A new study found that these strange creatures were water-dwelling. In addition, they were divided into two species.
Researchers at the Field Museum in Chicago (USA) and the University of Zurich in Switzerland have managed to unravel a centuries-old mystery about the prehistoric reptile Tanystropheus: it was not a flying pterosaur – the main hypothesis since it was first described in 1852 – but an aquatic animal.
The discovery was published this week in the journal Current Biology.
“I’ve been studying Tanystropheus for over thirty years, so it’s extremely satisfying to see these creatures demystified,” said Olivier Rieppel, a paleontologist at the Field Museum and one of the study’s authors, in a note.
Experts believed that Tanystropheus had long hollow bones to allow flight. However, they later discovered that these animals had really long necks – they were 6 meters long, but the neck alone was 3 meters, three times as long as its torso.
In the new study, researchers used CT scans to reassemble the fossils digitally, and what they saw on the screen led them to an unexpected conclusion: Tanystropheus lived in the water.
Tanystropheus lived 242 million years ago, right in the middle of the Triassic period, a time when land dinosaurs were beginning to appear, but aquatic reptiles were already common in the sea.
“The power of CT scanning allows us to see details that are otherwise impossible to observe in fossils,” said Stephan Spiekman, lead author of the study and a researcher at the University of Zurich. “From a strongly crushed skull we have been able to reconstruct an almost complete 3D skull, revealing crucial morphological details.”
Since paleontologists had several fossils of different sizes, they also wanted to know whether the remains belonged to the same species, but with different ages, or different species. And that’s how they found out that there were two species of the dinosaur.
They named the larger specimen Tanystropheus hydroides, after the monstrous water snakes from Greek mythology (Hydras). The smaller fossils kept their original name, Tanystropheus longobardicus.
Another finding is that the cone-shaped teeth in the large specimens and the crown-shaped teeth in the small ones indicate their diet was different, and therefore they did not compete for food.
“These two closely related species had evolved to use different food sources in the same environment,” Spiekman explained. “The small species likely fed on small shelled animals, like shrimp, in contrast to the fish and squid the large species ate.”
According to the scientist, they expected the neck of the dinosaur to have only one function. “But actually, it allowed for several lifestyles. This completely changes the way we look at this animal,” Spiekman said.