New crania from Seymour Island (Antarctica) that shed light on anatomy of Eocene penguins

ACOSTA HOSPITALECHE, C.

POLISH POLAR RESEARCH

POLISH ACAD SCIENCES COMMITTEE POLAR RESEARCH

Año: 2013 vol. 34 p. 397 - 412

0138-0338

Fossil record from Antarctica is very abundant, and penguins are the best represented vertebrates. However, cranial remains are scarce, probably because most of the bones are isolated and transported from near sites. Three new penguin crania from Antarctica are described. The fossils come from the uppermost Submeseta Allomember of the La Meseta Formation (Eocene-Oligocene?), Seymour Island (Marambio), Antarctic Peninsula. A comparative description including all the available cranial material is provided from which interesting anatomical conclusions are derived. It seems that Paleogene penguin species were long skull birds, with strong nuchal crests and deep temporal fossae. One of the specimens under study is a natural endocast, barely damaged, and its osteological details are not preserved. On the contrary, the other two materials are the best preserved penguin crania from Antarctica, enabling the study of characters not observed so far. Some features significant from a functional point of view are here identified. The configuration of the nuchal crests, the temporal fossae, and the parasphenoidal processes, indicates the development of powerful muscles, the shape of sulcus for the nasal gland without a supraorbital edge is typical of piscivorous forms.