Bird-Like Anatomy, Posture, and Behavior Revealed by an Early Jurassic Theropod Dinosaur Resting Trace
2009

Bird-Like Anatomy and Behavior in an Early Jurassic Dinosaur

publication Evidence: moderate

Author Information

Author(s): Andrew R. C. Milner, Jerald D. Harris, Martin G. Lockley, James I. Kirkland, Neffra A. Matthews

Primary Institution: St. George Dinosaur Discovery Site at Johnson Farm

Hypothesis

Did early theropods exhibit bird-like resting postures and forelimb orientations?

Conclusion

The study found that early theropods had a resting posture and forelimb orientation similar to modern birds, indicating these traits evolved much earlier than previously thought.

Supporting Evidence

  • The trackway included well-defined impressions of both hands and feet.
  • The dinosaur's posture while resting was symmetrical and similar to that of modern birds.
  • Manus impressions showed palms facing medially, unlike previously attributed theropod prints.

Takeaway

Scientists discovered that an ancient dinosaur rested like a bird, showing that some bird-like features appeared a long time ago.

Methodology

The researchers analyzed a well-preserved theropod trackway from the Lower Jurassic, documenting its morphology and associated behaviors.

Limitations

The study is based on fossil evidence, which may not capture all aspects of the dinosaur's behavior.

Digital Object Identifier (DOI)

10.1371/journal.pone.0004591

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