Un coracoides de ave del Cretácico Superior de Patagonia, Argentina

Abstract

In the present paper, the new genus and species of neornithine bird, Lamarqueavis australis is described. The specimen consists on an isolated coracoid collected in Campanian-Maastrichtian beds of the Allen Formation, at the Bajo Trapalcó fossiliferous locality, Río Negro Province, Argentina. The specimen constitutes the first record from South America of the neornithine clade Cimolopterygidae, a group of modern-like birds that previously were known from Cretaceous and Paleogene strata of North America, Europe, and Asia. The new genus Lamarqueavis also includes previously described taxa, such as “Cimolopteryx” minima and “C.” petra, from the Late Cretaceous of North America. The new specimen fits well with the traditional hypothesis that suggests that derived ornithurine birds were the dominant taxa of shoreline and marine habitats during the Cretaceous, whereas in inland environments basal taxa were more abundant. Finally, on the basis of the meagre fossil neornithine record of the Cretaceous, previous hypotheses concerning the place of cradle of modern birds in Antarctica or North America are discussed.