Hysodonty and Body size in rodent-like Notoungulates

REGUERO, MARCELO ALFREDO; CANDELA, ADRIANA MAGDALENA; CASSINI, GUILLERMO HERNÁN

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

Cambridge University Press

Lugar: Cambrige ; Año: 2010; p. 362 - 372

Four families of endemic rodent-like notoungulates Suborder Typotheria (“Archaeohyracidae”, Interatheriidae, Hegetotheriidae, and Mesotheriidae) show a high degree of hypsodonty. We infer the evolutionary process expressed by the variability of hypsodonty and body mass in this group, and explore if both traits are correlated. We used hypsodonty and body mass data for 36 species of Typotheria to test for an association between these features. Also we investigate the role of the occlusal designs in Typotheria and it probable association with the hypsodonty and body mass. At least two evolutionary trends were 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.