Medistylus is an extinct genus of pachyrukhine hegetotheriid. It lived in Argentina during the Late Oligocene. 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
Temporal range: Late Oligocene (Deseadan)
~29–21 Ma
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Notoungulata
Family: Hegetotheriidae
Subfamily: Pachyrukhinae
Genus: Medistylus
Ameghino 1903
Type species
Medistylus dorsatus
Ameghino, 1903

Description

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Medistylus was one of the largest members of the subfamily Pachyrukhinae and had continuously growing teeth, like Propachyrucos. It had a huge pair of front incisors, set obliquely. 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. It had a large fossa at the insertion of the superficial and deep masseter muscles.[1]

References

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  1. ^ a b Reguero, Marcelo A.; Dozo, María Teresa; Cerdeño, Esperanza (2007). "A poorly known rodentlike mammal (Pachyrukhinae, Hegetotheriidae, Notoungulata) from the Deseadan (Late Oligocene) of Argentina. Paleoecology, biogeography, and radiation of the rodentlike ungulates in South America". Journal of Paleontology. 81 (6): 1301–1307. Bibcode:2007JPal...81.1301R. doi:10.1666/05-100.1. ISSN 0022-3360. S2CID 55259241.