Recent research conducted on the territory of the Hateg Country UNESCO Global Geopark, managed by the University of Bucharest, has revealed one of the richest fossil sites, with an abundance of vertebrate remains never before documented in this area.

The site, discovered by a team of Romanian and Hungarian researchers in the western Hateg Basin, completes the picture of the evolution of the dinosaur fauna during the Upper Cretaceous and offers crucial insights into the final millions of years leading up to their extinction, representatives of the Geopark declared on Tuesday.

The Hateg Basin is internationally renowned for its fossil record of dwarf dinosaurs, documented over the past century across numerous sites. However, discoveries of partial dinosaur skeletons remain rare - making the newly identified site a remarkable exception. According to a recent release, researchers uncovered over a hundred vertebrate fossils per square meter, with large dinosaur bones densely packed atop one another.

'Beyond the exceptionally high concentration of fossils, the site's significance lies in its age - it represents the oldest known accumulation of such vertebrates in the Hateg Basin. Studying this fossil assemblage allows us to reconstruct the early composition of Hateg's dinosaur fauna and trace the evolutionary pathways that led to the species found in more recent Transylvanian sites. It also helps us understand the similarities and differences between these Late Cretaceous ecosystems,' said Zoltán Csiki-Sava, Romanian coordinator of the research team and professor at the Faculty of Geology and Geophysics, University of Bucharest.

The Valioara Paleontological Research Group, made up of Romanian and Hungarian paleontologists, has been conducting fieldwork in the Hateg Geopark for over five years. This region is renowned for its Upper Cretaceous continental deposits, which preserve invaluable evidence from the final millions of years before the extinction of the dinosaurs. During this period, the team has unearthed thousands of vertebrate fossil remains, including specimens of amphibians, turtles, crocodiles, dinosaurs, pterosaurs, and mammals.

Among these discoveries, one newly studied site stands out as the richest investigated to date, yielding over 800 vertebrate fossils within an area of less than five square meters. The detailed findings from this geological and paleontological investigation were recently published in the scientific journal PLOS ONE, the press release shows.

'In 2019, during our very first field survey in the Hateg Basin, we almost immediately came upon the K2 site - it was a defining moment for our team,' recalls Dr. Gábor Botfalvai, assistant professor at the Department of Paleontology, Eötvös Loránd University, and leader of the research group. 'We were struck by the sight of dozens of large, exceptionally well-preserved black dinosaur bones gleaming from the gray clay layers exposed in the stream bed. We got to work right away, and after several years of excavation, we recovered an extraordinarily rich vertebrate assemblage from the site.'

The paleoenvironmental conditions of the region help explain the extraordinary fossil accumulation at the site. Around 72 million years ago, the area now known as the Hateg Geopark was traversed by ephemeral rivers shaped by a subtropical climate. During episodes of intense rainfall, these streams would overflow, transporting the carcasses of animals caught in their path, as well as sweeping up scattered remains from across the floodplain.

The site yielded not only isolated bones but also associated remains of several partial skeletons belonging to two species of herbivorous dinosaurs. One of these is a predominantly bipedal dinosaur, approximately two meters in length, from the family Rhabdodontidae - a group commonly found in the Hateg Basin.

The remaining skeletons have been identified as belonging to a titanosaurian sauropod - a significant paleontological find, marking the first instance of such well-preserved specimens of this long-necked dinosaur type in Transylvania. Their study opens new avenues for research into the taxonomy and evolutionary history of titanosaurs in the region.

This discovery enhances the understanding of the evolutionary and ecological dynamics that shaped the Late Cretaceous dinosaur fauna of Eastern Europe.

The Hateg Country UNESCO Global Geopark, managed by the University of Bucharest, stands as a key reference site for the study of geodiversity and paleontological heritage. It offers an internationally recognized framework for scientific research, education, and the sustainable valorization of geological and paleontological discoveries.

This project was made possible through the support of the National Research, Development and Innovation Office of Hungary (NKFIH), the Supervisory Authority for Regulated Activities, the Romanian Ministry of Research, Innovation and Digital Transformation, and the University of Bucharest. AGERPRES (RO - writing by: Sorin Blada; EN - writing by: Simona Klodnischi)