Nearly 250 million years ago, a very quirky reptile patrolled the coasts and coves of the Trias Alps. Called Tanystropheus, it has a toothed head and a modern screen lizard-like body. But between them stretched a neck as horizontal as a giraffe.
Stephan Spiekman, a paleontologist at University University said: Zurich, in Switzerland. “How can this animal breathe or swallow? And then the evolutionary question: Why on earth did this animal evolve this ridiculously long neck? “
But research published last week in the journal Current Biology, including the reconstruction of its new skull, shows evidence that its body is prey to this strategy of preying on water and creatures. There are two types: regular size and miniature size.
Tanystropheus was originally described in the 1850s based on several tubular-like bones. It was only in the 1930s, when more complete fossils emerged from the Monte San Giorgio in Switzerland that scientists realized they were looking at the ancient vertebrae of a strange reptile that they could not. find a way to live.
It took decades until paleontologist Karl Tschanz showed in 1988 that the ribs below the cervical vertebra were interlocking, forming an extremely rigid, horizontal neck. Mr. Spiekman says that suggests an underwater lifestyle, because such a non-curved neck would make life on land inconvenient. But paleontologists continue to argue whether Tanystropheus actively chase prey underwater or perch on shore, using its long neck as a fishing rod.
To make matters even more confusing, excavations have found many smaller Tanystropheus skeletons. on the Monte San Giorgio. If they belong to young, as some argue, why do they have different teeth?
His team Spiekman sought the answer first by CT scanning of a specimen of Tanystropheus’ came from a Zurich museum, and reconstructed it, which proved difficult because “all the bones were messed up together, and because of Tanystropheus’s skull very different from other reptiles in many respects ”.
“I remember very well the day the model was completed and I was the first to see this animal’s face in 242 million years,” he said.
The reconstructed skull showed several underwater adaptations: the nostrils rested on top of the snout, resembling crocodile and long, curved fangs. Instead of actively pursuing prey, Spiekman said, it could ambush them in murky waters, rushing forward with a long neck to catch fish.
To test whether the bones of the smaller Tanystropheus belonged to a juvenile or a particular species, the team studied thin bones prepared by his supervisor Spiekman and co-author, Torsten Scheyer. A close look at the inside of these small bones reveals the clear signs of a fully grown adult. That means the two Tanystropheus species are different was Coexist in the same water body: one big, one small.
The team reported that two closely related animals appeared to have hunted different types of prey in one example of the phenomenon known as zoning. The larger animal – newly named Tanystropheus hydroides – used its sharp teeth to hunt fish and squid; The teeth of smaller species are geared towards the diet of marine invertebrates such as shrimp.
With two mysteries solved, Mr. Spiekman and his team hope to take a fresh look at the biomechanics of that strange long neck and jaws.
“People have always thought that Tanystropheus is a dead end of evolution,” he said. “But the fact that Tanystropheus evolved into different species with very different lifestyles suggests that Tanystropheus and its antiquity are quite evolutionary success.”