A review of the fossil record of gondwanan turtles of the clade meiolaniformes

Abstract

Gondwanan turtles of the clade Meiolaniformes have a fossil record that reaches back to the Early Cretaceous of Patagonia (South America) and Australia. From the Late Cretaceous to the Middle Eocene the group is restricted to Patagonia, but appears to be extirpated afterwards. However, the fossil record of the clade commences once again in the Late Oligocene in Australia and surrounding islands and continues until the Holocene. Current phylogenies recognize Meiolaniidae as a subclade within Meiolaniformes. Early meiolaniforms show terrestrial adaptations, but their dietary preferences remain unclear. Meiolaniids, in contrast, show strong terrestrial adaptations, were herbivorous and appear to have been preadapted to floating across short to intermediate oceanic distances. A taxonomic review of the group concludes that of the 15 named taxa, 11 are nomina valida, 3 are nomina invalida and 1 is not recognized as a meiolaniid.