Paleontology and stratigraphic implications of a late Paleocene elasmobranch assemblage in Talcahuano, southcentral Chile

Abstract

Late Paleocene elasmobranch findings are reported, along with reinterpretations of some previous taxonomic identifications in two main outcrops around Talcahuano area (Biobío region, Chile), and also delimiting the exposed lithostratigraphic units. Reviewed fossils are among 15 genera, comprising the species Paraorthacodus clarkii, Squalus minor, Squalus orpiensis, Centrophorus sp., Squatina prima, Anomotodon novus, Striatolamia striata, Carcharias spp., Sylvestrilamia teretidens, Odontaspis winkleri, Palaeohypotodus speyeri, Palaeohypotodus rutoti, Isurolamna inflata, Premontreia gilberti, Physogaleus secundus, Palaeogaleus vincenti and Hypolophodon sylvestris. The main elasmobranch assemblage, collected from the San Martín outcrop, indicates deposition in a shallow lower shoreface-uppermost offshore marine environment and warm-temperate water. Moreover, this elasmobranch assemblage constrains the age of Pilpilco Formation into the middle-late Thanetian, which implies a latest Thanetian-early Ypresian age for the overlying Curanilahue Formation and a Danian-early Thanetian hiatus with the underlying Quiriquina Formation.