New Glyptodont from the Codore Formation (Pliocene), Falcón State, Venezuela, its relationship with the Asterostemma problem and the palaeobiogeography of the Glyptodontinae

CARLINI, A. A; ZURITA, A. E; SCILLATO-YANÉ, G. J.; SÁNCHEZ, R.; AGUILERA, O.

Paläontologische Zeitschrift

German Paleontological Society

Lugar: Stuttgart; Año: 2008 vol. 82 p. 139 - 152

0031�0220

Abstract One of the basal Glyptodontidae groups is represented by the subfamily Propalaehoplophorinae (late Oligocene-middle Miocene), whose genera (Propalaehoplophorus, Eucinepeltus, Metopotoxus, Cochlops and Asterostemma) were initially recognized in Argentinian Patagonia. Among these, Asterostemma was characterized by its wide latitudinal distributional range, ranging from southernmost (Patagonia) to northernmost (Colombia and Venezuela) South America. However, the generic assignation of the Miocene species from Colombia and Venezuela (A?. acostae, A. gigantea and A. venezolensis) was contested by some authors who explicitly accepted the possibility that these species could correspond to a new genus, different from those recognized in southern areas. A new comparative study of taxa from Argentinian Patagonia, Colombia and Venezuela (together with the recognition of a new genus and species for the Pliocene of the latter country) indicates that the species in northern South America are not Propalaehoplophorinae but represent the first stages in the cladogenesis of the Glyptodontidae Glyptodontinae, whose history was heretofore restricted to the late Miocene-early Holocene of southernmost South America. Accordingly, we propose the recognition of a new genus, Boreostemma, for the species from northern South America, and the restriction of Asterostemma to the Miocene of Patagonia. Thus, evidences indicate that the Glyptodontinae would in fact have arisen in the northernmost regions of this subcontinent. Their arrival to more southerly areas coincides with the acme of the “Age of southern plains”. Finally, the Propalaehoplophorinae are geographically restricted to Patagonia.