The area on the edge of the Swabian Alb has long been known for its rich fossil finds. A dinosaur fossil discovered there 100 years ago has now turned out to be a previously unrecognized new genus and species. The prehistoric reptile baptized Tuebingosaurus maierfritzorum lived 203 to 211 million years ago and was an ancestor of the giant long-necked dinosaurs of the Jurassic and Cretaceous periods. Like them, he was a herbivore and walked around on four sturdy legs. He was already much more similar to the later sauropods than his contemporaries living in the same area. The find also shows that the diversity of the sauropod ancestors in today's Central Europe was greater than had long been assumed.
The long-necked sauropods gave rise to the largest and heaviest land animals that have ever walked our planet. These large, four-legged herbivores included well-known representatives such as Brachiosaurus, Diplodocus and the Titanosaurs. They evolved from smaller ancestors, the Sauropodomorpha, which evolved in the late Triassic. Some of these sauropod ancestors, who lived more than 200 million years ago, also occurred in what is now Central Europe. Many of these fossils have so far been assigned to the genus Plateosaurus - a bipedal herbivore with a small skull, long neck and a prehensile hand with an enlarged thumb claw.
New look at fossil of sauropod ancestor
A large part of the dinosaur fossils that were discovered in sites on the Swabian Jura from the 19th century were also considered plateosaurs. Recently, however, some new finds and re-analysis of older fossils have raised doubts about the previous classification. In a large-scale project, the paleontologists Omar Rafael Regalado Fernandez and Ingmar Werneburg from the University of Tübingen have therefore re-examined all bones of late Triassic dinosaurs stored in the Paleontological Collection in Tübingen. Among them was a partial skeleton found in a quarry in Trossingen in 1922. The fossil bones are from the rear half of a dinosaur previously classified as Plateosaurus pliengeri that lived between 203 and 211 million years ago.
When re-analyzing this dinosaur fossil, Regalado Fernandez and Werneburg found that many of its bones did not match those of a typical plateosaur. The partial skeleton exhibited, among other things, a broader and more powerfully built hip with fused sacral vertebrae and unusually large and robust long bones. This suggests that this animal moved on four legs, instead of just the two hind legs like the plateosaurs, as the paleontologists explain. Another difference became apparent when analyzing the bone structure: Tuebingosaurus did not grow continuously like Plateosaurus, but experienced rapid growth spurts that were interrupted by growth pauses. "That justifies considering Tuebingosaurus and Plateosaurus as two different species," explains Regalado Fernandez.
(Video: University of Tübingen)
No Plateosaurus, but a separate genus
According to the researchers, it is therefore clear that the fossil from Trossingen is not a Plateosaurus, but a previously unknown dinosaur genus and species. The paleontologists have named this new species Tuebingosaurus maierfritzorum. "Its genus name, Tuebingosaurus, is a homage to our beautiful university town and its residents," says Werneburg. The researchers honor the two German zoologists Wolfgang Maier from Tübingen and Uwe Fritz from the Senckenberg Natural History Collections in Dresden with the associated species name maierfritzorum. The Tuebingosaurus lived around 203 to 211 million years ago in what is now the Swabian Jura and was a herbivore. The surrounding sedimentary rock and the preservation of the bones suggest that this dinosaur died and sank in a swampy area. The bones on the left side of the body were probably exposed to the elements on the surface for a number of years, which is why they are hardly preserved.
The comparison of all anatomical features in a family tree analysis showed that the Tuebingosaurus was also an ancestor of the large long-necked dinosaurs. However, it possessed a unique mix of advanced and primitive traits, and was more closely related to later sauropods than the plateosaurs. The finding of the new species demonstrates on the one hand that other supposed plateosaurs may have been incorrectly classified. On the other hand, the identification of the Tuebingosaurus suggests that there was a greater diversity of sauropodomorphs in Central Europe at the time than had long been assumed.
Source: Omar Rafael Regalado Fernandez and Ingmar Werneburg (University of Tübingen), Vertebrate Zoology, doi: 10.3897/vz.72.e86348