PaleoBios 32:1–42, September 7, 2015 PaleoBios OFFICIAL PUBLICATION OF THE UNIVERSITY OF CALIFORNIA MUSEUM OF PALEONTOLOGY Edwin A. Cadena and James F. Parham (2015). Oldest known marine turtle? A new protostegid from the Lower Cretaceous of Colombia. Cover illustration: Desmatochelys padillai on an early Cretaceous beach. Reconstruction by artist Jorge Blanco, Argentina. Citation: Cadena, E.A. and J.F. Parham. 2015. Oldest known marine turtle? A new protostegid from the Lower Cretaceous of Colombia. PaleoBios 32. ucmp_paleobios_28615. PaleoBios 32:1–42, September 7, 2015 Oldest known marine turtle? A new protostegid from the Lower Cretaceous of Colombia EDWIN A. CADENA1, 2*AND JAMES F. PARHAM3 1 Centro de Investigaciones Paleontológicas, Villa de Leyva, Colombia;
[email protected]. 2 Department of Paleoherpetology, Senckenberg Naturmuseum, 60325 Frankfurt am Main, Germany. 3John D. Cooper Archaeological and Paleontological Center, Department of Geological Sciences, California State University, Fullerton, CA 92834, USA;
[email protected]. Recent studies suggested that many fossil marine turtles might not be closely related to extant marine turtles (Che- lonioidea). The uncertainty surrounding the origin and phylogenetic position of fossil marine turtles impacts our understanding of turtle evolution and complicates our attempts to develop and justify fossil calibrations for molecular divergence dating. Here we present the description and phylogenetic analysis of a new fossil marine turtle from the Lower Cretaceous (upper Barremian-lower Aptian, >120 Ma) of Colombia that has a minimum age that is >25 million years older than the minimum age of the previously recognized oldest chelonioid. This new fossil taxon,Desmatochelys padillai sp. nov., is represented by a nearly complete skeleton, four additional skulls with articulated lower jaws, and two partial shells.