Three-dimensional preservation of foot movements in Triassic theropod dinosaurs

Article Abstract:

Early Mesozoic theropods sank down, and forward, and extracted the foot with convergent toes, according to evidence provided by dinosaur trackways in the Orsted Dal Member of the uppermost Fleming Fjord Formation of Jameson Land, East Greenland. These elongate tracks show complete toe convergence, which is retained in birds as a primitive feature. It is possible that the Greenlandic trackways were created by cretosaur feet in which the hallux was somewhat abducted and flexed, but not reversed.

Author: Shubin, Neil H., Gatesy, Stephen M., Jenkins, Farish A., Jr., Middleton, Kevin M.
Dinosaurs, Evolution (Biology)

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An Early Jurassic jumping frog

Article Abstract:

The earliest known frogs are found to possess limbs resembling caecilians, but have some characteristics such as fusion of the caudal vertebrae that is similar to anurans. The caudopelvic transformation from Paleozoic amphibians to the present day frogs can perhaps be explained with respect to the Early Triassic amphibian, the Triadobatrachus massinoti, with features resembling frogs.

Author: Shubin, Neil H., Jenkins, Farish A., Jr.
Analysis, Observations, Morphology (Biology), Frogs, Paleontology, Paleozoic Era, Morphology

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