Therizinosaurs were a large group of primarily herbivorous theropod dinosaurs (dinosaurs with hollow bones and three-toed limbs). Therizinosaurs were first discovered in Asia; the fossil records in Asian countries such as China and Mongolia are rich in therizinosaurus fossils, and fossil fragments have also been reported from Japan.

Scientists from Japan and the U.S., led by Professor Yoshitsugu Kobayashi at the Hokkaido University Museum and Anthony R. Fiorillo at Southern Methodist University (SMU), have described a new species of therizinosaurid from Japan, and provide new insights into the function of therizinosaur claws. The findings were published in the journal Scientific Reports.

Co-authors of the study include Ryuji Takasaki of Okayama University of Science, Tsogtbaatar Chinzorig of North Carolina State University and Mongolian Academy of Sciences, and Yoshinori Hikida of Nakagawa Museum of Natural History.

The fossil described in this work consists of a partial vertebra and a partial wrist and forefoot, originally collected in 2008 from the Osoushinai Formation, a fossil-rich geological feature in Nakagawa, Hokkaido. At the time, it was described as belonging to a manitoraptan dinosaur, and was believed to belong to a therizinosaur. However, the lack of comparative data at the time made confirmation impracticable.