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Antetonitrus (Triassic sauropodomorph) anatomy and phylogeny

From: Ben Creisler

A new online paper:

Blair W. McPhee, Adam M. Yates, Jonah N. Choiniere, andFernando Abdala (2014)
The complete anatomy and phylogenetic relationships of Antetonitrus
ingenipes (Sauropodiformes, Dinosauria): implications for the origins
of Sauropoda.
Zoological Journal of the Linnean Society (advance online publication)
DOI: 10.1111/zoj.12127

We present a comprehensive description and phylogenetic analysis of
the important transitional sauropodomorph Antetonitrus ingenipes. New
information sheds light on the stepwise acquisition of sauropod-like
traits just prior to the Triassic/Jurassic boundary. Although the
forelimb of Antetonitrus and other closely related sauropodomorph taxa
retains the plesiomorphic morphology typical of a mobile grasping
structure, the changes in the weight-bearing dynamics of both the
musculature and the architecture of the hindlimb document the
progressive shift towards a sauropodan form of graviportal locomotion.
Nonetheless, the presence of hypertrophied muscle attachment sites in
the femur of Antetonitrus suggests the retention of an intermediary
form of facultative bipedalism. The term Sauropodiformes is adopted
here and given a novel definition intended to capture those
transitional sauropodomorph taxa occupying a contiguous position on
the pectinate line towards Sauropoda. A re-examination of the biased
distribution of Sauropodomorpha in the earliest Jurassic suggests the
presence of genuine palaeo-environmental processes that may have
excluded the large-bodied, graviportal taxa from participating in a
number of Early Jurassic ecosystems.