ENDOCASTS OF NOTOUNGULATES AND BRAIN EVOLUTION IN EXTINCT SOUTH AMERICAN UNGULATES

DOZO, MARÍA TERESA

Renaissance Cleveland Hotel, Cleveland, Ohio, USA

Simposio; Simposio: New Directions in the Study of Fossil Endocasts: a Symposium in Honour of Harry J. Jerison, Coord: G. Hurlburt and M. Silcox. Sixty-eighth Annual Meeting Society of Vertebrate Paleontology; 2008

Society of Vertebrate Paleontology

The Notoungulata were South America´s most diverse (morphologically as well as taxonomically) and successful indigenous ungulate group. Three suborders are recognized: Notioprogonia (primitive notoungulates of Paleocene and Eocene), Typotheria (notoungulates resembling  rabbits or large rodents) and Toxodontia (notoungulates which ranged from sheep-like to rhino-like in size body form). We studied endocasts from ten of the fourteen families of notoungulates, which were of Casamayoran, Divisaderan, Deseadan, Colhuehuapian, Santacrucian, Friasian, Montehermosan and Chapadmalalan South American Land Mammals Ages (Eocene-Pliocene). Paleoneurological studies of these notoungulates allow the following hypotheses as preliminary conclusions: It was not possible to discern or describe a single common encephalic pattern to the notoungulates with regard to external brain morphology. The neuromorphological diversity of the notoungulates is consistent with their morphological as well as taxonomical diversity. The neuromorphological diversity of the notoungulates is also consistent with different neurological response to of different ecological types. The neuromorphological traits are consistent with the osteological and dental traits that have been used to define different examples of convergence between notoungulates and North American (perissodactyls and artiodactyls) and South American (rodents) mammals. This indicates that equivalent ecological types develop brains with similar morphologies.