The newly identified dinosaur species Duonychus tsogtbaatari had two unusually long sickle-shaped claws on each limb. (Photo: Masato Hattori)
Paleontologists have found a new species of dinosaur with unusual claws in Mongolia.
The newly described genus and species belong to the therizinosaurs — long-clawed, bipedal, herbivorous giants. The remains were discovered in the Gobi Desert, according to a new study published Tuesday (March 25) in the journal iScience.
Unlike other therizinosaurs, which have three fingers on their hands, each equipped with long, sharp claws, this new species has only two fingers. This unique anatomy is the basis for its scientific name, Duonychus tsogtbaatari, which means “two fingers” in Greek and is named after Mongolian paleontologist Khishigjav Tsogtbaatar.
“There are many species of therizinosaurs, and this group was largely defined by their three-fingered hands with large claws,” study co-author Darla Zelenitsky, a paleontologist at the University of Calgary in Canada, told Live Science in an email. “Finding a specimen with two fingers/claws was surprising, as it is so unusual for this group of dinosaurs.”
Therizinosaurs are a group of dinosaurs that lived in what is now Asia and North America during the Late Cretaceous Period (100 to 66 million years ago). Although they belong to the theropod group of dinosaurs — commonly associated with carnivorous species like Tyrannosaurus rex — therizinosaurs were herbivores. These dinosaurs are known for their enormous sickle-shaped claws, with some species having claws that could reach 20 inches (50 centimeters).
All other previously discovered therizinosaurs, including Therizinosaurus and Beipiaosaurus, had three clawed fingers on their forelimbs, making the two-clawed D. tsogtbaatari find unique.
“Therizinosaurs are already some of the most unusual dinosaurs, but Duonychus tsogtbaatari takes it to the next level,” lead study author Yoshitsugu Kobayashi, a paleontologist at Hokkaido University in Japan, told Live Science in an email. “This newly discovered species from Mongolia breaks the mold by having just two fingers instead of the typical three, offering a rare glimpse into the evolution and adaptation of theropod hands.” “What really makes this discovery exciting, however, is the incredibly well-preserved keratin sheath on its claw — the first such case in a medium- to large-sized theropod dinosaur,” Kobayashi added.
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(Image credit: Kobayashi et al., 2025)
The claws of the newly discovered fossil Duonychus tsogtbaatari. The species is the first therizinosaur found with only two clawed fingers.
Sourse: www.livescience.com
