Massetognathus

Massetognathus ( ; Greek for "chewing muscle jaw") is an extinct genus of plant-eating traversodontid cynodonts. They lived during the Triassic Period about 235 million years ago, and are known from the Chañares Formation in Argentina and the Santa Maria Formation in Brazil.

== Description == Massetognathus species measured to about in length with an estimated weight between . Massetognathus was the smaller, plant-eating equivalent of the better-known Cynognathus with incisors, fang-like canines and flat-topped molars covered by low ridges, an adaptation for grinding tough plant stems, roots, and other plant materials. It had a low and flattened skull indicating that the specimen had a relatively shorter and broader snout than larger specimens. It was a fox sized animal with claws on its feet and a long dog-like tail. Like most cynodonts, there is some evidence that they laid eggs, were warm blooded, as indicated by the detailed structure of the bones, and had a body covered by hair.