Sierra del Tontal chinchilla rat Abrocoma schistacea, photographed by Ana Julia Sandoval.

Belongs within: Hystricognathi.
Contains: Cavioidea, Erethizontidae, Octodontoidea, Chinchillidae.

The Caviomorpha are a clade uniting the Neotropical hystricomorph rodents, supported by molecular analysis (e.g. Meredith et al. 2011). They are mostly restricted to South America and the Caribbean islands, with only a single species, the porcupine Erethizon dorsatum, found in North America. Molecular data support a division between the porcupines (Erethizontidae) and Cavioidea on one side, and the Chinchilloidea and Octodontoidea on the other (Meredith et al. 2011). The position of the Abrocomidae, chinchilla rats, within the latter clade has been the subject of some debate: whereas molecular data support a more traditional position for them with the Octodontoidea, Glanz & Anderson (1990) noted a number of morphological features such as a narrowed rostrum suggesting a more direct relationship to the Chinchillidae.

    |  i. s.: Eobranisamys romeropittmanaeSS09
    |  `--+--+--Incamys Hoffstetter & Lavocat 1970MHL03, SM93
    |     |  `--NeoreomysMHL03
    |     `--+--ProtosteiromysB74
    |        `--ErethizontidaeMJ11
                 |--Dinomys branickiiIT07
                 `--Scleromys Ameghino 1887SM93

*Type species of generic name indicated


[B74] Bugge, J. 1974. The cephalic arterial system in insectivores, primates, rodents and lagomorphs, with special reference to the systematic classification. Acta Anatomica 87 (Suppl 62): 1–160.

[GA90] Glanz, W. E., & S. Anderson. 1990. Notes on Bolivian mammals. 7. A new species of Abrocoma (Rodentia) and relationships of the Abrocomidae. American Museum Novitates 2991: 1–32.

[IT07] Isaac, N. J. B., S. T. Turvey, B. Collen, C. Waterman & J. E. M. Baillie. 2007. Mammals on the EDGE: conservation priorities based on threat and phylogeny. PloS One 2 (3): e296.

[MHL03] Meng, J., Y. Hu & C. Li. 2003. The osteology of Rhombomylus (Mammalia, Glires): Implications for phylogeny and evolution of Glires. Bulletin of the American Museum of Natural History 275: 1–247.

[MJ11] Meredith, R. W., J. E. Janečka, J. Gatesy, O. A. Ryder, C. A. Fisher, E. C. Teeling, A. Goodbla, E. Eizirik, T. L. L. Simão, T. Stadler, D. L. Rabosky, R. L. Honeycutt, J. J. Flynn, C. M. Ingram, C. Steiner, T. L. Williams, T. J. Robinson, A. Burk-Herrick, M. Westerman, N. A. Ayoub, M. S. Springer & W. J. Murphy. 2011. Impacts of the Cretaceous terrestrial revolution and KPg extinction on mammal diversification. Science 334: 521–524.

[SM93] Stucky, R. K., & M. C. McKenna. 1993. Mammalia. In: Benton, M. J. (ed.) The Fossil Record 2 pp. 739–771. Chapman & Hall: London.

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