Hypsodonty and body size in rodent-like notoungulates

REGUERO, CANDELA Y CASSINI

The Paleontology of Gran Barranca: Evolution and Environmental Change through the Middle Cenozoic of Patagonia

CAMBRIDGE UNIV PRESS

Año: 2010; p. 362 - 368

Four families of endemic rodent-like notoungulates of the Suborder Typotheria (“Archaeohyracidae,” Interatheriidae, Hegetotheriidae, and Mesotheriidae) show a high degree of hypsodonty. We evaluate the evolutionary pattern expressed by the variability of hypsodonty and body mass in this group, and consider whether the traits are correlated. We used hypsodonty and body mass data for 36 species of Typotheria to test for an association between these features. Major evolutionary changes in hypsodonty and body size in Typotheria occurred during the Eocene-Oligocene transition (EOT) and it is well documented in the Patagonian fossil record at Gran Barranca. At least two evolutionary trends are recognized in two clades of Typotheria: (1) in Mesotheriidae an increasing of the hypsodonty, associated with increasing of the body mass in species with complex occlusal designs, and (2) the Hegetotheriidae are characterized by possessing high crown teeth with simplified occlusal designs and small body sizes (Hegetotheriidae Pachyrukhinae). The Hegetotheriidae Pachyrukhinae show the highest indices of hypsodonty and were the smallest typotheres