Petrified Forest National Park Triassic Reptiles

Reptiles of the Late Triassic

Archosaurian reptiles were the predominant faunal element in the Late Triassic of Northern Arizona representing the majority of terrestrial carnivores and herbivores. The archosaurs or "ruling reptiles," consist of the dinosaurs, crocodiles, birds, and Triassic crocodile-like forms such as aetosaurs, phytosaurs, rauisuchians, and crocodylomorphs. Except for modern birds and crocodiles, all of these forms are now extinct. However, because of recent findings of dinosaurs with feathers in China and other similarities between the two groups, many paleontologists now consider birds a modern form of dinosaur!

Phytosaurs are the most common fossil vertebrate found at Petrified Forest National Park. These animals were very crocodilian in nature and probably lived a very similar lifestyle frequenting the streams and rivers of the Late Triassic. They most likely fed on fish and smaller reptiles.

Aetosaurs were large, quadrupedal, heavily armored crocodile-like reptiles. They had a short head with blunt peg-like teeth suggesting an herbivorous diet although it is possible they may have also fed on insects. Aetosaurs commonly found in the park include Typothorax and Stagonolepis .

The dominant terrestrial predators during the Late Triassic were the rauisuchians including the terrifying Postosuchus . This massively built animal was several meters in length with a heavy head full of sharp serrated teeth, similar but unrelated to the later tyrannosaurid dinosaurs.

The Paleontology Portal

The crocodylomorphs are distant ancestors of today's crocodiles. Interestingly these were very small, gracile carnivores that were completely terrestrial in nature. The most common crocodylomorph found in the park is the sphenosuchian Hesperosuchus.

Petrified Forest National Park Triassic Reptiles Taxa List

Acaenosuchus geoffreyi (Stagonolepididae)

Acallosuchus rectori (incertae sedis)

Chatterjeea elegans (Rauisuchidae)

Desmatosuchus haplocerus (Stagonolepididae)

Heliocanthus chamaensis (Stagonolepididae)

Hesperosuchus agilis (Sphenosuchidae)

Leptosuchus adamanensis (Phytosauridae)

Leptosuchus crosbiensis (Phytosauridae)

Paratypothorax sp. (Stagonolepididae)

"Parrishia mccreai" (Sphenosuchidae)

Postosuchus kirkpatricki (Rauisuchidae)

Pseudopalatus buceros (Phytosauridae)

Pseudopalatus macauleyi (Phytosauridae)

Pseudopalatus pristinus (Phytosauridae)

Revueltosaurus callenderi ( incertae sedis)

Smilosuchus gregorii (Phytosauridae)

Stagonolepis wellesi (Stagonolepididae)

Typothorax coccinarum (Stagonolepididae)

Vancleavea campi (incertae sedis)

Mantra V Werks Ski...
Price subject to change | Available through
Featured Park
Rising above a scene rich with extraordinary wildlife, pristine lakes, and alpine terrain, the Teton Range stands monument to the people who fought to protect it. These are mountains of the imagination. Mountains that led to the creation of Grand Teton National Park where you can explore over two hundred miles of trails, float the Snake River or enjoy the serenity of this remarkable place.
Featured Wildlife
The pika is a close relative of the rabbits and hares, with two upper incisors on each side of the jaw, one behind the other. Being rock-gray in color, pikas are seldom seen until their shrill, metallic call reveals their presence.