THE MOST COMPLETE KNOWN NEOGENE GLYPTODONTIDAE (MAMMALIA, XENARTHRA, CINGULATA) FROM NORTHERN SOUTH AMERICA: TAXONOMIC, PALEOBIOGEOGRAPHIC, AND PHYLOGENETIC IMPLICATIONS

The knowledge of northern South American Glyptodontidae (Mammalia, Xenarthra, Cingulata) is very scarce compared with that of southern South American taxa, which have been systematically studied since the 19th century. Recently, the northern taxa (originally assigned to the Glyptodontidae Propalaehoplophorinae Asterostemma and Propalaehoplophorus) have been reinterpreted as basal Glyptodontinae, belonging to the new genus Boreostemma. In this contribution, we present and describe the most complete Neogene Glyptodontidae from northern South America (middle Miocene of the Honda Group, La Venta, Colombia), and its main taxonomic, paleobiogeographic, and phylogenetic implications. This new material expands the morphological characterization of B. acostae and corroborates differences compared with Glyptodontidae from Miocene southern South America. A cladistic analysis corroborates the monophyly of the Glyptodontinae, that B. acostae and B. venezolensis being the sister group of the remaining taxa of Glyptodontinae. The traditionally recognized genera (e.g., Glyptodon and Glyptotherium) constitute natural groups. Whereas the Miocene seems to represent a diversification period for Glyptodontidae in southern South America, the recorded taxa in northern South America are restricted with certainty only to the Glyptodontinae Boreostemma.