Tetrastylus

Tetrastylus Temporal range: Miocene–Pleistocene PreꞒ Ꞓ O S D C P T J K Pg N
Skull of Tetrastylus intermedius, taken 2022
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Rodentia
Family:	Dinomyidae
Genus:	† Tetrastylus Ameghino, 1886
Species
Tetrastylus angustidensRusconi, 1934 Tetrastylus araucanusAmeghino, 1904 Tetrastylus atrophiatusRovereto, 1914 Tetrastylus intermediusRovereto, 1914 Tetrastylus laevigatusAmeghino, 1886 Tetrastylus montanusAmeghino, 1891

Tetrastylus is an extinct genus of dinomyid rodent that lived in South America during the Neogene and Quaternary periods. ^[1]

Distribution

Tetrastylus is known from Argentina, ^[2] Uruguay, ^[3] Brazil, and Venezuela. ^[1]

Palaeobiology

Analysis of the occipitocervical morphology of Tetrastylus intermedius specimens from northwestern Argentina suggests that this species was a terrestrial animal, but it still retained some holdover traits related to arborealism from its evolutionary past, such as larger paracondyles relative to the modern pacarana and a size-proportionate head. ^[2]

References

1. "PBDB Taxon" . Retrieved 17 November 2025.
2. Álvarez, Alicia; Ercoli, Marcos D. (2 November 2017). "Why pacaranas never say no: analysis of the unique occipitocervical configuration of † Tetrastylus intermedius Rovereto, 1914, and other dinomyids (Caviomorpha; Dinomyidae)" . Journal of Vertebrate Paleontology . 37 (6) e1385476. doi:10.1080/02724634.2017.1385476. ISSN   0272-4634 . Retrieved 17 November 2025– via Taylor and Francis Online.
3. Rinderknecht, Andrés; Ubilla, Martín; Manzuetti, Aldo; Toriño, Pablo; Perea, Daniel (5 May 2019). "First record of Tetrastylus Ameghino, 1886 (Rodentia; Dinomyidae) from the Upper Miocene of Uruguay". Revista Brasileira de Paleontologia. 22 (1): 30–37. doi:10.4072/rbp.2019.1.03. hdl: 20.500.12008/30077 . Retrieved 19 November 2025– via ResearchGate.