pseudohypolophus. Additionally, it represents the southernmost occurrence of the genus Hypolophodon and the first record for South America. The marine Ichtyofauna of the Jagüel Formation from north Patagonia evidences a strong relationship with coeval ichtyofauna from Brazil, Caribbean, North Africa and Madagascar, showing a clear distinction with selachian faunas from the Weddelian biogeographic Province