A new study has found that at least one species of dinosaur may have been a skilled swimmer, diving through water like a duck to hunt for prey.
The study, published in Communications Biology on Dec. 1, describes a recently discovered species, Natovenator polydontus. The theropod, or hollow-bodied dinosaur with three toes and claws on each limb, lived in Mongolia during the Late Cretaceous Period, 145 to 66 million years ago.
Scientists from Seoul National University, the University of Alberta and the Mongolian Academy of Sciences collaborated on the article.
The researchers pointed out that Natovenator had contoured ribs, like those of diving birds.
“The shape of its body suggests that Natovenator was a potentially capable swimming predator, and the streamlined body evolved independently in distinct lineages of theropod dinosaurs,” the authors wrote.
The Natovenator specimen is very similar to Halszkaraptor, another dinosaur discovered in Mongolia, which scientists say was probably semi-aquatic. But the Natovenator specimen is more complete than the Halszkaraptor, making it easier for scientists to see its streamlined shape.
Both Natovenator and Halszkaraptor likely used their forearms to propel them through the water, the researchers explained.
David Hone, a paleontologist and professor at Queen Mary University of London, told CNN it’s hard to say exactly where Natovenator falls on the spectrum from totally terrestrial to totally aquatic. But the specimen’s arms “look like they’re pretty good at moving water,” he said. Hone participated in the peer review of the Communications Biology study.
Additionally, Natovenator had dense bones, essential for animals diving below the surface of water.
As the authors wrote, he had a “relatively streamlined body.”
The next step, Hone said, would be to model the shape of the dinosaur’s body to help scientists figure out exactly how it might have moved. “Does he paddle with his feet, much like a paddle dog?” How fast could this go? »
Further research should also focus on the environment in which Natovenator lived. The specimen was discovered in the Gobi Desert in Mongolia, but there is evidence that there were lakes and other bodies of water in the desert in the past.
“There is a real question, OK, you have a dinosaur swimming in the desert, what is it swimming in?” he said. “Finding the fossil record of these lakes is going to be difficult, but sooner or later we just might find one. And when we do, we might just find a lot more of these things.
Nizar Ibrahim, a senior lecturer in paleontology at the University of Portsmouth, whose research has included findings indicating Spinosaurus was likely semi-aquatic, told CNN he was not yet fully convinced by the results of the study. the study. He argued that a more rigorous quantitative analysis would have made the results more convincing.
“I would have liked to see, for example, a real robust description of the bone density, the osteohistology of the animal, in a larger data set,” he said. “Even the rib anatomy, if they had kind of put that into a bigger picture – the big data set that would have been helpful.”
The “anatomical evidence is less straightforward” for a swimming Natovenator than for a swimming Spinosaurus, he said.
And like Hone, he’s also curious what exactly waters Natovenator might have been swimming in. “The environment this animal was found in in Mongolia is sort of the exact opposite of what you would expect for a water-loving animal,” he said.
But he hopes the study can help open the door to broader ideas about dinosaur behavior. Dinosaurs were previously considered strictly terrestrial, but more and more evidence has emerged suggesting that at least some species spent as much time in water as they did on land.
“I’m sure there will be many, many more surprises,” Ibrahim said. “And we’ll find that dinosaurs were not only around for a very long time, but also, you know, very diverse and very good at invading a new environment.”
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