Tetanurae

 Skeletal mount of Monolophosaurus jiangi, copyright Kabacchi.

Belongs within: Neotheropoda.
Contains: Megalosauroidea, Allosauroidea, Coelurosauria.

The clade Tetanurae includes all theropods more closely related to birds than to Ceratosaurus. The name of the clade refers to the development of a stiffened tail; members of the clade are also characterised by the loss of an external fourth digit on the hand. The clade is first definitely recorded from the beginning of the Middle Jurassic (Rauhut 2005).

Most basal members of the Tetanurae are large carnivorous species, the ‘carnosaurs’ of earlier authors. However, Chilesaurus diegosuarezi from the Late Jurassic (Tithonian) of Chile is a smaller herbivorous form (Novas et al. 2015); this species could be described as superficially similar to one of the basal sauropodomorphs. Other basal tetanurans include Condorraptor currumili and Piatnitzkysaurus floresi from the Middle Jurassic (Callovian) of Argentinean Patagonia, and Marshosaurus bicentesimus from the Late Jurassic (Kimmeridgian) of Utah (Holtz et al. 2004; Rauhut 2005); Piatnitzkysaurus is known from a relatively complete skeleton whereas Condorraptor and Marshosaurus are known from more fragmentary remains. Monolophosaurus jiangi from the Middle Jurassic of China is also known from a complete skull and pelvis and much of the vertebral column; this species is characterised by a distinctive hollow crest along the dorsal midline of the skull (Holtz et al. 2004). The Allosauroidea and Coelurosauria are united in a clade Avetheropoda to the exclusion of megalosauroids by several features including the presence of palatine recesses, an expanded ectopterygoid, laterally displaced zygapophyses on the cervical vertebrae, a widely open ventral floor to the pelvic canal, and L-shaped haemal arches in at least the distal half of the tail (Holtz et al. 2004).

Synapomorphies (from Novas et al. 2015): Metacarpal I closely appressed to proximal half of metacarpal II; metacarpal IV absent; antitrochanter posterior to acetabulum absent or poorly developed; brevis fossa narrow and with subparallel margins; femur with ratio between maximum transverse width of the distal end and total length of the bone of 0.20-0.25; femoral head horizontally directed; well-developed extensor groove present on anterior side of distal femur; tibia with lateral condyle of the proximal end anteriorly displaced from the posterior margin of the medial condyle but well on the posterior half of the bone in proximal view; tibia with deep and broad notch separating the posterior condyles of the proximal end; ridge on lateral side of tibia for connection with fibula present and clearly separated from proximal articular surface.

<==Tetanurae [Allosaurinae, Avipoda, Carnosauria, Eustreptospondylidae, Eustreptospondylinae, Torvosauridae, Torvosauroidea]
    |--Chilesaurus Novas, Salgado et al. 2015NS15
    |    `--*C. diegosuarezi Novas, Salgado et al. 2015NS15
    |--Chuandongocoelurus primitivus He 1984 (n. d.)RF12, HMC04
    `--+--+--Xuanhanosaurus Dong 1984RF12, HMC04
       |  |    `--X. qilixiaensis Dong 1984HMC04
       |  `--+--Marshosaurus Madsen 1976OES10, HMC04
       |     |    `--M. bicentesimus Madsen 1976HMC04
       |     `--+--Condorraptor Rauhut 2005NS15, R05
       |        |    `--*C. currumili Rauhut 2005R05
       |        `--Piatnitzkysaurus Bonaparte 1979NS15, HMC04
       |             `--P. floresi Bonaparte 1979HMC04
       `--+--MegalosauroideaNS15
          `--+--Monolophosaurus Zhao & Currie 1993NS15, HMC04
             |    `--M. jiangi Zhao & Currie 1993HMC04
             `--Avetheropoda [Allosauria, Dryptosauridae, Neotetanurae]HMC04
                  |  i. s.: Ozraptor Long & Molnar 1998HMC04
                  |           `--O. subotaii Long & Molnar 1998HMC04
                  |         Quilmesaurus Coria 2001HMC04
                  |           `--Q. curriei Coria 2001HMC04
                  |         Valdoraptor Olshevsky 1991HMC04
                  |           `--V. oweni (Lydekker 1889) [=Megalosaurus oweni]HMC04
                  |--AllosauroideaHMC04
                  `--CoelurosauriaHMC04
Tetanurae incertae sedis:
  Becklespinax Olshevsky 1991HMC04
    `--B. altispinax (Paul 1988) [=Acrocanthosaurus altispinax]HMC04
  Kaijiangosaurus He 1984HMC04
    `--K. lini He 1984HMC04
  Sigilmassaurus Russell 1996 [Sigilmassauridae]HMC04
    `--S. brevicollis Russell 1996HMC04
  ‘Zanclodon’ cambrensis Newton 1899HMC04
  Chienkosaurus ceratosauroides (Young 1942) (n. d.)HMC04
  Dandakosaurus indicus Yadagiri 1982 (n. d.)HMC04
  Embasaurus minax Riabinin 1931 (n. d.)HMC04
  Inosaurus tedreftensis Lapparent 1960 (n. d.)HMC04
  Betasuchus Huene 1932 (n. d.)HMC04
    `--*B. bredai (Seeley 1883) [=Megalosaurus bredai]HMC04
  Scrotum humanum Brookes 1763 (n. d.)HMC04
  Siamosaurus suteethorni Buffetaut & Ingavat 1986 (n. d.)HMC04
  Sinocoelurus fragilis Young 1942 (n. d.)HMC04
  Teinurosaurus Nopcsa 1928HMC04, O69 [=Caudocoelus Huene 1932HMC04]
    `--*T. sauvagei (Huene 1932) (n. d.)O69 [=*Caudocoelus sauvageiHMC04]
  Wakinosaurus satoi Okazaki 1992 (n. d.)HMC04
  Walgettosuchus woodwardi Huene 1932 (n. d.) [=Magnosaurus woodwardi]HMC04
  Shidaisaurus jinaeP10

*Type species of generic name indicated

References

[HMC04] Holtz, T. R., Jr, R. E. Molnar & P. J. Currie. 2004. Basal Tetanurae. In: Weishampel, D. B., P. Dodson & H. Osmólska (eds) The Dinosauria 2nd ed. pp. 71–110. University of California Press: Berkeley.

[NS15] Novas, F. E., L. Salgado, M. Suárez, F. L. Agnolin, M. D. Ezcurra, N. R. Chimento, R. de la Cruz, M. P. Isasi, A. O. Vargas & D. Rubilar-Rogers. 2015. An enigmatic plant-eating theropod from the Late Jurassic period of Chile. Nature 522: 331–334.

[OES10] Ortega, F., F. Escaso & J. L. Sanz. 2010. A bizarre, humped Carcharodontosauria (Theropoda) from the Lower Cretaceous of Spain. Nature 467: 203–206.

[O69] Ostrom, J. H. 1969. Osteology of Deinonychus antirrhopus, an unusual theropod from the Lower Cretaceous of Montana. Bulletin of the Peabody Museum of Natural History 30: 1–165.

[P10] Paul, G. S. 2010. Dinosaurs: A Field Guide. A & C Black.

[R05] Rauhut, O. W. M. 2005. Osteology and relationships of a new theropod dinosaur from the Middle Jurassic of Patagonia. Palaeontology 48 (1): 87–110.

[RF12] Rauhut, O. W. M., C. Foth, H. Tischlinger & M. A. Norell. 2012. Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany. Proceedings of the National Academy of Sciences of the USA 109 (29): 11746–11751.

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