First cranium of the giant penguin Anthropornis in Marambio/Seymour Island

REGUERO, MARCELO; ACOSTA HOSPITALECHE, CAROLINA; HAIDR, NADIA SOLEDAD

Davos

Conferencia; Polar 2018; 2018

Anthropornis, described more than a century ago, is one of the most fascinating species of fossil penguins. The robustness and massiveness of its bones caught the attention of Carl Wiman in 1905, and made it worthy of the name Anthropornis, which means "man-bird". Both species of this genus were only known through isolated bones (tarsometatarsi), until some articulated skeletons of Palaeeudyptes from the Antarctic Eocene allowed by comparison the reinterpretation and assignment of associated limb remains to Anthropornis sp. Now, a new skeleton found in Priabonian levels of the Submeseta Formation, Marambio (Seymour) Island, Antarctic Peninsula, constitutes the first specimen with a complete tarsometatarsus (that allowed the assignment to Anthropornis grandis), and the cranium, as well as many other bone fragments. The importance of this finding is that it is the first fossil cranium of Antarctica that can be assigned to any of the known species of penguins since all the other findings of cranial elements constitute isolated remains. Anthropornis grandis has an extremely elongated and slender bill and a small neurocranium, compared to modern penguins. Dimensions of the occipital condyle and the foramen magnum, however, are congruent with a large cranium and neck. These proportions seem to be the rule among large and giant penguins during the Paleogene.