"Austroraptor" shared its paleoenvironment in the Allen Formation with diverse dinosaurs and early mammals.The discovery of "Austroraptor" increases the understanding of ecological and morphological diversity among unenlagiines, demonstrating that members of the subfamily included giant short-armed and small long-armed members, and suggesting that during the end of the Cretaceous large coelurosaurs became common after the decreasing dominance of carcharodontosaurids.