The Bipedal Stem Crocodilian Poposaurus gracilis: Inferring Function in Fossils and Innovation in Archosaur Locomotion

  title={The Bipedal Stem Crocodilian Poposaurus gracilis: Inferring Function in Fossils and Innovation in Archosaur Locomotion},
  author={Jacques A. Gauthier and Sterling J. Nesbitt and Emma R. Schachner and Gabriel S Bever and Walter G. Joyce},
ABSTRACT We introduce a spectacular new specimen of a Late Triassic stem crocodilian identified as Poposaurus gracilis. It is part of a poorly known group, Poposauroidea, that, because of its striking similarities with contemporaneous stem avians (“dinosaurs”), has long puzzled archosaur paleontologists. Observed vertebrate locomotor behaviors, together with exceptional preservation of distinctive anatomical clues in this fossil, enable us to examine locomotor evolution in light of new… 

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