Paleontologists have described a rare representative of predatory theropods that hunted fish and looked like a hybrid of a velociraptor with a duck.
He looked like a duck, swam like a duck, but he was not a duck. The remains of a pangolin that lived for about 75 million years allow us to attribute it to the same group of carnivorous theropods, which include tyrannosaurs. However, the holscaraptor was well adapted to life on the water, and its appearance once again reminds of the relationship of this group with modern birds. A description of the dinosaur is presented in an article published in the journal Nature.
In general, while many birds do well in the air, on land, and on water, the flightless theropods were strictly terrestrial animals. Representatives leading a completely aquatic lifestyle, among them it is not known, how unclear is how much even winged species were able to fly. The Halszkaraptor escuilliei here is a striking exception, presenting a whole set of unique adaptations.
A rare find was made in the steppes of Mongolia, she left the country illegally and ended up on the "black market" of fossils, traveling for a long time around the world. Only in 2015 did the remains fall into the hands of real scientists, were examined and returned to Mongolia. The fragile bones encased in hard rocky rock have been studied with great care. "Shining through" them using the synchrotron radiation of the ESRF accelerator, it was possible to find out the detailed structure, shape and location of the fossils and show that this is not a jumble of bones of different types, but one, but very unusual.
Halszkaraptor escuilliei fossil undergoing synchrotron radiation tomography / copy; ESRF, P. Jayet.
Andrea Cau (Andrea Cau) and his colleagues attributed the lizard to the family of small dromaeosaurids, the most famous of which can be called the Velociraptor. However, there were enough differences to distinguish the holskaraptor into a separate species and even a subfamily, Halszkaraptorinae. Many of these differences indicate adaptation to permanent or temporary life in the aquatic environment.
The long, narrow jaw with short, numerous teeth is excellent for hunting fish. Numerous marks on the face indicate the development of senses similar to those that allow crocodiles to track their prey in the water. The structure of the long and flexible "swan" neck also resembles aquatic animals. It appears that the holskaraptor may have hunted by carefully tracking its prey, carefully sneaking up on it and delivering a final powerful blow at the expense of its neck and jaws.
The streamlined body of the lizard and the flipper-like forelimbs are adapted for this strategy: scientists have shown that their proportions are closer to the wings of penguins, which use them for rowing in water. Finally, the hind limbs located slightly closer to the front of the body led to a shift in the center of gravity, with a more comfortable position for swimming.
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Sergey Vasiliev