Priosphenodon

Priosphenodon is an extinct Rhynchocephalian known from the Late Cretaceous of Argentina. It is believed to have been a fairly large herbivore, having a longer snout than modern tuatara, with teeth specialised for shearing plant matter. In fact, a recent study found several structural similarities to mammal teeth. Two species are known, "P. avelesi" and "P. minimus".
Fossils of the genus have been found in the Candeleros and Cerro Barcino Formations in Argentina.