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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