Hungarian and Romanian palaeontologists have discovered a huge collection of vertebrate fossils at Hațeg Basin in Romania's historic Transylvania region.
The bonebed – which has been named the K2 site – included dozens of dinosaur bones, which appeared black in the clay-rich ground, along with the fossils of other animals such as pterosaurs, crocodiles, mammals, amphibians, fishes and turtles. In all, the remains of at least 17 species were found.
Recently published in the journal PLOS ONE, the findings offer scientists a clearer picture of the evolution and ecology of Eastern European dinosaurs during the Late Cretaceous, a period that included the final few million years before this diverse group of ancient reptiles went extinct.
“In 2019, during our first field survey in the Hațeg Basin, we almost immediately came across the K2 site,” explains Gábor Botfalvai, assistant professor at the Department of Palaeontology, Eötvös Loránd University, and leader of the Valiora Dinosaur Research Group.
“It was a defining moment for us – we instantly noticed dozens of large, exceptionally well-preserved black dinosaur bones gleaming in the grey clay layers exposed in the streambed.
“We immediately began our work, and through several years of excavation we collected an extraordinarily rich vertebrate assemblage from the site.”
The K2 site yielded more than 800 vertebrate fossils from an area of less than five square metres.
- These petrifying prehistoric beasts would have terrified early man
- How many species of dinosaurs were there?
Why were so many fossils found in one spot?
The authors explain that around 72 million years ago, what we now know as Romania had a subtropical climate. The landscape was threaded with rivers, which would swell during periods of heavy rain, often flooding their banks. As the water gushed downhill, it collected debris, including animal carcasses. Living creatures unable to escape the torrents were also washed away.
“Detailed study of the rocks at the K2 site indicates that a small lake once existed here, which was periodically fed by flash floods carrying animal carcasses,” says Soma Budai, researcher at the University of Pavia and co-author of the study.
“As the flow of the rivers slowed rapidly upon entering the lake, the transported bodies accumulated in the deltaic environment along the shore, producing this exceptionally high bone concentration.”
Alongside the individual bone specimens found at the site, the team also unearthed several dinosaur skeletons, belonging to two different herbivorous dinosaur species: a two-metre-long animal from the Rhabdodontidae family (one of the most common dinosaurs in the Hațeg Basin), and a long-necked titanosaurian sauropod dinosaur. The researchers say the latter is particularly exciting, as it’s the best-preserved titanosaurian sauropod skeleton ever found in Transylvania.
“Besides the remarkably high bone concentration, another key significance of this newly described site is that it represents the oldest known vertebrate accumulation in the Hațeg Basin,” adds Zoltán Csiki-Sava, associate professor at the University of Bucharest and Romanian leader of the research team.
“Studying this fossil assemblage allows us to look into the earliest composition of the Hațeg dinosaur fauna and trace the evolutionary directions and processes leading toward the dinosaurs known from younger Transylvanian sites – revealing how these Late Cretaceous ecosystems were similar or different from one another.”
Top image: Palaeontologists excavating fossils at the K2 site in Hațeg Basin, Transylvania, Romania. Credit: ELTE Eötvös Loránd University
More amazing wildlife stories from around the world
- Moss attached to the International Space Station. What happened next was astonishing
- Scientists resurrect 40,000-year-old organisms from Arctic ice – now they’re worried
- Mummified sabre-toothed cat cub found in Siberian permafrost stuns scientists
- Dinosaur hunters make “chilling” discovery deep in Canadian badlands
