Teeth complexity, hypsodonty and body mass in Santacrucian (Early Miocene) notoungulates (Mammalia)

CASSINI, GUILLERMO HERNÁN; HERNANDEZ DEL PINO, SANTIAGO; MUÑOZ, NAHUEL ANTÚ; ACOSTA, WALTER GUSTAVO; FERNANDEZ, MERCEDES; BARGO, MARÍA SUSANA; VIZCAÍNO, SERGIO FABIÁN

EARTH AND ENVIRONMENTAL SCIENCE TRANSACTIONS OF THE ROYAL SOCIETY OF EDINBURGH

ROYAL SOC EDINBURGH

Lugar: Edinburgo; Año: 2017 vol. 106 p. 303 - 313

1755-6910

Notoungulates, native South American fossil mammals, havebeen recently objective of several palaeoecological studies. Ecomorphology andbiomechanics of the masticatory apparatus, together with micro and mesowearanalyses on tooth enamel, were applied in order to understand their palaeobiology.In particular, the relationship between some dental traits (hypsodonty,occlusal surface area and complexity) and body mass is still poorly understood.These features were measured by means of the hypsodonty index (HI), occlusalsurface area (OSA) and tooth area (OTA), enamel crest complexity (ECC) andlength (OEL). The relationships between these indices were evaluated in fivepan-contemporaneous Santacrucian Notoungulata genera from Patagonia: Adinotherium and Nesodon (Toxodontia), Interatherium,Protypotherium and Hegetotherium (Typotheria). While OSA, OTAand OEL were size dependent and strongly correlated, HI and ECC were size independent.All notoungulates analysed have very hypsodont teeth, indicating high rates oftooth wear in response to an increase of abrasives consumed with the food;their tooth occlusal area and complexity could be related to chewing effortsassociated with the toughness of the plants consumed. HI, OSA and ECC wereconsidered useful for palaeoecological reconstructions, but the resultspresented here show that these three features are integrated as a complex, soshould not be evaluated separately.