First record of Toxodontidae (Mammalia, Notoungulata) from the late Miocene?early Pliocene of the southern central Andes, NW Argentina

BONINI, R., SHMIDT, G., CERDEÑO, E., REGUERO, M., CANDELA, A., SOLIS, N.

JOURNAL OF PALEONTOLOGY

PALEONTOLOGICAL SOC INC

Lugar: Lawrence; Año: 2017

0022-3360

A new species of toxodontid notoungulate, Xotodon maimarensis n. sp., is described from the MaimaráFormation (late Miocene?early Pliocene), Jujuy Province, northwestern Argentina. This is the first record of a toxodontidfrom the Eastern Cordillera. The specimen is housed at the Museo de Geología, Mineralogía y Paleontología,Instituto de Geología y Minería de la Universidad Nacional de Jujuy. It consists of an incomplete mandible preservingthe right mandibular ramus with part of the dental series, partially preserved symphysis with all the incisors, anda small portion of the left ramus without teeth. The following characters distinguish it as a new taxon: symphysislong and narrow with slight divergence of its lateral borders; strong procumbence of lower incisors and deeplyimplanted i3; chin angle lower than in X. major and X. cristatus and bulging labial keel limiting strong lateralconcavities. Comparative analysis in the context of the recently revised Neogene Toxodontidae indicates that theMaimará specimen shares mandibular features and dental characters with Xotodon and Mixotoxodon, differing fromthe latter by the more upraised symphysis. The phylogenetic position of Xotodon maimarensis n. sp. supports thetaxonomic interpretation of the studied specimen as a new species of Xotodon. This new Toxodontidae increases theknowledge of the diversity and radiation of this group of notoungulates in northwest Argentina.