New evidence of Dinocephalia in the Guadalupian (Permian) of Brazil

The Boqueirão Farm outcrop (Rio do Rasto Formation) in São Gabriel, Rio Grande do Sul, is amongst the Brazilian Guadalupian (Permian) fossil sites with the greatest tetrapod taxonomic diversity. The site has yielded the therapsids Rastodon procurvidens and Pampaphoneus biccai, and the temnospondyl Konzhukovia sangabrielensis, suggesting a Capitanian Age. Here, we present new dinocephalian specimens: a fibula (UNIPAMPA 0796), isolated teeth (UNIPAMPA 0938 and 0939), and re-evaluated mandibular elements of Pampaphoneus biccai (UNIPAMPA 0759). Due to the isolated nature of UNIPAMPA 0796, refined taxonomic attribution was not possible; however, comparisons with published specimens allowed its identification as a right dinocephalian fibula. Two isolated teeth (UNIPAMPA 0938 and 0939) were found in a conglomerate layer above that where UNIPAMPA 0759 was collected. Both teeth have broken crown apices and resemble the post-canines of Pampaphoneus biccai, though the serrations are not preserved. In addition, we reassess previously unidentified elements of UNIPAMPA 0759 and recognise a posterior portion of a mandibular ramus, contributing to understanding of the anatomy of P. biccai. The new specimens enhance the Brazilian record of Dinocephalia and indicate the presence of these animals at several distinct sedimentary levels of the Boqueirão Farm outcrop. Continuous exploration of productive outcrops in the Rio do Rasto Formation will undoubtedly enhance understanding of Permian tetrapod diversity in Western Gondwana.