For almost two centuries, fossil hunters have mused that the improbably lengthy necks of some historic marine reptiles made them tempting targets for hungry predators.
Now, researchers have uncovered grisly proof that sticking one’s neck out actually was a lethal weak spot: the stays of two creatures whose heads had been snapped off in acts of Triassic violence.
“We predict they had been grabbed by the neck and killed that manner, and since the neck doesn’t have a lot muscle, the predator left them and centered on the far more meaty physique,” mentioned Dr Stephan Spiekman, a palaeontologist on the State Museum of Pure Historical past in Stuttgart, Germany.
Spiekman and his colleague Dr Eudald Mujal, an skilled in prehistoric chunk marks, made the ugly discovery whereas analyzing a pair of 240m-year-old fossils of tanystropheus, a marine reptile recovered from Monte San Giorgio on the Swiss-Italian border.
On the time, earlier than the emergence of the dinosaurs, the mountain was house to a tropical lagoon. Fossils from the rocks protect such a spectacular range of prehistoric fish, reptiles, crustaceans and different species that it was designated a Unesco world heritage web site.
The fossils studied belong to 2 totally different species of tanystropheus, one smaller animal about 1.5m lengthy, and one other a lot bigger creature about 6m lengthy. In each circumstances, solely the small head and a part of the lengthy, slender neck stay. The our bodies, ominously, are lacking.
Shut inspection of the bigger fossil revealed two tooth-shaped holes within the vertebrae on the exact level the place the neck was cleanly damaged. “The entire neck is damaged in precisely one aircraft,” mentioned Spiekman. “The neck was damaged in a single go, and having the tooth marks there’s fairly conclusive proof that some animal bit its neck off.”
The smaller reptile appears to have suffered the identical destiny. Once more, the neck and slender supporting neck ribs which run parallel alongside the vertebrae to supply stiffness, had been damaged at a single level. This time, a small tooth-shaped gap was discovered additional up the neck, away from the fracture level. Scavenging seems to be extremely unlikely, the scientists say,as a result of chunk marks look totally different in lifeless animals, and scavengers are likely to trigger way more harm after they tuck in to a carcass.
The proof means that whereas many marine reptiles reaped clear advantages from exceptionally lengthy necks – the bigger tanystropheus had a neck comfortably over 2m – the benefits got here with a value. As depicted in Henry De la Bèche’s 1830 watercolour, Duria Antiquior, a protracted neck was a good way to lose one’s head.
Primarily based on the dimensions of the tooth marks, Spiekman and Mujal suspect the beheadings had been carried out by different marine reptiles, maybe a distant ancestor of the plesiosaur referred to as a nothosaur, an early ichthyosaur, or the stocky helveticosaurus. Particulars are revealed in Present Biology.
“These are among the most macabre fossils I’ve ever seen,” mentioned Steve Brusatte, a professor of vertebrate palaeontology at Edinburgh College, who was not concerned within the examine. “You may sense the violence of the reptile-eat-reptile world of the Mesozoic while you take a look at these fossils.”
“It looks like these lengthy necks had been a sort of superpower, which allowed these reptiles to ambush their prey by darting their heads like a spearfisherman,” he added. “However all superheroes have a weak spot, and these lengthy necks would have been kryptonite to those animals, as they left them susceptible to assault from different reptiles.
“Nonetheless, lengthy necks persevered in so many reptile teams, for thus lengthy, proper as much as the asteroid that knocked lots of them out, alongside their dinosaur cousins. The worth of a protracted neck should have usually outweighed the prices.”