Duonychus (meaning two claws) is an extinct genus of therizinosaurid theropod dinosaur that lived in Late Cretaceous of Mongolia. The type species is named Duonychus tsogbaatari.
Discovery and Naming[]
The holotype (MPC-D 100/85) was discovered in outcrops of Bayanshiree Formation in 2012. before its formal description, the fossil material was reported in two Society of Vertebrate Paleontology conference abstracts in 2015 and 2024. In 2025, Kobayashi described it as a new genus of therizinosaur. The generic name combines "Duo" and "Nychus" meaning "two claws", while the specific name is named after Khishigjav Tsogtbaatar.
Description[]
The holotype belongs to an immature individual, and could have been much larger when fully grown. The manus of Duonychus is well-preserved. The manual unguals are large and curved, as is generally seen in therizinosaurs. However, it contains keratinous sheath. It is from a partial skeleton.
Classification[]
It is classified as a member of the family Therizinosauridae, with its closest sister taxon as Nanshiungosaurus.
Paleoecology[]
It lived with Erketu, Talarurus, and others in the Bayanshriee Formation, where it browsed from the foliage in forested areas.
Gallery[]
