Two-fingered dinosaur used its enormous claws to eat leaves
A dinosaur fossil discovered in Mongolia boasts the largest ever complete claw, but the herbivorous species only used it to grasp vegetation
By James Woodford
20 March 2025
Illustration of Duonychus tsogtbaatari, a theropod dinosaur from the Cretaceous Period
Masato Hattori
A new species of dinosaur found at a Mongolian building site has the largest fully preserved claw ever found. The bipedal, herbivorous animal had only two fingers on each hand, which it may have used to grasp branches and pull them towards its mouth.
The 90-million-year-old fossil – which included parts of the pelvis, both arms and hands, and numerous vertebrae – was found near Khanbogd in the Gobi desert in 2012, but it has only now been properly studied and given the scientific name Duonychus tsogtbaatari. The genus name means “two claws” and the species name honours Mongolian palaeontologist Khishigjav Tsogtbaatar.
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Duonychus is a smaller relative of Therizinosaurus, which features in the film Jurassic World Dominion. Yoshitsugu Kobayashi at Hokkaido University in Japan and his colleagues estimate the dinosaur would have been around 3 metres long and weighed approximately 270 kilograms.
“The discovery of Duonychus tsogtbaatari is a big deal because it’s the first known therizinosaur with only two fingers,” says Kobayashi. “Most theropods, including other therizinosaurs, kept three functional fingers, so finding one that lost a digit is pretty unexpected.”
Altogether, five groups of theropods evolved to have only two fingers, the most famous being Tyrannosaurus.
