In 2010, Lindsay Zanno revised the taxonomy of therizinosaurs with extensive detail. She found that many parts on therizinosaur holotypes 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 include the specimen in her taxonomic analysis due to the lack of 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. Cladogram below shows the placement of "Therizinosaurus" within Therizinosauria according to Hartman and colleagues in 2019: