The sweltering deserts of present day Nevada were once covered with water and home to an extinct crocodile relative. A team of scientists found this newly discovered species in the Triassic Era Favret Formation of Nevada that changes the story of life along both coasts of the United States when dinosaurs roamed the Earth. The new species is named Benggwigwishingasuchus eremicarminis or “Fisherman Croc’s Desert Song,” and is derived in a study published July 10 in the journal Biology Letters.
B. eremicarminis belongs to a group of ancient relatives of the crocodile known as pseudosuchian archosaurs. They lived during the Middle Triassic Period, or between 247.2 and 237 million years ago. While the ichthyosaurs ruled the oceans, this ancient croc ruled the shores.
[Related: Millions of years ago, marine reptiles may have used Nevada as a birthing ground.]
“This exciting new species demonstrates that pseudosuchians were occupying coastal habitats on a global basis during the Middle Triassic,” Nate Smith, a study co-author and Director and Curator of the Dinosaur Institute at the Natural History Museum of Los Angeles County (NHMLAC) said in a statement.
Millions of years ago, this area including the Favret Formation was the eastern Panthalassan Ocean. It is rich with the fossils of sea-going creatures, including the giant ichthyosaur C. youngorum and tiny ammonites. However, this new extinct marine reptile was a bit of a surprise.
“Our first reaction was: What the hell is this?” study co-author and University of Bonn paleontologist Nicole Klein said in a statement. “We were expecting to find things like marine reptiles. We couldn’t understand how a terrestrial animal could end up so far out in the sea among the ichthyosaurs and ammonites. It wasn’t until seeing the nearly completely prepared specimen in person that I was convinced it really was a terrestrial animal.”
Pseudosuchian archosaurs like this one have been discovered on what used to be the shores of the ancient Tethys Ocean in what is now Europe. B. eremicarminis is the first coastal representative from the Panthalassan Ocean and western hemisphere. This means that these crocodile relatives lived in coastal environments worldwide during the Middle Triassic. These coastal species do not all belong in the same evolutionary group. Pseudosuchians–and archosauriforms more broadly–were potentially adapting to life along various shores independent of one another.
“Essentially, it looks like you had a bunch of very different archosauriform groups deciding to dip their toes in the water during the Middle Triassic. What’s interesting, is that it doesn’t look like many of these ‘independent experiments’ led to broader radiations of semi-aquatic groups,” said Smith.
Archosaurs were once “ruling reptiles” that split into two groups during the Triassic. Both of these groups have surviving representatives: the descendants of dinosaurs (aka birds) and crocodilians (alligators, crocodiles, and gharials). The crocodilians are the descendants of pseudosuchian archosaurs like B. eremicarminis. Modern crocs are similar enough to be mistaken for one another by most people, but their ancient ancestors had a variety of sizes and lifestyles. The evolutionary relationships of B. eremicarminis and its living relatives suggests that pseudosuchians reached great diversity quickly following the devastating End-Permian mass extinction. Just how diverse these reptiles got is still waiting to be discovered deep in the fossil record.
“A growing number of recent discoveries of Middle Triassic pseudosuchians are hinting that an underappreciated amount of morphological and ecological diversity and experimentation was happening early in the group’s history. While a lot of the public’s fascination with the Triassic focuses on the origin of dinosaurs, it’s really the pseudosuchians that were doing interesting things at the beginning of the Mesozoic,” Smith said.
[Related: New species of extinct marine reptile found with help from 11-year-old child.]
B. eremicarminis likely would have been about five to six feet long, but the team does not know exactly how large it was. They found a few elements of the individual’s skull, but any clues to how it fed and hunted are also absent. However, what is more clear is that B. eremicarminis likely stayed fairly close to the shore. Its limbs were well-preserved over time and well-developed without any of the signs of aquatic living, including flippers or altered bone density.
To name the new species, the team consumed with a member of the Fallon Paiute Shoshone Tribe. They are the original human inhabitants of the Augusta Mountains where the specimen was unearthed. Benggwi-Gwishinga is a word that means “catching fish” in Shoshone. This was combined with the Greek word for Sobek–the Egyptian crocodile-headed god–for the genus name, Benggwigwishingasuchus. The species name eremicarminis translates to “desert song,” in honor of two supporters of NHMLAC who have a passion for both opera and paleontology.
