Its upper articulation was divided into three parts. The lower articular head was asymmetrical with deep and broad openings. As in metacarpal II, the lateral connecting openings were poorly developed. Only the second of the manus is known in Therizinosaurus. It consisted of two and a large . The first and second phalanges were somewhat equal in shape and length ( and , respectively), and shared the robust and stocky structure. The upper articular facets were very symmetrical and had a crest—particularly taller in the first phalanx. The top border of this crest was very pointed and thick; it likely served as the site for attachment of the extensor tendons in life. The lower heads were nearly symmetrical, but the central depression was considerably wider and deeper in the first phalanx. The manual unguals of Therizinosaurus were especially enormous and long, estimated to have covered approximately in length. Unlike other therizinosaurs they were very straight, side to side flattened, and had sharp curvatures only at the tips, a unique feature of Therizinosaurus. The lower tubercle, where the flexor tendons attached to the ungual, was thick and robust, indicating a large pad in life. The articulation surface that connected the preceding phalanx was slightly concave and divided into two by a central ridge. Hindlimbs Therizinosaurus had a rather stocky and robust that was very wide on its lower end. The was robust and short (almost sauropodomorph-like), and composed of five . The first four were functional and terminated in weight-bearing digits, hence having a tetradactyl (four-toed) condition. The last or fifth metatarsal was highly reduced bone located at the lateral side of the metatarsus and had no functional significance. Unlike most other theropods groups, the first pedal digit was—though shorter than the others—functional and weight-bearing. The second and third were equally long while the fourth was smaller and somewhat thinner. The pedal unguals were side to side flattened and likely sharp. The morphology of the feet of Therizinosaurus and other therizinosaurids was unique, as the general theropod formula includes tridactyl (three-toed) feet in which the first toe was reduced to a dewclaw and held off the ground. Classification Maleev originally classified Therizinosaurus as a giant marine turtle and the genus was assigned by him to a separate family, Therizinosauridae given how enigmatic the specimen was. The fossils remained with uncertainty among the scientific community; however, in 1970 Rozhdestvensky was one of