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

A new basal theropod dinosaur, previously unidentified, was discovered in the Ischigualasto Formation of northwestern Argentina, shedding light on the dawn of the dinosaur era around 230 million years ago. This finding challenges the traditional view that dinosaurs rose to dominance by replacing non-dinosaurian herbivores, as the study reveals a sequential extinction pattern unrelated to increasing dinosaur diversity. Researchers also reassessed Eoraptor, reclassifying it as a basal sauropodomorph, and divided the faunal record into biozones using (40)Ar/(39)Ar dating techniques. This work provides critical insights into the ecological dynamics of southwestern Pangaea during the Late Triassic.

Martinez, R. N., Sereno, P. C., Alcober, O. A., Colombi, C. E., Renne, P. R., Montañez, I. P., & Currie, B. S. (2011). A Basal Dinosaur from the Dawn of the Dinosaur Era in Southwestern Pangaea. Science, 331(6014), 206–210. https://doi.org/10.1126/science.1198467