LAGOSTOMUS TELENKECHANUM, SP. NOV., A NEW LAGOSTOMINE RODENT (CAVIOMORPHA, CHINCHILLIDAE) FROM THE ARROYO CHASIC
O FORMATION (LATE MIOCENE; BUENOS AIRES PROVINCE, ARGENTINA)

LUCIANO RASIA, ADRIANA CANDELA

JOURNAL OF VERTEBRATE PALEONTOLOGY

SOC VERTEBRATE PALEONTOLOGY

Lugar: Lawrence; Año: 2017

0272-4634

We describe a new lagostomine rodent (Caviomorpha, Chinchillidae), Lagostomus telenkechanum, sp. nov.,from the Arroyo Chasic_o Formation (late Miocene; Buenos Aires Province, Argentina). Three characters permit it?s10 assignation to Lagostomus: suborbital canal for the infraorbital nerve limited by a bony lamina, well-developed posteriorprocess of the palatine, and posterior maxillary foramen located at the midpoint of the M3. In addition, we identify the newspecies based on a unique character combination (e.g., small size, palatines reaching anterior to the level of the midpoint ofP4, anterior margin of mesopterygoid fossa at the level of the anterior border of M3, upper cheek teeth more compressedanteroposteriorly and more obliquely implanted in the maxilla than in L. pretrichodactyla, L. compressidens, and L. maximus15 but less than in L. incisus, and thick cement layer in the hypoflexus). Because the early Miocene?middle Miocene genera,Prolagostomus and Pliolagostomus, are no longer recorded during the late Miocene, whereas the oldest record of the extantgenus Lagostomus is recognized at that time, we consider this period as an important turnover time in the taxonomiccomposition of the Chinchillidae. This study increases understanding of the taxonomic diversity of the late Cenozoiclagostomines, contributing to the further knowledge of the evolutionary and paleobiogeographic history of chinchillids.