A new peculiar species of the subterranean rodent Ctenomys (Rodentia, Ctenomyidae) from the Holocene of central Argentina

DE SANTI, NAHUEL A.; VERZI, DIEGO H.; OLIVARES, A. ITATÍ; PIÑERO, PEDRO; MORGAN, CECILIA C.; MEDINA, MATÍAS E.; RIVERO, DIEGO E.; TONNI, EDUARDO P.

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2020

0895-9811

The subterranean rodent Ctenomys is the single living representative of the familyCtenomyidae, and the most diverse genus within Hystricomorpha. Its fossil record beginsin the late Pliocene and shows an increase in diversity since the Pleistocene. Here wedescribe a new middle-sized Ctenomys species from a large cranial sample collected at thearchaeological site Quebrada del Real 1 in the high plains of the Pampa de Achala(Córdoba, Argentina). For this goal, we analyzed the cranial and mandibular shapevariation through a geometric morphometric approach, and performed a comparativemorphological analysis in the context of the living Ctenomys. The new species ischaracterized by having a wide rostrum with a deep rostral fossa, strong temporal fossa inthe frontal, upper incisors strongly procumbent and with grooved enamel, and mandiblewith low corpus, long procumbent diastema and descending masseteric crest. Aphylogenetic analysis demonstrated its close affinity with Ctenomys osvaldoreigi, an extantspecies from a nearby area. The new species represents the first notice of an extinctCtenomys species from the Holocene. Given its peculiar morphology, the extinction of thisspecies would have resulted in significant loss of morphological diversity, thus constrainingthe current boundaries of variation of the genus. The last record of the new species occursin a period characterized by marked extinction of small mammals in southern SouthAmerica mainly due to anthropic causes.