A new study has found evidence that at least one type of dinosaur may have been skilled swimmers, plunging into the water like a duck to stalk its prey.
the study, Published in Communications Biology On December 1, he described a newly discovered species, Natovenator polydontus. The theropod, or hollow-bodied dinosaur with three toes and claws on each end, lived in Mongolia during the Upper Cretaceous period, from 145 to 66 million years ago.
Scientists from Seoul National University, the University of Alberta, and the Mongolian Academy of Sciences collaborated on the research.
The researchers noted that the nattovenator had streamlined ribs, like those of diving birds.
“Its body shape suggests that Natovenator was a capable, swimming predator, and that the streamlined body evolved independently in separate lineages of theropod dinosaurs,” the authors wrote.
The natovinator specimen resembles Halszkaraptor, another dinosaur discovered in Mongolia, and scientists think it was likely semi-aquatic. But the Natovenator specimen is more complete than Halszkaraptor, making it easier for scientists to see its streamlined body shape.
The researchers explain that both Natovenator and Halszkaraptor used their arms to propel themselves through the water.
David Hone, a paleontologist and professor at Queen Mary University of London, told CNN that it’s hard to pinpoint exactly where Natuvinator is on the spectrum from all-terrestrial to completely aquatic. But he said the sample’s arms “look like they’re going to be pretty good for moving water.” Hon participated in a peer-reviewed study of the biology of communication.
In addition, Natovenator had dense bones, which are essential for animals diving below the surface of the water.
As the authors write, it had a “relatively hydrodynamic body”.
Hoon said the next step would be to model the dinosaur’s body shape to help scientists understand exactly how it moved. “Is she paddling with her feet, a kind of dog-swatter? How fast can she go?”
Further research should also look at the environment in which Natuvinator lived. The specimen was discovered in the Gobi Desert in Mongolia, but there is evidence that lakes and other bodies of water existed in the desert in the past.
“There’s a real question, well, you’ve got a dinosaur swimming in the desert, what’s it swimming in?” He said. “Finding the fossil record of those lakes is going to be hard, but sooner or later we might find one. And when we do, we might find a lot more of these things.”
Nizar Ibrahim, a senior lecturer in paleontology at the University of Portsmouth whose research includes findings indicating that Spinosaurus was likely semi-aquatic, told CNN he’s not entirely convinced by the study’s findings yet. He argued that more rigorous quantitative analysis would have made the results more convincing.
“I wanted to see, for example, a truly robust description of the bone density, bone histology of an animal, within a larger data set,” he said. “Even rib anatomy, if they kind of put that into a bigger picture — the massive dataset that would have been useful.”
He said the “anatomical evidence is less clear” for a swimming nattovinator than it was for Spinosaurus.
And like Hone, he’s also curious about exactly what waters the Natovenator might have been swimming in. “The environment that this animal was found in, in Mongolia, is kind of the opposite of what you would expect for a water-loving animal,” he said.
But he hopes the study will help open the door to more expanded insights into dinosaur behavior. Dinosaurs were once thought of as purely terrestrial, but increasing evidence is emerging to suggest that at least some species spent as much time in the water as they did on land.
“I am sure there will be many, many surprises,” Ibrahim said. “And we’ll discover that not only have dinosaurs been around for a very long time, but they’re also, you know, really diverse and really good at conquering a new environment.”