A 215-million-year-old crocodile ancestor has been identified that predates dinosaurs

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

The study was conducted by researchers at the University of Texas at Austin and published in the journal Anatomical record Earlier this year, it announced a new species of aetosaur: Garzapelta muelleri.

“Unlike their dinosaur relatives, aetosaurs are not the group of animals that are commonly talked about,” William Reyes, a doctoral student at the UT Jackson School of Geosciences who led the study, told ABC News.

Aetosaurs are a species similar to modern crocodiles that lived during the Triassic Period, 229 million to 200 million years ago, which preceded the Jurassic Period, according to the researchers, who also note that Aetosaur fossils have been discovered on every continent except Antarctica and Australia. .

According to the researchers, Garzapelta muelleri's fossilized dorsal carapace — the hard, armored plating that covers its back — is 70% complete, with large pieces from its neck and shoulder region to the end of its tail intact.

William Reyes, a doctoral student at the UT Jackson School of Geosciences who led the study, which was published in January, said. Phys.org On Monday, the results are remarkable because “usually, you find very limited material.”

The outer part of Garzapelta's skeleton is called the osteoderm, which consists of tough rocky plates and curved calluses, both made of bone, according to the study.

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

The study found that garzapelta fossils date back 215 million years, and that the species was largely carnivorous, which contrasts with its modern cousin, the carnivorous crocodile.

The name Garzapelta muelleri is a reference to Garza County in northwest Texas, where the fossil was discovered, while “pelta” is the Latin word for armor, referring to the armor-like shell of this species. The second half of the name, Muelleri, is a reference to Bill Mueller, the Texas Tech paleontologist who initially discovered the fossilized skeleton of Aetosaurus with local amateur collector Emmett Shedd in 1989, according to Reiss, who noted Mueller's death in 2019.

“They found the fossil one day while excavating the grounds,” Reyes told ABC News. “They noticed some bone fragments on the surface and decided to dig, and realized they had found armor associated with a large aetosaur.”

After Mueller's death, Reyes said that the late scientist's colleagues “met to finish some of Bill's projects, as he was working on very important material.”

To determine that Garzapelta is actually a new species of aetosaur, the researchers compared the skeleton with those of similar ancient aetosaurs.

“The carapace of G. muelleri shows a striking degree of similarity between the carapace of the paratipothoracine Rioarriba suchus chamaensis and desmato suchins,” the researchers said in the study.

However, the unique features of Garzapelta's skeleton, from the formation of osteoderm plates to the distinctive marks and ridges on the species' bones, make it distinctly different from its aetosaur relatives, according to Reiss.

“Since its original discovery, many aetosaur specialists have been puzzled by the taxonomic identity of Garzapelta,” Reyes said. “Everyone agreed that it was indeed a new species because it showed many unique features.”

Reyes spoke about the impact of his findings, saying: “Garzapelta is a great example of how amazing these animals are, and it is great that we are in a position to introduce the public to the 'moving tanks' that existed millions of years before ankylosaurids.” Dinosaurs.”