Peltephilidae and Mesotheriidae (Mammalia) from late Miocene strata of Northern Chilean Andes, Caragua

摘要

Until now, only one Cenozoic fossil mammal from the Chilean Precordillera (Arica and Parinacota Region) has been reported, Caraguatypotherium munozi (Mesotheriidae: Notoungulata). In this study, we describe a fourth specimen of C. munozi and a new armadillo species, Epipeltephilus caraguensis (Peltephilidae: Cingulata), both collected from a new site closer to the fossiliferous outcrops of the Caragua area (Serravallian Tortonian). E. caraguensis differs from other members of the family in having: two sulci in the articular surface of the mobile osteoderm; having a tubular, rough and raised anterior edge; a conspicuous transverse depression; and four widely spaced foramina. This taxon represents the youngest known peltephilid from intermediate latitudes and indicates a wide geographic distribution (Patagonia to Central Andes) of the family just prior to its extinction. The new mesothere specimen is 19% larger than previous records. The revision of the dental features of C munozi allowed the identification of an ambiguous trait in its original diagnosis, i.e. an enamel fracture was misinterpreted with the presence of a posterior sulcus on the talonid of the m(3), suggesting that further taxonomic and systematic revision for the Caragua mesothere is necessary. Although the fossil record from the Caragua area is still scarce, mesotheriines seem to be abundant at this latitude, just as has been observed at several early to late Miocene sites such as Chucal (Chile), Cerdas and Nazareno (Bolivia), as well as in southern regions such as Arroyo Chasico and Mendoza (Argentina). The presence of a new peltephilid species in Caragua sustains the hypothesis of provincialism during the Miocene in intermediate latitudes. Our findings also provide further support for probable faunal movements between intermediate and higher latitudes rather than to lower ones. (C) 2017 Elsevier Ltd. All rights reserved.