A new species of penguin-like diving dinosaur has been discovered
A new study has found evidence that at least one species of dinosaur may have been a skilled swimmer, diving into the water like a duck to catch its prey.
learning, published in Communications Biology on December 1, describes a newly discovered species, Natovenator polydontus. The theropod, or hollow-bodied dinosaur with three toes and claws on each limb, lived in Mongolia during the Upper 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 paper.
The researchers pointed out that Natovenator had simplified ribs, like those of diving birds.
“Its body shape suggests that Nattovenator was a potentially capable swimming predator, and the simplified body evolved independently in separate lineages of theropod dinosaurs,” the authors wrote.
The Natovenator specimen is very similar to Halszkaraptor, another dinosaur found in Mongolia that scientists believe may have been semi-aquatic. But the Natovenator specimen is more complete than Halszkaraptor, making it easier for scientists to see its simplified body shape.
Both Natovenator and Halszkaraptor probably used their forearms to propel them through the water, the researchers explained.
David Hawn, 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 fully terrestrial to fully aquatic. But the specimen’s hands “look like they would be pretty good for moving water,” he said. Hone participated in the peer review of the Communications Biology study.
In addition, Natovenator had dense bones, which are essential for animals that dive below the water’s surface.
As the authors write, it had a “comparatively hydrodynamic body.”
The next step, Hawn said, will be to model the shape of the dinosaur’s body to help scientists understand exactly how it might have moved. “Are you scratching with your feet, a bit like a puppy? How fast can it go?’
Further research should also examine the environment in which Natovenator lived. The specimen was found 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’s a real question, well, you’ve got a dinosaur swimming in the desert, what is it swimming in?” he said. “Finding fossils from these lakes will be difficult, but sooner or later we may find one.” And when we do, we may find many more of these things.
Nizar Ibrahim, a senior lecturer in paleontology at the University of Portsmouth, whose research includes findings showing that Spinosaurus was probably semi-aquatic, told CNN that he is still not entirely convinced by the study’s findings. He argued that a more rigorous quantitative analysis would have made the findings more conclusive.
“I would like to see, for example, a real robust description of the bone density, the osteohistology of the animal, within a larger data set,” he said. “Even the anatomy of the ribs, if they had put that into a bigger picture — the big data set that would have been useful.”
“The anatomical evidence is less clear” for a swimming Nattovenator than for a swimming Spinosaurus, he said.
And like Hone, he’s also curious as to exactly what waters Natovenator might have been swimming in. “The environment that this animal was found in Mongolia is 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 thought to be strictly terrestrial, but evidence is emerging to suggest that at least some species spent as much time in the water as they did on land.
“I’m sure there will be many, many more surprises,” Ibrahim said. “And we’re going to find out that not only were dinosaurs around for a very long time, but they were also, you know, really diverse and very good at invading new environments.”