Martinez RN, Alcober OA (2009) A Basal Sauropodomorph (Dinosauria: Saurischia) from the Ischigualasto Formation (Triassic, Carnian) and the Early Evolution of Sauropodomorpha. PLoS ONE 4(2): e4397. doi:10.1371/journal.pone.0004397 [Panphagia protos]

Abstract: The early evolution of the Dinosauria, including the split between its two main clades Saurischia and Ornithischia, remains poorly understood because of the scarcity of fossiliferous terrestrial beds covering the late Middle Triassic (Ladinian) and early Late Triassic (Carnian).

The best preserved record of Ladinian continental tetrapod assemblages comes from the Chan˜ ares Formation in Northwestern Argentina. The representative fauna includes the best known sister taxa of Dinosauria, the dinosauriforms Marasuchus lilloensis and Pseudolagosuchus talampayensis.

The recently described non-dinosaurian dinosauromorphs Dromomeron romeri and Silesaurus opolensis, found in rocks of younger (Norian) age, demonstrate that basal dinosauromorphs survived into the Late Triassic. Judging from the record of the Carnian Ischigualasto Formation assemblage (ca. 228 Ma), in which the two main clades of Dinosauria has been established, the radiation of Dinosauria, and the split of Saurischia into its two main branches, Theropoda and Sauropodomorpha, occurred in a few million years, between the sedimentation of the Ladinian Chan˜ ares and the Carnian Ischigualasto Formations

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