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Panphagia protos, a VERY basal sauropodomorph



Very cool stuff in PLoS ONE.  

Link: http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0004397

Abstract: 

Background: 
The earliest dinosaurs are from the early Late Triassic (Carnian) of South 
America. By the Carnian the main clades Saurischia and Ornithischia were 
already established, and the presence of the most primitive known 
sauropodomorph Saturnalia suggests also that Saurischia had already diverged 
into Theropoda and Sauropodomorpha. Knowledge of Carnian sauropodomorphs has 
been restricted to this single species.

Methodology/Principal Findings:
We describe a new small sauropodomorph dinosaur from the Ischigualsto Formation 
(Carnian) in northwest Argentina, Panphagia protos gen. et sp. nov., on the 
basis of a partial skeleton. The genus and species are characterized by an 
anteroposteriorly elongated fossa on the base of the anteroventral process of 
the nasal; wide lateral flange on the quadrate with a large foramen; deep 
groove on the lateral surface of the lower jaw surrounded by prominent dorsal 
and ventral ridges; bifurcated posteroventral process of the dentary; long 
retroarticular process transversally wider than the articular area for the 
quadrate; oval scars on the lateral surface of the posterior border of the 
centra of cervical vertebrae; distinct prominences on the neural arc of the 
anterior cervical vertebra; distal end of the scapular blade nearly three times 
wider than the neck; scapular blade with an expanded posterodistal corner; and 
medial lamina of brevis fossa twice as wide as the iliac spine.

Conclusions/Significance: 
We regard Panphagia as the most basal sauropodomorph, which shares the 
following apomorphies with Saturnalia and more derived sauropodomorphs: basally 
constricted crowns; lanceolate crowns; teeth of the anterior quarter of the 
dentary higher than the others; and short posterolateral flange of distal 
tibia. The presence of Panphagia at the base of the early Carnian Ischigualasto 
Formation suggests an earlier origin of Sauropodomorpha during the Middle 
Triassic.


Adam Pritchard

acp002@mcdaniel.edu