Close relative of Triassic alligator from New Mexico’s Ghost Ranch finally identified after nearly 80 years in museum basement

A newly identified relative of modern crocodiles chased prey during the Triassic period, about 205 million years ago, but did not move underwater, a new study has found.

Like other members of the ancient crocodile family, this newly identified species had not yet entered the water. Instead, they hunted on land, much like modern foxes and jackals, the researchers said.

It may have been a formidable predator, and its remains suggest a “specialized capability for powerful bites,” the researchers said in the study.

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This specimen was originally discovered decades ago in 1948 at Ghost Ranch in New Mexico, on the deathbed of a famous dinosaur. At the time, it was tentatively cataloged as a specimen of Hesperoscus agilis, an early small relative of crocodiles and crocodiles. But the new study shows that even though the creature lived and died at the same time and place as H. agilis, its unusually short snout and thick, reinforced skull distinguish it as an entirely new genus and species.

“This is the first strong evidence that two functionally distinct crocodilian species coexist,” study co-author Miranda Margulis Onuma, a paleontologist at Yale University, told Live Science. Crocodiformes include modern crocodiles, alligators, caimans, and their extinct relatives.

The fossils of this short-nosed creature, newly named Eosphorosuchus lacrimosa, were discovered in geological formations from the late Triassic period (237 million to 201 million years ago). The animal’s skull, one hind leg bone, one vertebrae and three scales were preserved. The creature would have been about the size of a large dog.

“It was in the basement of the Peabody Museum.” [at Yale] Literally for 75 years,” Margulis Onuma said. “People would come and look at it from time to time, but it was never identified.”

In a new study published Wednesday (April 15) in the journal Proceedings of the Royal Society B: Biological Sciences, Margulis-Onuma and colleagues cataloged the fossil in detail and compared it to H. agilis fossils found about 15 feet (5 meters) away. The animals that lived in this area of ​​Ghost Ranch lived at the same time, but probably died and were buried by a single event, such as a flood.

The researchers found that E. lacromisa has a much shorter snout than H. agilis. It also had a larger triangular retroorbital socket (a bone in the skull) and matching lower jaw features, which would have accommodated powerful muscles for munching. Taken together, these characteristics suggest that this creature had a very powerful bite.

Because E. lacrimosa and H. agilis coexisted with each other, the researchers believe they may have occupied different ecological niches. For example, crocodiles with short snouts may have eaten larger, less agile prey than species with long snouts.

“It’s really great that it’s not just a pedigree struggling to take off. There’s already diversity at this point,” Margulis Ohnuma said. “We are at the very beginning of functional diversity across Crocs.”

Scientists don’t know much about the early stages of crocodilian evolution. Margulis Onuma said there aren’t many of these animals in the fossil record, and many species of Triassic crocodilians are represented by a single fossil specimen.

“There is a huge lack of data on early crocodiles, so the picture changes with each new fossil,” Margulis Onuma told Live Science. “If we can continue to describe this material that we have and ideally find new fossils, the story will change every time.”