Open Paleo

Therizinosauroidea

Maleev, 1954 Type genus Therizinosaurus

Its genera lived 125.8–66.0 million years ago Early Cretaceous–Late Cretaceous
Early Cretaceous and Late Cretaceous stages

Therizinosauroidea is a superfamily of large, herbivorous maniraptoran theropod dinosaurs known mainly from the Cretaceous of Asia, with a possible Jurassic tooth from England representing its oldest record. In the restricted sense, it comprises the more derived therizinosaurs, including genera such as Beipiaosaurus, Enigmosaurus, Erliansaurus, Neimongosaurus, and Suzhousaurus together with the families Alxasauridae and Therizinosauridae, and excludes the most primitive members of the broader group Therizinosauria, such as Falcarius. Its members share the distinctive therizinosaur mix of features: long necks, wide torsos, and four-toed weight-bearing feet reminiscent of early plant-eating dinosaurs, backward-pointing and partially fused hip bones once thought to recall those of ornithischians, and greatly enlarged, strongly curved hand claws. The name has largely replaced the older term Segnosauria in phylogenetic work, though some studies instead apply it to the entire therizinosaur lineage rather than to this more nested grouping.

Diagnosis

  1. Loss of the plesiomorphic subcondylar recess retained in Falcarius
  2. Coossification of the sacral neural spines into a supraneural plate
  3. Deep, anteriorly hooked cervical epipophyses
  4. Femoral head confluent with the neck without an evident transition
  5. Progressively enlarged, transversely broadened preacetabular ala of the ilium

Clades within Therizinosauroidea

Genera placed directly in Therizinosauroidea

  • Alxasaurus Russell & Dong, 1993 Albian (113.2–100.5 Ma)China
  • Beipiaosaurus Xu et al., 1999 Barremian (125.8–121.4 Ma)China
  • Enigmosaurus Barsbold, 1983 Cenomanian–Turonian (100.5–89.8 Ma)Mongoliaunder dispute
  • Erliansaurus Xu et al., 2002 Coniacian–Maastrichtian (89.8–66.0 Ma)Chinaunder dispute
  • Lingyuanosaurus Yao et al., 2019 Barremian–Aptian (125.8–113.2 Ma)China
  • Neimongosaurus Zhang et al., 2001 Coniacian–Maastrichtian (89.8–66.0 Ma)Chinaunder dispute
  • Suzhousaurus Li et al., 2007 Aptian–Albian (121.4–100.5 Ma)Chinaunder dispute

References

  1. Maleev, E. A. (1954). Noviy cherepachoobrazhniy yashcher v Mongolii [New tortoise-like saurian from Mongolia]. Priroda 1954(3): 106-108.

    Origin of the family-group name (Therizinosauridae), and by coordination the superfamily Therizinosauroidea.

    maleev1954a
  2. Russell, D. A.; Dong, Z. M. (1993). The affinities of a new theropod from the Alxa Desert, Inner Mongolia, People's Republic of China. Canadian Journal of Earth Sciences 30(10): 2107-2127. Canadian Science Publishing. doi:10.1139/e93-183

    Raised Maleev's family-group name to superfamily rank as Therizinosauroidea, new rank, with the new family Alxasauridae within it.

    russell1993b
  3. Zanno, L. E. (2010). A taxonomic and phylogenetic re-evaluation of Therizinosauria (Dinosauria: Maniraptora). Journal of Systematic Palaeontology 8(4): 503-543. doi:10.1080/14772019.2010.488045 zanno2010a