Prorotodactylus
From Niedźwiedzki et al., 2013
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Prorotodactylus is an ichnofossil from a Dinosauromorph, and so we’re doing it here during our coverage of Dinosauromorphs! It is a footprint known from the Holy Cross Mountains of Poland. It is known from the Early and Middle Triassic, so sometime between 251 and 247 million years ago. As such it helps to provide more evidence to the idea that Dinosaurmorphs evolved much earlier than previously supposed - instead of evolving midway through the Triassic, the general group must have evolved close to the start of the Early Triassic, or potentially even earlier, right in the crux of the Permian-Triassic mass extinction event.
Protodactylus are tracks made by a small quadrupedal animal with a long stride, with the hind feet placed on the same line as the fore feet. it had claws on its feet and it shows distinctly Archosaurian features, with a narrow trackway and a particular pace angle that showed that Protodactylus had an erect gait like later Dinosaurs rather than a sprawling one, and also a digitigrade posture like Dinosaurs did. In fact, its tracks line up fairly neatly with Lagerpeton, and could have been made by an animal similar to Lagerpeton. It was probably transitioning to a bipedal form of locomotion.
Sources:
https://en.wikipedia.org/wiki/Prorotodactylus
Niedźwiedzki, G., S. L. Brusatte, R. J. Butler. 2013. Protodactylus and Rotodactylus tracks: an ichnological record of dinosauromorphs from the Early-Middle Triassic of Poland. Anatomy, Phylogeny, and Palaeobiology of Early Archosaurs and their Kin. Geological Society, London, Special Publications, 379.
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