New rhynchocephalian specimen in the Late Triassic of southern Brazil and comments on the palatine bone of Brazilian rhynchocephalians

Abstract

Triassic rhynchocephalians from South America are relatively sparse, based on one taxon from the Norian of Argentina (i.e., Sphenotitan leyesi) and three records from the Late Carnian (i.e., indet. taxon) and Norian (i.e., Clevosaurus brasiliensis and indet. taxon) of Brazil. We described here a new occurrence of rhynchocephalians from a new Late Carnian locality of southern Brazil, based on an isolated palatine with teeth, referred to that group due to the morphological similarity whit the palatines of the other taxa of the same group. The specimen comes from the municipality of Vale do Sol, collected within a layer with abundant material of Hyperodapedon sp. (Rhynchosauria), which is referred to the Hyperodapedon Assemblage Zone (Late Carnian) of the Candelária Sequence, Santa Maria Supersequence. The isolated palatine here described cannot be referred to any hitherto known species, but it provides an additional record for the few putative ones of Carnian age in South America. Moreover, we figure and describe the palatine anatomy of Clevosaurus brasiliensis, based on two specimens, which have relevant data poorly addressed in previous contributions.