A new species of turtle, contemporary with dwarf dinosaurs in Transylvania, has been discovered by paleontologists on the territory of the Hateg UNESCO Global Geopark, according to Bucharest University.
The paleontologists have named the new discovery Dortoka premier, in honor of the famous Romanian paleontologist Matyas Vremir, who died in July 2020.
The newly discovered species is part of a larger family of turtles more specific to the southern hemisphere. The fossils of its closest relatives date back about 57 million years and have been identified in north-western Romania. Thus, this new discovery offers an important perspective on the identity of the survivors of mass extinctions at the end of the Cretaceous, which led to the extinction of the dinosaurs.
„Kallokibotion bajazidi was the first fossil turtle species to be identified in the present-day Hateg Geopark territory, contemporary with dwarf dinosaurs. This species was common, as evidenced by its remains, which are found in abundance in the fossiliferous rocks here. It was described by Franz Nopcsa in 1923, almost a century ago; in a way, our discovery is a centennial homage to the work of this important researcher from the Hateg region, the discoverer of the famous dwarf dinosaurs. Dortoka, unlike the Kallokibotion, was a rarer species. That reason, and also its smaller size, explains how it came to be identified only after a century of research. Even after the discovery of the specimen described by us, almost 30 years passed before we managed to establish its identity,” says Zoltan Csiki-Sava, associate professor at the Faculty of Geology and Geophysics of Bucharest University, co-author of the study.
The studied fossil specimen is very well preserved and provides a lot of details regarding this species of turtle. The uncovered shell is almost complete, about 19 cm long and oval in shape. The breastplate (abdomen), of a length of 15.5 cm, was kept intact. Both the carapace and the plastron have ornaments characteristic of the Dortoka turtle genus and are thinner than those of their contemporaries, the Kallokibotion turtles, which were significantly larger in size.
„The only turtle we know that coexisted with the newly discovered species lived on land and did not survive a mass extinction. Instead, this new species was a freshwater turtle. That matches a pattern previously observed in contemporary North American fauna, where terrestrial vertebrates disappeared significantly more than freshwater vertebrates by the end of the Cretaceous,” says Felix Augustin, a Ph.D. student at the University of Tubingen and lead author of the article.
Researchers hypothesize that this may be possible because aquatic food chains rely heavily on decaying organic matter that may be available even under extreme environmental conditions when terrestrial food chains are destroyed.
The discovery was recently published in the Journal of Systematic Palaeontology, and the study was conducted by an international team made up of Felix J. Augustin and Andreas T. Matzke of the University of Tubingen (Germany); Zoltan Csiki-Sava of Bucharest University; Gabor Botfalvai from the Museum of Natural History and Eotvos Lorand University – Budapest, Hungary, and Marton Rabi from the University of Halle-Wittenberg in Germany.
The team of researchers involved in the discovery brings together the universities of Tubingen (Germany) and Bucharest (Romania) – members of the CIVIS University Consortium – and scientific institutions from Hungary with which the Faculty of Geology and Geophysics of Bucharest University has concluded a five-year co-operation agreement years for conducting palaeontological studies on fossils discovered on the current territory of the Hateg UNESCO Global Geopark.