A new fossil turtle ends the controversy on the occurrence of the extant genus Podocnemis Wagler, 1830 at the Miocene fauna of La Venta, Colombia

Abstract

The estimate divergence time for extant taxa based on molecules usually exceed the age of their oldest fossil evidence; a situation that turtles do not scape. An extant genus with this situation, and thus having a controversial oldest record is Podocnemis Wagler, 1830. Here we present a new fossil turtle that constitutes a new species for this genus and represents its oldest so far known record, from the Miocene (Serravallian) of La Tatacoa Desert, Colombia. The new taxon named Podocnemis tatacoensis n. sp. shares with all extant members of Podocnemis a nuchal bone wider than long; lateral musk foramina at the hyoplastron-peripherals (except P. sextuberculata Cornalia, 1849), pectoral scales do not contact mesoplastra, but do contact entoplastron and epiplastra. We explored the phylogenetic position of P. tatacoensis n. sp. finding support for its inclusion as part of Podocnemis clade, particularly in a clade composed by the extant P. unifilis Troschel, 1848, suggesting a potential closer relationship of the new fossil taxon with this taxon.