New Species of Vegavis (Neornithes) from Antarctica Highlights Unexpected Cretaceous Antarctic Diversity

A fossil bird (MLP-PV 15-I-7-52) from Marambio (Seymour) Island, Antarctica, is described, representing the best-preserved skull reported for a Cretaceous neornithine and associated postcranial elements. Morphological analysis of the articular portion of the mandible, the pterygoid, and the femur supports the assignment of this specimen to the genus Vegavis. The palatine morphology exhibits a combination of plesiomorphic and autapomorphic characters within Neognathae. Substantial differences in the size relationship between the ala preacetabularis and the femur, as well as differences between the femora of V. iaai and MLP-PV 15-I-7-52, indicate that the latter represents a new species of Vegavis. In addition, a third species of Vegavis is proposed based on the AMNH FARB 30899 specimen, previously assigned to V. iaai, which exhibits substantial differences with the above-mentioned specimens, particularly in the mandibular morphology.