year, David B. Norman considered Therizinosaurus to be a theropod of uncertain classification. However, with the unexpected discovery and description of Alxasaurus in 1993, the widely accepted sauropodomorph affinities of segnosaurs were questioned by paleontologists Dale Russell and Dong Zhiming. This new genus was far more complete than any other segnosaur and multiple anatomical features indicated that it was related to Therizinosaurus. With this, they identified the Therizinosauridae along with the Segnosauridae to be the same group, the former name having taxonomic priority. Due to some primitive characters present in Alxasaurus they coined a new taxonomic rank, the Therizinosauroidea, containing the new taxon and Therizinosauridae. All of the new information provided data on the affinities of the new-named therizinosauroids. Russell and Dong concluded that they were theropods with unusual features. In 1994, Clark and colleagues redescribed the very complete skull of Erlikosaurus and even more theropod traits were found this time. They also validated the synonymy of the Segnosauridae with Therizinosauridae and considered therizinosauroids as maniraptoran dinosaurs. In 1997, Rusell coined the infraorder Therizinosauria in order to contain all segnosaurs. This new infraorder was composed of Therizinosauroidea and the more advanced Therizinosauridae. Consequently, Segnosauria became a synonym of Therizinosauria. Though some uncertainties remained, a small and feathered therizinosauroid from China was described in 1999 by Xu Xing and colleagues: the new genus Beipiaosaurus. It confirmed the placement of therizinosaurs among theropods and also their taxonomic place on the Coelurosauria. The discovery also indicated that feathers were highly distributed among theropod dinosaurs. In 2010, Lindsay Zanno revised the taxonomy of therizinosaurs in extensive detail. She found that many parts on therizinosaur holotype and referred specimens were lost or damaged, and sparse specimens with no overlapping elements were disadvantages when concluding the relationships of the members. Zanno accepted the referral of the specimen IGM 100/45 to Therizinosaurus since it matches multiple therizinosaurid traits, but decided not to include the specimen in her taxonomic analysis due to the lack of comparative forelimb remains. She also excluded the supposed ribs that were present on the holotype since they likely came from a different animal and not Therizinosaurus. In 2019, Hartman and colleagues also performed a large phylogenetic analysis of Therizinosauria based on the characters provided by Zanno in her revision. They found similar results to Zanno regarding the family Therizinosauridae but this time with the inclusion of more taxa and specimens. The cladogram below