New study proves theory
Marine dinosaurs with giraffe necks were deliberately decapitated by predators
Reconstruction and illustration of the giraffe necked dinosaur Tanystropheus being attacked by its predator, the marine dinosaur Nothosaurus giganteus, in the primeval ocean
© Roc Olive (Institut Català de Paleontologia Miquel Crusafont) / FECYT
Prehistoric marine dinosaurs adapted to their living conditions – successfully for a long time. For millions of years they inhabited the seas of the world. But her long neck was also her greatest weakness. Researchers from Stuttgart have now proven this.
In the time of the dinosaurs, a whole range of primeval sea reptiles lived in the waters of our earth. One feature was remarkable: Many of these creatures had an extremely long neck – sometimes twice or three times as long as their torso. Over a long period of time, this adaptation turned out to be an evolutionary advantage. Marine reptiles like the Tanystropheus were apparently able to surprise their prey when they were looking for food – and with success. The long-necked sea creatures lived for almost 175 million years before becoming extinct.
Marine dinosaurs: Tanystropheus was deliberately decapitated by predators
But since the time of Charles Darwin, researchers have speculated that the long neck was also a dangerous target for the animals. However, this could not be proven – until now. Scientists from the Natural History Museum in Stuttgart have examined two fossils of 242-million-year-old Tanystropheus in a new study. The bodies of these so-called giraffe neck dinosaurs were completely severed from the neck and show bite marks from predatory dinosaurs.
This is the first clear evidence that despite their evolutionary success in marine reptiles, the elongated necks were vulnerable, the researchers said in a press release. They published the detailed research results in the journal “Current Biology“
As expected as the results are, for scientists they are an “important piece of the puzzle with regard to the evolution and interaction of marine dinosaurs in their ecosystems.” Fossil evidence of predator-prey interactions is very rare. The research results support the interpretation of many scientists.
The paleontologist Stephan Spiekman, an expert on Triassic reptiles, explained: “Of the different forms of marine reptiles, the giraffe necked dinosaur Tanystropheus was perhaps one of the most bizarre examples: it had a neck three times the length of its torso, but only 13 extremely elongated vertebrae. ” This made his neck particularly long, lean and stiff. It was probably used to catch prey from an ambush.
Examined specimens lived 242 million years ago between what is now Switzerland and Italy
The examined specimens lived 242 million years ago in a shallow sea between what is now Switzerland and Italy, the researchers explained. One of them was almost 1.5 meters tall and probably fed on shrimp and other invertebrates. His conspecific was almost six meters long and ate fish and squid.
“Our most important finding is direct evidence of predatory decapitation of extinct long-necked marine reptiles,” Spiekman said. The presence of bite marks is also noteworthy. “In addition, the repeated occurrence of severed necks shows us that the elongated neck was indeed a functional weakness of the animals,” the researcher continues.
The investigation showed that both specimens had been deliberately hunted. Both the broken bones and the character of the bite marks suggest that the necks were severed with a single bite. The neck and head of both animals are almost perfectly preserved, but there is no trace of the bodies, leading to the conclusion that the attacking predator may have fed on them while leaving the skinny neck behind.
The smaller Tanystropheus species could have fallen victim to various predatory fish or other marine reptiles due to its small size. The situation is different for the larger species studied.
“Research shows that evolution is a game of trade-offs”
Only a very large sea reptile was able to bite off the neck of a four meter long Tanystropheus. An ancestor of the plesiosaurs, Nothosaurus giganteus, is one of the prime suspects here,” said Eudald Mujal, a paleontologist at the Stuttgart Natural History Museum.
Tanystropheus was evolutionarily quite successful, the researchers estimate, lived for at least 10 million years, and was found in Europe, the Middle East, China, North America, and possibly South America.
“Our research shows that evolution, in the broadest sense, is a game of trade-offs. However, the benefit of a long neck appears to have outweighed the risk of being attacked by a predator,” Spiekman explained.