Division of Paleontology, American Museum of Natural History, New York, NY 10024, USA.
Science. 2009 Dec 11;326(5959):1530-3. doi: 10.1126/science.1180350.
Characterizing the evolutionary history of early dinosaurs is central to understanding their rise and diversification in the Late Triassic. However, fossils from basal lineages are rare. A new theropod dinosaur from New Mexico is a representative of the early North American diversification. Known from several nearly complete skeletons, it reveals a mosaic of plesiomorphic and derived features that clarify early saurischian dinosaur evolution and provide evidence for the antiquity of novel avian character systems including skeletal pneumaticity. The taxon further reveals latitudinal differences among saurischian assemblages during the Late Triassic, demonstrates that the theropod fauna from the Late Triassic of North America was not endemic, and suggests that intercontinental dispersal was prevalent during this time.
描述早期恐龙的进化历史是理解它们在晚三叠世崛起和多样化的关键。然而，基础谱系的化石却很罕见。来自新墨西哥州的一种新的兽脚亚目恐龙是北美早期多样化的代表。它有几个几乎完整的骨骼，揭示了一系列原始和衍生的特征，这些特征阐明了早期蜥脚类恐龙的进化，并为包括骨骼气腔在内的新型鸟类特征系统的古老性提供了证据。该分类单元进一步揭示了晚三叠世蜥脚类动物群之间的纬度差异，表明来自北美的晚三叠世兽脚类动物群并非特有，并且表明在这段时间内存在洲际扩散。
