YOU ARE WHAT YOU EAT: PRELIMINARY SEM-EDS ANALYSES IN ISOLATED TEETH OF VERTEBRATES FROM CAÑADÓN ASFALTO FM. (EARLY JURASSIC) TO ADDRESS THE POSSIBLE DIET OF MANIDENS CONDORENSIS

BECERRA, MARCOS G.

Congreso; 1° Reunion Virtual de Comunicaciones de la Asociación Paleontológica Argentina; 2020

Asociación Paleontológica Argentina

The Queso Rallado locality (Cañadón Asfalto Fm., early Jurassic) provided abundant isolated teeth of easy taxonomic identification representing species with known diets. Manidens condorensis is a small ornithischian whose craniomandibular morphology and function support a poor adaptation to herbivory, while its dentition indicates the opposite. The dietary characterization of extinct species can be performed by isotope analysis in enamel samples, a highly effective but destructive and expensive quantitative practice. Contrarily, SEM-EDS analyzes allow characterizing the relative atomic composition of a sample, are easily accessible and non-destructive. Preliminary SEM-EDS analyses were performed on teeth from this locality assigned to Sauropodomorpha (herbivores); Theropoda, Crocodylomorpha (carnivores); Pterosauria, Sphenodontia (omnivores); and Manidens to determine their relative atomic composition; and Cluster Analysis (CA, paired groups, Euclidean distances) and Principal Component Analysis (PCA) were realized. On average, major components are O (41.7%), C (18.9%), Ca (16.8%), and P (10.8%), and others with relative abundance less than 3.5%. PCA depicts Manidens with other herbivores in the same quadrant and differentiated from omnivorous and carnivorous groups. CA groups Manidens with other herbivorous species, and separates the three dietary groups, where the difference in Carbon levels between species is enough to justify the separation between dietary assemblages. This study points to a herbivore diet for Manidens, which shares high Carbon proportions with the herbivorous species, while carnivores show intermediate and omnivores show low values. The preliminary results are encouraging, but comprehensive SEM-SPC sampling and more detailed studies are needed to firmly support this method for dietary inference on fossil species.