They identify a crocodile ancestor from 215 million years before the dinosaurs

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By journalsofus.com


Aetosaurs are a species of reptile that lived during the Triassic Period.

The recent identification of fossils of an ancient, heavily armored ancestral species of crocodile, known as aetosaurs, provides a glimpse into our world 215 million years ago.

The study, led by researchers at the University of Texas at Austin and published in the journal The anatomical record Earlier this year, he announced a new species of aetosaur: Garzapelta gallinari.

Ethosauruses are a species similar to modern crocodiles that lived during the Triassic period, between 229 and 200 million years ago, prior to the Jurassic period, according to the researchers, who also point out that fossils of ethosauruses have been discovered on all continents, except in Antarctica and Australia. .

The fossilized dorsal shell of Garzapelta gallinari (the hard armored plate that covered its back) is 70% complete, according to the researchers, with important pieces from the neck and shoulder region to the end of the tail intact.

William Reyes, a doctoral student at UT’s Jackson School of Geosciences who led the study, published in January, said Phys.org Monday that the finds are notable because “usually very limited material is found.”

According to the study, the outside of the Egret’s skeleton is called osteoderm and is made up of rock-hard plates and curved spikes, both made of bone.

“Take a modern-day crocodile and turn it into an armadillo,” Reyes told the publication, describing the ancient creature.

The study determined that Egret fossils date back 215 million years and that the species was largely omnivorous, in contradiction to its modern cousin, the carnivorous crocodile.

The name Garzapelta cercari is a nod to Garza County in northwest Texas, where the fossil was discovered, while “pelta” is the Latin word for shield, meaning the armor-like shell of the species. The second half of the name, tumbari, is a nod to Bill Mueller, the paleontologist who initially discovered the fossilized skeleton of the aetosaur.

To determine that Garzapelta is, in fact, a new species of aetosaur, the researchers compared the skeleton to that of similar ancient aetosaurs.

“The shell of G.piereri shows a surprising degree of similarity between that of the paratipothoracin Rioarribasuchus chamaensis and that of desmatosuchines,” the researchers said in the study.

However, according to the study, the unique qualities of Egret’s skeleton, from the formation of osteoderm plates to the distinct markings and ridges on the species’ bones, make it clearly different from its aetosaur relatives.

“Convergence of osteoderms between distant etosaurs has been observed before, but the shell of Garzapelta tumbari is the best example of this and shows the extent to which it can happen and the problems it causes in our phylogenetic analyses,” Reyes told Phys.org. . .

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