Medistylus is known from its upper teeth and isolated skulls, however, its lower dentition is currently unknown.

Its fossilized remains were found at the Cabeza Blanca and Las Cascadas localities of the Sarmiento Formation in Chubut Province of Argentina.

[1] Medistylus was one of the largest members of the subfamily Pachyrukhinae and had continuously growing teeth, like Propachyrucos.

It lacked the teeth between the first incisor and the second molar, and instead had a toothless space, known as a diastema.

It fed on low-lying grass, which caused it to incorporate abrasive particles into its common diet.