The Triassic eucynodont Candelariodon barberenai revisited and the early diversity of stem prozostrodontians

MARTINELLI, AGUSTIN; SOARES, MARINA; OLIVEIRA, TÉO; RODRIGUES, PABLO; SCHULTZ, CESAR

ACTA PALAEONTOLOGICA POLONICA

INST PALEOBIOLOGII PAN

Año: 2017 vol. 62

0567-7920

The dental anatomy of Candelariodon barberenai Oliveira, Schultz, Soares and Rodrigues, 2011, from the Dinodontosaurus Assemblage Zone (Pinheiros-Chiniquá Sequence ?late Ladinian-early Carnian? Santa Maria Supersequence) of south Brazil, is redescribed. Candelariodon was originally classified as Eucynodontia incertae sedis and our analysis recovered this taxon deeply nested within Probainognathia, as the sister taxon of Potheriodon plus Prozostrodontia. The lower postcanine dentition of Candelariodon has several apomorphies shared with Prozostrodon, Santacruzgnathus, Brasilodon/Brasilitherium, and some basal mammaliaforms (Morganucodon, Megazostrodon), such as a lingual cingulum with discrete cusps "e" and "g" and two distinct morphologies in the tooth row. The reinterpretation of Candelariodon as a probainognatian cynodont more derived than Probainognathus and the rich Brazilian fossil record documents an important adaptive radiation of non-mammaliaform prozostrodontians and closely related forms prior to the origin of the mammaliaform clade.