Scientists have discovered a complete fossil of a giant-headed sea turtle dating back approximately 150 million years.
This Jurassic sea turtle species is named Solnhofia parsonsi. The fossil find is particularly notable because all of its limbs and the entire structure of its feet are almost perfectly preserved. This is also the first time the shape and structure of the limbs of this turtle species have been revealed.
All modern sea turtles possess long, rigid flippers that provide propulsion, enabling them to navigate the depths of the ocean. However, the limbs of the newly discovered fossil turtle are more robust compared to those of contemporary sea turtles.
Well-preserved fossil of the Solnhofia parsonsi turtle from the Jurassic period. (Photo: Felix Augustine).
In a report published in the journal PLOS One on July 26, scientists asserted that these short limbs indicate that Solnhofia parsonsi likely swam in coastal waters rather than the open ocean.
The lead author of the study, Felix Augustin, a Ph.D. candidate in the Department of Geosciences at the University of Tübingen in Germany, stated that the fossil of this sea turtle was first discovered in the 1970s. However, the newly discovered specimen is “the best-preserved individual of this species.”
According to the research team’s calculations, the living Solnhofia parsonsi would have been approximately 12 inches (30 cm) long from snout to tail. Its head is considered to be “relatively large,” with a skull measuring about 4 inches (10 cm) in length.
Augustin noted that such a large skull would facilitate the crushing of the hard shells of crustaceans and mollusks living on the seafloor. However, Dr. Márton Rabi from the Department of Geosciences at the University of Tübingen cautioned that this conclusion “is highly subjective” since paleontologists have yet to find direct evidence of the diet of this extinct turtle species.
The Solnhofia parsonsi fossil was excavated from a limestone quarry in southeastern Germany in 2014, at a site rich in fossils from the late Jurassic period (approximately 199.6 million to 145.5 million years ago). The research indicates that numerous species of turtles, marine fish, crocodiles, and even giant marine reptiles like plesiosaurs and ichthyosaurs have been fossilized in this area.
This limestone quarry has been actively mined since the 1950s, but fossil excavations there only began about 20 years ago.
Discoveries regarding the sedimentary layers beneath the sea over several decades have provided additional insights into the anatomy and aquatic lifestyle of this Jurassic turtle species. In 2000, scientists discovered a skeleton with a complete shell of Solnhofia parsonsi, which also included several bones from the flippers of this reptile.
According to the scientists, the new fossil provides a much fuller view of these limbs, showing that they are significantly different from the limbs of modern sea turtles.
“In modern sea turtles, the limbs are elongated, particularly the fingers and phalanges. They serve as flippers in a marine environment. In contrast, the limbs and feet of the Solnhofia parsonsi fossil from Bavaria are shorter, suggesting that this species was likely well-adapted to swimming closer to shore rather than hundreds of miles offshore,” Augustin explained.
Dr. Rabi believes this hypothesis is relatively reasonable when considering the location where the fossil was excavated. During the Jurassic period, the region of southern Germany was an archipelago of small islands. Rabi stated that the habitat of Solnhofia parsonsi could have been a network of coral reefs and coastal lagoons, and these turtles “were likely always close to the shoreline.”
Many fossils from these rich and diverse coastal ecosystems have been found in fine-grained limestone sediments throughout southern Germany. However, these sites are still relatively new, so many of the fossils remain unstudied and undescribed scientifically.
Augustin emphasized that there is still much for humanity to learn about each species and their coastal habitats, where they coexisted millions of years ago: “We are particularly interested in reconstructing the entire ecosystem to illustrate the diversity and functioning of the species and the various components of the ecosystem that existed during the Jurassic.”
