A new guinea pig (Rodentia, Caviomorpha) from northwestern Argentina: implications for the origin of the genus Cavia.

We describe a new caviomorph rodent,Cavia cabrerai, sp. nov. (Caviidae, Caviinae), from the upper levels of Andalhuala Formation (San Fernando Norte locality, Catamarca Province, northwestern Argentina), which represents the oldest fossil record of the genus. The new species differs from extant and extinct species ofCaviaby a unique combination of characters: large size, proportionally anteroposteriorly elongated molars, slightly anteroposteriorly compressed prisms, relatively shallow primary lingual flexids, abundant cement in the lingual flexids, and anterolingual widening of the second crests of cheek teeth. A phylogenetic analysis indicates thatCavia cabrerai, sp. nov., is the sister taxon of extantCaviaspecies and displays dental characters more plesiomorphic than the latter. Some characters ofC. cabrerai, sp. nov., namely, compression of prisms and depth of flexids, are morphologically intermediate between the related extinct CaviinaePalaeocaviaand the extant species ofCavia. An ash bed dated at 4.72 ± 0.08 Ma that overlies the fossiliferous level of the new material supports the presence ofCaviaclose to the Miocene-Pliocene boundary. The origin ofCaviamay have been triggered by the expansion of relatively open and arid environments that arose near the Miocene-Pliocene boundary.http://zoobank.org/urn:lsid:zoobank.org:pub:3A6E6666-1FBE-4C6E-95CA-4B33927A414D SUPPLEMENTAL DATA—Supplemental materials are available for this article for free atwww.tandfonline.com/UJVP Citation for this article: Candela, A. M., and R. A. Bonini. 2017. A new guinea pig (Rodentia, Caviomorpha) from northwestern Argentina: Implications for the origin of the genusCavia. Journal of Vertebrate Paleontology. DOI: 10.1080/02724634.2017.1352591. [ABSTRACT FROM PUBLISHER]