Make a crocodile out of taffy. Take his head and dress him until his neck extends a few feet from his body. If you look squinting, it could be a strange Triassic reptile Tanystropheus looked like. More or less.
This animal’s variety of ridiculously long petrified neck bones has confused paleontologists for almost 170 years. Using CT scans to unpack the crushed skulls from the remains of the reptiles, researchers finally solved some nagging questions surrounding this strange animal in August last year.
Samples of Tanystropheus can be longer than 5 meters (16 feet) long, with its tail about a third of its length and its body perhaps a quarter. The rest are all neck.
Tanystropheus sizes compared to humans. (Spiekman, et al., Current Biology, 2020)
“Tanystropheus looks like a blunt crocodile with a very, very long neck, ‘said paleontologist Olivier Rieppel of Chicago’s Field Museum.
The reason why this reptile has developed such extensive dimensions is a complete mystery. The fact that no one could determine whether it was preferable to be immersed in water or to litter on the ground made it more difficult to decide on any conclusions.
Part of its strangeness is the shape of the neck bones. Unlike those in a snake or lizard, the cervical vertebrae are in Tanystropheus fossils are stretched out like a giraffe. In fact, when the remains of his remains were first uncovered in 1852, it is assumed that the scattered bones are the elongated wing bones of a flying pterosaur.
Also, not all of the people we dug up are crocodile size. A number is much smaller, leading paleontologists to ask whether some of the specimens in their archives belong to juveniles, or are a very different species.
This is a common problem in paleontology – the small fossil of a dwarf species can be almost the same as the immature bones of a young person. To separate them, you need to look for clues as to whether the skeleton has not yet reached its full size, or that it is still growing.
Fortunately, such clues can be found deep in the fossils. Just as the rings in a tree trunk contain a record of their age, bones can do the same.
To find it, Rieppel and his colleagues use X-rays on a variety of Tanystropheus skeletons, which transform the scans into 3D models through high-resolution computed tomography (CT) technology.
“The power of CT scanning allows us to see details that would otherwise be impossible to observe in fossils,” said lead author Stephan Spiekman, an expert on Triassic reptile evolution at the University of Zurich.
The growth rings revealed the smaller Tanystropheus bodies do indeed belong to adults, making it fairly clear that the researchers have two separate species.
To distinguish them, the team calls the bigger one T. hydroides, to the hydra in Greek mythology. His younger cousin kept the original species name T. longobardicus.
The transformation of the scans into digital models also gave the researchers a way to rearrange the broken bones in a clearer configuration, making it much easier to take a good look at the anatomy of the animal.
“From a strongly crushed skull, we were able to reconstruct an almost complete 3D skull, revealing important morphological details,” Spiekman said.
With all its bone fragments in place, it looks like Tanystropheus could still be good in the water.
The reptile’s nostrils sit on top, just like a crocodile’s snout – just the thing for an ambush predator to keep a lung full of air while waiting for a meal to pass.
(Spiekman et al., Current Biology, 2020)
What was a cluttered pile of pointed teeth can also be seen forming a fairly effective trap to snatch a head pot, at least for the king-size species.
“The small species that are likely to be fed with small scalloped animals, such as shrimp, as opposed to the fish and squid have eaten the large species,” Spiekman said.
‘This is really remarkable, because we expected the bizarre neck of Tanystropheus to be specialized for a single task, such as the neck of a giraffe. But actually, it made several lifestyles possible. It changes the way we look at this animal. “
An illustration that shows T. hydroides hunt. (Emma Finley-Jacob)
The fact that the two, very similar species had different ways of using their long bodies, made it much easier for them to exist in the same habitats and share their environment without competing for the same food sources.
We can almost imagine the animal’s squatting, crooked body lying on the floor of a shallow shoreline about 242 million years ago, its head rising high to the surface so that its nostrils could sift into the air, with its bursting mouth slightly sloping in anticipation of a stray squid to stumble upon.
As familiar as the scene feels, Tanystropheus is still a strange critter.
This research was published in Current biology.
A version of this article was first published in August 2020.