Supplementary material from "A late Cretaceous mammal from Brazil and the first radioisotopic age for the Bauru Group"

Published on 2018-05-11T17:14:50Z (GMT) by
In the last three decades, records of tribosphenidan mammals from India, continental Africa, Madagascar and South America have challenged the notion of a strictly Laurasian distribution of the group during the Cretaceous. Here, we describe a lower premolar from the Late Cretaceous Adamantina Formation, São Paulo State, Brazil. It differs from all known fossil mammals, except for a putative eutherian from the same geologic unity and <i>Deccanolestes hislopi</i>, from the Maastrichtian of India. The incompleteness of the material precludes narrowing down its taxonomic attribution further than Tribosphenida, but it is larger than most coeval mammals and shows a thin layer of parallel crystallite enamel. The new taxon helps filling two major gaps in the fossil record: the paucity of Mesozoic mammals in more northern parts of South America and of tribosphenidans in the Cretaceous of that continent. In addition, high-precision U-Pb geochronology provided a post-Turonian maximal age (≤ 87.8 Ma) for the type stratum, which is overlain by the dinosaur-bearing Marília Formation, constraining the age of the Adamantina Formation at the site to late Coniacian–late Maastrichtian. This represents the first radioisotopic age for the Bauru Group, a key stratigraphic unit for the study of Cretaceous tetrapods in Gondwana.

Cite this collection

Castro, Mariela C.; J. Goin, Francisco; Ortiz-Jaureguizar, Edgardo; Carolina Vieytes, E.; Tsukui, Kaori; Ramezani, Jahandar; et al. (2018): Supplementary material from "A late Cretaceous mammal from Brazil and the first radioisotopic age for the Bauru Group". The Royal Society. Collection.