Tetanurae

Tetanurans
Thời điểm hóa thạch: Late Triassic–Present, 201–0 triệu năm trước đây TiềnЄ Є O S D C P T J K Pg N
Skeleton of the basalmost tetanuran, Sinosaurus triassicus
Keel-billed Toucan perched on a branch
Phân loại khoa học
Subgroups
†Sinosaurus †Cryolophosaurus †Chuandongocoelurus †Monolophosaurus †Cruxicheiros? †Kaijiangosaurus? Orionides
Danh pháp đồng nghĩa
Avipoda Novas, 1992

Tetanurae, or "stiff tails", is a clade that includes most theropod dinosaurs, including birds. Tetanurans (or tetanurines) first appear during the early or middle Jurassic Period.

Definition

Illustration of a megalosauroid (Monolophosaurus)

Tetanurae meaning "stiff tails", was named by Jacques Gauthier on cladistic grounds in 1986 for a large group of theropod dinosaurs. Gauthier's paper was the first serious application of the science of cladistics to vertebrate paleontology.

Tetanurae are defined as all theropods more closely related to modern birds than to Ceratosaurus (e.g. Padian et al., 1999). Gauthier considered it to consist of Carnosauria and Coelurosauria, although many of what he considered carnosaurs have been regarded as coelurosaurs or basal tetanurans by subsequent workers (but see Rauhut, 2003). Paul Sereno (1999) named Neotetanurae for the node joining Carnosauria (his Allosauroidea) and Coelurosauria, excluding other tetanurans such as megalosauroids. Padian et al. (1999) gave a synonymous definition for Gregory Paul's (1988) Avetheropoda, but this definition was published slightly later.

Classification

The cladogram presented below follows a phylogenetic analysis published by Zanno and Makovicky in 2013.

Tetanurae	Cryolophosaurus     Sinosaurus       Chuandongocoelurus     Monolophosaurus   Orionides Megalosauroidea   Piatnitzkysauridae   Megalosauria   Spinosauridae     Megalosauridae       Avetheropoda   Coelurosauria   Allosauroidea   Metriacanthosauridae   Allosauria   Allosauridae   Carcharodontosauria   Neovenatoridae     Carcharodontosauridae

Range

It is not entirely clear where the origins of Tetanurae are. Cryolophosaurus has been claimed as the first true member of the group (although this identification has been disputed and Cryolophosaurus may be closer to the dilophosaurids). Even if Cryolophosaurus was a tetanuran, this leaves no true tetanuran fossils from the Triassic, when the group should have originated based on the presence of coelophysoids (if the old definition of Ceratosauria is used). This gives heavier validity to the more recent view of tetanurans and ceratosaurs sharing a common ancestor and forming a clade of advanced theropods together.

Large, predatory spinosaurids and allosaurids flourished during the Late Jurassic and Early Cretaceous, especially in Gondwana, but seem to have died out before the end of the Cretaceous, possibly due to competition from abelisaurid ceratosaurs and tyrannosaurid coelurosaurs. The diverse coelurosaurs persisted until the end of the Mesozoic Era, when all except for crown clade avians died out. Modern birds are the only living representatives of the clade Tetanurae.

References

• Gauthier, J. A. (1986). “Saurischian monophyly and the origin of birds”. Trong Padian, K. (biên tập). The Origin of Birds and the Evolution of Flight, Memoirs of the California Academy of Sciences. 8. California Academy of Sciences. tr. 1–55. ISBN 0-940228-14-9 http://books.google.com/books?id=B1d0QgAACAAJ. Truy cập ngày 25 tháng 9 năm 2010.
• Padian, K.; Hutchinson, R. M.; Holtz, T.R. Jr. (1999). “Phylogenetic definitions and nomenclature of the major taxonomic categories of the carnivorous Dinosauria (Theropoda)”. Journal of Vertebrate Paleontology. 19 (1): 69–80. doi:10.1080/02724634.1999.10011123.
• Paul, G. S. (1988). Predatory Dinosaurs of the World. New York: Simon and Schuster. ISBN 0-671-61946-2.
• Rauhut, O. W. M. (2003). The interrelationships and evolution of basal theropod dinosaurs. Special Papers in Palaeontology. 69. Wiley. ISBN 0-901702-79-X.
• Sereno, P. C. (1999). “The evolution of dinosaurs”. Science. 284 (5423): 2137–2147. doi:10.1126/science.284.5423.2137. PMID 10381873.