Maastrichtian plesiosaurs from northern Patagonia

Three relatively complete elasmosaurid plesiosaurs were recently recovered from the north of Patagonia, Argentina. They were found in the uppermost levels of the Jagüel Formation (upper Maastrichtian). One of the specimens was found only 0.3 m below the Cretaceous/Paleogene boundary, this being the youngest record of a Mesozoic reptile in Patagonia. Two specimens are referred to cf. Mauisaurus sp. and the other to Tuarangisaurus? cabazai sp. nov. This study has revealed that some character states, previously regarded as mere ontogenetic variations, could be taxonomically valid. Comparison of the Upper Cretaceous elasmosaurids of Patagonia with those from the Upper Cretaceous of central Chile, the northeastern islands of the Antarctic Peninsula, and New Zealand reinforce the hypothesis of a south Gondwanan distribution for some pelagic reptiles.