From the mighty titanosaurs of South America to the tiny microraptors of China, dinosaurs were a diverse bunch. For hundreds of millions of years, they dominated every major environment except for one blinding admission: the water.
Now, researchers are claiming that a new fossil might be an incredibly rare example of a 75-million-year-old dinosaur showing signs of adaptations to an aquatic lifestyle. Discovered in Mongolia, the bizarre creature contains a hodgepodge of features, from a long slender neck to short dumpy wings, which might indicate that it was well-suited for life in the water.
Described in Nature, the dinosaur would have walked on two legs on land like an ostrich, sat in the water like a duck, but paddled around with its forelimbs like a penguin and used its swan-like neck to ambush prey.
When researchers got their hands on the fossil, which has been named Halszkaraptor escuilliei, and nicknamed Halszka, their first job was to prove it was actually real, not unlike when Victorian collectors first got their hands on the platypus. “The first time I examined the specimen, I even questioned whether it was a genuine fossil,” said Andrea Cau, who led the research. “This unexpected mix of traits makes it difficult to place Halszka within traditional classifications.”
It is thought to belong to the therapod dinosaur group, and more specifically the maniraptorans. These dinosaurs are well-known for showing a high degree of specialism to adapt to their different lifestyles, including for running swiftly, herbivory, and active flight.
Halszka was a small bipedal dinosaur, and in a nod towards its theropod cousin the Velociraptor, had sickle-shaped “killer claws” on its feet. But it doesn’t stop there. The dinosaur had a curiously long swan-like neck, in addition to a long tail and short, stumpy forelimbs, which look not unlike flippers. X-ray imaging of the fossil also revealed teeth in the skull and a neurovascular mesh in the snout similar to that of crocodiles.
The researchers argue that these features show a strong similarity to other modern-day birds that have adapted to semi-aquatic lifestyles, and coupled with the internal structure of the skull, suggest that it may well have been a specialized aquatic hunter.
“When we look beyond fossil dinosaurs, we find most of Halszkaraptor's unusual features among aquatic reptiles and swimming birds,” concluded Cau. “The peculiar morphology of Halszkaraptor fits best with that of an amphibious predator that was adapted to a combined terrestrial and aquatic ecology: a peculiar lifestyle that was previously unreported in these dinosaurs.”
The fossil was actually poached from Mongolia a while ago, bouncing around private collections before being given to researchers. Eventually, it will be returned to its country of origin.