Deinosuchus fossils were first discovered in the United States in the 1850s and have been studied for more than a century, but the classifications of species within the genus have long been debated.
In a new study, researchers at the University of Iowa have revisited existing fossil evidence and also examined newly collected fossil specimens.
The results of their phylogenetic reassessment suggest three distinct species of Deinosuchus can be discerned in the fossil record: the suggested type species D. riograndensis, D. hatcheri, and a newly identified species, D. schwimmeri.
« Deinosuchus was a giant who must have terrorized the dinosaurs who came to the water’s edge to drink, ”says senior researcher and paleontologist Adam Cossette, now at the New York Institute of Technology.
“Until now, the complete animal was unknown. These new specimens we’ve looked at reveal a bizarre, monstrous predator with teeth the size of a banana. ”
While the oldest known Deinosuchus specimen to date is around 82 million years old, researchers say a common ancestral population for all different species is likely, and would have existed in North America before the rising seas led to the Seaway western interior cutting the continent in two.
When this happened, the researcher speculates that different environments on the east and west coasts led to evolutionary adaptations that resulted in slightly divergent body shapes and sizes. D. riograndensis, D. hatcheri, and D. schwimmeri.
“It was a strange animal,” says paleontologist Christopher Brochu. “This shows that crocodylians are not ‘living fossils’ that haven’t changed since the dinosaur era. They have evolved as dynamically as any other group. ”
Based on fossil evidence, D. riograndensis and D. hatcheri spent their days hunting dinosaurs in western North America, from Montana to northern Mexico. D. schwimmeri, meanwhile, lived along the Atlantic coast, between New Jersey and Mississippi.
Regardless of their coastal affiliations, however, these giant creatures – which measured up to 10 meters in length – were among the largest and most formidable crocodylians of all time, and were closer to modern alligators than to crocodiles.
“When he lived here in the eastern United States, there was nothing greater,” said David Schwimmer, a geologist and paleontologist at Columbus State University. Ledger-Enquirer.
Schwimmer was not involved in the new study, but was the inspiration for the naming of D. schwimmeri, given his contributions in the field.
“We actually have bite marks from these guys on dinosaur bones. Now the only question you can ask yourself: were they scavengers or predators? Schwimmer said.
“I guess it’s a predator… This creature was big enough to take down most dinosaurs.” Additionally, it is interesting to note that most of the bites we see are in the bones of the legs and tailbones. If you’re going to catch a dinosaur, this is where you are. you will catch them. ”
The results are reported in Journal of Vertebrate Paleontology.