A collaborative effort by an international team of Romanian, Hungarian, and Italian paleontologists has led to the identification of a new genus and species of herbivorous duck-billed dinosaur, discovered from an incomplete skeleton in the Hersheg Basin, located in the Carpathian Mountains of present-day Romania.

Cryptohadros Kallaiae inhabited our planet during the Maastrichtian period of the Late Cretaceous, approximately 70 million years ago.

This dinosaur belongs to the Hadrosauridae family, which includes iconic duck-billed dinosaurs and their relatives.

The holotype specimen of this species was uncovered in continental deposits at the vertebrate site of Fantanelle-3, near the village of Valioara, within the Denshu-Siura Formation in Romania.

This region is renowned among paleontologists for its unique and rare dinosaur fossils.

“Complete skeletons, including cranial elements, vertebrae, and limb bones, are incredibly rare in the Haseg Basin, particularly for hadrosaur fossils,” stated paleontologist Dr. Attila Sisi from ELTE Eötvös Lorand University.

“Most sites yield only isolated bone elements, often mistakenly attributed to known dinosaur groups, despite lacking definitive features.

The skeleton of Cryptohadros Kallaiae is a partial specimen comprising the skull, rib fragments, caudal vertebrae, and parts of the hind limbs.”

Nevertheless, this fragmentary material was sufficient to distinguish the new species from other known dinosaurs, particularly from Thelmatosaurus transsylvanicus, a duck-billed dinosaur that has been misidentified for over a century.

This discovery suggests that at least two closely related duck-billed dinosaurs coexisted in the region during the Late Cretaceous.

“The morphological similarities with Thelmatosaurus are significant, indicating a close relationship,” remarked János Magyar, a PhD student at ELTE Eötvös Lorand University and the Hungarian Museum of Natural History.

“The differences largely pertain to the morphology of the skull elements.”

The researchers classified Cryptohadros Kallaiae, Thelmatosaurus transsylvanicus, and Tethyshadros from Italy as part of a newly recognized evolutionary group known as Telmatosauridae, a distinct lineage that evolved in southeastern Europe’s island environments.

“Our phylogenetic analysis reveals close relationships among all known Late Cretaceous hadrosaurids in southeastern Europe, including Thelmatosaurus, Tethyshadros, and Cryptohadros,” the researchers concluded.

“Furthermore, this analysis identifies several distinct evolutionary lineages of hadrosaurids within the European archipelago during the Late Cretaceous, suggesting multiple dispersal events between Asia and Europe during this period.”

The findings on Cryptohadros Kallaiae are detailed in a study published in the Journal of Systematic Paleontology.

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Janos Magyar et al. 2026. A new early Maastrichtian “duck-billed” dinosaur from the Haseg Basin (Densus-Siura Formation, Romania) documents a unique clade of non-hadrosaurid hadrosaurids from the southeastern Late Cretaceous European archipelago. Journal of Systematic Paleontology 24(1); doi: 10.1080/14772019.2025.2607800