CHEEK TEETH CHARACTERIZATION IN PYROTHERIUM (MAMMALIA: PYROTHERIA)

FOLINO, MICAELA; VERA, BÁRBARA

Congreso; 4th Palaeontological Virtual Congress; 2023

Pyrotheria is an order of Native Ungulates of South America exclusive to the Paleogene, with Pyrotherium as the best-represented genus from the Late Oligocene. It is known by a few skulls and mandibles, and a dental formula: I2/1, C0/0, P3/2, M3/3; however, the published descriptions of its teeth morphology are not sufficiently diagnostic. The objective of this work is to provide a better characterization of the dentition of Pyrotherium to differentiate upper from lower isolated cheek teeth and premolars from molars. A total of nine dental series belonging to the Museo Argentino de Ciencias Naturales "Bernardino Rivadavia", Museo de La Plata, and Museo Paleontológico "Egidio Feruglio" were studied in detail. 1) P2 and p3 have a triangular contour, P2 has conspicuous cusps, while p3 presents three well-formed lophids; in turn, P3-M3 and p4-m3 are fully bilophodont; 2) upper cheek teeth differ from the lower by a thin and occlusally straight anterior cingulum vs an expanded and occlusally curved posterior cingulid (m3 has a well-developed posterior heel); and 3) premolars distinguish from molars essentially by size: width ratio between anterior and posterior lophs, WRAP, differentiates P3 (WRAP