Enigmosauria Naish, Hutt and Martill, 2001
= Oviraptorosauria sensu Currie and Padian, 1997
Definition- (Oviraptor philoceratops <- Passer domesticus) (modified)
= Oviraptoriformes Benson, 2008
Definition- (Oviraptor philoceratops <- Passer domesticus) (Sereno, in press)
Comments- Naish et al. (2001) named Enigmosauria in a cladogram for a maniraptoran clade containing therizinosauroids and oviraptorosaurs, but not paravians. It was not defined or mentioned in the text, as the authors had only accidentally left in in the figure after they decided not to formally name the clade in that publication. Sereno proposed the name Oviraptoriformes on the Taxon Search website with a phylogenetic definition, crediting it to Sereno, 2005. Yet online citations do not count for nomenclature, rendering this a nomen nudum until recently. Benson (2008) is the first author to publish the name Oviraptoriformes, though he did such undefined in a cladogram. Thus neither proposed name for this clade has a published definition.
References- Naish, Hutt and Martill, 2001. Saurichian dinosaurs 2: theropods. in Martill and Naish (eds). Dinosaurs of the Isle of Wight. The Palaeontological Association. 242-309.
Sereno, 2005. Stem Archosauria - TaxonSearch. http://www.taxonsearch.org/dev/file_home.php [version 1.0, 2005 November 7]
Benson, 2008. New information on Stokesosaurus, a tyrannosauroid (Dinosauria: Theropoda) from North America and the United Kingdom. Journal of Vertebrate Paleontology. 28(3), 732-750.

Therizinosauria Russell, 1997
Definition- (Alxasaurus elesitaiensis, Enigmosaurus mongoliensis, Erlikosaurus andrewsi, Nanshiungosaurus brevispinus, Segnosaurus galbinensis, Therizinosaurus cheloniformis <- Ornithomimus velox, Troodon formosus, Oviraptor philoceratops) (modified from Russell, 1997)
Other definitions- (Therizinosaurus cheloniformis <- Tyrannosaurus rex, Ornithomimus edmontonicus, Mononykus olecranus, Oviraptor philoceratops, Troodon formosus) (Zanno, 2010)
(Therizinosaurus cheloniformis <- Tyrannosaurus rex, Ornithomimus edmontonicus, Shuvuuia deserti, Oviraptor philoceratops, Troodon formosus) (Sereno, in press)
= Segnosauria Barsbold, 1980
= Segnosaurischia Dong, 1987
= Therizinosauria sensu Russell, 1997
Definition- (Alxasaurus elesitaiensis, Enigmosaurus mongoliensis, Erlikosaurus andrewsi, Nanshiungosaurus brevispinus, Segnosaurus galbinensis, Therizinosaurus cheloniformis <- Ornithomimus velox, Troodon formosus, Oviraptor philoceratops) (modified)
= Therizinosauridae sensu Sereno, 1999
Definition- (Erlikosaurus andrewsi <- Ornithomimus velox, Oviraptor philoceratops, Passer domesticus) (modified)
= Therizinosauroidea sensu Zhang et al., 2001
Definition- (Therizinosaurus cheloniformis <- Ornithomimus velox, Oviraptor philoceratops, Velociraptor mongoliensis, Passer domesticus)
= Therizinosauroidea sensu Hu, Hou, Zhang and Xu, 2009
Definition- (Therizinosaurus cheloniformis <- Oviraptor philoceratops, Passer domesticus) (modified)
= Therizinosauria sensu Zanno, 2010
Definition- (Therizinosaurus cheloniformis <- Tyrannosaurus rex, Ornithomimus edmontonicus, Mononykus olecranus, Oviraptor philoceratops, Troodon formosus)
= Therizinosauria Sereno, in press
Definition- (Therizinosaurus cheloniformis <- Tyrannosaurus rex, Ornithomimus edmontonicus, Shuvuuia deserti, Oviraptor philoceratops, Troodon formosus)
Comments- Sereno's (in press) definition is a redefinition of Russell's (1997) attempt, deleting all internal specifiers except Therizinosaurus and adding Tyrannosaurus and Shuvuuia as external specifiers. The first change is good (why bother forcing Alxasaurus, Enigmosaurus, Erlikosaurus, Segnosaurus and Nanshiungosaurus to be in the clade?), but the second doesn't appear very pointful to me. I'm unaware of any suggested topology- (Ornithomimus, Oviraptor, Troodon (Tyrannosaurus, Shuvuuia, Therizinosaurus)). If anything, I might suggest using Plateosaurus and Stegosaurus as additional specifiers instead, just to ensure views like Paul's (1984, 1988), Sereno's (1992) and Olshevsky's are covered.
Dong and Yu (1997) place therizinosaurs in the Segnosaurischia and divide them between the Segnosauridae and the newly formed Nanshiungosauridae, based on whether they are theropod-like or sauropod-like. This is contrary to current cladistic consensus, and based more on past misidentification than morphology.
Ex-therizinosaurs- Mateer (1987) described a pedal ungual which Nessov (1995) referred it to Therizinosauria or "groups most closely related to them" (which in his opinion consisted of spinosaurids and dryptosaurids). Provisional comparisons suggest it more closely resembles pedal unguals of Sinraptor and Poekilopleuron than those of any therizinosaurs (Beipiaosaurus, Alxasaurus, Nothronychus, Erlikosaurus), which tend to be deeper and more curved.
A distal phalanx was discovered in 1931 and referred to Theropoda indet. by Riabinin (1937), but referred to Therizinosauridae based on the unequally deep collateral ligament pits by Averianov et al. (2003). Zanno (2008) noted both sides having well defined pits (albeit better developed on one side) is unlike therizinosaurs.
References- Riabin, 1937. A new discovery of dinosaurs in Transbaikalia. Ezhegodnik Vsesoyuznogo Paleontologicheskogo Obshchestva. 11, 141-144.
Mateer, 1987. A new report of a theropod dinosaur from South Africa. Palaeontology. 30(1), 141-145.
Nessov, 1995. Dinosaurs of nothern Eurasia: new data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 1-156.
Averianov, Starkov and Skutschas, 2003. Dinosaurs from the Early Cretaceous Murtoi Formation in Buryatia, Eastern Russia. Journal of Vertebrate Paleontology. 23(3), 586-594.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

undescribed Therizinosauria (Dmitriev, 1960)
Late Barremian-Mid Aptian, Early Cretaceous
Mogoito Member of Murtoi Formation, Russia

Material- (ZIN PH 2/13) proximal pedal ungual (Averianov et al., 2003)
(lost) manual ungual II (Dmitriev, 1960)
manual ungual (Starkov pers. comm. to Nessov, 1995)
Comments- Dmitriev (1960) described a large theropod manual ungual found in 1959, which was later referred to Carnosauria by Rozhdestvensky (1970). Nessov (1995) noted Rozhdestvensky's specimen was a possible therizinosaur and remarked on another similar specimen. Averianov et al. (2003) confirmed the therizinosaurian identity for Dmitriev's specimen and an additional partial pedal ungual they describe and illustrate.
References- Dmitriev, 1960. New findings of dinosaurs in Buryatia. Paleontologicheskii Zhurnal. 1, 148.
Rozhdestvensky, 1970. Giant claws of enigmatic Mesozoic reptiles. Paleontological Journal. 1970(1), 131-141.
Nessov, 1995. Dinosaurs of nothern Eurasia: new data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 1-156.
Averianov, Starkov and Skutschas, 2003. Dinosaurs from the Early Cretaceous Murtoi Formation in Buryatia, Eastern Russia. Journal of Vertebrate Paleontology. 23(3), 586-594.

undescribed therizinosaur (Nessov, 1995)
Mid Albian, Early Cretaceous
Lower Khodzhakul Formation, Uzbekistan

Material- ungual
Reference- Nessov, 1995. Dinosaurs of nothern Eurasia: new data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 1-156.

undescribed therizinosaur (Nessov, 1995)
Early Cenomanian, Late Cretaceous
Upper Khodzhakul Formation, Uzbekistan

Material- (N 457/12457) ungual
Reference- Nessov, 1995. Dinosaurs of nothern Eurasia: new data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 1-156.

undescribed Therizinosauria (Watabe and Weishampel, 1994)
Cenomanian-Santonian, Late Cretaceous
Baynshirenskaya Formation, Mongolia

Material- (IGM 100/84) femoral (or tibial?) shaft (~1050 mm) (Zanno, 2008)
(Field number 930820 BTs-II-4) humerus (Watabe and Suzuki, 2000)
(Field number 930820 BTs-II-8) pubis (Watabe and Suzuki, 2000)
(Field number 940625 BTs II) fragmentary skull, mandible, cervical vertebrae (Watabe and Suzuki, 2000)
Comments- The material reported by Watabe and Suzuki is possibly Erlikosaurus, Enigmosaurus and/or Segnosaurus, but has yet to be described. The femoral shaft is catalogued under the same number as Enigmosaurus' holotype, but is too large to belong to that individual (Zanno, 2008).
References- Watabe and Weishampel, 1994. Results of Hayashibara Museum of Natural Sciences–Institute of Geology, Academy of Sciences of Mongolia Joint Paleontological Expedition to the Gobi Desert in 1993. Journal of Vertebrate Paleontology. 14(3), 51A.
Watabe and Suzuki, 2000. Report on the Japan-Mongolia Joint Paleontological Expedition to the Gobi desert, 1993: In: Results of the Hayashibara Museum of Natural Sciences, Mongolian Academy of Sciences, Mongolian Paleontological Center, Joint Paleontological Expedition, n. 1, Hayashibara Museum of Natural Sciences, Research Bulletin. 1, 17-29.
Watabe and Suzuki, 2000. Report on the Japan-Mongolia Joint Paleontological Expedition to the Gobi desert, 1994: In: Results of the Hayashibara Museum of Natural Sciences, Mongolian Academy of Sciences, Mongolian Paleontological Center, Joint Paleontological Expedition, n. 1, Hayashibara Museum of Natural Sciences, Research Bulletin. 1, 30-44.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

undescribed possible therizinosaur (Nessov, 1995)
Santonian, Late Cretaceous
Syuk Syuk Formation, Kazakhstan

Material- unguals
Comments- This is based on unguals tentatively referred to Alectrosaurus by Prinada (1925, 1927) and/or Riabinin (1938), since the well known unguals originally referred to Alectrosaurus by Gilmore are therizinosaurian.
References- Prinada, 1925. Search for remains of large vertebrates of Upper Cretaceous age in Turkestan. Report on the state of activities of the Geological Committee for 1924. Part II, III. Izvyestiya Gyeologichyeskogo komityeta. 44(2), 257.
Prinada, 1927. Report on the excavation at the localities where dinosaur bones were discovered. Report on the state of activities of the Geological Committee for 1925. Part II, III. Izvyestiya Gyeologichyeskogo komityeta. 45(4), 453-454.
Riabinin, 1938. Some results of the study of the Upper Cretaceous dinosaur fauna from the vicinity of st. Sary-Agachin, Southern Kazakhstan. Problyemy palyeontologii. 4, 125-135.
Nessov, 1995. Dinosaurs of nothern Eurasia: new data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 1-156.

undescribed possible therizinosaur (Carpenter, online)
Late Albian, Early Cretaceous
Mussentuchit Member of the Cedar Mountain Formation, Utah, US

Material- teeth
Reference- https://scientists.dmns.org/sites/kencarpenter/Cedar%20Mountain%20storage/Dinosaurs.aspx

undescribed therizinosaur (Russell, 1984)
Late Maastrichtian, Late Cretaceous
Hell Creek Formation, US
Material
- astragalus
Comments- This was cited as therizinosaurid indet. by Russell (1984).
Reference- Russell, 1984. A checklist of the families and genera of North American dinosaurs. National Museum of Natural Science, National Museums of Canada, Syllogeus. 53, 1-35.

undescribed therizinosaur (Ryan and Russell, 2001)
Late Maastrichtian, Late Cretaceous
Scollard Formation, Alberta, Canada
Material
- (RTMP 86.207.17) cervical vertebra
Comments- Cited as Segnosauridae indet. by Ryan and Russell (2001).
Reference- Ryan and Russell, 2001. Dinosaurs of Alberta (exclusive of Aves). in Tanke and Carpenter (eds). Mesozoic Vertebrate Life. Indiana University Press. 279-297.

undescribed therizinosaur (Manning, Joysey and Cruikshank, 1997)
Santonian-Campanian, Late Cretaceous
Nanchao Formation, Henan, China

Material- embryos, eggs
Description- This belongs to the oospecies Macroelongatoolithus xixiaensis. The eggs are elongate, unlike the dendroolithid therizinosaur eggs.
Reference- Manning, Joysey and Cruikshank, 1997. Observations of microstructures within dinosaur eggs from Henan Province, Peoples Republic of China. in Wolberg, Stump and Rosenburg eds. Dinofest International: Proceedings of a Symposium held at Arizona State University. Philadelphia: Academy of Sciences. 287-290.

unnamed possible therizinosaur (Young, 1958)
Campanian, Late Cretaceous
Wangshi Group, Shandong, China

Material- ungual
Comments- Described as a carnosaur by Young (1958), but identified as a probable segnosaur by Nessov (1995).
References- Young, 1958.
Nessov, 1995. Dinosaurs of nothern Eurasia: new data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 1-156.

undescribed therizinosaur (Long, 1992)
Late Maastrichtian, Late Cretaceous
Miria Formation, Western Australia, Australia

Material- proximal humerus (~350 mm)
Reference- Long, 1992. First dinosaur bones from Western Australia. The Beagle, Records of the Northern Territory Museum of Arts and Sciences. 9, 21-28.

unnamed possible therizinosaur (Rauhut, 1999)
Cenomanian, Late Cretaceous
Wadi Milk Formation, Sudan

Material- (Vb-839) incomplete pedal ungual (~50 mm)
Comments- Rauhut believes this is a manual ungual and places it in the Coelurosauria based on its proximodorsal lip, but a small lip appears to be present in Sinraptor dongi too. Within coelurosaurs, a lip is not developed until the Maniraptoriformes (and then only variably, both between taxa and digits). This ungual has several strange characters, but of described manual unguals resembles Elmisaurus' the most. It differs from the latter in being shallower, being wider proximally, having a wider proximodorsal lip, a slightly more proximally placed flexor tubercle that is less separated from the ventral articular lip, a groove ventrally distal to the flexor tubercle, artery grooves that run dorsodistally to join ~1/3 down the ungual, and a more concave articular surface with no central ridge. The ventral groove, lack of a central proximal ridge and artery groove arrangement are unique among described manual unguals. Elmisaurus is said to have a very indistinctly divided articular surface however, and even that is only present in the ventral portion. The broad proximal surface and lack of a central proximal ridge are more similar to a pedal ungual, but the prominent rounded flexor tubercle, proximodorsal lip and narrow main body are not. Some dromaeosaurs (Saurornitholestes, Achillobator, Sudanese taxon) have pedal unguals with such flexor tubercles (on their second digits), and these have especially distinct central proximal ridges, slender proximal ends and sharp ventral edges. These and therizinosaurs have narrow main bodies on their pedal claws. Among therizinosaurs, it resembles "Chilantaisaurus" zheziangensis the most, especially in the slight proximodorsal lip and prominent flexor tubercle. Additionally, the proximal outline is similar to Nothronychus. I provisionally consider this a therizinosaur pedal ungual, the priminent proximodorsal lip and dorsally angled artery grooves indicate a diagnosable taxon.
Reference- Rauhut, 1999. A dinosaur fauna from the Late Cretaceous (Cenomanian) of Northern Sudan. Palaeontologia Africana. 35, 61-84.

undescribed therizinosaur (Kobayashi et al., 2013)
Late Cretaceous
Javkhlant Formation, Mongolia
Material
- seventeen egg clutches (510x430 mm; eggs 130 mm in diameter)
Comments- The eggs are dendroolithid, prompting the authors to refer them to therizinosauroids.
Reference- Kobayashi, Lee, Barsbold, Zelenitsky and Tanaka, 2013. First record of a dinosaur nesting colony from Mongolia reveals nesting behavior of therizinosauroids. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 155.

Thecocoelurus Huene, 1923
T. daviesi (Seeley, 1888) Huene, 1923
= Thecospondylus daviesi Seeley, 1888
= Coelurus daviesi (Seeley, 1888) Nopsca, 1901
Barremian, Early Cretaceous
Wessex Formation, England

Holotype- (BMNH R181) anterior half of cervical vertebra (~70 mm)
Comments- After a long history as a generic small theropod, Naish et al. (2001) identified Thecocoelurus as an oviraptorosaur based on the round pneumatic foramina and gracile neural spine. However, Kirkland et al. (2004) later noted strong similarities with their new basal therizinosaur Falcarius, suggesting placement in this clade instead. Indeed, Zanno (2008) notes Falcarius has both of the characters Naish et al. used to place it in Oviraptorosauria. However, Naish (online, 2007) has suggested Thecocoelurus isn't a therizinosaur after all (citing Naish and Martill, in press).
References- Seeley, 1888. On Thecospondylus daviesi (Seeley), with some remarks on the classification of the Dinosauria. Quarterly Journal of the Geological Society, London. 44, 79-86.
Nopcsa, 1901. Synopsis und Abstammung der Dinosaurier. Foldt. Kozl. 31, 247-288.
Huene, 1923. Carnivorous Saurischia in Europe since the Triassic. Bulletin of the Geological Society of America. 34, 449-458.
Naish, 1999. Studies on Wealden Group theropods – an investigation into the historical taxonomy and phylogenetic affinities of new and previously neglected specimens. MPhil thesis, University of Portsmouth.
Naish, Hutt and Martill, 2001. Saurichian dinosaurs 2: theropods. in Martill and Naish (eds). Dinosaurs of the Isle of Wight. The Palaeontological Association. 242-309.
Naish and Martill, 2002. A reappraisal of Thecocoelurus daviesi (Dinosauria: Theropoda) from the Early Cretaceous of the Isle of Wight. Proceedings of the Geologists’ Association. 113, 23-30.
Kirkland, Zanno, DeBlieux, Smith and Sampson, 2004. A new, basal-most therizinosauroid (Theropoda: Maniraptora) from Utah demonstrates a Pan-Laurasian distribution for Early Cretaceous therizinosauroids. Journal of Vertebrate Paleontology. 24(3).
http://scienceblogs.com/tetrapodzoology/2007/02/therizinosauroids_and_altanger.php
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.
Naish and Martill, in press.

Falcarius Kirkland, Zanno, Sampson, Clark and DeBlieux, 2005
F. utahensis Kirkland, Zanno, Sampson, Clark and DeBlieux, 2005
Barremian, Early Cretaceous
Yellow Cat Member of Cedar Mountain Formation, Utah, US

Holotype- (UMNH VP 15000) (subadult) incomplete braincase
Paratypes- (UMNH VP 12283, 12285, 12286, 12288, 12290, 12292, 12293, 12315, 12321-12329, 12343-12345, 12347-12349, 12360, 12363, 12366, 12369-12373, 12377, 12380, 12383-12384, 12386-12389, 12392-12394, 12396-12400, 12402-12404, 12406, 12410-12417, 12419-12425, 12427-12439, 12441-12443, 14530-14533, 14537-14538, 14542-14557, 14560-14565, 14568-14582, 14584-14656, 14658-14666, 14668-14670, 14672-14676, 14678-14680, 14682-14690, 14692-14699, 14701-14999, 15002-15149) (at least ten individuals; up to 4 m) basioccipital, splenial, fifteen anterior and mid cervical vertebrae, two mid dorsal vertebrae, posterior dorsal vertebra, eight dorsal vertebrae, few dorsal ribs, gastralium, sacral vertebrae, fifty-eight caudal vertebrae, four chevrons, ischium, three proximal fibulae, astragali, three distal tarsals, seven pedal phalanges, few pedal unguals
(UMNH VP 12279) incomplete scapula (234 mm)
....(UMNH VP 12281) partial coracoid
(UMNH VP 12280) scapula (290 mm)
(UMNH VP 12282) coracoid
(UMNH VP 12284) humerus (255 mm)
....(UMNH VP 12287) ulna (197 mm)
....(UMNH VP 12289) radius (184 mm)
(UMNH VP 12291) semilunate carpal
(UMNH VP 12292) distal carpal I
(UMNH VP 12293) distal carpal II
(UMNH VP 12294) radiale
(UMNH VP 12295) intermedium?
(UMNH VP 12296) metacarpal I (42 mm)
(UMNH VP 12297) metacarpal I (43 mm)
....(UMNH VP 12299) metacarpal II (96 mm)
....(UMNH VP 12301) metacarpal III (76 mm)
....(UMNH VP 12303) manual phalanx I-1 (89 mm)
....(UMNH VP 12305) manual phalanx II-1 (69 mm)
....(UMNH VP 12307) manual phalanx II-2 (87 mm)
....(UMNH VP 12309) manual phalanx III-1 (31 mm)
....(UMNH VP 12311) manual phalanx III-2 (28 mm)
....(UMNH VP 12313) manual phalanx III-3 (47 mm)
....(UMNH VP 12314) manual ungual I
....(UMNH VP 12316) manual ungual II
....(UMNH VP 12320) manual ungual III
(UMNH VP 12298) metacarpal II (91 mm)
(UMNH VP 12300) metacarpal III (75 mm)
(UMNH VP 12302) manual phalanx I-1 (81 mm)
(UMNH VP 12304) manual phalanx II-1 (69 mm)
(UMNH VP 12306) manual phalanx II-2 (85 mm)
(UMNH VP 12308) manual phalanx III-1 (38 mm)
(UMNH VP 12310) manual phalanx III-2 (30 mm)
(UMNH VP 12312) manual phalanx III-3 (48 mm)
(UMNH VP 12317) manual ungual II
(UMNH VP 12318) manual ungual II
(UMNH VP 12319) (juvenile) manual ungual I (82 mm)
(UMNH VP 12330) pedal ungual II
(UMNH VP 12331) pedal phalanx
(UMNH VP 12332) pedal phalanx
(UMNH VP 12333) pedal phalanx
(UMNH VP 12334) pedal phalanx
(UMNH VP 12335) pedal phalanx
(UMNH VP 12336) pedal phalanx
(UMNH VP 12337) pedal phalanx
(UMNH VP 12338) pedal phalanx
(UMNH VP 12339) pedal phalanx
(UMNH VP 12340) pedal phalanx
(UMNH VP 12341) pedal phalanx
(UMNH VP 12342) pedal phalanx
(UMNH VP 12346) pedal phalanx
(UMNH VP 12350) pedal phalanx
(UMNH VP 12351) pedal phalanx
(UMNH VP 12352) pedal phalanx
(UMNH VP 12353) pedal phalanx
(UMNH VP 12354) metatarsal II
....(UMNH VP 12355) metatarsal III
....(UMNH VP 12356) metatarsal IV
(UMNH VP 12357) metatarsal IV
....(UMNH VP 12358) metatarsal III
....(UMNH VP 12359) metatarsal II
(UMNH VP 12361) femur
(UMNH VP 12362) tibia
(UMNH VP 12364) astragalus
....(UMNH VP 12365) calcaneum
(UMNH VP 12367) (subadult) proximal fibula
(UMNH VP 12368) partial ilium
(UMNH VP 12374) ischium
(UMNH VP 12375) ischium
(UMNH VP 12376) pedal phalanx I-1
(UMNH VP 12378) three fused sacral centra
(UMNH VP 12379) mid caudal vertebra
(UMNH VP 12381) proximal caudal vertebra
(UMNH VP 12382) first sacral vertebra
(UMNH VP 12385) mid caudal vertebra
(UMNH VP 12390) proximal chevron
(UMNH VP 12391) proximal chevron
(UMNH VP 12395) proximal chevron
(UMNH VP 12401) mid chevron
(UMNH VP 12405) distal caudal vertebra
(UMNH VP 12407) distal caudal vertebra
(UMNH VP 12408) distal caudal vertebra
(UMNH VP 12409) distal caudal vertebra
(UMNH VP 12418) distal caudal vertebra
(UMNH VP 12426) distal caudal vertebra
(UMNH VP 12440) posterior dorsal vertebra
(UMNH VP 14524) frontal
....(UMNH VP 14525) frontal
(UMNH VP 14526) partial maxilla, teeth
(UMNH VP 14527) partial dentary, teeth
(UMNH VP 14528) incomplete dentary, teeth
(UMNH VP 14529) incomplete dentary, teeth
(UMNH VP 14534) mid dorsal vertebra
(UMNH VP 14535) mid dorsal vertebra
(UMNH VP 14536) first dorsal vertebra
(UMNH VP 14539) pubis
(UMNH VP 14540) pubis
(UMNH VP 14541) incomplete ischium
(UMNH VP 14558) quadrate
(UMNH VP 14559) quadrate
(UMNH VP 14566) frontal
(UMNH VP 14567) postorbital
(UMNH VP 14583) pedal phalanx
(UMNH VP 14657) incomplete posterior cervical vertebra
(UMNH VP 14667) (adult) femur
(UMNH VP 14671) furcula
(UMNH VP 14677) (juvenile) atlantal intercentrum
(UMNH VP 14681) posterior surangular fragment
(UMNH VP 14691) second dorsal vertebra
(UMNH VP 14700) mid cervical vertebra
(UMNH VP 15000) incomplete braincase
Referred- ?(CEUM coll.) (multiple individuals; some adult) many elements including vertebrae and pelvic elements (Zanno, 2008)
?(CEUM 52399) pedal phalanx IV-2 (Zanno, 2008)
?(CEUM 53282) pedal phalanx III-2 (Zanno, 2008)
(UMNH VP 12447) distal tarsal III (Zanno, 2008)
(UMNH VP 12451) distal tarsal IV (Zanno, 2008)
(UMNH VP 12476) distal chevron (Zanno, 2008)
(UMNH VP 16020) posterior surangular fragment (Zanno, 2008)
(UMNH VP 16021) partial anterior tooth (Zanno, 2008)
(UMNH VP 16022) nasal (Zanno, 2008)
(UMNH VP 16023) partial anterior tooth (Zanno, 2008)
(UMNH VP 16024) (juvenile) partial fibula (Zanno, 2008)
Diagnosis- (after Kirkland et al., 2005) hypertrophied basisphenoidal recess; extensive, deeply depressed subcondylar and subotic recesses, each with multiple pneumatic fossae; flexor tubercle of manual ungual I with deep collateral ligament pits.
(after Zanno, 2008) antorbital fossa extends onto lateral surface of nasal; at least five pairs of conical anterior dentary teeth (also in Erlikosaurus); anteriormost teeth lingually cupped (inapplicable in other therizinosaurs); median ridge on ventral sulcus of cervical vertebrae; infraprezygapophyseal fossa on mid dorsal vertebrae divided into three accessory fossae; accessory caudal centrodiapophyseal lamina on mid dorsal vertebra; hypertrophied, obliquely oriented humeral enteipcondyle with concave posterior margin; pubic tubercle well developed and posterolaterally oriented, placed on anterior edge of acetabulum.
Other diagnoses- Of Kirkland et al.'s (2005) original diagnostic characters, several are now invalid. A ventrally directed basisphenoid recess is plesiomorphic for theropods. The reported enlarged first dentary alveolus is either a preservational or preparation artifact, as there is a small replacement crown preserved in part of it (Zanno, 2006). Zanno states the posterior tuberosity on the distal end of the humerus opposite the radial condyle is more widely distributed among coelurosaurs. In addition, she finds the laterally deflected and biconcave apex of the deltopectoral crest is diagnostic of a more inclusive clade of therizinosaurs, based on unpublished data. The depth of manual ungual I's flexor tubercle is not diagnostic, though the ligament pits are. The lack of a lateral dentary shelf and the elongate distal caudal vertebrae are plesiomorphic for coelurosaurs, while the short distal caudal prezygapophyses are present in all therizinosaurs.
Of Zanno's (2008) diagnostic characters, an inflated basisphenoid is present in Erlikosaurus and Nothronychus. The posterorbital which extends anterior to the postorbital process on the frontal is primitive, being seen in Incisivosaurus as well. Anterior teeth which lack serrations are primitive for metornithines. The groove extending proximally from the entepicondyle of the humerus may be plesiomorphic, as it is also present in Tanycolagreus, Coelurus and Khaan. Zanno also lists "midseries chevrons possessing markedly distinct cranial tubercles", but this is plesiomorphic, being also seen in Caudipteryx and Nomingia.
Comments- The above material comes from at least ten individuals. Some of the pedal phalanges listed under UMNH VP 12331-12353 are pedal unguals. Several mistakes are present regarding the numbering of elements by Zanno (2008)- UMNH VP 14526 is listed as UMNH VP 14565 in her text; 14525 is mistyped 12525 in figure 2; 14539 mislabeled 14529 in figure 13; 12359 is mislabeled 12357 in figure 20A. In addition, UMNH VP 12401 is mislabeled as 12391 in Kirkland et al. (2005).
Zanno (2008) notes the presence of a second quarry containing Falcarius-like specimens, but which differ in vertebral and pelvic morphology from the type material. However, as the type material is largely subadult and contains few presacral elements, this variation could merely be ontogenetic.
References- Kirkland, Zanno, DeBlieux, Smith and Sampson, 2004. A new, basal-most therizinosauroid (Theropoda: Maniraptora) from Utah demonstrates a Pan-Laurasian distribution for Early Cretaceous therizinosauroids. Journal of Vertebrate Paleontology. 24(3), 78A.
Smith, Kirkland, Sanders, Zanno and DeBlieux, 2004. A comparison of North American therizinosaur (Theropoda: Dinosauria) braincases. Journal of Vertebrate Paleontology. 24(3).
Zanno, 2004. The pectoral girdle and forelimb of a primitive therizinosauroid (Theropoda: Maniraptora): New information on the phylogenetics and evolution of therizinosaurs. Journal of Vertebrate Paleontology. 24(3), 134A.
Kirkland, Zanno, Sampson, Clark and DeBlieux, 2005. A primitive therizinosauroid dinosaur from the Early Cretaceous of Utah. Nature. 435, 84-87.
Zanno, 2006. The pectoral girdle and forelimb of a basal therizinosauroid (Theropoda, Maniraptora) with phylogenetic and fuctional implications. Master's Thesis.
Zanno, 2006. The pectoral girle and forelimb of the primitive therizinosauroid Falcarius utahensis (Theropoda, Maniraptora): Analyzing evolutionary trends within Therizinosauroidea. Journal of Vertebrate Paleontology. 26(3), 636-650.
Zanno and Erickson, 2006. Ontogeny and life history of Falcarius utahensis, a primitive therizinosauroid from the Early Cretaceous of Utah. Journal of Vertebrate Paleontology. 26(3), 143A.
Zanno and Erickson, 2006. Ontogeny and life history of Falcarius utahensis, a primitive therizinosauroid from the Early Cretaceous of Utah. in Yang, Wang and Weldon (eds). Acient life and modern approaches: Abstracts of the second International Paleontological Congress. University of Science and Technology of China Press, Hefei. 453-454.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.
Zanno, 2010. Osteology of Falcarius utahensis: Characterizing the anatomy of basal therizinosaurs. Zoological Journal of the Linnaean Society. 158, 196-230.
Smith, Zanno, Sanders, Deblieux and Kirkland, 2011. New information on the braincase of the North American therizinosaurian (Theropoda, Maniraptora) Falcarius utahensis. Journal of Vertebrate Paleontology. 31(2), 387-404.
Lautenschlager, Rayfield, Perle, Zanno and Witmer, 2012. The endocranial anatomy of Therizinosauria and its implications for sensory and cognitive function. PLoS ONE. 7(12), e52289.
Button and Zanno, 2013. Tooth enamel microstructure of the Early Cretaceous therizinosaurian Falcarius utahensis (Theropoda, Maniraptora). Journal of Vertebrate Paleontology. Program and Abstracts 2013, 98.

Eshanosaurus Xu, Zhao and Clark, 2001
E. deguchiianus Xu, Zhao and Clark, 2001
Hettangian, Early Jurassic
Lower Lufeng Formation, Yunnan, China

Holotype- (IVPP V11579) (mandible ~170 mm) dentary, partial splenial
Diagnosis- (after Xu et al., 2001) round fenestra in posterior portion of the dentary.
Other diagnoses- Tooth serrations which are small compared to therizinosauroids and perpendicular to the crown are plesiomorphic for therizinosaurs and also known in Falcarius.
Comments- This taxon may be a sauropodomorph, especially since the much later Falcarius is nonetheless less derived in respect to serration size, dentary curvature and the absence of a lateral dentary ridge. Most recently, Barrett (2009) notes that basal sauropodomorphs lack the anteriorly extensive well defined lateral dentary shelf, anteriorly increasing tooth size, more than thirty dentary teeth, lingual cingulum on teeth, apicobasally oriented lingual ridge on teeth, and tooth roots that expand mesiodistally to equal crown width. These characters are shared with therizinosaurs, leading Barrett to conclude Eshanosaurus was most parsimoniously a member of that clade.
References- Zhao and Xu, 1998. The oldest coelurosaurian. Nature. 394, 234-235.
Xu, Zhao and Clark, 2001. A new therizinosaur from the Lower Jurassic lower Lufeng Formation of Yunnan, China. Journal of Vertebrate Paleontology. 21(3), 477-483.
Barrett, 2009. The affinities of the enigmatic dinosaur Eshanosaurus deguchiianus from the Early Jurassic of Yunnan Province, People's Republic of China. Palaeontology. 52(4), 681-688.

Jianchangosaurus Pu, Kobayashi, Lu, Xu, Wu, Chang, Zhang and Jia, 2013
J. yixianensis Pu, Kobayashi, Lu, Xu, Wu, Chang, Zhang and Jia, 2013
Barremian-Aptian, Early Cretaceous
Yixian Formation, Liaoning, China
Holotype
- (~1.9 m; juvenile) incomplete skull, mandibles, hyoid, atlas, axis (25.2 mm), third cervical vertebra (42.5 mm), fourth cervical vertebra (33.2 mm), fifth cervical vertebra (42.6 mm), sixth cervical vertebra (47.4 mm), seventh cervical vertebra (45.5 mm), eighth cervical vertebra (45.9 mm), ninth cervical vertebra (45.5 mm), tenth cervical vertebra (47.2 mm), cervical ribs, first dorsal vertebra, second dorsal vertebra (23 mm), third dorsal vertebra, fourth dorsal vertebra, fifth dorsal vertebra (25.4 mm), sixth dorsal vertebra, seventh dorsal vertebra, eight dorsal vertebra (27.4 mm), ninth dorsal vertebra (27.3 mm), tenth dorsal vertebra, eleventh dorsal vertebra, twelfth dorsal vertebra (26.9 mm), dorsal ribs, sixteen gastralia, first sacral vertebra (29.9 mm), second sacral vertebra, third sacral vertebra, fourth sacral vertebra (30.9 mm), fifth sacral vertebra (28.6 mm), first caudal vertebra (26.6 mm), second caudal vertebra (18.2 mm), third caudal vertebra (23.2 mm), fourth caudal vertebra (24.2 mm), fifth caudal vertebra (25.5 mm), sixth caudal vertebra, seventrh caudal vertebra, eighth caudal vertebra, ninth caudal vertebra, tenth caudal vertebra, eleventh caudal vertebra, four chevrons, scapulae (170.8 mm), coracoids, partial furcula, humeri (158.5 mm), radii (112 mm), ulnae (124.3 mm), radiales, partial semilunate carpal, carpal, metacarpals I (28.3 mm), phalanges I-1 (46.6 mm), manual unguals I (54.7 mm), metacarpal II (61 mm), phalanx II-1, phalanx II-2 (40.7 mm), manual ungual II (45.4 mm), metacarpal III (43.9 mm), phalanx III-3 (29.7 mm), incomplete ilum (202.9 mm), pubis (177.8 mm), ischium (148.2 mm), femora (206.6 mm), tibiae (316 mm), fibula (167.1 mm), partial metatarsals (mtIII ~171 mm), five pedal phalanges, four pedal unguals, feathers
Diagnosis- (after Pu et al., 2013) 27 tightly packed maxillary teeth; dorsal border of the antorbital fenestra formed by maxilla, nasal, and lacrimal, with the majority of the border formed by the nasal; no participation of jugal in margin of antorbital fenestra; a short diastema in anterior tip of dentary; concave labial surface and convex lingual surface of dentary teeth (except six anterior teeth); lack of prominent hypapophyses in anterior dorsal vertebrae; proximal caudal centra with an oval cross section and articular facet as tall as wide; weakly curved manual unguals with weak flexor tubercles ventral to articular facet; shallow and elongated ilium; a ridge bounding cuppedicus fossa confluent with acetabular rim; extensive contact between pubic apron.
Comments- The holotype was bought by the Henan Geological Museum from a private dealer, so lacks an exact stratigraphic position and has been partially rearranged with mostly sculpted metatarsals. In addition, the authors misidentified some elements. The supposed right surangular and angular seem to just be the left surangular, while the supposed left jugal is the left prearticular. The supposed left articular is too large, and seems better identified with the supposed left angular as the right surangular. In the postcranium, the supposed right metacarpal II is shorter and differently shaped compared to the left. It would make more sense as a phalanx II-1.
References- Lu, Kobayashi, Xu, Pu and Wu, 2010. A new basal therizinosauroid from the Lower Cretaceous Yixian Formation of Liaoning, China. Journal of Vertebrate Paleontology. Program and Abstracts 2010, 124A.
Kobayashi, Lu, Pu, Xu and Wu, 2012. Ornithischian-like dental arrangement in a basal therizinosaur dinosaur from Northeastern China. Journal of Vertebrate Paleontology. Program and Abstracts 2012, 122.
Pu, Kobayashi, Lu, Xu, Wu, Chang, Zhang and Jia, 2013. An unusual basal therizinosaur dinosaur with an ornithischian dental arrangement from Northeastern China. PLoS ONE. 8(5), e63423.

Therizinosauroidea Maleev, 1954 vide Russell and Dong, 1994
Definition- (Beipiaosaurus inexpectus + Therizinosaurus cheloniformis) (Zanno, 2010; modified from Clark, Maryanska and Barsbold, 2004)
Other definitions- (Therizinosaurus cheloniformis <- Ornithomimus velox, Oviraptor philoceratops, Velociraptor mongoliensis, Passer domesticus) (modified from Zhang et al., 2001)
(Therizinosaurus cheloniformis <- Oviraptor philoceratops, Passer domesticus) (modified from Hu, Hou, Zhang and Xu, 2009)

"Chilantaisaurus" zheziangensis Dong, 1979
Cenomanian-Turonian, Late Cretaceous
Tangshang Formation (=Fangyan Formation), Zhejiang, China

Holotype- (ZhM V.001) (~5 m; ~900 kg) proximal tibia, pedal ungual I, incomplete metatarsal II, phalanx II-1, phalanx II-2 (74 mm), pedal ungual II, incomplete metatarsal III, phalanx III-1, phalanx III-2, phalanx III-3, pedal ungual III, incomplete metatarsal IV
Other diagnoses- Dong (1979) distinguished this species from C. tashuikouensis based on the slightly more robust ungual and later temporal occurence. Yet he was comparing a pedal ungual to a manual ungual, so the diagnosis and taxonomic referral are invalid.
Comments- This specimen was discovered in 1972 and initially described as a megalosaurid referrable to Chilantaisaurus based on perceived similarities between its pedal ungual I and C. tashuikouensis' manual ungual I. Only pedal ungual I and pedal digits II and III are illustrated, though the rest of digit I and IV may be preserved as well. Barsbold and Maryanska (1990) considered this a possible "segnosaur" based on its short pedal phalanges and enlarged, strongly curved unguals. Although Glut (1997) stated this specimen may have been based on part of the holotype of Nanshiungosaurus brevispinus (based on a pers. comm from Dong to Molnar in 1984), they are from different formations and provinces.
The remains are about 77% as large as the referred Therizinosaurus pes, giving the taxon an approximate length of 5 meters.
References- Dong, 1979. The Cretaceous dinosaur fossils in southern China. In: Mesozoic and Cenozoic Red Beds in Southern China. Inst. Vert. Paleontol. Paleoanthropol. Nanjing Geol. Paleontol. Inst. Sci.. Press, Beijing. 342-350.
Barsbold and Maryanska, 1990. Saurischia sedis mutabilis: Segnosauria. in Weishampel, Dodson and Osmolska (eds). The Dinosauria. University of California Press. 408-415.
Glut, 1997. Dinosaurs - The Encyclopedia. McFarland Press, Jefferson, NC. 1076 pp.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

Inosaurus Lapparent, 1960
I. tedreftensis Lapparent, 1960
Berriasian-Barremian, Early Cretaceous
Irhazer Group, Niger

Syntypes- (MNNHN coll.) two anterior dorsal vertebrae (30 mm), two posterior dorsal vertebrae (33 mm), two sacral vertebrae, five mid-distal caudal vertebrae (50 mm), seven caudal vertebrae fragments, proximal tibia
Albian-Early Cenomanian, Early Cretaceous-Late Cretaceous
Tegama Group, Niger

Syntypes- ?(MNNHN coll.) partial fourth sacral vertebra, fifth sacral vertebra (44 mm)
?(MNNHN coll.) proximal caudal centrum (40 mm)
?(MNNHN coll.) mid caudal vertebra (30 mm)
?(MNNHN coll.) distal caudal vertebra (12 mm)
Early Cenomanian, Late Cretaceous
Baharija Formation, Egypt

Referred- ?(IPHG 1912 VIII 63c) caudal vertebra (Stromer, 1934)
?(IPHG 1912 VIII 63e) caudal vertebra (Stromer, 1934)
?(IPHG 1912 VIII 63g) caudal vertebra (Stromer, 1934)
Comments- This taxon is based on a series of eighteen vertebrae and a proximal tibia from the Berriasian-Barremian Irhazer Group of Niger. This may belong to a single individual, and is the specimen Lapparent (1960) based Inosaurus' diagnosis and species name on. It should therefore probably be made lectotype of the species when it is redescribed. He also based the taxon on three isolated caudals and a partial sacrum from the Albian-Early Cenomanian Tegama Group of Niger. They were referred to Inosaurus by Lapparent (1960) because of their shorteness relative to their height. In addition, the mid caudal was said to "present some rather close characters" to the proximal caudal, while the sacral centrum proportions were said to be similar. Only the proximal caudal was illustrated. Finally, Lapparent found three caudals described by Stromer (1934) from the Early Cenomanian Baharija Formation of Egypt to be similar, without further justification. The referral of of the Tegama and Baharija specimens to a single taxon, let alone Inosaurus, is dubious.
The general caudal morphology of the two illustrated Nigerian specimens is most similar to Yangchuanosaurus, Nomingia and Alxasaurus. The enlarged chevron facets are only known in Nothronychus mckinleyi, however. The distally reduced centrum length is reminiscent of oviraptoriformes, while the apparent presence of pleurocoels in one of the Baharija specimens is similar to Nothronychus and derived oviraptorosaurs. These facts lead me to tentatively assign Inosaurus to the Therizinosauroidea.
References- Stromer, 1934. Wirbeltierreste der Baharije-Stufe (unterstes Cenoman). 13. Dinosauria. Abh. Bayer. Akad. Wissensch. Math.-naturwiss. Abt. 22:1-79.
Lapparent, 1960. Les dinosauriens du "Continental intercalaire" du Sahara central. Mem. Soc. Geol. France. 88A 1-57.

undescribed therizinosauroid (Barsbold and Maryanska, 1990)
Material- distal tibia, astragalus, calcaneum
Comments- This specimen was illustrated in figire 18.2K of Barsbold and Maryanska's (1990) segnosaur chapter as segnosaurid indet.. The laterally deflected astragalar ascending process and reduced astragalar body are characteristic of therizinosauroids.
Reference- Barsbold and Maryanska, 1990. Saurischia sedis mutabilis: Segnosauria. in Weishampel, Dodson and Osmolska (eds). The Dinosauria. University of California Press. 408-415.

unnamed Therizinosauroidea (Mader and Bradley, 1989)
Late Campanian-Early Maastrichtian, Late Cretaceous
Iren Dabasu Formation, Inner Mongolia, China

Material- ?(AMNH 21597) incomplete ungual (AMNH online)
(AMNH 21784) four caudal vertebrae (Mader and Bradley, 1989)
(Erenhot Dinosaur Museum coll.) dentary, teeth (Currie and Eberth, 1993)
limb bones (Dong, 1992)
many isolated elements (Currie and Eberth, 1993)
Comments- AMNH 21784 was discovered in 1923 along with Alectrosaurus and the therizinosauroid forelimb AMNH 6368, but not described until 1989 by Mader and Bradley. While those authors described them as Theropoda incertae sedis, they may be therizinosauroid instead.
AMNH 21597 is a rather straight ungual identified as a tyrannosaurid or therizinosauroid on the AMNH website.
Therizinosauroid remains were commonly recovered from the Iren Dabasu Formation. These include a dentary with teeth. The elements are reportedly indistinguishable from Erlikosaurus and Segnosaurus, but may actually be from Erliansaurus, Neimongosaurus, and/or the taxon to which the forelimb AMNH 6368 belongs.
References- Mader and Bradley, 1989. A redescription and revised diagnosis of the syntypes of the Mongolian tyrannosaur Alectrosaurus olseni. Journal of Vertebrate Paleontology. 9(1), 41-55.
Dong, 1992. Dinosaurian Faunas of China: China Ocean Press. 188 pp.
Currie and Eberth, 1993. Palaeontology, sedimentology and palaeoecology of the Iren Dabasu Formation (Upper Cretaceous), Inner Mongolia, People’s Republic of China. Cretaceous Research. 14, 127-144.
http://paleo.amnh.org/fossil/show.html?cat_num=FR%2021597

undescribed Therizinosauroidea (Nessov, 1995)
Late Turonian-Coniacian, Late Cretaceous
Bissekty Formation, Uzbekistan

Material- (CGMP 1980.14) anterior cervical vertebra (Britt, 1993)
(N 3/11822) tooth (Nessov, 1981)
(N 443/12457) ungual (Nessov, 1995)
(N 453/12457) ungual (Nessov, 1995)
(N 454/12457) ungual (Nessov, 1995)
(N 455/12457) ungual (Nessov, 1995)
(N 456/12457) dorsal vertebra (Nessov, 1995)
(N 462/12457) frontal (Nessov, 1995)
(N 628/12457) braincase (Nessov, 1995)
(N 699-702/12457) manual phalanges (Nessov, 1995)
(N 704-710/12457) cervical vertebrae (Nessov, 1995)
(N 711-712/12457) anterior cervical or anterior dorsal vertebrae (Nessov, 1995)
(N 713/12457) anterior dorsal vertebra (Nessov, 1995)
(N 714/12457) posterior dorsal vertebra (Nessov, 1995)
(N 715-716/12457) distal humeri (Nessov, 1995)
(N 719/12457) basisphenoid (Nessov, 1995)
(N 721-722/12457) proximal humeri (Nessov, 1995)
?(N 725/12457) caudal vertebra (Nessov, 1995)
teeth, proximal and distal portions of scapulae (Sues and Averianov, 2004)
femora (Averianov, 2007)
Comments- CGMP 1980.14 was described by Britt (1993) and Makovicky (1995). The braincase was originally referred to Turanoceratops by Nessov (1995), but reidentified by Sues and Averianov (2004). A tooth originally identified as a pachycephalosaur (Nessov, 1981), is probably therizinosaurian instead (Nessov, 1995). The phalanges are said to differ from Segnosaurus and Erlikosaurus in being more elongate, but this is probably because they are manual phalanges instead of pedal phalanges (their ligament pits are reduced). The caudal vertebrae may be tyrannosauroid or hadrosaurid instead (they were compared to Dryptosaurus or Hypsibema by Nessov, and by Ryan, 1997). At least two taxa are present, differing in postcranial morphology (Averianov, 2007).
References- Nessov, 1981. [Amphibians and reptiles in the ecosystems of the Cretaceous of Middle Asia]. Voprosy gyerpyetologii. Pyataya Vsyesoyuznaya gyerpyetologichyeskaya konfyeryentsiya, Ashkhabad, Avtoryefyerat doklada. Lyeningrad, Nauka. 91-92.
Britt, 1993. Pneumatic postcranial bones in dinosaurs and other archosaurs. PhD Thesis, University of Calgary (Canada), Alberta.
Makovicky, 1995. Phylogenetic aspects of the vertebral morphology of Coelurosauria (Dinosauria: Theropoda). M.S. thesis, Copenhagen University, Copenhagen, Denmark.
Nessov, 1995. Dinosaurs of Northern Eurasia: new data about assemblages, ecology and paleobiogeography. Scientific Research Institute of the Earth's Crust, St. Petersburg State University, St. Petersburg, Russia. 156 pp. + 14 pl.
Ryan, 1997. Middle Asian Dinosaurs: in Currie and Padian (eds). Encyclopedia of Dinosaurs. Academic Press. 442-444.
Sues and Averianov, 2004. Dinosaurs from the Upper Cretaceous (Turonian) of Dzharakuduk, Kyzylkum Desert, Uzbekistan. Journal of Vertebrate Paleontology. 24(3).
Averianov, 2007. Theropod dinosaurs from Late Cretaceous deposits in the northeastern Aral Sea region, Kazakhstan. Cretaceous Research. 28(3), 532-544.

undescribed therizinosauroid (Rauhut, 1999)
Cenomanian, Late Cretaceous
Wadi Milk Formation, Sudan

Material- (Vb coll.) tooth
Reference- Rauhut, 1999. A dinosaur fauna from the Late Cretaceous (Cenomanian) of Northern Sudan. Palaeontologia Africana. 35, 61-84.

undescribed therizinosauroid (Ikegami, 2002)
Late Cretaceous
Mifunemachi, Kumamoto, Japan

Material- two teeth (6.5 mm)
Comments- Found in 1993 and 1995.
Reference- Shimbun, 2002. Rare dinosaur teeth found in Kumamoto.

"Nanshiungosaurus" bohlini Dong and Yu, 1997
Late Barremian-Aptian, Early Cretaceous
Upper Xinminbao Group, Gansu, China

Holotype- (IVPP V 11116; lost) (5.3 m; ~1 ton) atlas, axis (148 mm), third cervical vertebra (146 mm), fourth cervical vertebra (161 mm), fifth cervical vertebra (163 mm), sixth cervical vertebra (164 mm), seventh cervical vertebra (183 mm), eighth cervical vertebra (183 mm), ninth cervical vertebra (184 mm), tenth cervical vertebra (183 mm), eleventh cervical vertebra, cervical ribs, first dorsal vertebra (124 mm), second dorsal vertebra, third dorsal vertebra, fourth dorsal vertebra, fragmentary dorsal ribs
Diagnosis- (after Dong and Yu, 1997) differs from Falcarius, Alxasaurus, Neimongosaurus and Nanshiungosaurus brevispinus in having platycoelous cervical centra; primitively differs from Nanshiungosaurus brevispinus in having transversely narrow anterior dorsal neural spines.
(proposed) primitively differs from Nanshiungosaurus brevispinus and Neimongosaurus in having eleven cervical vertebrae; primitively differs from Beipiaosaurus in having an axial neural spine which rises anteriorly; primitively differs from Falcarius and Erliansaurus in having cervicals without a median keel; differs from Neimongosaurus in that cervical centra 7-10 are longer than 5-6; differs from Beipiaosaurus, Alxasaurus, Nothronychus mckinleyi, Erliansaurus and Neimongosaurus in having fused cervical ribs; differs from Nothronychus? graffami, Erliansaurus and Nanshiungosaurus brevispinus in having amphiplatyan dorsal centra; primitively differs from Erliansaurus in having anterior dorsal pleurocoels.
Other diagnoses- Dong and Yu (1997) included several additional characters in their diagnosis. The large size is matched or exceeded by several other therizinosaurs (Therizinosaurus, Segnosaurus, Suzhousaurus, etc.). They use the platycoelous cervicals and anterior dorsals as a diagnostic character, contrasting them with Nanshiungosaurus brevispinus' opisthocoelous posterior cervicals and platycoelous anterior cervicals and dorsals. The cervical centra are also platycoelous in Nothronychus, Erlikosaurus, Segnosaurus, posterior cervicals of Falcarius, and anterior cervicals of Nanshiungosaurus brevispinus, but amphiplatyan in Alxasaurus, and amphicoelous in Neimongosaurus and posterior cervicals of Falcarius. Which state is derived is difficult to determine, as Caudipteryx has amphicoelous centra, Microvenator has platycoelous centra and the Morrison oviraptoriform has opisthocoelous centra. Low and long cervical neural spines are found in all therizinosaurs. The cervical zygapophyses are not longer or wider than in other taxa such as Neimongosaurus or Falcarius. Dong and Yu state the cervical zygapophyses are placed well above the neural canals, which is true in Falcarius as well, especially in posterior cervicals. It is also true in Neimongosaurus' mid cervicals and Nanshiungosaurus brevispinus' posterior cervicals, while the dorsally exposed neural canal in Nothronychus may be due to damage. The anterior dorsal neural spines are said to be low, which matches Falcarius, Nanshiungosaurus brevispinus, Nothronychus mckinleyi and N? graffami, though those of Alxasaurus and Neimongosaurus are tall. They are also diagnosed as being narrow, which matches Falcarius, though Alxasaurus and the Nothronychus species have spines which taper to narrow apices, and Nanshiungosaurus brevispinus' is broad. Finally, anterior dorsal vertebrae with ventral keels are present in all therizinosaurs.
The number of cervical vertebrae is lower than Nanshiungosaurus brevispinus (12) or Neimongosaurus (14), but may be the same as Beipiaosaurus (11-12) and basal oviraptorosaurs. Fused cervical ribs are present, like Falcarius, Erlikosaurus, Nanshiungosaurus brevispinus and Segnosaurus, but unlike Beipiaosaurus, Alxasaurus, Erliansaurus, Nothronychus mckinleyi and Neimongosaurus.
Description- The cervical series is 1515 mm long, though it only contains ten vertebrae according to Dong and Yu (1997). The anterior dorsals are 23% larger than N. brevispinus', suggesting a dorsal length of 1035 if two more vertebrae are added to make up for N. brevispinus' high number of cervicals. Scaling up cranial, sacral and caudal lengths from N. brevispinus adds 460 mm, 835 mm and 1480 mm respectively. Nanshiungosaurus? bohlini was thus about 5.3 meters long.
The atlas is represented by an odontoid and the neuropophyses. The odontoid is subcircular and fused to the dorsal half of the axial centrum. The neuropophysis is apparently wing-like in proximal view and has a long sauropod-like posterior process. It is unfortunately not figured.
The axis has relatively long prezygopophyses and well-developed dorsomedially inclined postzygopophyses. The neural arch and spine are long and low.
The postaxial cervical vertebrae have elongate platycoelous centra with pleurocoels. Ventrally, there are two parallel ridges. The neural arches are low, long and massive with long, stout zygopophyses, while the neural spines are also long and low. Three laminae form the diapophyses, which are declined and fused to the cervical ribs. The parapophyses are large rounded cavities on the anterolateral surface. The internal structure of the cervical vertebrae is cancellous. Dong and Yu find that there are eleven cervical vertebrae.
The cervical ribs are fused with their respective centra.
The dorsal vertebrae have amphiplatyan centra with ventral keels. The keel is poorly developed on the first centrum. Large pleurocoels are present. The zygapophyses are long and stout, while the neural arches and spines are low and narrow.
The dorsal ribs are undescribed.
Comments- Dong and Yu (1997) list different lengths for vertebral centra in the text than they do in the measurement table. In the text, the axis is 152 mm, the seventh and eighth cervicals are 192 mm and the ninth and tenth are 143 mm. They also later state the dorsals are platycoelous, instead of amphiplatyan. Zanno (2008) indicates the specimen is lost.
This is a difficult specimen to evaluate, as the description is brief, only the cervicals in dorsal and ventral views were photographed, the specimen is lost, comparative vertebrae in other therizinosaurs are often broken or distorted, and most other therizinosaur vertebrae are from uncertain positions in the presacral column. Consequently, there are no known diagnostic characters for the species, though a combination of primitive characters does distinguish it from most contemporaneous therizinosaurs (Falcarius, Beipiaosaurus, Alxasaurus). However, it cannot be compared with Suzhousaurus from the same stratigraphic group besides agreeing in general anterior dorsal morphology, and may be synonymous. If they are indeed synonymous, Li et al. (2007) note the correct name will be Suzhousaurus bohlini. Dong and Yu gave no reason to refer the species to Nanshiungosaurus, it lived much earlier than that genus, and the number of cervical vertebrae may indicate it is outside the clade formed by Nanshiungosaurus and Neimongosaurus. Li et al. and Zanno agree the species is not Nanshiungosaurus and put the genus in quotes.
References- Dong and Yu, 1997. A new segnosaur from Mazongshan Area, Gansu Province, China. in Dong (ed). Sino-Japanese Silk Road Dinosaur Expedition. China Ocean Press, Beijing. 90-95.
Tang, Luo, Zhou, You, Georgi, Tang, and Wang, 2001. Biostratigraphy and palaeoenvironment of the dinosaur-bearing sediments in Lower Cretaceous of Mazongshan area, Gansu Province, China. Cretaceous Research. 22(1), 115-129.
Li, Peng, You, Lamanna, Harris, Lacovata and Zhang, 2007. A large therizinosauroid (Dinosauria: Theropoda) from the Early Cretaceous of northwestern China. Acta Geologica Sinica (English Edition). 81(4), 539-549.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

Beipiaosaurus Xu, Tang and Wang, 1999
B. inexpectus Xu, Tang and Wang, 1999
Late Barremian-Early Aptian, Early Cretaceous
Jianshangou member of Yixian Formation, Liaoning, China

Holotype- (IVPP 11559) (~1.85 m; 45 kg; subadult) (skull ~265 mm) nasal?, postorbital, parietal, prootic, skull fragments, dentary (~172 mm), teeth, three cervical vertebrae (~32 mm), four fused posterior dorsal vertebrae (each ~44 mm), four proximal dorsal ribs, fourth sacral vertebra, fifth sacral vertebra, first caudal vertebra, second caudal vertebra, third caudal vertebra, fourth caudal vertebra, fifth caudal vertebra, sixth caudal vertebra, seventh caudal vertebra, eighth caudal vertebra, ninth caudal vertebra, tenth caudal vertebra, eleventh caudal vertebra, twelfth caudal vertebra, two mid caudal vertebrae, mid caudal centrum (lost), eight distal caudal vertebrae, two fused distal caudal vertebrae, pygostyle, fourth chevron, sixth chevron, tenth chevron, incomplete scapula, coracoids, partial furcula, partial humeri (distal humerus lost), proximal radii (one lost), distal radii, proximal ulna (lost), distal ulnae, radiale, proximal carpal, distal carpal I, distal carpals II, metacarpals I, partial phalanges I-1, manual ungual I, metacarpals II (70 mm), phalanges II-1, phalanges II-2, manual unguals II, metacarpal III, phalanges III-1, phalanges III-2, phalanges III-3, manual unguals III (one proximal), ilia (193 mm), incomplete pubis, incomplete ischia, ischial fragment (lost), femur (265 mm), femoral fragment, tibiae (one incomplete) (275 mm), incomplete fibula, astragalus, calcaneum, distal tarsal, metatarsal I, pedal ungual I, metatarsal II (97 mm), metatarsal III (107 mm), metatarsal IV, metatarsal V, three pedal phalanges, pedal ungual (lost), feathers
Referred- (STM31-1) skull, sclerotic ring, mandible, atlas, axis, third cervical vertebra, fourth cervical vertebra, fifth cervical vertebra, sixth cervical vertebra, seventh cervical vertebra, eighth cervical vertebra, ninth cervical vertebra, tenth cervical vertebra, eleventh cervical vertebra, seventeen cervical ribs, dorsal vertebrae, twelve dorsal ribs, scapulae, coracoids, humeri (one proximal), radii (one distal), ulnae (one distal), carpals, metacarpal I, proximal metacarpal II, proximal metacarpal III, feathers (Xu, Zheng and You, 2009)
Diagnosis- (after Xu et al., 1999) large skull, about equal to femoral length; proximodistally elongate lateral articular surface on the flexor side of manual phalanx I-1.
(after Zanno, 2008) four fused posterior dorsal vertebrae; pygostyle; lateral buttress of metacarpal I triangular; obturator process of ischium sinusoidal with ventrally deflected distal portion; ischial boot twice width of distal shaft; mediodistal ridge on anterior femur.
(proposed) lateral buttress of metacarpal I developed about 40% down shaft.
Other diagnoses- Several characters listed by Xu et al. (1999) in their diagnosis are plesiomorphic for therizinosaurs- short and bulbous tooth crowns; large tibiofemoral ratio (104%); first metatarsal does not contact tarsus; proximally compressed metatarsus. The elongate manus (>110% of femoral length) may be plesiomorphic too, as it is shared with Protarchaeopteryx and avialans, and approached by microraptorians and Jinfengopteryx. The large skull (about equal to femoral length) may not be plesiomorphic though (contra Zanno), as outgroups (oviraptorosaurs, most basal troodontids, scansoriopterygids, arctometatarsalians, Ornitholestes) have smaller skulls. The discovery of a complete ilium by Xu et al. (2003) shows the preacetabular process is not shallow.
Clark et al. (2004) listed the subequal pre- and postacetabular processes and uncompressed ischial shaft in their diagnosis, but these are primitive for therizinosaurs.
Comments- This taxon was originally announced by Josh Smith at SVP 1998.
The cervicals were about 32 mm, while the posterior dorsals were 44 mm. The cervical series is estimated to be 304 mm, and the dorsal series was about 430 mm. This is based on comparison to Neimongosaurus, compensating for a vertebral count of twelve cervicals and ten dorsals. The preserved caudal is most similar to the fourth of Neimongosaurus in central proportions and was about 32 mm, suggesting a tail length of 635 mm. The sacrum may have been about 220 mm, assuming it had five vertebrae. The skull length is difficult to determine precisely because how much of the dentary is preserved is neither described, nor discernable from the photos. The preserved length is said to be 65% of femoral length, which results in 172 mm. In Erlikosaurus, the dentary is 68% of mandibular length, so Beipiaosaurus' mandible was at least 253 mm long. Again, using Erlikosaurus for a craniomandibular ratio results in a skull at least 265 mm long. The total length of Beipiaosaurus was therefore about 1.85 meters long.
References- Xu, Tang and Wang 1999. A therizinosauroid dinosaur with integumentary structures in China. Nature. 399, 350-354.
Xu, Cheng, Wang and Chang, 2003. Pygostyle-like structure from Beipiaosaurus (Theropoda, Therizinosauroidea) from the Lower Cretaceous Yixian Formation of Liaoning, China. Acta Geologica Sinica. 77(3), 294-298.
Clark, Maryanska and Barsbold, 2004. Therizinosauroidea. in In Weishampel, Dodson and Osmolska (eds). The Dinosauria Second Edition. University of California Press. 151-164.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.
Xu, Zheng and You, 2009. A new feather type in a nonavian theropod and the early evolution of feathers. Proceedings of the National Academy of Sciences. 106(3), 832-834.

unnamed possible therizinosaur (Averianov, 2007)
Santonian, Late Cretaceous
Bostobe Formation, Kazakhstan

Material- (N 601/12457) (~3.26 m; adult) femur (512 mm)
Comments- Nessov (1995) referred the femur N 601/12457 to Tarbosaurus sp., but Carr (2005) determined it lacks the synapomorphies of Tarbosaurus + Tyrannosaurus and of Alectrosaurus. Averianov (2007) later excluded the femur from Tyrannosauridae (cylindrical anterior trochanter, extensor groove absent) and noted particular characters similar to therizinosauroids (low and rounded greater trochanter; straight lateral margin with little or no lateral expansion of the lateral condyle; low crescentic fourth trochanter). In particular, Averianov found it to be virtually identical to Neimongosaurus, except for being larger and more robust, referring to it as cf. Neimongosaurus sp.. However, Zanno (2008) noted the femur lacks three characters found in Neimongosaurus and other derived therizinosaurs- elevated head; greater trochanter separated from head by cleft; head with constricted connection to greater trochanter in proximal view. Zanno did not state whether she believed the femur could be from a less derived therizinosaur, though Falcarius does lack these characters, while Beipiaosaurus has the first but not the second. Alxasaurus seems to have the second two characters at least. Yet Falcarius and Beipiaosaurus differ from this femur and Alxasaurus in having wing-like anterior trochanters. Falcarius also lacks the straight lateral margin and cresentric fourth trochanter present in this femur and Beipiaosaurus. Thus if it is a therizinosaur, it seems closest to Beipiaosaurus. Olshevsky (DML, 1996) incorrectly translated 'femur' as 'ilium', leading to the records of a Kazakh Tarbosaurus ilium.
References- Nessov, 1995. Dinosaurs of Northern Eurasia: new data about assemblages, ecology and paleobiogeography. Scientific Research Institute of the Earth's Crust, St. Petersburg State University, St. Petersburg, Russia: 156 pp. + 14 pl. [in Russian with short English, German, and French abstracts].
Olshevsky, DML 1996. http://dml.cmnh.org/1996Feb/msg00835.html
Kordikova, Gunnell, Polly and Kovrizhnykh, 1996. Late Cretaceous and Paleocene vertebrate paleontology and stratigraphy in the North-eastern Aral Sea region, Kazakhstan. Journal of Vertebrate Paleontology. 16(3), 46A.
Carr, 2005. Phylogeny of Tyrannosauroidea (Dinosauria: Coelurosauria) with special reference to North American forms. Unpublished PhD dissertation. University of Toronto. 1170 pp.
Averianov, 2007. Theropod dinosaurs from Late Cretaceous deposits in the northeastern Aral Sea region, Kazakhstan. Cretaceous Research. 28(3), 532-544.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

unnamed therizinosauroid (Manning, Joysey and Cruikshank, 1997)
Santonian-Campanian, Late Cretaceous
Nanchao Formation, Henan, China

Material- (CAGS-01-IG-1; = RAP 194D) incomplete skull, mandible, vertebrae, three manual unguals, egg
(CAGS-01-IG-2; = RAP 3495D) (embryo) egg, parabasisphenoid, two metacarpals, partial femora, partial tibiae, metatarsal, fragments
(CAGS-01-IG-4; = RAP 3494D) (embryo) egg, posterior dorsal centrum, dorsal neural arch, humerus, ulna, femur, tibia, fragments
(CAGS-01-IG-5; = RAP 10495D) (embryo) egg, atlantal centrum, atlantal arch, axis, third cervical vertebra, fourth cervical vertebra, fifth cervical vertebra, cervical ribs, several dorsal vertebrae, six dorsal ribs, scapula, humerus, radius, ulna, pubes, incomplete ischia, partial femur, partial tibiae, fibula, metatarsal
(CAGS-01-IG-7; = RAP 7294D) (embryo) egg, fragments
(CAGS-01-IG-11; = RAP 1294D) (embryo) egg, fragments
(CAGS-01-IG-12; = RAP 294D) (embryo) egg, dorsal centra, dorsal neural arch, dorsal rib, humerus, ilium, fragments
(CAGS-01-IG-13) nest of seven eggs
....(RAP 596D) egg
....(RAP 696D) egg
....(RAP 796D) (embryo) egg, elements
....(RAP 1196D) (embryo) egg, elements
....(CAGS-01-IG-6; = RAP 1496D) (embryo) egg, parabasisphenoid, two cervical centra, anterior dorsal centrum, two dorsal rib, mid caudal vertebra, coracoid, furcula, partial ilium, two pedal unguals, fragments
(RAP 195D) egg
(RAP 896D) egg
(RAP 1094D) egg
(RAP 1096D) egg
(RAP 2395D) egg
(RAP 10494D) disarticulated skull and partial postcrania, egg
Description- The eggs are dendroolithid.
Comments- Sigogneau-Russell et al. (1998) referenced RAP 194D to compare its tooth size to isolated theropod teeth from the Berriasian of Anoual, Morocco. This was misinterpreted by Ford (www.paleofile.com) as a reference to a Moroccan therizinosaur egg and embryo.
References- Cohen, Cruickshank, Joysey, Manning and Upchurch, 1995. The Dinosaur Egg and Embryo Project. Exhibition Guide. Rock Art, Leicester.
Manning, Joysey and Cruikshank, 1997. Observations of microstructures within dinosaur eggs from Henan Province, Peoples Republic of China. in Wolberg, Stump and Rosenburg eds. Dinofest International: Proceedings of a Symposium held at Arizona State University. Philadelphia: Academy of Sciences. 287-290.
Sigogneau-Russell, Evans, Levine and Russell, 1998. The Early Cretaceous microvertebrate locality of Anoual, Morocco: A glimpse at the small vertebrate assemblages of Africa. in Lucas, Kirkland and Estep (eds.). Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Mesuem of Natural History and Science. 14, 177-181.
Manning, Joysey and Cruikshank, 2000. In ovo tooth replacement in a therizinosaurid dinosaur. First International Symposium on Dinosaur Eggs and Babies. Extended Abstracts. 129-134.
Kundrat, Cruickshank, Manning and Joysey, 2001. Structure of the embryonic parabasisphenoid in a therizinosauroid dinosaur. Journal of Morphology. 248(3), 251-252.
Kundrat, Cruickshank, Manning and Nudds, 2004. Therizinosauroid affinities within maniraptoriform theropods based on embryonic data. EAVP 2, abstracts, pg. 20.
Kundrát, Cruickshank, Manning and Nudds, 2007. Embryos of therizinosauroid theropods from the Upper Cretaceous of China: Diagnosis and analysis of ossification patterns. Acta Zoologica. 89(3), 231-251.

unnamed clade (Alxasaurus elesitaiensis + Therizinosaurus cheloniformis)

undescribed therizinosauroid (Alifanov and Averianov, 2006)
Early Santonian, Late Cretaceous
Yalovach Formation, Tajikistan
Material
- (PIN coll.) sacral vertebra, manual phalanges, manual unguals, femur
Comments- The femur is very similar to Erliansaurus, Bissekty therizinosaurs and ZIN PH 24/49 from the Bostobe Formation (Averianov, 2007). Supposed oviraptorids mentioned by Nessov (1995) from this formation are likely based on therizinosaur remains (Alifanov and Averianov, 2006).
Reference- Alifanov and Averianov, 2006. On the finding of ornithomimid dinosaurs (Saurischia, Ornithomimosauria) in the Upper Cretaceous beds of Tajikistan. Paleontological Journal. 40(1), 103-108.
Averianov, 2007. Theropod dinosaurs from Late Cretaceous deposits in the northeastern Aral Sea region, Kazakhstan. Cretaceous Research. 28(3), 532-544.

Therizinosauroidea indet. (Averianov, 2007)
Turonian-Coniacian, Late Cretaceous
Zhirkindek Formation, Kazakhstan

Material- (ZIN PH 1/49) distal metacarpal III
(ZIN PH 32/49) (juvenile) sacral centrum (43.9 mm)
(ZIN PH 38/49) proximal femur
(ZIN PH 39/49) proximal femur
Comments- The femora differ from N 601/12457 from the Bostobe Formation, but are similar to other Bostobe therizinosaur femora, Erliansaurus, Bissekty therizinosaurs and a femur from the Yalovach Formation.
Reference- Averianov, 2007. Theropod dinosaurs from Late Cretaceous deposits in the northeastern Aral Sea region, Kazakhstan. Cretaceous Research. 28(3), 532-544.

Therizinosauroidea indet. (Rozhdestvensky, 1964)
Santonian, Late Cretaceous
Bostobe Formation, Kazakhstan

Material- (IZK 2/1) manual ungual (Suslov, 1982)
(IZK 2/2) pedal(?) ungual (Suslov, 1982)
(IZK 2/3) pedal(?) ungual (Suslov, 1982)
(PIN 2229/19) manual ungual (~200 mm) (Rozhdestvensky, 1964)
(ZIN PH 24/49) proximal femur (Averianov, 2007)
(ZIN PH 25/49) pedal phalanx III/IV-? (42.2 mm) (Averianov, 2007)
(ZIN PH 35/49) tooth (FABL 2.2 mm) (Averianov, 2007)
(ZIN PH 37/49) proximal femur (Averianov, 2007)
Comments- Rozhdestvensky (1964) described a manual ungual as a therizinosaurid, and later (Rozhdestvensky and Khozatsky, 1967) referred it to cf. Alectrosaurus based on similarity to the therizinosauroid manual ungual preserved with that tyrannosauroid. Suslov (1982) described three unguals as dromaeosaurid, but these were reidentified as therizinosaurian by Nessov (1995). Averianov (2007) also noted the therizinosauroid identity of these remains and described additional elements from the same formation. The femora differ from N 601/12457 from the same formation, but are similar to Erliansaurus, Zhirkindek and Bissekty therizinosaurs and a femur from the Yalovach Formation. The other material is also indistinguishable from Bissekty therizinosaurs.
References- Rozhdestvensky, 1964. New data on occurrences of dinosaurs in Kazakhstan and Central Asia. Tashkent State University, Scientific Publications: Geology. 234, 227-241.
Rozhdestvensky and Khozatsky, 1967. Late Mesozoic terrestrial vertebrates of Asiatic part of the USSR. in Martinson (ed). Stratigraphy and Paleontology of Mesozoic and Paleogene–Neogene Continental Deposits of Asiatic Part of the USSR. Nauka, Leningrad. 82-92. in Russian]
Rozhdestvensky, 1970. About giant ungual phalanges of enigmatic Mesozoic vertebrates. Paleontologicheskii Zhurnal. 1, 131-141.
Suslov, 1982. Ungual phalanges of a dromaeosaurid from the Upper Cretaceous deposits of the Kzyl-Ordinskaya Region. Matyerialy po istorii fauny i flory Kazakhstana. 8, 5-16.
Nessov, 1995. Dinosaurs of nothern Eurasia: new data about assemblages, ecology, and paleobiogeography. Institute for Scientific Research on the Earth's Crust, St. Petersburg State University, St. Petersburg. 1-156.
Averianov, 2007. Theropod dinosaurs from Late Cretaceous deposits in the northeastern Aral Sea region, Kazakhstan. Cretaceous Research. 28(3), 532-544.

Alxasauridae Russell and Dong, 1994
Alxasaurus Russell and Dong, 1994
A. elesitaiensis Russell and Dong, 1994
Aptian, Early Cretaceous
Bayin Gobi Formation, Inner Mongolia, China

Holotype- (IVPP 88402a; some lost, see comments) (3.78 m; 380 kg) dentary, teeth (3.7-7.2 mm), cervical vertebra (95 mm), cervical vertebra, cervical vertebra, cervical vertebra (95 mm), cervical vertebra (90 mm), two cervical ribs (95, 95 mm), posterior dorsal vertebra, posterior dorsal vertebra, posterior dorsal vertebra (80 mm), posterior dorsal vertebra (80 mm), posterior dorsal vertebra (80 mm), posterior dorsal vertebra, posterior dorsal vertebra (62 mm), six incomplete dorsal ribs, dorsal rib fragments, (sacrum- 345 mm), first sacral vertebra (61 mm), second sacral vertebra (63 mm), third sacral vertebra (70 mm), fourth sacral vertebra (77 mm), fifth sacral vertebra (70 mm), sacral ribs 1-4, caudal vertebrae 1-19 (first caudal vertebra (60 mm), second caudal vertebra (63 mm), third caudal vertebra (61 mm), fourth caudal vertebra (65 mm), fifth caudal vertebra (65 mm), sixth caudal vertebra (62 mm), seventh caudal vertebra (60 mm), eighth caudal vertebra (60 mm), ninth caudal vertebra (58 mm), tenth caudal vertebra (56 mm), eleventh caudal vertebra (51 mm), twelfth caudal vertebra (52 mm), thirteenth caudal vertebra (49 mm), fourteenth caudal vertebra (42 mm), fifteenth caudal vertebra (44 mm), sixteenth caudal vertebra (44 mm), seventeenth caudal vertebra (42 mm), eighteenth caudal vertebra (39 mm), ninteenth caudal vertebra (35 mm), distal caudal vertebra (29 mm), distal caudal vertebra (26 mm), first chevron (114 mm), second chevron (102 mm), third chevron (91 mm), fourth chevron (85 mm), fifth chevron (78 mm), sixth chevron (75 mm), seventh chevron (73 mm), eighth chevron (65 mm), ninth chevron (61 mm), tenth chevron (61 mm), eleventh chevron (52 mm), twefth chevron (55 mm), fourteenth chevron (45 mm), fifteenth chevron (40 mm), scapulocoracoids (520+98 mm), humeri (375 mm), radii (245 mm), ulnae (268 mm), radiale, intermedium, ulnare, distal carpals I, distal carpal II, metacarpals I (one fragmentary; 55 mm), partial phalanx I-1, manual ungual I (130 mm), metacarpals II (one fragmentary; 111 mm), partial phalanx II-1, partial phalanx II-2, manual ungual II (113 mm), metacarpals III (one fragmentary; 85 mm), partial phalanx III-1, proximal phalanx III-2, ilia (500 mm), ischial shafts, femora (one proximal; 555 mm)
Paratypes- (IVPP 88402b; some lost, see comments) (~2.49 m; 110 kg) posterior cervical vertebra (70 mm), posterior cervical vertebra (70 mm), posterior cervical vertebra (60 mm), dorsal vertebra, dorsal vertebra (45 mm), dorsal vertebra (48 mm), dorsal vertebra (45 mm)
(IVPP 88501; some lost, see comments) (~2.83 m; 160 kg) dorsal vertebra (48 mm), dorsal vertebra (48 mm), dorsal vertebra (53 mm), dorsal vertebra (54 mm), dorsal vertebra (56 mm), first sacral centrum (55 mm), incomplete second sacral centrum, proximal metacarpal I, partial phalanx I-1, manual ungual I (111 mm straight, 128 mm on curve), proximal phalanx II-1, distal phalanx II-2, manual ungual II (105 mm straight, 121 mm on curve), distal metacarpal III, phalanx III-2 (44 mm), proximal manual ungual III, posterior ilium, proximal femora, distal femur, proximal tibiae, distal tibia, proximal fibulae, distal metatarsal I, distal metatarsal II, phalanx II-1 (69 mm), phalanx II-2 (43 mm), pedal ungual II (65 mm straight, 73 mm on curve), distal metatarsal III, phalanx III-1 (60 mm), phalanx III-2 (35 mm), phalanx III-3 (37 mm), pedal ungual III (63 mm straight, 68 mm on curve), distal metatarsal IV, phalanx IV-1 (58 mm), phalanx IV-2 (32 mm), phalanx IV-4 (28 mm), pedal ungual IV (55 mm straight, 62 mm on curve)
Referred- ?(IVPP 88301) vertebrae, ribs, appendicular material (Russell and Dong, 1994)
?(IVPP 88510) appendicular material (Russell and Dong, 1994)
incomplete skull (Dong, 2003)
Diagnosis- (after Russell and Dong, 1994) about forty dentary teeth (also in Beipiaosaurus); preacetabular process ~170% of length across peduncles.
(after Zanno, 2008) anteroproximal blade of proximal chevrons with pronounced lateral flare at region of bifurcation into articular facet.
Other diagnoses- A few of the characters listed by Russell and Dong (1994) in their diagnosis are plesiomorphic- teeth in symphyseal region of dentary; ligament pits well developed in manual phalanges; preacetabular process of ilium moderately expanded; pedal unguals II-IV shorter or subequal to first phalanx in digit. The absence of fusion between cervical ribs and vertebrae is possibly ontogenetic, as it is present in the more basal Falcarius. Contra Zanno (2008), the elongate preacetabular process is not primitive, as it is only otherwise seen in Epidexipteryx and some birds. Similarly, the large number of dentary teeth is not necessarily plesiomorphic, as Falcarius, oviraptorosaurs, and basal members of paravian lineages have less, though Beipiaosaurus and arctometatarsalians have at least as many.
Comments- Note that while volume 30(10) of the Canadian Journal of Earth Sciences lists its date as October 1993, it was not published until February or March of 1994.
Zanno (2008) notes most of the material of IVPP 88402 could not be located when she visited the museum. Material which was present is- five dorsal vertebrae, proximal dorsal ribs, two sacral vertebrae, fourteen caudal vertebrae, ten chevrons, radiale, distal carpal I, proximal metacarpal I, manual ungual I, proximal metacarpal II, manual ungual II, and two appendicular fragments. Material of IVPP 88501 which was present includes- three dorsal centra, one and a half sacral centra, proximal metacarpal I, proximal manual ungual I, proximal metacarpal II, distal phalanx II-1, proximal phalanx III-3, proximal manual ungual III, manual phalangeal fragments, distal metatarsals and partial pedal phalanges.
Alxasaurus elesitaiensis is known from five individuals, but only three have published measurements. The holotype (IVPP 88402a) is largest, while IVPP 88501 is about 75% as large, and IVPP 88402b is said to be about 66% as large. The skull was about 370 mm long, judging by the dentary. Using Neimongosaurus, but estimating for a more plesiomorphic vertebral count, generates lengths of 904 mm and 605 mm for the cervical and dorsal series respectively. The cervicals were comparatively shorter in Alxasaurus. Finally, the sacrum was 345 mm long, and the tail was 1554 mm long, accounting for the several missing vertebrae (which also total around 28). This totals to 3.78 meters, remarkably close to Russell and Dong's 3.8 meter estimate based on a probably inaccurate presacral formula (10 cervicals, 13 dorsals). IVPP 88501 would then be about 2.83 meters, and IVPP 88402b about 2.49 meters.
References- Russell and Dong, 1994. 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.
Dong, 2003. Contributions to new dinosaur materials from China to dinosaurology. Memoir of the Fukui Prefectural Dinosaur Museum. 2, 123-132.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

unnamed clade (Erliansaurus bellamanus + Therizinosaurus cheloniformis)

unnamed therizinosauroid (Gilmore, 1933)
Late Campanian-Early Maastrichtian, Late Cretaceous
Iren Dabasu Formation, Inner Mongolia, China

Material- (AMNH 6368; paratype of Alectrosaurus olseni) humerus (390 mm), manual phalanx II-1 (74 mm), manual ungual I (190 mm on curve) (Gilmore, 1933)
Comments- AMNH 6368 was found 100 feet from the lectotype of Alectrosaurus olseni in 1923 and was thought to belong to the same individual in the field. Gilmore (1933) prefered to treat them as two individuals. He placed them in the same species due to the similarity between the manual unguals, which are “laterally compressed, strongly curved and have sharply curved extremities”, as well as the association in the field and slenderness. He originally diagnosed A. olseni partially on the characteristics of this specimen. Perle (1979) recognized AMNH 6368 was therizinosaurian, which was confirmed by Mader and Bradley (1989). Zanno (2008) notes the slender proportions, poorly defined medial tuberosity, and posterior humeral trochanter indicates it is not referable to Neimongosaurus, and it is more gracile than Erliansaurus and lacks that genus' distinctive crest-shaped posterior trochanter. Zanno (2006) found the specimen to be more derived than Alxasaurus in her phylogenetic analysis.
References- Gilmore, 1933. On the Dinosaurian Fauna of the Iren Dabasu Formation. Bulletin American Museum of Natural History. 67, 23-78.
Perle, 1979. Segnosauridae - A new family of theropods from the Late Cretaceous of Mongolia. Sovm. Soviet-Mongolean Paleontol. Eksped. Trudy. 8, 45-55.
Mader and Bradley, 1989. A redescription and revised diagnosis of the syntypes of the Mongolian tyrannosaur Alectrosaurus olseni. Journal of Vertebrate Paleontology. 9(1), 41-55.
Dong, 1992. Dinosaurian Faunas of China: China Ocean Press. 188 pp.
Currie and Eberth, 1993. Palaeontology, sedimentology and palaeoecology of the Iren Dabasu Formation (Upper Cretaceous), Inner Mongolia, People’s Republic of China. Cretaceous Research. 14, 127-144.
http://paleo.amnh.org/fossil/show.html?cat_num=FR%2021597
Zanno, 2006. The pectoral girle and forelimb of the primitive therizinosauroid Falcarius utahensis (Theropoda, Maniraptora): Analyzing evolutionary trends within Therizinosauroidea. Journal of Vertebrate Paleontology. 26(3), 636-650.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

undescribed therizinosauroid (Ikegami and Tomida, 2005)
Cenomanian-Turonian, Late Cretaceous
Mifune Group, Japan

Material- parasphenoid, basisphenoid, basioccipital, exoccipital, supraoccipital, three teeth, incomplete humerus
Description- extremely swollen, pneumatic basisphenoid; reduced basipterygoid processes; three exits for the n. hypoglossus; exoccipital depression of Erlikosaurus absent; low nuchal crest on midline of supraoccipital; anterior dentary tooth subcircular in section and lacking serrations; posterior teeth lanceolate with constricted bases and large serrations on both carinae; twisted humeral shaft with posterior trochantor.
Reference- Ikegami and Tomida, 2005. A therizinosaurid dinosaur from the Upper Cretaceous Mifune Group in Kyushu, Japan. Journal of Vertebrate Paleontology. 25(3), 73A.

Erliansaurus Xu, Zhang, Sereno, Zhao, Kuang, Han and Tan, 2002
E. bellamanus Xu, Zhang, Sereno, Zhao, Kuang, Han and Tan, 2002
Late Campanian-Early Maastrichtian, Late Cretaceous
Iren Dabasu Formation, Inner Mongolia, China

Holotype- (LH V0002) (~2.57 m; 120 kg; subadult) mid cervical vertebra (61 mm), posterior cervical vertebra (50 mm), anterior dorsal vertebra (45 mm), two proximal caudal vertebrae (50, 47 mm), scapula (227 mm), humerus (276 mm), radius (220 mm), ulna (237 mm), metacarpal I (57 mm), phalanx I-1 (58 mm), manual ungual I (91 mm), metacarpal II (116 mm), phalanx II-1 (40 mm), phalanx II-2 (45 mm), manual ungual II (~76 mm), metacarpal III (79 mm), phalanx III-1 (17 mm), phalanx III-2 (14 mm), phalanx III-3 (33 mm), manual ungual III, partial ilium, pubic fragments, ischial fragments, femur (412 mm), tibiae (373 mm), fibula (~350 mm), partial metatarsals
Diagnosis- (after Xu et al., 2002) enlarged nutrient foramen on proximal caudal vertebrae; crest-like posterior trochanter on humerus; anterior margin of proximal tibia significantly higher than posterior margin; distally located hypertrophied iliofibularis tubercle on fibula (also in Nothronychus?).
(proposed) manual phalanges of digit II each shorter than 40% of metacarpal II length.
Other diagnoses- Xu et al. note the presence of an oval fossa by the posterior humeral trochanter, but this is present in other therizinosaurs as well (e.g. Falcarius, Neimongosaurus- Zanno, 2008). Zanno (2008) believes the supposed supratrochanteric process on the ilium is merely the anterior portion of the postacetabular tuber present in derived therizinosaurs, as the ilium is crushed and poorly preserved. Xu et al. note Nothronychus and Segnosaurus also have a distally placed m. iliofibularis tubercle on their fibula, but state Erliansaurus' is larger. Zanno states Nothronychus also has a hypertrophied tubercle, but the issue cannot be resolved with current illustrations.
Comments- Erliansaurus bellamanus has wonderful appendicular preservation, but very few known vertebrae. The mid-cervical vertebra is actually shorter than Neimongosaurus' (~85%), indicating a much shorter neck proportionately, as all other dimensions are larger (appendicular elements 13-24% larger). The cervical series was approximately 680 mm, assuming a similar number of cervicals. The anterior dorsal centrum is 13% larger than Neimongosaurus', giving a dorsal length estimate of 355 mm. A sacrum about 20% larger than Neimongosaurus' would be about 290 mm long. The proximal caudal centrum resembles the third of Neimongosaurus and is about 1.32 times as long, suggesting a tail length of 990 mm. Finally, the skull was probably about 255 mm long, judging by the humeral length. Thus, Erliansaurus was approximately 2.57 meters.
References- Xu, Zhang, Sereno, Zhao, Kuang, Han and Tan, 2002. A new therizinosauroid (Dinosauria, Theropoda) from the Upper Cretaceous Iren Dabau Formation of Nei Mongol. Vertebrate Palasiatica. 40(3), 228-240.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

Therizinosauridae sensu Sereno, in press
Definition- (Therizinosaurus cheloniformis + Nothronychus mckinleyi + Neimongosaurus yangi)

Neimongosaurus Zhang, Xu, Sereno, Kwang and Tan, 2001
N. yangi Zhang, Xu, Sereno, Kwang and Tan, 2001
Late Campanian-Early Maastrichtian, Late Cretaceous
Iren Dabasu Formation, Inner Mongolia, China

Holotype- (LH V0001) (2.33 m; 90 kg) partial braincase, anterior dentary, axis (~55 mm), third cervical vertebra (55 mm), fourth cervical vertebra (65 mm), fifth cervical vertebra (72 mm), sixth cervical vertebra (72 mm), seventh cervical vertebra (72 mm), eighth cervical vertebra (72 mm), ninth cervical vertebra (72 mm), tenth cervical vertebra (72 mm), eleventh cervical vertebra (72 mm), twelfth cervical vertebra (47 mm), thirteenth cervical vertebra (47 mm), fourteenth cervical vertebra (31 mm), several cervical ribs, first dorsal vertebra (~35 mm), second dorsal vertebra (~35 mm), third dorsal vertebra (40 mm), fourth dorsal vertebra (40 mm), fifth dorsal vertebra, sixth dorsal vertebra, seventh dorsal vertebra, eighth dorsal vertebra, sacrum, first caudal vertebra (39 mm), second caudal vertebra (38 mm), third caudal vertebra (35 mm), fourth caudal vertebra (38 mm), fifth caudal vertebra (39 mm), sixth caudal vertebra (38 mm), seventh caudal vertebra (38 mm), eighth caudal vertebra (38 mm), ninth caudal vertebra (36 mm), tenth caudal vertebra (36 mm), eleventh caudal vertebra (34 mm), twelfth caudal vertebra (33 mm), thirteenth caudal vertebra (31 mm), fourteenth caudal vertebra (31 mm), fifteenth caudal vertebra (31 mm), sixteenth caudal vertebra (28 mm), seventeenth caudal vertebra (28 mm), eighteenth caudal vertebra (26 mm), nineteenth caudal vertebra (22 mm), twentieth caudal vertebra (22 mm), twenty-first caudal vertebra (18 mm), twenty-second caudal vertebra (13 mm), several chevrons, partial scapulocoracoids, furcula (128 mm), humeri (222 mm), radius (180 mm), partial ilia, femora (366 mm), tibiae (310 mm), distal tarsal III, distal tarsal IV, metatarsal I (57 mm), phalanx I-1 (33 mm), metatarsal II (116 mm), phalanx II-1 (30 mm), phalanx II-2, metatarsal III (120 mm), phalanx III-1 (27 mm), phalanx III-2, phalanx III-3, metatarsal IV, phalanx IV-1 (27 mm), phalanx IV-2, phalanx IV-3, partial metatarsal V
Paratype- (LH V0008) sacrum, ilia
Diagnosis- (after Zhang et al., 2001) radius with a prominent biceps tuberosity; tibia with an extremely long fibular crest that ends at over 50% the length of the tibia (also in Nothronychus? graffami).
(proposed) distal humerus expanded more than three times shaft width.
Other diagnoses- Most of Zhang et al.'s (2001) listed diagnostic characters are more widely distributed, as noted by Zanno (2008). In particular, Zanno stated the distal caudal prezygapophyses were not more divergent than other therizinosaurs, based on unpublished data probably referring to Nothronychus? graffami. Proximal caudal vertebrae with a fossa ventral to the transverse process are also known in Nothronychus mckinleyi and N? graffami, as well as oviraptorosaurs such as Nomingia. The lateral surface of the preacetabular process is twisted dorsally in most therizinosaurs (e.g. Falcarius, Nothronychus? graffami, Segnosaurus). The fibular crest of the tibia is not significantly more elongate (57%) than in Nothronychus? graffami (55%), though is longer than Nothronychus mckinleyi (50%), Segnosaurus and Erliansaurus (both 48%). Proximal pedal phalanges with well developed heels are present in Erlikosaurus, Therizinosaurus, Nothronychus mckinleyi and N? graffami.
Comments- Neimongosaurus has an almost complete vertebral column preserved, assuming 22 presacrals like Nanshiungosaurus. The fourteen cervicals are 804 mm long, the eight dorsals are 315 mm and the estimated 28 caudals are about 755 mm (it appears about six are missing). Though no sacral measurements are given, both the last dorsal and the first caudal are about 40 mm. Estimating for Neimongosaurus' six sacral vertebrae leads to a length of 240 mm. Assuming the skull is about 95% of humeral length (93% in Erlikosaurus, 98% in Alxasaurus), that means a 211 mm long skull. These all total to 2.33 meters.
References- Zhang, Xu, Sereno, Kwang and Tan, 2001. A long-necked therizinosauroid dinosaur from the Upper Cretaceous Iren Dabasu Formation of Nei Mongol, People’s Republic of China. Vertebrata PalAsiatica. 39(4), 282-290.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

Therizinosauridae Maleev, 1954
Definition- (Therizinosaurus cheloniformis + Segnosaurus galbinensis + Erlikosaurus andrewsi + Nanshiungosaurus brevispinus) (modified from Zhang et al., 2001)
Other definitions- (Erlikosaurus andrewsi <- Ornithomimus velox) (modified from Sereno, 1998)
(Erlikosaurus andrewsi <- Ornithomimus velox, Oviraptor philoceratops, Passer domesticus) (modified from Sereno, 1999)
(Therizinosaurus cheloniformis + Erlikosaurus andrewsi) (modified from Clark, Maryanska and Barsbold, 2004)
(Therizinosaurus cheloniformis + Segnosaurus galbinensis + Erlikosaurus andrewsi + Nothronychus graffami) (Zanno, Gillette, Albright and Titus, 2009)
(Therizinosaurus cheloniformis + Nothronychus mckinleyi + Neimongosaurus yangi) (Sereno, in press)
= Segnosauridae Perle, 1979
= Enigmosauridae Barsbold and Perle in Barsbold, 1983
= Nanshiungosauridae Dong and Yu, 1997
= "Erlikosauridae" Ryan and Russell, 2001
= Therizinosauridae sensu Clark, Maryanska and Barsbold, 2004
Definition- (Therizinosaurus cheloniformis + Erlikosaurus andrewsi) (modified)
= Therizinosauridae sensu Zanno, Gillette, Albright and Titus, 2009
Definition- (Therizinosaurus cheloniformis + Segnosaurus galbinensis + Erlikosaurus andrewsi + Nothronychus graffami)
Comments- Ryan and Russell (2001) only used Erlikosauridae in a faunal list, making it a nomen nudum (ICZN Article 13.1.1).
References- Ryan and Russell, 2001. Dinosaurs of Alberta (exclusive of Aves). In Tanke and Carpenter (eds). Mesozoic Vertebrate Life. 279-297.

Erlikosaurus Perle in Barsbold and Perle, 1980
= Erlicosaurus Perle, 1981
E. andrewsi Perle in Barsbold and Perle, 1980
= Erlicosaurus andrewsi Perle, 1981
Cenomanian-Santonian, Late Cretaceous
Baynshiren Formation, Mongolia

Holotype- (IGM 100/111) (~3.4 m; ~275 kg) incomplete skull (237 mm, 258 to the occipital condyle), mandibles (246 mm), several fragmentary cervical vertebrae, humerus (300 mm), metatarsal I (71 mm), phalanx I-1 (42 mm), pedal ungual I (100 mm), metatarsal II (120 mm), phalanx II-1 (44 mm), phalanx II-2 (42 mm), pedal ungual II (89 mm), distal metatarsal III (~122 mm), phalanx III-1 (40 mm), phalanx III-2 (36 mm), phalanx III-3 (35 mm), pedal ungual III (84 mm), distal metatarsal IV, phalanx IV-1 (38 mm), phalanx IV-2 (15 mm), phalanx IV-3 (15 mm), phalanx IV-4 (27 mm), pedal ungual IV (73 mm)
Diagnosis- (after Barsbold and Perle, 1980) lateral pedal unguals narrow.
(after Perle, 1981) twenty-three maxillary teeth (unknown in other therizinosaurs); dentary symphysis more medially recurved than Segnosaurus, Neimongosaurus or Falcarius; dentary teeth not at all recurved (also in CAGS-01-IG-1); distal condyles of humerus sharply separated proximally from shaft (also in Neimongosaurus); .
(after Clark et al., 1994) premaxillary fenestra absent (unknown in other therizinosaurs); maxillary fenestra absent; maxillary teeth inset from lateral margin (unknown in other therizinosaurs); vomer extremely elongate and extending posteriorly to meet cultriform process (also in an undescribed Chinese therizinosaur- Zanno, 2008); passage for internal carotid artery enclosed on occiput; external auditory meatus restricted ventrally by lateral expansion of braincase (unknown in other therizinosaurs); trigeminal opening divides into three branches within side wall of braincase (unknown in other therizinosaurs); lateral dentary shelf begins at fifth tooth position.
Other diagnoses- Contra Zanno (2008), the transversely compressed pedal unguals noted by Barsbold and Perle (1980) are diagnostic, as they differ from Alxasaurus, "Chilantaisaurus" zheziangensis, Nothronychus? graffami and Segnosaurus. Nothronychus mckinleyi has narrow medial pedal unguals (originally identified as manual unguals), but thick lateral unguals, unlike Erlikosaurus.
Perle (1981) included several characters in his diagnosis which distinguish Erlikosaurus from Segnosaurus, the only other recognized therizinosaur at the time. The sharp raised alveolar edge on the dentary symphysis and extensive length of this toothless area are also present in Neimongosaurus. While Perle lists the maxillary tooth count as being 24(25?), it is really 23, which is only diagnostic due to the unknown counts in other therizinosaurs. The 31 dentary teeth are not significantly more numerous than the 28 teeth in Falcarius. The lack of a coronoid prominence on the surangular is primitive. The metatarsal II / humeral ratios of Erlikosaurus and Segnosaurus are not significantly different- 36% vs. 38%.
Barsbold (1983) listed small, closely positioned teeth in his diagnosis, but these are present in all therizinosaurs. The toothless dentary symphysis is present in other derived therizinosaurids as well (e.g. Neimongosaurus; Segnosaurus).
Barsbold and Maryanska (1990) listed the less flattened anterior dentary teeth compared to Segnosaurus, but this is plesiomorphic.
Relatively few therizinosaurs can be evaluated for the characters listed by Clark et al. (1994) in their diagnosis, as cranial remains are rare and the complete skull of Beipiaosaurus is still undescribed. A toothless premaxilla with sharp ventral edges is also present in the Nanchao therizinosaur embryo (CAGS-01-IG-1). The elongate external nares are also present in Beipiaosaurus and the Nanchao embryo. The sharp ventral edge of the antorbital fossa is also observed in Falcarius. The antorbital fossa is equally extensive in Beipiaosaurus, though not in the Nanchao embryo (perhaps due to ontogenetic shortening of the snout). Both Beipiaosaurus and the Nanchao embryo have a maxillary fenestra, unlike Erlikosaurus, though other therizinosaurs cannot be evaluated. A reduced number of nutrient foramina are present on the posterior maxilla in both Falcarius and the Nanchao embryo. The posterodorsal jugal process also extends dorsally up the laterotemporal fenestra margin in the Nanchao embryo. The basisphenoid also has extremely large peumatic spaces in the Nanchao embryo and Nothronychus mckinleyi. The anterior carotid foramen does not seem to be exposed on the occiput of Falcarius, Nothronychus mckinleyi or the Nanchao embryo, though it is unknown in other therizinosaurs. A generally homodont dentition of linguolabially flattened teeth is primitive for theropods, while maxillary teeth which are small, lanceolate, unrecurved and constricted at the base are present in Falcarius and likely all therizinosaurs, as maxillary and dentary dentition is usually extremely similar. Likewise, coarsely serrated maxillary teeth are not currently known for any other therizinosaur (Falcarius has plesiomorphically small serrations), but are likely present in all derived therizinosaurs, as their dentary teeth are coarsely serrated. Clark et al. note that Erlikosaurus has fewer elongate anterior teeth than Segnosaurus, but this is probably primitive, as Falcarius is similar in this regard. The other mandibular characters listed in their diagnosis are specified either as being shared with other therizinosauroids, or as being shared with either Alxasaurus or Segnosaurus.
Comments- Discovered in 1972, Erlikosaurus was confusingly described as gen. et sp. nov. in both Barsbold and Perle (1980) and Perle (1981), though the former attributes the name to Perle only. Perle (1981) spelled the genus name Erlicosaurus, which has been followed by some authors (e.g. Barsbold, 1983; Clark et al., 1994). However, according to the ICZN (Article 32.5), since there is no evidence in the original publication that the name is spelled incorrectly, and the issue is not with suffix or gender, Erlikosaurus is the correct original spelling. This makes Erlicosaurus an unjustified emendation (Article 33.2), since there is no evidence in Perle (1981) that he purposefully changed the spelling, and the original spelling is not cited. According to Article 33.2.3, "the name thus emended is available and it has its own author and date and is a junior objective synonym of the name in its original spelling." An unjustified emendation can become justified it it has prevailing usage and is attributed the the original author and date, but Erlikosaurus has 101,000 Google hits vs. 397 for Erlicosaurus, and 58 vs. 50 Google Scholar hits. Thus the genus should be spelled Erlikosaurus. Barsbold and Perle (1980) note a left and right pes, but only a single pes is described by Perle (1981).
Currie and Eberth (1993) suggested that a few elements from the Iren Dabasu Formation (Late Campanian-Early Maastrichtian) may be referable to Erlikosaurus. It is more likely these are Erliansaurus and/or Neimongosaurus.
Erlikosaurus andrewsi is known from a skull, fragmentary cervical vertebrae, humerus and pes. Unfortunately, the vertebral dimensions are undescribed, so the length can be only loosely estimated. Based on the humeral, cranial and metatarsal lengths, Erlikosaurus was somewhere around 3.4 meters long.
References- Barsbold and Perle, 1980. Segnosauria, a new infraorder of carnivorous dinosaurs. Acta Palaeontologica Polonica. 25, 185-195.
Perle, 1981. [A new segnosaurid from the Upper Cretaceous of Mongolia]. Sovm. Soviet-Mongolean Paleontol. Eksped. Trudy. 15, 50-59. [in Russian]
Barsbold, 1983. Carnivorous dinosaurs from the Cretaceous of Mongolia. Transactions of the Joint Soviet-Mongolian Palaeontological Expedition. 19, 117 pp.
Barsbold and Maryanska, 1990. Saurischia sedis mutabilis: Segnosauria. in Weishampel, Dodson and Osmolska (eds). The Dinosauria. University of California Press. 408-415.
Currie and Eberth, 1993. Palaeontology, sedimentology and palaeoecology of the Iren Dabasu Formation (Upper Cretaceous), Inner Mongolia, People’s Republic of China. Cretaceous Research. 14, 127-144.
Clark, Perle and Norell, 1994. The skull of Erlicosaurus andrewsi, a Late Cretaceous "segnosaur" (Theropoda: Therizinosauridae) from Mongolia. American Museum Noviates. 3115, 39 pp.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.
Lautenschlager, Rayfield, Witmer and Perle, 2011. The endocranial anatomy of the Mongolian therizinosauroid dinosaur Erlikosaurus andrewsi as revealed by 3D visualization. Journal of Vertebrate Paleontology. Program and Abstracts 2011, 141.
Lautenschlager, Rayfield, Witmer and Perle, 2012. A biomechanical model of Erlikosaurus andrewsi (Dinosauria: Therizinosauria) with implications for cranial function and dietary preferences. Journal of Vertebrate Paleontology. Program and Abstracts 2012, 126.
Lautenschlager, Rayfield, Perle, Zanno and Witmer, 2012. The endocranial anatomy of Therizinosauria and its implications for sensory and cognitive function. PLoS ONE. 7(12), e52289.
Lautenschlager, 2013a. Unravleing therizinosaur paleobiology - a multi-angle approach. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 160.
Lautenschlager, 2013b. Cranial myology and bite force performance of Erlikosaurus andrewsi: A novel approach for digital muscle reconstructions. Journal of Anatomy. 222(2), 260-272.

Therizinosaurus Maleev, 1954
T. cheloniformis Maleev, 1954
Late Campanian-Early Maastrichtian, Late Cretaceous
Nemegt Formation, Mongolia

Holotype- (PIN 551-483) (~8.2 m; ~3.9 tons) several dorsal rib fragments, incomplete manual ungual I (~655 mm), proximal manual ungual I, incomplete manual ungual II (~500 mm), metatarsal(?) (270 mm),
Referred- (IGM 100/15; lost) (9.6 m; ~6.2 tons) dorsal rib fragments, gastralial fragments, scapulocoracoids (one incomplete; coracoid 360 mm), humeri (760 mm), radii (550.4 mm), ulna (620.2 mm), distal carpal I, distal carpal II, metacarpal I (145.5 mm), metacarpal II (286.8 mm), phalanx II-1 (141.7 mm), phalanx II-2 (145.8 mm), manual ungual II (~585 mm), metacarpal III (191.6 mm) (Barsbold, 1976)
(IGM 100/16; lost) distal manual ungual I (Barsbold, 1976)
(IGM 100/17; lost) (~5.4 m; ~1.1 tons) proximal manual ungual I (~435 mm) (Barsbold, 1976)
?(IGM 100/45; lost) (~6.5 m; ~1.9 tons) femoral fragments, tibial fragments (distal end 253 mm wide), astragalus, calcaneum, distal tarsal IV, proximal metatarsal I, distal phalanx I-1, proximal pedal ungual I, metatarsal II (200 mm), phalanx II-1 (85 mm), phalanx II-2 (95 mm), metatarsal III (250 mm), phalanx III-2 (~64.9 mm), proximal pedal ungual III, proximal metatarsal IV, phalanx IV-1 (70 mm), phalanx IV-2 (30 mm), phalanx IV-3 (33 mm), phalanx IV-4 (~65 mm) (Perle, 1982)
Late Campanian-Early Maastrichtian, Late Cretaceous
White Beds of Khermeen Tsav, Mongolia

? material
Diagnosis- (after Maleev, 1955) large size; hypertrophied manual unguals, longer than four times proximal height; manual unguals highly compressed transversely (<20% of dorsoventral height).
(after Barsbold, 1976) humerus with hypertrophied deltopectoral crest, exceeding 60% of humeral length; deep incision into lateral margin of distal carpal I; manual unguals very slightly curved; manual unguals with only slight decrease in height distally.
(after Clark et al., 2004) distal carpals partially fused to metacarpals I and II.
(after Zanno, 2008) enlarged medial longitudinal crest on metacarpal I; manual ungual I nearly flat ventrally in lateral view.
Other diagnoses- Maleev's (1955) original diagnosis was based on comparison to protostegids, so included the absence of dorsal armor, which is of course plesiomorphic for theropods. However, the body was probably not broad and depressed, and the "nearly derived forelimbs" are too ambiguous to evaluate.
Barsbold (1976) listed many additional characters. The short scapular blade is probably caused by a missing distal end, while the "elongated ventral expansion" of the scapulocoracoid, whether referring to the acromion of posteroventral coracoid process, is primitive for therizinosaurs. The distal humerus is expanded more in Neimongosaurus. The untwisted humerus and sigmoid radial shaft are found in several other therizinosaurs. The olecranon fossa of the ulna (described as semilunate) seems to be shaped similarly to that of Falcarius. The semilunate distal carpus is plesiomorphic for therizinosaurs. The first metacarpal is shortest and dorsoventrally flattened, second longest, and third most slender in all therizinosaurs. The manual phalanges are comparatively longer than in Erliansaurus.
Of Zanno's (2008) characters, Erliansaurus and Nothronychus? graffami also have metacarpal I over 66% of metacarpal III length (72% and 75% respectively vs. 76% in Therizinosaurus). Zanno says Therizinosaurus' manual unguals lack ventrally projecting flexor tubercles, but that on ungual II is comparable to those of Erliansaurus in extending to the proximal ungual edge and only having a low ventral corner. Manual ungual I does have an extremely reduced ventral corner however, giving the illusion of a non-projected flexor tubercle.
Comments- The holotype (PIN 551-483) was discovered in 1948 and described by Maleev in 1954 as a new taxon of turtle, related to protostegids. It consists of rib fragments, a metacarpal and three incomplete manual unguals. Maleev illustrated a rib fragment and ungual, while Rozhdestvensky (1970) illustrated all three unguals. Rozhdestvensky reidentified the metacarpal as a metatarsal (he writes metatarsus, but Maleev described a single element), and referred both it and the ribs to Sauropoda without justification. The dorsal rib fragments are described as having T-shaped to triangular sections, which differs from the round sections in titanosaurs and embryonic therizinosaurs. Unfortunately, no adult therizinosaur ribs have had their cross sections described yet, though some theropods are known to have T-shaped sections (e.g. Tugulusaurus). Notably, the photographed ribs of Suzhousaurus suggest they have a longitudinal ridge that could indicate a T-shaped section. However, Barsbold (1976) states the rib fragments found with IGM 100/15 are more slender than those found with the holotype. This may indicate the ribs do not belong to Therizinosaurus, or that different sections or positions of rib were preserved with each specimen. The metapodial is described as 270 mm long, which is close in size to metacarpal II in IGM 100/15, but too short to be any metatarsal except metatarsal I unless Therizinosaurus had a much shorter pes than Nothronychus? graffami. The reported dorsoventral width of the proximal end (20 mm) is too small to be any metapodial, except perhaps metatarsal I, which only has a narrow contact with the tarsus. The cylindrical distal condyle resembles metatarsals more than the ginglymoid metacarpals of therizinosaurs. This may therefore be a metatarsal I, but the narrow proximal dimension of metatarsal I in Therizinosaurus is transverse instead of dorsoventral, and the "short, low crest" present on the dorsal surface mentioned by Maleev is of unknown homology. Metacarpals of titanosaurs differ in lacking distal condyles, with both sauropod metacarpals and metatarsals are too deep proximally to match Maleev's measurements. There seems to be no reason to suggest it is a sauropod metatarsal instead of a therizinosaur metatarsal, and Rozhdestvensky could have been easily confused by the derived morphology of therizinosaurs (stout metatarsals with wide ends) which is somewhat sauropod like. Of the three manual unguals, I believe two belong to the first digits, with the smaller one belonging to the second digit. This is supported by the resemblence of the smaller one to an ungual associated with the second digit in a referred specimen, the fact Erliansaurus' largest ungual is the first, the strong resemblence between the two large unguals, and the theropod rule that manual ungual III is always smallest (the exception being confuciusornithids).
The referred specimen IGM 100/15 was discovered in 1973 and includes pectoral girdles, forelimbs (missing digits I and III), dorsal ribs and gastralia. The forelimb is proportioned very much like Nothronychus, and is about 1.8 times larger, leading to a length of 9.6 meters. The holotype is about 85% as large, so 8.2 meters long. Another proximal end of manual ungual I (IGM 100/17) was about 66% as long as the holotype, so was 5.4 meters long. Another referred manual ungual lacks the proximal portion, so cannot be measured accurately. The hindlimb specimen (IGM 100/45) was also discovered in 1973 but is not directly comparable, so is referred only tentatively. It is actually only 94% as large as Segnosaurus specimen IGM 100/82, so would be about 6.5 meters long. Zanno (2008) notes the IGM material is all lost.
References- Maleev, 1954. New turtle-like reptile in Mongolia. Priroda. 1954, 106-108.
Rozhdestvensky, 1970. Giant claws of enigmatic Mesozoic reptiles. Paleontological Journal. 1970(1), 131-141.
Barsbold, 1976. New data on Therizinosaurus (Therizinosauridae, Theropoda). Sovm. Sov.-Mong. Paleontol. Eksped. Trudy. 3, 76-92.
Perle, 1982. On a new finding of the hindlimb of Therizinosaurus sp. from the Late Cretaceous of Mongolia. Problems in Mongolian Geology. 5, 94-98.
Clark, Maryanska and Barsbold, 2004. Therizinosauroidea. in In Weishampel, Dodson and Osmolska (eds). The Dinosauria Second Edition. University of California Press. 151-164.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

undescribed Therizinosauridae (Sues, 1978)
Late Campanian, Late Cretaceous
Dinosaur Park Formation, Alberta, Canada

Material- (CMN 12349) frontal (Sues, 1978)
(CMN 12355) frontal (Sues, 1978)
(RTMP 81.16.231) frontal (Currie, 1992)
(RTMP 79.15.1) pedal ungual (Currie, 1992)
Comments- Sues (1978) identified CMN 12349 as Dromaeosaurus and CMN 12355 as Theropoda indet.. Currie (1987) and Ryan and Russell (2001) referred CMN 12355 to cf. Erlikosaurus sp.. Currie (2005) refers CMN 12349 and RTMP 79.15.1 to Erlikosaurus sp. as well. No other therizinosaur frontals were known at the time however, making identification to the genus level problematic. The pedal ungual resembles Erlikosaurus and Therizinosaurus more than Alxasaurus in having a dorsally angled articular facet. It is similar to Beipiaosaurus, Erlikosaurus and Therizinosaurus (but differs from Alxasaurus) in its proximodorsal lip. The flexor tubercle is larger than these therizinosaurs. Unlike Erlikosaurus, the proximoventral base doesn't extend proximally past the articular surface, and the transverse width is much greater. Overall, it is most similar to Therizinosaurus.
References- Sues, 1978. A new small theropod dinosaur from the Judith River Formation (Campanian) of Alberta, Canada. Zoological Journal of the Linnaean Society of London. 62, 381-400.
Currie, 1987. Theropods of the Judith River Formation of Dinosaur Frovincial Park, Alberta. in Currie and Koster (eds). 4th Symposium of Mesozoic Terrestrial Ecosystems Short Papers. Tyrell Museum of Palaeontology, Drumheller, Alberta. 52-60.
Currie, 1992. Saurischian dinosaurs of the Late Cretaceous of Asia and North America. in Mateer and Chen (eds). Aspects of Nonmarine Cretaceous Geology. Beijing: China Ocean Press. 237-249.
Ryan and Russell, 2001. Dinosaurs of Alberta (exclusive of Aves). in Tanke and Carpenter (eds). Mesozoic Vertebrate Life. Indiana University Press. 279-297.

Enigmosaurus Barsbold and Perle in Barsbold, 1983
E. mongoliensis Barsbold and Perle in Barsbold, 1983
Cenomanian-Santonian, Late Cretaceous
Baynshirenskaya Formation, Mongolia

Holotype- (IGM 100/84) (~5 m; ~900 kg; old adult) dorsal ribs, sacrum, distal humerus, radius(?), proximal ulna, ventral ilia (~650 mm), pubes (634 mm), incomplete ischium (524 mm), proximal femur
Diagnosis- (after Barsbold, 1983) elongate narrow obturator process (also in Falcarius).
(after Zanno, 2008) ischial obturator processes fused.
Other diagnoses- Barsbold (1983) also listed narrow pubic and ischial shafts in his diagnosis, but these are plesiomorphic. The v-shaped anterior trough formed by the fused pubes would be matched by other therizinosaur pubes, as their pubic apron is posteriorly placed. The proximodistally shallow pubic boot is plesiomorphic for theropods, while the "shoe-like" shape is common in therizinosaurs (e.g. Nothronychus? graffami, Segnosaurus).
Barsbold and Maryanska (1990) listed the uncompressed pubic shaft in their diagnosis, but this is plesiomorphic for therizinosaurs (e.g. Falcarius, Beipiaosaurus).
The posterior pubic boot listed by Clark et al. (2004) as diagnostic is primitive for therizinosaurs.
Of Zanno's (2008) listed diagnostic characters, the subequal anterior and posterior portions of the pubic boot are primitive, being present in Falcarius and basal oviraptorosaurs for instance. The fusion of the pubic symphysis may be due to old age, as Zanno notes large amounts of resorbed bone.
Comments- The holotype was first illustrated and briefly described by Barsbold (1979) as "dinosaur from Khara Khutul", who noted it probably represented a new family. Barsbold and Perle (1980) later described and illustrated it as Segnosaurian indet., before it was named in 1983. Zanno (2008) noted additional elements were present in the holotype material (dorsal ribs, distal humerus, possible radius, proximal ulna, proximal femur), as well as a large therizinosaur femoral shaft which is not referrable to the type specimen. Zanno is the first author to photograph the type material, which differs greatly from the drawing in Barsbold and Perle (1980). In particular, the pubic peduncle is anteroposteriorly narrower, the ischial peduncle more massive, the postacetabular process more complete and deeper than reconstructed, the puboischial contact is deeper, the pubic shaft is thicker and more anteriorly concave, the pubic boot is deeper, the ischial shaft is thicker, the puboischial fenestra is much shorter, the obturator process longer, and the distal ischium broken.
Currie and Eberth (1993) suggested that a few elements from the Iren Dabasu Formation (Late Campanian-Early Maastrichtian) may be referable to Enigmosaurus. It is more likely these are Erliansaurus and/or Neimongosaurus.
Enigmosaurus mongoliensis is only known from an incomplete pelvis, which is about 95% the size of Segnosaurus' holotype. This leads to a tentative length estimate of 5 meters.
Barsbold and Perle (1983) placed this species in the Segnosauria, but separated it from Segnosaurus and Erlikosaurus in a separate family- the Enigmosauridae. This was based on several of the features (narrow pubis and ischium; anterior pubic symphyseal trough; narrow and elongate obturator process), which at the time simply distinguished it from Segnosaurus (Erlikosaurus' pelvis is unknown). Enigmosaurus could be the pelvis of Erlikosaurus, but Barsbold and Perle claimed that Segnosaurus and Erlikosaurus were too similar otherwise to have such different pelves. This is not apparent, though with the new discovery of a distal humerus in the type material, comparison with Erlikosaurus is possible.
References- Barsbold, 1979. Opisthopubic pelvis in the carnivorous dinosaurs. Nature. 279, 792-793.
Barsbold and Perle, 1980. Segnosauria, a new infraorder of carnivorous dinosaurs. Acta Palaeontologica Polonica. 25(2), 187-195.
Barsbold, 1983. Carnivorous dinosaurs from the Cretaceous of Mongolia. Transactions of the Joint Soviet-Mongolian Palaeontological Expedition. 19, 117 pp.
Barsbold and Maryanska, 1990. Saurischia sedis mutabilis: Segnosauria. in Weishampel, Dodson and Osmolska (eds). The Dinosauria. University of California Press. 408-415.
Currie and Eberth, 1993. Palaeontology, sedimentology and palaeoecology of the Iren Dabasu Formation (Upper Cretaceous), Inner Mongolia, People's Republic of China. Cretaceous Research. 14, 127-144.
Clark, Maryanska and Barsbold, 2004. Therizinosauroidea. in In Weishampel, Dodson and Osmolska (eds). The Dinosauria Second Edition. University of California Press. 151-164.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

Suzhousaurus Li, Peng, You, Lamanna, Harris, Lacovata and Zhang, 2007
S. megatherioides Li, Peng, You, Lamanna, Harris, Lacovata and Zhang, 2007
Aptian-Albian?, Early Cretaceous
Xinminpu (=Xinminbao) Group, Gansu, China
Holotype
- (FRDC-GSJB-99) ten incomplete to complete dorsal vertebrae, several incomplete dorsal ribs, incomplete scapulocoracoid (scap ~705 mm), humerus (550 mm), (?)ilial fragment, incomplete pubes, fragments
Referred- eighth dorsal vertebra (115 mm), ninth dorsal vertebra (115 mm), tenth dorsal vertebra (117.5 mm), seven dorsal ribs, sacrum (80, 90, 115, 105, 100 mm), first caudal vertebra (87.5 mm), second caudal vertebra (87.5 mm), third caudal vertebra (82.5 mm), fourth caudal vertebra (90 mm), fifth caudal vertebra (97.5 mm), sixth caudal vertebra (97.5 mm), six chevrons, ilium (~790 mm), incomplete pubis, ischium (660 mm), femora (one partial; 840 mm) (Li et al., 2008)
Diagnosis- (after Li et al., 2008) transversely expanded distal ends of sacral and proximal caudal neural spines (possibly in Nanshiungosaurus); preacetabular process of ilium straight and untwisted in dorsal/ventral view.
Other diagnoses- Li et al. (2007) listed a pubis with a strongly concave anterior margin as an apomorphy, but this is also present in Segnosaurus (Zanno, 2008; contra earlier illustrations) and Nothronychus? graffami. Zanno notes the glenoid is damaged, so the poor demarcation noted by Li et al. cannot be confirmed. Further, she notes the "prominent rounded and striated tumescence on the dorsomedial surface of its scapular portion" is common in derived therizinosaurs.
Li et al. (2008) also listed posterior dorsal spine tables in their diagnosis, but these are also present in Falcarius (though that taxon lacks caudal spine tables) and possibly Nanshiungosaurus. Lateral deflection of the preacetabular process is present in all therizinosauroids, nor does the blade seem particularily thin compared to Neimongosaurus for instance. But the flatness is diagnostic compared to the twisted blades in taxa such as Falcarius and Segnosaurus. The preacetabular process has a smoothly rounded anterodorsal edge in Beipiaosaurus, Nanshiungosaurus, Nothronychus? graffami, and probably Segnosaurus (Zanno, 2008; contra earlier illustrations).
Comments- Suzhousaurus cannot be compared with "Nanshiungosaurus" bohlini from the same stratigraphic group, and may be synonymous. If they are indeed synonymous, Li et al. (2007) note the correct name will be Suzhousaurus bohlini.
References- Li, Peng, You, Lamanna, Harris, Lacovata and Zhang, 2007. A large therizinosauroid (Dinosauria: Theropoda) from the Early Cretaceous of northwestern China. Acta Geologica Sinica (English Edition). 81(4), 539-549.
Lamanna, You, Li, Peng and Harris, 2007. A new large-bodied therizinosauroid (Dinosauria: Theropoda) from the Early Cretaceos of Northwestern China. Journal of Vertebrate Paleontology. 27(3), 103A.
Li, You and Zhang, 2008. A new specimen of Suzhousaurus megatherioides (Dinosauria: Therizinosauroidea) from the Early Cretaceous of northwestern China. Canadian Journal of Earth Sciences. 45, 769-779.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

Nothronychus Kirkland and Wolfe, 2001
Diagnosis- (after Zanno et al., 2009) scapula with distally tapering blade.
Other diagnoses- Contra Zanno et al. (2009), graffami does not share many unique characters with Nothronychus mckinleyi. Notably, the obturator process of Nothronychus graffami is not necessarily more subcircular than that of Segnosaurus and Nanshiungosaurus. The puboischial fenestra's elongation cannot be measured in N. mckinleyi due to the missing pubes and seems equally elongate in Nanshiungosaurus in any case. The pubic contact on the obturator process is also limited to its distal portion in Suzhousaurus and probably Enigmosaurus and Nanshiungosaurus. The deep post-obturator notch on the ischium is also present in Suzhousaurus. This limits their shared characters to just the distally tapering scapula, which is only known to be absent in Segnosaurus and Suzhousaurus among therizinosaurids. As both species share derived characters with other therizinosaurid genera (Suzhousaurus, Segnosaurus, etc.), graffami may deserve its own genus.
References- Kirkland and Wolfe, 2001. First definitive therizinosaurid (Dinosauria; Theropoda) from North America. Journal of Vertebrate Paleontology. 21(3), 410-414.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.
Zanno, Gillette, Albright and Titus, 2009. A new North American therizinosaurid and the role of herbivory in 'predatory' dinosaur evolution. Proceedings of the Royal Society B. 76(1672), 3505-3511.
N. mckinleyi Kirkland and Wolf, 2001
Mid Turonian, Late Cretaceous
Moreno Hill Formation, New Mexico, US

Holotype- (MSM P2106) (5.26 m; 1 ton) partial braincase, two cranial fragments, teeth (8.4 mm), eight cervical vertebrae (125.5, 133.5, 187, 188 mm), cervical ribs, first dorsal vertebra (67 mm), dorsal centrum, dorsal ribs, gastralia, sixth or seventh caudal vertebra (64 mm), chevron fragment, scapula (518 mm), humerus (418 mm), ulna (302 mm), radial or ulnar shaft, phalanx I-1, distal metacarpal II, phalanx II-1, ischia (534 mm), tibiae (614 mm), fibula, distal metatarsal I, phalanx I-1, pedal ungual I (138 mm), pedal ungual II (124 mm), phalanx III-3 (37 mm), pedal ungual III (99 mm), phalanx IV-2 (41 mm), pedal ungual IV (92 mm)
Diagnosis- (after Kirkland and Wolfe, 2001) serrations on teeth extend basally to constriction (unknown in N. graffami; also in Alxasaurus); laterally facing scapular glenoid (also in Segnosaurus).
(after Kirkland et al., 2005) braincase narrow (unknown in N. graffami).
(after Zanno et al., 2009) heel on posteroventral surface of caudal centra hypertrophied (approximately one third the dorsoventral length of the caudal centrum); post-obturator notch narrow (also in Suzhousaurus).
Other diagnoses- Kirkland and Wolfe (2001) included several characters in their diagnosis, which Zanno et al. (2009) note are invalid. The coarse serrations and circular root of the tooth are typical for therizinosaurs. Anterior dorsals with "long pedicle and large pleurocoel encasing multiple separate pneumatic foramina" are present in Nanshiungosaurus? bohlini. The slender scapula is shared with N. graffami, so is listed in the Nothronychus diagnosis. The humeral characters (straight, slender shaft; short deltopectoral crest; humeral trochanter absent) are all plesiomorphic. The manual ungual characters (flexor tubercle not extending below the proximal articulation; proximodorsal lip absent) are based on misidentified pedal unguals. The "thin ischium nearly excluded from acetabulum with large, rectangular, medially situated, obturator process" is present in other therizinosauroids such as Segnosaurus and Suzhousaurus. The distally placed m. iliofibularis tubercle on the fibula is shared with other derived therizinosauroids. While the lateral pedal unguals are indeed thick, this is plesiomorphic for therizinosaurs.
Kirkland et al. (2005) listed the almost horizontally oriented supraoccipital in their diagnosis, but this is shared by Falcarius, so may be plesiomorphic. They also revised the pedal ungual thickness character to indicate pedal unguals II-IV are thin and straight, while I is thicker. The pedal unguals are not straight, however. Furthermore, pedal unguals I and II are largest in Erlikosaurus, so the large thin unguals previously identified as manual unguals would be more likely to be unguals I and II in Nothronychus. This leaves the smaller, thicker unguals two be from digits III and IV, reversing Kirkland et al.'s character.
Zanno et al. (2009) also listed platycoelous proximal caudal centra in their diagnosis, as it does differ from the amphicoelous condition in N. graffami. Yet Suzhousaurus and Segnosaurus also share this character. The elongate mid dorsal ischial process which extends opposite to the obturator process and scapular glenoid lacking a buttress are plesiomorphic, shared with most derived therizinosauroids.
Comments- The ischium was originally identified as a Zuniceratops squamosal (Wolfe and Kirkland, 1998). Kirkland et al. (2005) described the braincase, and reidentified the manual unguals as pedal unguals based on comparisons to the then undescribed N? graffami, which was confirmed by Zanno et al. (2009). Zanno et al. also recognized additional elements not noted by Kirkland and Wolfe- three cervical vertebrae, a dorsal centrum, a chevron fragment, and pedal phalanx I-1. They also reidentified pedal phalanges IV-3 and IV-4 as III-3 and IV-2, and a supposed ulna as an indeterminate radial or ulnar shaft.
Nothronychus mckinleyi is known from a partial skeleton which includes many appendicular elements, but only a few vertebrae. The longest cervicals are about 2.6 times longer than Neimongosaurus, leading to a cervical length of 1780 mm, assuming only twelve vertebrae. The width and height of the anterior dorsal vertebra (which is one of the first three because it has a hypapophysis) averages 118% (110-132%) of the equivalents in Nanshiungosaurus brevispinus' twelfth dorsal and third dorsal. A dorsal column 1.18 times larger than Nanshiungosaurus' would be 860 mm. The proximal caudal vertebra is most similar to the third in Neimongosaurus, which would indicate a tail 1380 mm long when scaled up. Finally, scaling Segnosaurus' skull and Nanshiungosaurus' sacrum adds 440 mm and 800 mm respectively. Combining these leads to a total length estimate of 5.26 meters.
References- Wolfe and Kirkland. 1998. Zuniceratops christopheri n. gen. & n. sp., a ceratopsian dinosaur from the Moreno Hill Formation (Cretaceous, Turonian) of west-central New Mexico. In Lucas, Kirkland, and Estep (eds.). Lower and Middle Cretaceous Terrestrial Ecosystems. New Mexico Museum of Natural History and Science Bulletin. 14, 307-317.
Kirkland and Wolfe, 2001. First definitive therizinosaurid (Dinosauria; Theropoda) from North America. Journal of Vertebrate Paleontology. 21(3), 410-414.
Kirkland and Wolfe, 2001. A therizinosaurid (Dinosauria: Theropoda) braincase from the Middle Turonian (Cretaceous) of North America. Journal of Vertebrate Paleontology. 21(3), 68A.
Kirkland, Smith and Wolfe, 2005. Holotype braincase of Nothronychus mckinleyi Kirkland and Wolfe 2001 (Theropoda; Therizinosauridae) from the Upper Cretaceous (Turonian) of West-Central New Mexico. in Carpenter (ed.). The Carnivorous Dinosaurs. 87-96.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.
Zanno, Gillette, Albright and Titus, 2009. A new North American therizinosaurid and the role of herbivory in 'predatory' dinosaur evolution. Proceedings of the Royal Society B. 76(1672), 3505-3511.
Lautenschlager, Rayfield, Perle, Zanno and Witmer, 2012. The endocranial anatomy of Therizinosauria and its implications for sensory and cognitive function. PLoS ONE. 7(12), e52289.
Smith, 2013. Reconstruction of the braincase and associated soft tissues of the North American therizinosaur Nothronychus mckinleyi. Journal of Vertebrate Paleontology. Program and Abstracts 2013, 213.

N? graffami Zanno, Gillette, Albright and Titus, 2009
= Nothronychus "graffami" Zanno, 2008
Early Turonian, Late Cretaceous
Tropic Shale, Utah, US

Holotype- (UMNH VP 16420) (adult) two cervical vertebrae, cervical rib, first dorsal vertebra (~65 mm), second dorsal centrum, third dorsal centrum, fourth dorsal vertebra (~90 mm), fifth dorsal vertebra (~91 mm), sixth dorsal vertebra (~95.6 mm), seventh dorsal centrum, eighth dorsal vertebra (~55 mm), tenth dorsal vertebra (~53 mm), at least ten dorsal ribs, gastralia, sacrum (525 mm), first caudal vertebra (73 mm), second caudal vertebra (57 mm), third caudal vertebra (55 mm), fourth caudal vertebra (70 mm), fifth caudal vertebra (80 mm), sixth caudal vertebra (68 mm), seventh caudal vertebra (72 mm), eighth caudal vertebra (70 mm), ninth caudal vertebra (67 mm), tenth caudal vertebra (72 mm), eleventh caudal vertebra (70 mm), twelfth caudal vertebra (60 mm), thirteenth caudal vertebra (60 mm), fourteenth caudal vertebra (60 mm), fifteenth caudal vertebra (55 mm), sixteenth caudal vertebra (50 mm), seventeenth caudal vertebra (50 mm), eighteenth caudal vertebra (35 mm), nineteenth caudal vertebra (33 mm), twentieth caudal vertebra (34 mm), twenty-first caudal vertebra (28 mm), twenty-second caudal vertebra (21 mm), twenty-third caudal vertebra (24 mm), eight chevrons (~75, 95, 85, ~90, ~63, 55 mm), incomplete scapulocoracoid (~540 mm + ~165 mm), scapula (~570 mm), coracoid (~175 mm), incomplete furcula, humeri (424, 415 mm), radii (274, 275 mm), ulnae (309, 303 mm), metacarpal I (90.5 mm), phalanges I-1 (134 mm), manual ungual I (182 mm straight, 215 mm on curve), metacarpal II (141.2 mm), phalanges II-1 (102 mm), phalanx II-2 (133.4 mm), manual unguals II (187 mm straight, 220 mm on curve, ~198 mm straight, ~270 mm on curve), metacarpals III (121, 126 mm), manual ungual III (177 mm straight, 210 mm on curve), ilia (one incomplete), pubes (587, 575 mm), incomplete ischia (536, 548 mm), femora (696, 656 mm), tibiae (~654, 644 mm), incomplete fibulae (522 mm), astragali (171, 173 mm transversely), metatarsal I (133 mm), phalanx I-1 (86.7 mm), metatarsals II (182, 187 mm), phalanx II-1 (78.9 mm), phalanx II-2 (74 mm), pedal ungual II, metatarsals III (215, 217 mm), phalanx III-1 (75.5 mm), phalanx III-3 (70 mm), metatarsal IV (232 mm), phalanx IV-1 (54 mm), phalanx IV-2 (45 mm), phalanx IV-3 (43 mm), phalanx IV-4 (35.6 mm), metatarsal V (74 mm)
Diagnosis- (after Zanno et al., 2009) scapular glenoid with pronounced buttress; pubic boot with small posterior process (unknown in N. mckinleyi); posteroventral margin of pubic boot concave (unknown in N. mckinleyi); mid dorsal process of ischium proximodistally short (less than 5% of the total length of ischium); mid dorsal process of ischium located proximal to obturator foramen.
Other diagnoses- Zanno et al. also listed amphicoelous proximal caudal centra in their diagnosis, as it does differ from the platycoelous condition in N. mckinleyi. Yet Neimongosaurus, Erliansaurus and Nanshiungosaurus share this character. The wide post-obturator notch on the ischium is possibly plesiomorphic, being seen in Segnosaurus and probably Enigmosaurus and is plausibly derived from the absent notch found in most coelurosaurs. The caudal centra lack a strong posteroventral heel unlike N. mckinleyi, but most other therizinosaurs lack this as well. The straight ulna does differ from N. mckinleyi, but is also shared with Alxasaurus, Erliansaurus and Therizinosaurus.
Comments- This specimen was discovered in 2000 and first identified as therizinosaurid (Gillette et al., 2001), then more specifically as a species of Nothronychus (Gillette et al., 2005). Zanno (2008) referred to it as Nothronychus sp. A, but (accidentally?) labeled it Nothronychus graffami in figure 31 of his unpublished thesis, though this was a nomen nudum at the time since theses don't count according to the ICZN. Zanno et al. (2009) later described and officially named the species. As noted above under the Nothronychus comments, it may not be referrable to that genus.
References- Gillette, 2001. A Late Cretaceous (Early Turonian) therizinosaurid dinosaur (Therizinosauridae, Theropoda) from the Tropic Shale of Southern Utah, USA. NAPC 2001 abstracts.
Gillette, Albright, Titus and Graffam, 2001. Discovery and paleogeographic implications of a therizinosaurid dinosaur from the Turonian (Late Cretaceous) of Southern Utah. Journal of Vertebrate Paleontology. 21(3), 54A.
Gillette, Titus, Albright and Zanno, 2005. Osteology of Nothronychus sp., a Late Cretaceous (Lower Turonian) therizinosaurid dinosaur from Southern Utah. Journal of Vertebrate Paleontology. 25(3), 63A.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.
Zanno, Gillette, Albright and Titus, 2009. A new North American therizinosaurid and the role of herbivory in 'predatory' dinosaur evolution. Proceedings of the Royal Society B. 76(1672), 3505-3511.

Nanshiungosaurus Dong, 1979
N. brevispinus Dong, 1979
Campanian, Late Cretaceous
Yuanpu (=Nanxiong) Formation, Guandong, China

Holotype- (IVPP V4731) (~4.40 m; 600 kg) axis (135 mm; lost), third through twelfth cervical vertebrae (1.27 m; twelfth cervical 76 mm; all lost), first through tenth dorsal vertebrae (730 mm; lost), sacrum (six vertebrae- 680 mm), first caudal vertebra (lost), incomplete ilium (726 mm), proximal pubis, proximal ischia (474 mm)
Diagnosis- (after Dong, 1979) twelve cervical vertebrae; highly elongate cervical vertebrae (2.5 times length of dorsal centra) (also in Nothronychus mckinleyi); opisthocoelous posterior cervical centra; ten dorsal vertebrae (unknown in other therizinosaurs more derived than Beipiaosaurus); sacral spine tables (also in Suzhousaurus); sacral neural spines with saddle shaped depressions on apex; narrow, elongate preacetabular process (also in Nothronychus? graffami).
(after Clark et al., 2004) proximal puboischial contact much deeper than acetabulum.
(proposed) ventral edge of preacetabular process cenvex.
Other diagnoses- As Nanshiungosaurus was originally identified as a sauropod by Dong (1979), most of the diagnostic character he listed are now known to be plesiomorphic for therizinosaurs- short neck compared to sauropods; platycoelous anterior cervical centra; cervical pleurocoels poorly developed compared to sauropods; low cervical neural spines; cervical neural spines not bifid; platycoelous dorsal centra; dorsal centrum height and length subequal; dorsal pleurocoels shallow compared to sauropods; low and broad dorsal neural spines; short sacral neural spines; sacral neural spines fused into lamina; low ilium compared to sauropods; pubis not twisted; obturator foramen absent in pubis; thick lateral margin of pubis (as contrasted to the pubic apron); plate-like ischium; fused ischial symphysis. The presence of ten dorsal vertebrae is less than the at least twelve present in Beipiaosaurus, but is unknown in other more derived therizinosaurids. Dorsal neural spine tables are also present in Falcarius and Suzhousaurus. Zanno (2008) notes there are actually six sacral vertebrae in Nanshiungosaurus, not five as described by Dong. The pubic peduncle of the ilium is neither straight nor robust. The expanded distal ischium is near certainly the obturator process and mid dorsal process as found in other therizinosaurs, with the narrow distal tip broken off.
Comments- Zanno (2008) notes much material is lost, and the pelvis is less complete than when described by Dong.
One potential problem with size estimates for this species is that both the line drawings and the plates are said to be at 1/4 size, but the plates are 1.7 times larger. The line drawing scale is correct, as shown by two pieces of evidence. First, Russell and Dong (1994) estimate Nanshiungosaurus' mass as 1.5 tons, compared to Segnosaurus' 1.9 tons. The pelvis of Segnosaurus (GM 100/80) and Nanshiungosaurus are similar in size assuming the smaller size estimate, with two other Segnosaurus specimens being slightly larger. Russell and Dong's mass estimates make sense in this case. If Nanshiungosaurus were 1.7 times larger though, it would also be 1.7 times larger than Segnosaurus' holotype. It would then be almost 5 times heavier, putting the mass estimate at over 9 tons. Second, Dong and Yu (1997) diagnosed Nanshiungosaurus? bohlini as being larger than any known segnosaur. The first dorsal vertebra in this taxon is 124 mm long. If the smaller size estimate is correct, Nanshiungosaurus brevispinus' twelfth cervical (topologically equivalent to N? bohlini's first dorsal, as the latter has two less cervicals) is 76 mm long, but if the larger estimate is correct, it is 129 mm long. This would make N. brevispinus equivalent to N? bohlini in size, clearly not what Dong thought was true when describing the latter species. Note both of the reasons involve Dong, who described Nanshiungosaurus and should therefore know its size.
The pelvis is of similar size to Enigmosaurus, Nothronychus and Segnosaurus (IGM 100/80). The width and height of the illustrated twelfth cervical and third dorsal average 85% (76-91%) of the equivalents in Nothronychus' anterior dorsal (which is one of the first three in the series). Subtracting for spaces between centra in the mounted specimen gives a cervical length of 1400 mm, a dorsal length of 730 mm and a sacral length of 680 mm. Adding 440 mm for a Segnosaurus-sized skull and 1200 mm for a Neimongosaurus-proportioned tail gives a total length of 4.45 meters.
References- Dong, 1979. The Cretaceous dinosaur fossils in southern China. In: Mesozoic and Cenozoic Red Beds in Southern China. Inst. Vert. Paleontol. Paleoanthropol. Nanjing Geol. Paleontol. Inst. Sci.. Press, Beijing. 342-350.
Russell and Dong, 1994. The affinities of a new theropod from the Alxa Desert, Inner Mongolia, People’s Republic of China. Canadian Journal of Earth Sciences. 30, 2107-2127.
Dong and Yu, 1997. A new segnosaur from Mazongshan Area, Gansu Province, China. in Dong (ed). Sino-Japanese Silk Road Dinosaur Expedition. China Ocean Press, Beijing. 90-95.
Clark, Maryanska and Barsbold, 2004. Therizinosauroidea. in In Weishampel, Dodson and Osmolska (eds). The Dinosauria Second Edition. University of California Press. 151-164.
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.

Segnosaurus Perle, 1979
S. galbinensis Perle, 1979
Cenomanian-Santonian, Late Cretaceous
Baynshiren Formation, Mongolia

Holotype- (IGM 100/80) (5.3 m; 1 ton) mandible (420 mm), basioccipital, dorsal rib fragments (lost), median gastralium (lost), sacrum, ten proximal caudal vertebrae (lost), fifteen distal caudal vertebrae (lost), incomplete humerus (lost), radius (lost), ulna (lost), phalanx II-1 (99 mm; lost), phalanx II-2 (100 mm; lost), manual ungual II (195 mm; lost), incomplete ilia (750 mm; one lost), pubes (750 mm; one lost), ischia (650 mm; one lost), incomplete femur
Paratypes- (IGM 100/82) (7.0 m; 2.4 tons) dorsal rib fragments (lost), incomplete ilia (one lost), distal pubis (lost), proximal ischium (lost), femur (~1050 mm; only shaft fragment not lost), proximal femur, tibia (860 mm, 260 wide; proximal portion lost), fibula (765 mm; lost), astragalus, calcaneum, distal tarsal III, distal tarsal IV, metatarsal I (145 mm; lost), phalanx I-1 (82 mm; lost), pedal ungual I (lost), metatarsal II (218 mm; lost), phalanx II-1 (88 mm; lost), metatarsal III (274 mm; lost), phalanx III-1 (88 mm; lost), metatarsal IV (266 mm; lost), phalanx IV-1 (51 mm; lost), metatarsal V (96 mm; lost)
(>7 m) posterior ilium
(IGM 100/83) (6.3 m; 1.8 tons) fragmentary cervical neural arch, scapulocoracoid (lost), humeri (one proximal; 560 mm), radii (335 mm), ulna (390 mm), manual ungual (lost)
Referred- (IGM 100/81) tibia, fibula, astragalus, calcaneum (Barsbold and Perle, 1980)
?(IGM coll.; field #8) fibula (Zanno, 2008)
(IGM coll.; field #93) pubis (Zanno, 2008)
Diagnosis- (after Perle, 1979) anterior dentary teeth highly linguolabially compressed; dorsoventrally compressed manual phalanges II-1 and II-2.
(after Clark et al., 1994) dentary teeth with high DSDI; at least nine pairs of elongate anterior dentary teeth.
(after Clark et al., 2004) twenty-four dentary teeth.
(after Zanno, 2008) coronoid process on surangular; humerus straight in lateral view; deep brevis fossa; pubic foot only very slightly projected posteriorly.
Other diagnoses- As this was the first recognized "segnosaur", most of Perle's (1979) original diagnostic characters are now known to have a wider distribution. Some are primitive for therizinosaurs- mandible slender; teeth small; anterior dentary teeth recurved; posterior dentary teeth lanceolate; bipedal; unreduced forelimbs; well developed deltopectoral crest; manual ungual I highly curved, pointed and transversely compressed; elongate pubic symphysis. Many are now diagnostic of more inclusive therizinosaur clades- closely packed dentary teeth; anterior dentary teeth larger than posterior teeth; posterior dentary teeth slightly recurved; posterior dentary teeth slightly labiolingually compressed; short distal caudal vertebrae; fused scapulocoracoid; ligament pits poorly developed on manual phalanges; ilia widely separated due to elongate sacral ribs and transverse processes; laterally flared preacetabular process; short postacetabular process; lateral tuberosity on postacetabular process; opisthopubic pelvis; transversely flattened ischium; distally placed obturator process; obturator process contacts pubis; astragalar ascending process laterally deflected; calcaneum fits into deep notch on astragalus; calcaneum has mobile articulation with astragalus; metatarsal I contacts tarsus; short metatarsus; metatarsals not compressed proximally. A few are too vague to evaluate- sacral ribs and transverse processes, scapulocoracoid, pelvis and metatarsus massive.
Barsbold and Perle (1980) diagnosed Segnosaurus by its thick pedal unguals, but these are plesiomorphic for therizinosaurs.
Barsbold (1983) lists the small symphyseal diastema in the dentary, but this is plesiomorphic.
Clark et al. (2004) listed six sacral vertebrae in their diagnosis, but this is also present in Nothronychus? graffami and Nanshiungosaurus.
Of Zanno's (2008) diagnostic characters, an overhanging dorsal ilial margin is present in Nothronychus? graffami (due to crushing?) and possibly Alxasaurus. A deep distodorsal ischial process is also present in Suzhousaurus and probably Nanshiungosaurus. She also lists hypertrophied distal epiphyses of the metatarsals, but there seems to be little difference between Segnosaurus and other therizinosaurs more derived than Falcarius in this regard. A subrectangular obturator process is also present in Suzhousaurus and Nothronychus? graffami. The subcircular puboischial fenestra is also present in Enigmosaurus and Suzhousaurus. A proximodistally deep obturator process is also present in Nothronychus mckinleyi and probably N? graffami. The absence of medial fusion of the obturator processes is plesiomorphic, while the absence of a fused pubic symphysis may be ontogenetic. An anteroposteriorly wide distal pubic shaft is also present in Suzhousaurus and Nothronychus? graffami. The brevis fossa may not be deeper than that of Neimongosaurus, which is described as having a "moderately developed" brevis shelf.
Comments- Currie and Eberth (1993) suggested that a few elements from the Iren Dabasu Formation (Late Campanian-Early Maastrichtian) may be referable to Segnosaurus. It is more likely these are Erliansaurus and/or Neimongosaurus.
The remains of Segnosaurus were discovered in 1973-1975, and were first illustrated and briefly described merely as "segnosaurid" by Barsbold (1979), as the official description was in press. The holotype of Segnosaurus galbinensis (IGM 100/80; mistyped 100/90 by Barsbold, 1983) includes a mandible, pelvis and forelimb and vertebral elements. Unfortunately, only the mandibular, manual and pelvic dimensions are described. Naish (online, 2007) noted a basioccipital is also present, as was shown to him by Perle, though never mentioned in the literature. Barsbold (1983) also lists carpal remains for the holotype. Zanno (2008) notes the vertebral, forelimb and hindlimb material is lost, and the pelvis is damaged. Zanno also photographs the holotype pelvis, which differs from earlier illustrations in several respects- the anterodorsal ilial margin is more rounded, the ischial peduncle of the ilium larger, the postacetabular process is rectangular and projects ventrally, the pubis is extremely concave anteriorly and expands gradually toward the boot, the distodorsal ischial process is larger, the distal ischial end is longer and narrower, and the obturator process is much larger. The pelvis is of virtually identical size to Nothronychus, suggesting this specimen was also close to 5.3 meters. A referred specimen (IGM 100/83) is a cervical neural arch, pectoral girdle and forelimb, the latter missing all manual material save an ungual. Zanno notes that the pectoral girdle and manual ungual are lost. The forelimb elements are about 20% larger than Nothronychus', so the specimen may have been about 6.3 meters long. Another possibility is that this was similar in size to the holotype, but Segnosaurus has proportionately longer arms than Nothronychus. The holotype includes comparable elements (humerus, radius, ulna), so the problem is soluble granted someone examines the remains. The second referred specimen (IGM 100/82) includes rib fragments, partial pelvis and virtually complete hindlimb. Zanno notes the ribs, most of the pelvic material, and some of the hindlimb material including the pes are lost. He also finds a posterior ilium which is not referrable to this individual catalogued under the same number. There is confusion regarding the limb element length in this specimen. Barsbold and Perle (1980) state the tibia is shorter than the femur, but cite a femoral length of 840 mm and a tibial length of 860 mm. Barsbold and Maryanska (1990) stated the tibia was "more than 80%" of femoral length. The illustration in Barsbold and Perle suggests the tibia is about 830 mm long. This is very close to the cited measurement, suggesting the latter is accurate. The femur would then be slightly less than 1075 mm in length. Comparing the hindlimb elements to other segnosaurs indicates it was approximately 7.0 meters long. Again, it's possible this was similar in size to the type, but had proportionately longer hindlimbs than Nothronychus. And again, examination of the partial pelvis the two share in common could resolve the problem. Barsbold (1983) lists IGM 100/87 and 100/88 as referred specimens, but these are probably typos for 100/82 and 100/83.
References- Barsbold, 1979. Opisthopubic pelvis in the carnivorous dinosaurs. Nature. 279, 792-793.
Perle, 1979. Segnosauridae - A new family of theropods from the Late Cretaceous of Mongolia. Sovm. Soviet-Mongolean Paleontol. Eksped. Trudy. 8, 45-55.
Barsbold and Perle, 1980. Segnosauria, a new infraorder of carnivorous dinosaurs. Acta Palaeontologica Polonica. 25, 185-195.
Barsbold, 1983. Carnivorous dinosaurs from the Cretaceous of Mongolia. Transactions of the Joint Soviet-Mongolian Palaeontological Expedition. 19, 117 pp.
Barsbold and Maryanska, 1990. Saurischia sedis mutabilis: Segnosauria. in Weishampel, Dodson and Osmolska (eds). The Dinosauria. University of California Press. 408-415.
Currie and Eberth, 1993. Palaeontology, sedimentology and palaeoecology of the Iren Dabasu Formation (Upper Cretaceous), Inner Mongolia, People’s Republic of China. Cretaceous Research. 14, 127-144.
Clark, Maryanska and Barsbold, 2004. Therizinosauroidea. in In Weishampel, Dodson and Osmolska (eds). The Dinosauria Second Edition. University of California Press. 151-164.
http://scienceblogs.com/tetrapodzoology/2007/02/therizinosauroids_and_altanger.php
Zanno, 2008. A taxonomic and phylogenetic reevaluation of Therizinosauria (Dinosauria: Theropoda): Implications for the evolution of Maniraptora. PhD Thesis. The University of Utah. 329 pp.