• DOI:10.1126/science.1198467
• Corpus ID: 33506648

A Basal Dinosaur from the Dawn of the Dinosaur Era in Southwestern Pangaea

@article{Martnez2011ABD,
  title={A Basal Dinosaur from the Dawn of the Dinosaur Era in Southwestern Pangaea},
  author={Ricardo N. Mart{\'i}nez and Paul C. Sereno and Oscar A. Alcober and Carina E. Colombi and Paul R. Renne and Isabel Patricia Monta{\~n}ez and Brian S. Currie},
  journal={Science},
  year={2011},
  volume={331},
  pages={206 - 210}
}

• R. Martínez, P. Sereno, +4 authors B. Currie
• Published 14 January 2011
• Environmental Science, Geography
• Science

Two hundred thirty million years ago, in what is now Argentina, dinosaurs could be found as the dominant carnivores or as small herbivores. Upper Triassic rocks in northwestern Argentina preserve the most complete record of dinosaurs before their rise to dominance in the Early Jurassic. Here, we describe a previously unidentified basal theropod, reassess its contemporary Eoraptor as a basal sauropodomorph, divide the faunal record of the Ischigualasto Formation with biozones, and bracket the formation with 40Ar/39Ar ages. Some 230 million years ago in the Late Triassic (mid Carnian), the earliest dinosaurs were the dominant terrestrial carnivores and small herbivores in southwestern Pangaea. The extinction of nondinosaurian herbivores is sequential and is not linked to an increase in dinosaurian diversity, which weakens the predominant scenario for dinosaurian ascendancy as opportunistic replacement.