A new capybara (Rodentia, Caviidae) from late Miocene Las Flores Formation, San Juan Province, Argentina, and its phylogenetic implications

CERDEÑO, E; CONTRERAS, V.H.; DESCHAMPS, C.; PÉREZ, M.E.

ACTA PALAEONTOLOGICA POLONICA

INST PALEOBIOLOGII PAN

Lugar: Varsovia; Año: 2019 vol. 64 p. 199 - 212

0567-7920

A new Hydrochoerinae rodent (Caviidae) is described based on thespecimen INGEO-PV 87. It was recovered from the Late Miocene Las FloresFormation, outcropping at the Puchuzum locality, San Juan Province, Argentina.The comparative study allows us to recognize it as a new species of the genus Cardiatherium, C. calingastaense sp. nov., based on a particular combination ofcharacters, among which the following can be highlighted: p4 with internalfissures (h2i and h3i) equally deep as in Cardiatheriumparanense, secondary external fissure (h2e) as in C. patagonicum, and lacking the fifth internal fissure (h5i) and supernumeraryinternal fissure (hsni), as in C.paranense; m3 with a conspicuous labial column in the posterior ramus of thesecond prism (prIIa); very deep primary and secondary external fissures (HPE,HSE) in upper cheek teeth, the former producing a labial strong step-shapedprofile in M2; sagittal crest on the parietals; bullae small in ventral view; scars of theorigin of the masseter medialis muscle with an anterior projection up to the level ofthe incisive foramen and the maxilla-premaxilla suture. The phylogeneticanalysis supports the taxonomic proposal of creating a new species of Cardiatherium and shows C. calingastaense sp. nov. as the sistergroup of the other species of the genus. The lineage leading to the clade Cardiatherium + largest capybaras wouldhave originated at least during the Chasicoan SALMA (early Late Miocene). C. calingastaense sp. nov. adds to theprevious record of C. chasicoense andC. paranense in the Late Miocene of SanJuan and Mendoza provinces, respectively, thus increasing the diversity ofcapybaras in central-west Argentina.