New findings in the Adamantina Formation (Bauru Group) at Campina Verde municipality enlarge the diversity of vertebrates from the Late Cretaceous of Triângulo Mineiro (MG).

AGUSTIN MARTINELLI; MARINHO, THIAGO S.; FABIANO IORI; LUIZ CARLOS RIBEIRO

Simposio; X Simpósio Brasileiro de Paleontologia de Vertebrados; 2016

Field work conducted by the staff of the Centro de Pesquisas Paleontológicas Llewellyn Ivor Price of the Universidade Federal do Triângulo Mineiro since 2009 at Campina Verde municipality (MG) have resulted in the discovery of a diverse vertebrate fauna from the Adamantina Formation (Bauru Basin). It represents massive red sandstones associated to fluvial deposits. The baurusuchid Campinasuchus dinizi was described in 2011 from Fazenda Três Antas (FTA) site and after that, preliminary descriptions of a partial crocodyliform egg, abelisaurid teeth and fish remains have been done. Recently, the fossil sample has been considerably increased including the following specimens: (i) more and partially articulated fish remains referred to Lepisosteiformes from FTA site. Antero-posteriorly short and medially convex jaws are similar to those of Atractosteus and Cuneatus. Also, the subopercular bone has a denticulated distal edge similar to A. falipoui from the Lower Cretaceous of Africa. (ii) An almost complete and articulated skeleton referred to Caipirasuchus sp. (Notosuchia, Sphagesauridae) was found in FTA site. At present, this genus is restricted to the Adamantina Formation outcropping in São Paulo state, with the species C. paulistanus, C. stenognathus and C. montealtensis. The new specimen, with a total body length of 70 cm, has a combination of features that does not allow its inclusion in any of the hitherto known species. Those observed differences (e.g., last two maxillary teeth located posterior to anterior edge of infraorbital fenestra, elongated lateroventral maxillo-jugal suture ?about ½ the anteroposterior maxillar length?, large facial process of premaxilla, contact between posterior crest of quadrate and posterior end of squamosal forming an almost 90° flaring roof of the squamosal) could have intra-specific or inter-specific significance, and if confirmed, the latter could correspond to temporal and/or phylogenetic differences among the genus. (iii) Finally, an isolated right femur of Noasauridae was found in a new outcrop located about 6kms from FTA. It is a slender bone, anteriorly bowed, with 13.2cm of total length. It is similar to that of the nosaurids Masiakasaurus and Velocisaurus from the Late Cretaceous of Madagascar and Argentina, respectively, all sharing a sub-triangular proximal shaft section and a large medial fossa next to the 4° trochanter. Field works at the west portion of Triângulo Mineiro are providing new clues on the diversity of the Late Cretaceous communities of the Bauru Group, but this assemblage is still less diverse than those from western São Paulo, probably due to sampling.