A new species of penguin-like diving dinosaurs has been discovered



CNN

A new study found evidence that at least one dinosaur species may have been adept swimmers, diving into the water like a duck to hunt its prey.

The study, published Dec. 1 in Communications Biology, details a newly discovered species, Natovenator polydontus. The theropod, or hollow dinosaur with three toes and claws on each limb, lived in Mongolia from 145 to 66 million years ago in the Upper Cretaceous Period.

Scientists from Seoul National University, the University of Alberta and the Mongolian Academy of Sciences collaborated on the publication.

The researchers pointed out that Natovenator had streamlined ribs, like those of diving birds.

“Its body shape suggests that Natovenator was a potentially capable swimming predator, and the streamlined body evolved independently in separate lineages of theropod dinosaurs,” the authors wrote.

The Natovenator specimen is very similar to Halszkaraptor, another dinosaur discovered in Mongolia that scientists believe was likely semiaquatic. But the Natovenator specimen is more complete than the Halszkaraptor, making it easier for scientists to discern its streamlined body shape.

Both the 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 difficult to say exactly where Natovenator falls on the spectrum from fully terrestrial to fully aquatic. But the specimen’s arms “look like they’re pretty good at moving water,” he said. Hone participated in the peer review for the Communications Biology study.

In addition, Natovenator had dense bones, which are essential for animals that dive below the surface of the water.

As the authors wrote, it had a “relatively hydrodynamic body”.

The next step, Hone said, would be to model the dinosaur’s body shape to help scientists understand exactly how it might have moved. “Does it paddle with its feet, a bit like a doggy paddle? How fast could it go?”

Further research should also look into the environment in which Natovenator lived. The specimen was discovered in Mongolia’s Gobi Desert, but evidence suggests there may have been lakes and other bodies of water in the desert in the past.

“It’s a real question, OK, you have a swimming dinosaur in the desert, what is it swimming in?” he said. “It’s going to be difficult to find the fossil record of these lakes, but we may well find one sooner or later.” And if we do that, we might find a lot more of those things.”

Nizar Ibrahim, a senior lecturer in paleontology at the University of Portsmouth whose research includes findings suggesting Spinosaurus was likely semiaquatic, told CNN he’s not yet fully convinced of the study’s results. He argued that more rigorous quantitative analysis would have made the results more convincing.

“For example, I would have liked to see a really solid description of the animal’s bone density, osteohistology, in a larger data set,” he said. “Even the rib anatomy if they somehow put that into a bigger picture – the big dataset that would have been helpful.”

The “anatomical evidence is less conclusive” for a swimming Natovenator than for a swimming Spinosaurus, he said.

And like Hone, he’s curious as to what exact waters Natovenator might have swum in. “The environment in which this animal was found in Mongolia is exactly the opposite of what one 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 once thought to be purely terrestrial, but increasing evidence suggests 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,” said Ibrahim. “And what we’re going to find out is that not only have dinosaurs been around for a very long time, but they’re also really diverse and very good at invading new environments.”

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