About 150 million years ago, a sea turtle with an enormous head dove into a shallow tropical sea that covers what is now Europe. Few complete fossils of this Jurassic sea turtle, called Solnhofia parsonsiwere discovered.
However, scientists have recently described a remarkable fossil that has all of its limbs with nearly all of its foot bones in place – revealing for the first time the shape and structure of the tortoise’s extremities.
All species of sea turtles today have elongated, rigid fins to propel them through the depths of the ocean. But the described fossil’s limbs were stockier than modern sea turtles relative to body size.
These shorter limbs suggest that s. parsonsi swam in coastal waters rather than the open ocean, scientists report at PLOS One magazine from Wednesday (26).
Fossils of this sea turtle were first discovered in the 1970s, but the new specimen “is the best-preserved individual of this species,” said study lead author Felix Augustin, a doctoral candidate in the department of geosciences at the University of Tübingen. , in Germany. “It is the first that preserves the skull, the complete hull and also the complete four limbs.”
In life, s. parsonsi it measured about 30 centimeters in length from nose to tail, and its head was “relatively large” – the skull measured about 10 centimeters in length, Augustin told the magazine. CNN .
Such a large skull could have been useful for grinding up the hard shells of bottom-dwelling crustaceans and molluscs, but such conclusions are “highly speculative at this time” as paleontologists have yet to find direct evidence of the extinct turtle’s diet, the report said. study co-author Dr. Márton Rabi, postdoctoral researcher in the department of geosciences at the University of Tübingen.
The fossil was excavated in 2014 in a limestone quarry in southeastern Germany in a site rich in fossils from the latter part of the Jurassic period (199.6 million to 145.5 million years ago). Many turtles are preserved there, along with fish, crocodilians and even marine reptile giants such as plesiosaurs It is ichthyosaursaccording to the study.
The site has been an actively mined quarry since the 1950s, but excavations for fossils only started about 20 years ago.

s. parsonsi was described as a species in 1975 based on two nearly complete skulls: one from Bavaria and one from Switzerland. Over the decades, discoveries of partial skeletons – all found in Jurassic marine deposits – have provided further clues about the turtle’s anatomy and aquatic lifestyle.
In 2000, scientists discovered a skeleton with a more complete shell than had ever been found. The specimen also included some bones from the reptile’s rowing limbs. The newly described fossil presents a much fuller picture of these limbs, showing that they differed dramatically from the extremities of sea turtles alive today.
“In modern sea turtles, the limbs are really elongated – especially the fingers and finger phalanges – to serve as flippers in this marine environment,” said Augustin. In comparison, the limbs and feet of the fossil of s. parsonsi from Bavaria were less elongated, so the species was probably better adapted for swimming closer to shore rather than hundreds of kilometers away in open water.
This hypothesis makes sense considering the site where the fossil was excavated, Rabi told the CNN . During the Jurassic period, what is now southern Germany was an archipelago of small islands. the habitat of s. parsonsi it was probably a network of coastal reefs and lagoons. The turtles “were always more or less close to shore,” said Rabi.
Numerous fossils from these rich and diverse coastal ecosystems are found in fine-grained limestone deposits known as “plattenkalk” in southern Germany. This rock is known for preserving fossils in exquisite detail, and the quarry where the turtle was unearthed has yielded many examples of marine animals and plants, as well as fossils of land dinosaurs and pterosaurs.
But because the site is relatively new, many of these fossils have yet to be scientifically studied and described, and there’s much to be learned about the individual species and the coastal habitat where they coexisted millions of years ago, Augustin said.
“We are particularly interested in reconstructing the ecosystem as a whole to show diversity – how it functioned and what different constituents of ecosystems were present during the Late Jurassic,” he said.
*Mindy Weisberger is a science writer and media producer whose work has appeared in Live Science, Scientific American, and How It Works magazines.
Source: CNN Brasil

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