Make a taffy crocodile. Take his head and pull it until his neck extends a few meters from his body. If you grimace, this could be what he called a strange-looking Triassic reptile Tanistrofeu looks like. More or less.
The assortment of this ridiculous, long-lasting fossilized neck bone animal has confused paleontologists’ demons for nearly 170 years. Using CT scans to unpack the crushed skulls of reptile remains, the researchers finally solved some misleading questions about this strange animal in August last year.
Copies of Tanistrofeu it can reach more than 5 meters (16 feet) in length, with the tail representing about a third of its length, and its body can be a quarter. The rest is the neck.
Tanistrophy sizes compared to a human. (Spiekman et al., Current Biology, 2020)
“Tanistrofeu he looked like a stubborn crocodile with a very, very long neck, “said paleontologist Olivier Rieppel of Chicago’s Field Museum.
Why this reptile evolved to such large dimensions is a complete mystery. The fact that no one could tell if he preferred to be submerged in water or step on land only made it more difficult to draw conclusions.
Part of its oddity is the shape of its neck bones. Unlike those in a snake or lizard, the cervical vertebrae in Tanistrofeu the fossils are like a giraffe. In fact, when its remains were first discovered in 1852, the scattered bones were thought to be the bones of the elongated wings of a flying pterosaur.
The people I dug up don’t have the size of a crocodile either. A number is much smaller, which leads paleontologists to wonder if some of the specimens in their archives belong to juveniles or represent a completely different species.
This is a common problem in paleontology – the diminutive fossil of a dwarf species can be almost identical to the immature bones of a young man. Their separation requires looking for clues as to whether the skeleton has not yet reached its maximum size or has anything to do.
Fortunately, such clues can be found deep inside the fossils. Just as the rings in the trunk of a tree show evidence of their age, the bones can do the same.
To find them, Rieppel and his colleagues used X-rays on an assortment of Tanistrofeu skeletons, transforming scans into 3D models using high-resolution computed tomography (CT) technology.
“The power of CT scanning allows us to see details that are otherwise impossible to observe in fossils,” said lead author Stephan Spiekman, an expert on the evolution of Triassic reptiles at the University of Zurich.
Growth rings revealed the smallest Tanistrofeu the bodies did belong to adults, which made it quite clear that the researchers had two separate species in their hands.
To distinguish them, the team named the largest T. hydroids, after the hydra from Greek mythology. Its younger cousin has kept the original name of the species T longobardico.
Turning scans into digital models has also given researchers a way to rearrange crushed bones into a clearer configuration, making it much easier to take a good look at the entire anatomy of the creature.
“From a heavily crushed skull we were able to reconstruct an almost complete 3D skull, revealing crucial morphological details,” Spiekman said.
With all its bone fragments in place, it seems Tanistrofeu it would be good at home in the water after all.
The reptile’s skull has its nostrils perched on top, like the snout of a crocodile – just the thing for an ambush predator to hold a lung full of air while waiting for a table to pass.
(Spiekman et al., Current Biology, 2020)
What had been a mixed pile of sharp teeth can also be seen forming a trap effective enough to snatch a cephalopod, at least for royal-sized species.
“Small species probably fed on small-shelled animals, such as shrimp, unlike fish and squid that large species ate,” Spiekman said.
“This is really remarkable, because we were expecting the bizarre neck of Tanistrofeu be specialized for a single task, like the neck of a giraffe. But in fact, it allowed for more lifestyles. This completely changes the way we look at this animal. “
An illustration that shows T. hydroids hunting. (Emma Finley-Jacob)
The fact that the two very similar species have such different ways of using their long bodies has made it much easier for them to exist in the same habitats, sharing their environment without competing for the same food sources.
We can almost imagine the crouched body of the animal, resembling a croc, lying on the floor of a shallow coastline about 242 million years ago, with its head rising to the surface so that its nostrils can siphon the air, his slightly thrown mouth squinted in a stray squid to stumble over.
How familiar the scene feels, Tanistrofeu he is still a strange creator.
This research was published in Current biology.
A version of this article was first published in August 2020.