INIBIOMA   20415
INSTITUTO DE INVESTIGACIONES EN BIODIVERSIDAD Y MEDIOAMBIENTE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Skull morphology of Spheniscus urbinai (Aves, Sphenisciformes) and the evolution of the cranial pneumatic systems in penguins
Autor/es:
ACOSTA HOSPITALECHE, C.; PAULINA CARABAJAL, A.
Lugar:
VIRTUAL
Reunión:
Conferencia; The Palaeontological Association Annual Meeting; 2020
Resumen:
New data on the osteology, palaeoneurology and the pneumatic system of Spheniscusurbinai from the Miocene of southern South America are provided. Based on theexamination of eight crania, and after extensive comparisons with living species ofSpheniscus, we conclude that, even considering the intraspecific differences, the skullof S. urbinai is larger, the fossa temporalis is deeper, and the bill is characterized bythe widening of the base and the rostrum, and the curvature of the apex. The markedreduction of the cranial pneumaticity of penguins in comparison, for example, with thealbatross Diomedea exulans was present early in the Eocene, as observed in the Antarcticpenguin MLP 12-I-20-1 (although not in the coeval Anthropornis grandis). S. urbinaiexhibits slightly larger cranial pneumaticity than that observed in the living Spheniscusand Pygoscelis, and also that in the Miocene P. calderensis. Other differences include areduction of absolute brain size, the wulst, the olfactory passages, and nasal cavities inliving taxa. The skull cavities, restricted to the olfactory region, correspond to pneumatictrabecular cells in the Eocene specimens, whereas they merge forming passages and largerdiverticula sinuses in the Miocene specimens. These structures also form a ring surroundingthe cerebellar region dorsolaterally in living Spheniscus and Pygoscelis.