A new species of extinct reptile has been discovered at Petrified Forest National Park/Image by Jeffrey Martz (NPS)

Though well-known for its colorful slabs of petrified wood, Petrified Forest National Park in Arizona harbors much more in its badlands. A decade of work recently was followed with the announcement that the fossilized remains of a new species of Triassic reptile has been discovered in the park.

Four skeletons collected by paleontologists from the park decade have been used to identify the reptile, which has been named Scutarx deltatylus (SKOO-tarks del-tuh-TIE-lus). Park paleontologist Bill Park says the reptile, which would tower over a modern-day human if it could balance on its tail, roamed what is now the American Southwest between 217 and 220 million years ago during the Late Triassic Period. The remains of Scutarx are found in rocks of the Chinle Formation, which were deposited by a large river system during the Triassic.

The name Scutarx means “shield fortress” in Latin; one skeleton was found near a geographic feature at Petrified Forest called “the Sandcastle.” The species name ‘deltatylus’ means ‘triangle knob’ in Greek and describes a characteristic feature of the bony plates that covered the back of each animal in life, said the paleontologist in a release last week.

Scutarx belongs to an extinct group of reptiles called aetosaurs. Aetosaurs are distant relatives of crocodiles and alligators, but their leaf-shaped teeth suggest that they ate plants and insects. Seven species of aetosaurs are now known from the park, which demonstrates that these animals were common members of the Triassic fauna. Aetosaurs had a valuable role in the ecosystem as one of the only recognized groups of reptiles that ate plants during that time.

“Scutarx is an important discovery because it shows how diverse and numerous Triassic reptiles were before the rise of the dinosaurs," said Dr. Parker. "Animals such as aetosaurs were dominant on the landscape, and it was not until their extinction at the end of the Triassic Period that the dinosaurs became the dominant terrestrial animals.”

This find also emphasizes the importance of national parks as areas of significant scientific value where ongoing research contributes to the understanding of the evolution of life on Earth.