An international team of paleontologists discovered two previously unknown species of sauropod dinosaurs in Romania's Hațeg Basin, challenging existing theories about dinosaur evolution on ancient European islands. The findings, led by Dr. Verónica Díez Díaz from the Museum für Naturkunde Berlin, were recently published in the scientific journal Journal of Systematic Palaeontology.
The newly identified species, Petrustitan hungaricus and Uriash kadici, lived approximately 66 million years ago at the end of the Cretaceous period. Their fossils were unearthed in the Hațeg Basin, a region renowned for its rich deposits of dinosaur remains and designated as the UNESCO International Geopark.
Uriash kadici, in particular, stood out due to its size. Measuring over ten meters in length and weighing up to eight tons, it was nearly four times larger than its relative, the dwarf sauropod Magyarosaurus dacus. "Uriash was a true giant among dwarfs," the researchers noted, emphasizing its significance in understanding dinosaur diversity on the ancient European islands.
The research team included specialists from the University of Bucharest, Museum für Naturkunde Berlin, and University College London. Associate Professor Dr. Zoltán Csiki-Sava, a co-author of the study and a researcher at the Faculty of Geology and Geophysics of the University of Bucharest, emphasized the importance of the discovery. "Previously, the dinosaurs from Hațeg Island were thought to have adapted to the insular habitat by reducing their size, a phenomenon called 'insular dwarfism'," he explained, according to Origo.
"But now we are discovering the presence of a large-sized sauropod, Uriash, which lived on Hațeg Island alongside the smaller herbivores, demonstrating that at least some species managed to maintain their large size, which requires other interpretations," Csiki-Sava observed.
In addition to Uriash kadici, the team discovered Petrustitan hungaricus, a sauropod similar in size to Magyarosaurus dacus. The size of Petrustitan hungaricus was approximately three to four meters in length.
Dr. Philip Mannion, a researcher and faculty member at University College London and co-author of the study, remarked on the broader implications of the findings. "In particular, it is evident that the 11 species of Late Cretaceous sauropods in Europe are not closely related to each other, but often have close relatives in Africa, Asia, and sometimes even in South America, indicating biogeographic connections with these landmasses," he said.
These connections suggest that migrations through temporary land bridges or even long-distance swimming could have contributed to the diversity of sauropod species in Europe. "These migrations seem to often coincide with a lower level of the planetary ocean, which could have created temporary land routes to Europe from Africa and Asia," said co-author Paul Upchurch, also from University College London.
"According to our hypothesis, the large-sized species did not reduce in size because dwarf herbivores were already living in the area, so the ecological niche available to them was saturated," said Csiki-Sava.
"This diversity provides new clues about the environment in which these animals lived and the conditions that allowed the coexistence of different species," the University of Bucharest stated, according to Gândul. The discovery increases the number of known sauropod species in Europe to eleven, with four of these species discovered in the Hațeg Geopark.
The article was written with the assistance of a news analysis system.