Tanystropheus hydroids, the newly described reptile species that lived 242 million years ago (Triassic period), was about 6 m (20 feet) long, with the neck covering half that length – three times as long as its torso.
Tanystropheus hydroids. Image credit: Emma Finley-Jacob.
One of the most striking Triassic reptiles, Tanystropheus is characterized by an extremely long and stiff neck that is almost three times the length of his torso, despite the fact that it consists of only 13 hyper-elongated vertebrae.
It was first described as a single species, Tanystropheus longobardicus, in 1852, and it has been surprisingly paleontologists since.
For a long time, scientists were unsure whether this reptile lived on land or in the water. The bizarre body did not make things clear in one way or another.
“Tanystropheus looked like a blunt crocodile with a very, very long neck, ”said Dr. Olivier Rieppel, a paleontologist at the Field Museum.
In the same region where many of the large Tanystropheus fossils were found, in what was now Switzerland, there were also fossils of reptiles with similar visibility that were only about 1.2 m (4 feet) long.
Not only were scientists unsure if these were landowners as marine animals, but they also did not know if the smaller specimens were juveniles or even a separate species.
To solve these two long-standing mysteries, Drs. Rieppel and colleagues use newer technologies to see details of animals’ bones.
The big one Tanystropheus fossils’ skulls were crushed, but the researchers were able to take CT scans of the fossil plates and generate 3D images of the bone fragments inside.
The skulls had important features, including nostrils on top of the snout like a crocodile, which suggested Tanystropheus lived in the water.
It probably lay waiting, waiting for fish and squirrel-like animals to swim through, and then snagged them with its long, curved teeth. It may have come ashore to lay eggs, but overall it remained in the ocean.
Two types of Tanystropheus co-occur in a Middle Triassic coastal area. Image Credit: Spiekman and others, doi: 10.1016 / j.cub.2020.07.025.
“That neck makes no sense in an earthly environment. It’s just an awkward structure to transfer, “said Dr. Rieppel.
To learn if the small specimens were juveniles or a separate species, the scientists examined the bones for signs of growth and aging.
“We looked at cross sections of small type bones and were very excited to find many growth rings. This tells us that these animals were mediocre, ”said Dr Torsten Scheyer, a paleontologist at the University of Zurich.
The authors named the larger species Tanystropheus hydroids. The small form has the original name Tanystropheus longobardicus.
“The small species that are likely to feed on small shellfish, such as shrimp, as opposed to the large species that would eat fish and squid,” said Drs. Stephan Spiekman, a paleontologist at the University of Zurich.
“It simply came to our notice then Tanystropheus to be specialized for one task, such as the neck of a giraffe. But in fact, it allowed for different lifestyles. ”
“For many years we have had our suspicions that there were two types Tanystropheus, but until we could scan the larger specimens CT, we had no definitive evidence. Now we do it, ”said Dr Nick Fraser, keeper of natural sciences at National Museums Scotland.
“It is very important to discover that there were two rather distinct species of this bizarre long-necked reptile that swam about 240 million years ago and sat side by side in the coastal waters of the great sea of Tethys.”
The team paper was published in the journal Current biology.
_____
Stephan NF Spiekman and others. Aquatic habits and niche distribution in the extraordinarily long-necked Triassic reptile Tanystropheus. Current biology, published online August 6, 2020; doi: 10.1016 / j.cub.2020.07.025
