2023-06-19 18:32:44
In 1830, Henry de la Bèche created a famous watercolour: “Duria Antiquior” (the older Dorset) it is titled and in it the British geologist reconstructed the animal world of the early Jurassic period as described by the paleontological pioneer Mary Anning (1799 to 1847 ) collected fossils from the almost 200 million year old limestone formations of Lyme Regis in Dorset on the coast of southern England.
Ulf von Rauchhaupt
Editor in the “Science” section of the Frankfurter Allgemeine Sunday newspaper.
The painting was soon copied and pirated countless times and there is hardly a book on prehistory that does not feature it – at least in the history of prehistoric research section. In fact, it is the earliest scientifically based primeval scene and thus the founding document of Paleo-Art.
Classic of the early Paleo Art: A detail from the 1830 watercolor “Duria Antiquior”. : Image: Henry De la Beche (1796-1855)
One detail in “Duria Antiquior” is sure to be the first thing that catches the eye of every viewer: a large, fish-shaped ichtyosaur bites into a sea reptile called a plesiosaur with a comparatively squat trunk and overly long neck. The scene is, as we say today, “graphic”: blood squirts and in the next moment the ichthyode should have decapitated the plesiosaur. Neither predator nor prey was de la Bèche’s imagination – Mary Anning had found fossils of both groups of animals and, more importantly, correctly interpreted them. The geologist had only thought of the decapitation. Such a long neck is an invitation to the predators to bite here.
However, there has not yet been any paleontological evidence for this. Fossils of large vertebrates from the Mesozoic are rare – and therefore veritable collector’s items, and those showing traces of predator-prey interaction are even rarer. So far, this has also applied to what are probably the most extravagant long-necks in the history of the earth, the members of the genus Tanystropheus, also sometimes called giraffe-necked dinosaurs. They lived in or around Triassic seas about 247 to 209 million years ago, slightly earlier than, but not closely related to, the Dorset Lower Jurassic animals.
They weren’t giants. specimens of the species Tanystropheus hydroides were only up to six meters long, those of the smaller ones Tanystropheus longobardicus about 1.5 meters. The torso of such an animal was hardly larger than that of a modern-day dog, while its neck was three times as long as the entire torso. Such anatomy must have had certain advantages in the early Mesozoic, for a number of Triassic and Jurassic marine reptiles looked like it, though not always to the extreme of the genus Tanystropheus, including the Dorset plesiosaurs. Nevertheless, from the days of Henry de la Bèche the disadvantage of such snake necks in confrontations with robbers was obvious.
Bitten off head of a Tanystropheus longobardicus from the Bosano Formation of Monte San Giorgio in Ticino. Without the neck, the skull is only about two inches long. : Image: Stephan Spiekman
Now Stephan Spiekman from the State Museum of Natural History in Stuttgart and his colleague Eudald Mujal in an article for “Current Biology” two fossils of the heads of the two named Tanystropheus species, which had been found on Monte San Giorgio in Swiss Ticino, were examined more closely. They were able to prove that the heads must have been completely intact when, after separating them from the rest of the body, they sank to the sea floor, where their soft tissues were left to rot undisturbed and the skeletonized remains were finally able to fossilize covered in sediment.
The separation points on the seventh and tenth of the 13 extra-long cervical vertebrae also indicate that the heads had actually been bitten off. “The robber presumably attacked the part behind the severed neck,” Spiekman and Mujal write. “It was quite nutritious, in contrast to the slender neck and the head, which was not eaten but just left there.”
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Who could have feasted here can only be roughly determined. the smaller one Tanystropheus longobardicus a medium-sized marine reptile with suitable dentition could have bitten in two – or even a predatory fish. In the case of the four meter overall length, it is significantly larger Tanystropheus hydroides the circle of perpetrators is already smaller. In their publication, the two authors name three species of predatory marine reptiles that could be considered here and conclude that the attack took place under water and not on a Tanystropheus standing on the shore, which itself was waiting for prey swimming by. Presumably, the animals usually protected themselves by staying in shallow water where large predators could not get, or by hiding on the seabed.
The question remains as to what happened to the plesiosaurs, which also have very long necks but probably live in open water, such as those visualized by Henry de la Bèche in “Duria Antiquior”. Despite a plethora of fossils found of them, Spiekman and Mujal write, there is no clear evidence anywhere that any of them suffered an attack on their long necks.
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