A new plesiosaur (Reptilia: Sauropterygia) specimen from the Upper Cretaceous of West Antarctica, with comments on the ontogeny and morphological diversity of the elasmosaurid pelvic girdle

Although knowledge of Mesozoic marine reptiles from Antarctica has improved considerably in recent years, associated and well-preserved skeletal material of these animals remains uncommon. Here we describe a largely complete, closely associated plesiosaur pelvic girdle recovered from the uppermost Cretaceous (Maastrichtian) Sandwich Bluff Member of the Lopez de Bertodano Formation of Vega Island, in the James Ross Basin of the northernmost Antarctic Peninsula. The new specimen exhibits characters that allow its referral to Elasmosauridae, but its incompleteness precludes a more precise taxonomic determination. Ontogenetically variable and systematically useful features of the clasmosaurid pelvis are reviewed and discussed. The new specimen improves knowledge of Southern Hemisphere clasmosaurids just prior to the K/Pg extinction event.

Annals of Carnegie Museum

Annals of Carnegie Museum

86

1943-6300

N/A

2

14