Tetanurae

Tetanurans Temporal range: Early Jurassic–Present, 201–0 Ma PreЄ Є O S D C P T J K Pg N
Skull of Sinosaurus triassicus
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Order:	Saurischia
Suborder:	Theropoda
Clade:	Averostra
Clade:	Tetanurae Gauthier, 1986
Subgroups[1][2]
†Chilesaurus[3] †Sinosaurus †Cryolophosaurus? †Chuandongocoelurus †Monolophosaurus †Cruxicheiros?[4] †Kaijiangosaurus? Orionides
Synonyms
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 Monolophosaurus jiangi

Tetanurae meaning "stiff tails", was named by Jacques Gauthier in 1986 for a large group of theropod dinosaurs.^[5] Gauthier's paper was the first serious application of the science of cladistics to vertebrate paleontology.

Tetanurae is defined as all theropods more closely related to modern birds than to Ceratosaurus.^[6] Gauthier originally classified two main groups within the larger group Tetanurae: Carnosauria and Coelurosauria. However, many of what he considered carnosaurs have been since been re-classified as coelurosaurs or primitive tetanurans by later research.^[7]

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.

Classification

The cladogram presented below follows a phylogenetic analysis published by Zanno and Makovicky in 2013.^[8]

References