Duonychus
"two claws"
- Length
- 3 m (9.8 ft)
- Period
- Late Cretaceous (96–90 Mya)
- Place
- Mongolia
- Food
- Herbivore
- Clade
- Therizinosauridae Dinosauria Saurischia Theropoda Coelurosauria Pot-bellied theropods with giant claws — secondarily plant-eating.
Duonychus (meaning “two claws”) is an extinct genus of therizinosaurid theropod dinosaurs that lived during the Late Cretaceous (Cenomanian to early Coniacian age) of what is now Mongolia. It is known from a partial skeleton, including several vertebrae, most of the forelimbs, and part of the pelvic girdle, found in outcrops of the Bayanshiree Formation. The remains were discovered in 2012 by the Mongolian Academy of Sciences and briefly mentioned in later conference abstracts. The genus contains a single species, Duonychus tsogtbaatari, which was formally described in 2025.
The hand of Duonychus only has two fingers, similar to tyrannosaurids, compared to the three commonly found in most theropods. This anatomical feature—in addition to its long, strongly curved claws—may have allowed Duonychus to efficiently grasp plant material to consume.
What we know
- Named by Kobayashi et al., 2025.
- Body length estimated at about 3 m.
- Fossils found in Mongolia.
What we guess
The reconstruction notes for Duonychus — soft tissue, color, behavior — haven't been written up yet. Only the recorded basics above are filled in so far.