Paleontologists Reveal New Species of Ancient Crocodile Was Triassic Tank

A recently discovered species of ancient crocodile was found to be much sturdier than even our modern-day crocs.

Indeed these reptiles, knowns as aetosaurs, which are thought to have gone extinct around 200 million years ago, have been dubbed the "tanks of the Triassic" by paleontologists who were able to study a carapace that was 70 percent complete—a rarity!

"We have elements from the back of the neck and shoulder region all the way to the tip of the tail," paper author William Reyes, a doctoral student at the UT Jackson School of Geosciences, said in a press release. "Usually, you find very limited material."

This is what allowed for the identification of a new species from the Triassic period, which has been named Garzapelta muelleri, according to a paper that was published in January in the journal The Anatomical Record.

The Garzapelta muelleri specimen had been unearthed years prior, and had spent 30 years sitting on a shelf at the Texas Tech University fossil collections before it was examined by researchers and found to be a brand new species. It was named after Garza County in northwest Texas, where the aetosaur was found, with "pelta" being Latin for shield. The species name "muelleri" is named for the paleontologist who originally discovered it, Bill Mueller.

Aetosaurs were particularly abundant and diverse during the Late Triassic, with various species found across various parts of the world, including North and South America, Europe, Africa, and Asia. These creatures were characterized by their extensive bony armor covering much of their bodies, which likely served as protection against predators.

They are thought to have been primarily omnivores and were likely preyed upon by larger carnivorous reptiles. The extinction of aetosaurs occurred during the Late Triassic, possibly due to environmental changes or competition from newly evolving dinosaur groups.

The bony plates that make up the creature's armor are named osteoderms. Rather than forming a separate layer of protection like a shell, these osteoderms were embedded directly into the skin, and knitted together like a mosaic. This new species has also been found to have curved spikes along its sides. These plates and spikes helped the researchers identify the specimen as a new species and gave clues as to where the species lay in the evolutionary tree of other known aetosaur species.

The spikes were found to be very similar to those of another species of aetosaur, but it turned out that the species were distantly related, meaning that the spikes had evolved via convergent evolution. This is the process by which similar traits evolve in unrelated lineages to perform a similar purpose, such as wings in bats, insects and birds.

"Convergence of the osteoderms across distantly related aetosaurs has been noted before, but the carapace of Garzapelta muelleri is the best example of it and shows to what extent it can happen and the problems it causes in our phylogenetic analyses," Reyes said.

The appearance of the armor may also be influenced by the ancient animal's age or sex, which further complicates using the osteoderms and spikes to determine where the species is placed on the evolutionary tree.

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