Huge “terrorist crocodiles” once roamed the earth and exchanged dinosaurs, according to a new study examining fossils from the giant late Cretaceous crocodile, deinosuchus.
The research, published in the Journal of Vertebrate Paleontology, repeats this deinosuchus was among the largest crocodiles that ever existed and reached up to 33 feet in length. New in this study is a look at the anatomy of deinosuchus, which was achieved by bringing together different specimens unknown hitherto, which gave a more complete picture of the animal.
Adam Cossette, a paleobiologist in vertebrate animals at the New York Institute of Technology College of Osteopathic Medicine at Arkansas State University, led the study, which corrected some misconceptions about deinosuchus.
“Until now, the whole animal was unknown,” Cossette said. “These new specimens that we have examined reveal a bizarre, monstrous predator with teeth the size of bananas.”
Previous studies of cranial remains and bite marks on dinosaur bones led paleontologists to believe in the massive deinosuchus was an opportunistic predator, according to the press release. Fossil samples now make it clear deinosuchus really had head size and jaw strength to get its prey, including large dinosaurs.
“deinosuchus was a giant who must have terrorized dinosaurs who came to the water and drank, “said Cossette.
University of Iowa spine paleontologist Christopher Brochu, co-author of the study, said another important insight from the thesis is that there were several species of deinosuchus which flowed over North America 75 to 82 million years ago.
The study notes Deinosuchus hatcheri and Deinosuchus riograndensis lived in the west, from what is now Montana to northern Mexico. Deinosuchus swimmeri lived east from New Jersey to Mississippi.
“Some of them were separated by a sea route that at one point cut North America in half from what is now the Gulf of Mexico up to the Arctic Ocean,” Brochu said. “And it may have driven what we call speciation. There may have been an ancestral dinosaur form in North America, and then shipping dropped that population in half and on one side it evolved in one direction, the other side in another direction.”
Despite the nickname “terrorist crocodiles”, Brochu said deinosuchus were closely related to alligators other than crocodiles but “did not look like any of them.”
deinosuchus had a snout that was long and wide, with the front appearing inflated unlike any other live or extinct crocodile. At the tip of the nose is a large pair of holes. Researchers are still unsure of their function.
Both Brouchu and Cossette claim that this paper disproves the idea that crocodiles are living fossils, or in other words, animals that never evolved.
“There is this concept that crocodiles are immutable forms,” Brochu said. “That they seem far back in the distant past and have not changed since the days of the dinosaurs. That is simply not true.”
If you look at the modern species of crocodile, Cossette explained, there are only a handful and they all look and act very similarly. But if you look at the fossil record, there is diversity in size, shape, diet and lifestyle.
“Most people believe that crocodiles have not changed in 75 million years,” Cossette said. “This study shows that the ancestors of today’s American alligator did not look anything like them.”
“Crocodiles are actually these incredibly dynamic creatures who have experienced incredible evolutionary stories, have lived in places that modern crocodiles do not live, done things that modern crocodiles do not do and have grown to sizes that modern crocodiles never achieve. I think that’s the cool part [of the study]”At least for me,” Cossette added.