Category: Dinosaur

Postosuchus (Poest-oh-sook-us), Crocodile from Post, was a rauisuchian popularlised by the ‘Walking with Dinosaurs’ documentary. Rauisuchians were archosaurs, like dinosaurs and crocodilians. They became the top predators in the Triassic. Their extinction at the end of the Triassic allowed theropods to become the apex predators for the rest of Mesozoic.



Genera and Species

Classification: Rauisuchia, ‬Rauisuchidae

Species: P. ‬kirkpatricki, ‬P. ‬alisonae


Postosuchus had rear feet that were larger than the forefeet. The jaws had powerful biting muscles with serrated teeth and reached ‬seven ‬centimeters in length. The hide was armored like those of the crocodilians they resembled. It had an erect posture with the legs oriented beneath the body rather than sprawling outward, but it was distinct from the erect posture of dinosaurs.


LENGTH: 4 – 5 m (10 - 15 ft).

WEIGHT: 1000 – 1500 lbs.


Postosuchus was probably a solitary ambush predator, preying on the medium size Placerias. It could have reared up on its hind legs and even run short distances, but would have been primarily a quadruped.

History of Discovery

Discovery, Chatterjee ‬- ‬1985; the original fossils were scrappy and the reconstructions were based on the related Batrachotomus. Later on, better fossils allowed more detailed reconstructions.


Found in North America and best known from the Chinle where the climate was arid in northern limits and more humid in the south. The terrain was flood plains and braided rivers that supported amphibians and phytosaurs. The vegetation was varied and rich along the rivers; it included ferns, lycopsids and horsetails.


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