Tetanurae
Encyclopedia
Tetanurae, or "stiff tails", is a clade
that includes most theropod dinosaurs, as well as bird
s. Tetanurans (or tetanurines) first appear during the early or middle Jurassic
Period.
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.
has been claimed as the first true member of the group (although this identification has been disputed and Cryolophosaurus now appears to 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.
, Oviraptor
, Spinosaurus
, Tyrannosaurus
, Velociraptor
, as well as the ancient bird Archaeopteryx
and all species of modern birds. The first Mesozoic
dinosaur to be named was Megalosaurus bucklandii
, a basal
tetanuran.
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
that includes most theropod dinosaurs, as well as bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
s. Tetanurans (or tetanurines) first appear during the early or middle Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
Period.
Definition
Jacques Gauthier
Jacques Armand Gauthier is a vertebrate paleontologist, comparative morphologist, and systematist, and one of the founders of the use of cladistics in biology....
on cladistic
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
grounds in 1986 for a large group of theropod
Theropoda
Theropoda is both a suborder of bipedal saurischian dinosaurs, and a clade consisting of that suborder and its descendants . Dinosaurs belonging to the suborder theropoda were primarily carnivorous, although a number of theropod groups evolved herbivory, omnivory, and insectivory...
dinosaurs. Gauthier's paper was the first serious application of the science of cladistics
Cladistics
Cladistics is a method of classifying species of organisms into groups called clades, which consist of an ancestor organism and all its descendants . For example, birds, dinosaurs, crocodiles, and all descendants of their most recent common ancestor form a clade...
to vertebrate paleontology
Vertebrate paleontology
Vertebrate paleontology is a large subfield to paleontology seeking to discover the behavior, reproduction and appearance of extinct animals with vertebrae or a notochord, through the study of their fossilized remains...
.
Tetanurae are defined as all theropods
Theropoda
Theropoda is both a suborder of bipedal saurischian dinosaurs, and a clade consisting of that suborder and its descendants . Dinosaurs belonging to the suborder theropoda were primarily carnivorous, although a number of theropod groups evolved herbivory, omnivory, and insectivory...
more closely related to modern birds than to Ceratosaurus
Ceratosaurus
Ceratosaurus meaning "horned lizard", in reference to the horn on its nose , was a large predatory theropod dinosaur from the Late Jurassic Period , found in the Morrison Formation of North America, in Tanzania and Portugal...
(e.g. Padian
Kevin Padian
Kevin Padian is a Professor of Integrative Biology at the University of California, Berkeley, Curator of Paleontology, University of California Museum of Paleontology and President of the National Center for Science Education. Padian's area of interest is in vertebrate evolution, especially the...
et al., 1999). Gauthier considered it to consist of Carnosauria
Carnosauria
Carnosauria is a group of large predatory dinosaurs that lived during the Jurassic and Cretaceous periods. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin...
and Coelurosauria
Coelurosauria
Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. In the past, it was used to refer to all small theropods, although this classification has been abolished...
, although many of what he considered carnosaurs
Carnosauria
Carnosauria is a group of large predatory dinosaurs that lived during the Jurassic and Cretaceous periods. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin...
have been regarded as coelurosaurs
Coelurosauria
Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. In the past, it was used to refer to all small theropods, although this classification has been abolished...
or basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
tetanurans by subsequent workers (but see Rauhut, 2003). Paul Sereno
Paul Sereno
Paul Callistus Sereno is an American paleontologist from the University of Chicago who discovered several new dinosaur species on several continents. He has conducted excavations at sites as varied as Inner Mongolia, Argentina, Morocco, and Niger...
(1999) named Neotetanurae for the node joining Carnosauria
Carnosauria
Carnosauria is a group of large predatory dinosaurs that lived during the Jurassic and Cretaceous periods. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin...
(his Allosauroidea
Allosauroidea
Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Sinraptoridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae...
) and Coelurosauria
Coelurosauria
Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. In the past, it was used to refer to all small theropods, although this classification has been abolished...
, excluding other tetanurans such as megalosauroids
Megalosauroidea
Megalosauroidea is a group of tetanuran theropod dinosaurs that lived from the Middle Jurassic to the Late Cretaceous period.-Classification:...
. Padian et al. (1999) gave a synonymous definition for Gregory Paul's (1988) Avetheropoda, but this definition was published slightly later.
Range
It is not entirely clear where the origins of Tetanurae are. CryolophosaurusCryolophosaurus
Cryolophosaurus was a large theropod dinosaur, with a crest on its head that looked like a Spanish comb. Due to the resemblance of this feature to Elvis Presley's pompadour haircut from the 1950s, this dinosaur was at one point informally known as "Elvisaurus".Cryolophosaurus was excavated from...
has been claimed as the first true member of the group (although this identification has been disputed and Cryolophosaurus now appears to be closer to the dilophosaurids
Dilophosauridae
Dilophosauridae is a family of early carnivorous dinosaurs. They are well-known for their distinctive head crests, which were probably used for mating displays, or to intimidate rivals. The family was proposed by Alan Charig and Andrew Milner in 1990 to contain only the type genus, Dilophosaurus...
). Even if Cryolophosaurus was a tetanuran, this leaves no true tetanuran fossils from the Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
, 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
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
of advanced theropods together.
Large, predatory spinosaurids
Spinosauridae
Spinosauridae is a family of specialised theropod dinosaurs. Members of this family were large, bipedal predators with elongated, crocodile-like skulls, sporting conical teeth with no or only very tiny serrations. The front dentary teeth fanned out, giving the animal a characteristic look...
and allosaurids flourished during the Late Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
and Early Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
, especially in Gondwana
Gondwana
In paleogeography, Gondwana , originally Gondwanaland, was the southernmost of two supercontinents that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago . Gondwana is believed to have sutured between ca. 570 and 510 Mya,...
, but seem to have died out before the end of the Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...
, possibly due to competition from abelisaurid
Abelisauridae
Abelisauridae is a family of ceratosaurian theropod dinosaurs. Abelisaurids thrived during the Cretaceous Period, on the ancient southern supercontinent of Gondwana, and today their fossil remains are found on the modern continents of Africa and South America, as well as on the Indian...
ceratosaurs
Ceratosauria
Ceratosaurs are members of a group of theropod dinosaurs defined as all theropods sharing a more recent common ancestry with Ceratosaurus than with birds. There is presently no universally agreed upon listing of species or diagnostic characters of Ceratosauria, though they were less derived...
and tyrannosaurid
Tyrannosauridae
Tyrannosauridae is a family of coelurosaurian theropod dinosaurs which comprises two subfamilies containing up to six genera, including the eponymous Tyrannosaurus. The exact number of genera is controversial, with some experts recognizing as few as three...
coelurosaurs
Coelurosauria
Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. In the past, it was used to refer to all small theropods, although this classification has been abolished...
. The diverse coelurosaurs
Coelurosauria
Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. In the past, it was used to refer to all small theropods, although this classification has been abolished...
persisted until the end of the Mesozoic Era
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
, when all except for crown clade avians died out. Modern birds are the only living representatives of the clade Tetanurae.
Classification
- Tetanurae
- †CruxicheirosCruxicheirosCruxicheiros is a genus of tetanuran theropod dinosaur which lived in the Middle Jurassic of England. The type species is C. newmanorum, described by Roger Benson and Jonathan Radley in 2010.-Discovery:...
- †GasosaurusGasosaurusGasosaurus was a tetanuran dinosaur discovered in Dashanpu, China. The scientific name, meaning "Gas Lizard", honours the gasoline company that found the Dashanpu fossil quarry in Sichuan Province, now named as the Lower Shaximiao Formation. It had strong legs but short arms, and like most...
- †KaijiangosaurusKaijiangosaurusKaijiangosaurus is the name given to a genus of dinosaur from the Middle Jurassic. It was a theropod like Megalosaurus. Its fossils, fragmentary remains of the skull, cervical vertebrae and elements of the pectoral girdle and both limbs, were found in China...
- †KayentavenatorKayentavenatorKayentavenator is a small carnivorous dinosaur genus which lived during the Early Jurassic Period; fossils were recovered from the Kayenta Formation of northeastern Arizona and were described in 2010.-Description:...
- †ShidaisaurusShidaisaurusShidaisaurus is a genus of basal tetanuran theropod dinosaur. Its fossil was found in early Middle Jurassic-age rocks of the Upper Lufeng Formation in Yunnan, China. It is known from a partial skeleton, holotype DML-LCA 9701-IV, found at the bottom of an assemblage of nine dinosaur individuals,...
- †SzechuanosaurusSzechuanosaurusSzechuanosaurus is a dubious genus of theropod dinosaur from the Late Jurassic. This dinosaur lived in the Asia in the Oxfordian and early Kimmeridgian . It is based on four undiagnostic teeth from the Shangshaximiao Formation.-Discovery and species:Three species have been assigned to this genus...
- †XuanhanosaurusXuanhanosaurusXuanhanosaurus is a genus of theropod dinosaur which lived during the Jurassic of China.The type species Xuanhanosaurus qilixiaensis was named by Dong Zhiming in 1984. The generic name refers to Xuanhan County in Sichuan. The specific name is derived from the town of Qilixia...
- †Megalosauroidea [=Spinosauroidea]
- †Megalosauridae
- †SpinosauridaeSpinosauridaeSpinosauridae is a family of specialised theropod dinosaurs. Members of this family were large, bipedal predators with elongated, crocodile-like skulls, sporting conical teeth with no or only very tiny serrations. The front dentary teeth fanned out, giving the animal a characteristic look...
- Avetheropoda
- †AllosauroideaAllosauroideaAllosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Sinraptoridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae...
(see also CarnosauriaCarnosauriaCarnosauria is a group of large predatory dinosaurs that lived during the Jurassic and Cretaceous periods. While it originally contained a wide assortment of giant theropods that were not closely related, the group has since been defined to encompass only the allosaurs and their closest kin...
)- †Allosauridae
- †CarcharodontosauridaeCarcharodontosauridaeCarcharodontosaurids were a group of carnivorous theropod dinosaurs. In 1931 Ernst Stromer named Carcharodontosauridae as a family, in modern paleontology this name indicates a clade within Carnosauria...
- †NeovenatoridaeNeovenatoridaeNeovenatoridae is a family of large carnivorous dinosaurs. The group is a branch of the allosauroids, a large group of carnosaurs that also includes the sinraptorids, carcharodontosaurids, and allosaurids...
- †SinraptoridaeSinraptoridaeSinraptorids were a family of carnivorous theropod dinosaurs. They tended to be large predators, some growing to sizes of . Sinraptorids are carnosaurs, and many were initially classified within Megalosauridae or Allosauridae prior to recent analysis...
- CoelurosauriaCoelurosauriaCoelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. In the past, it was used to refer to all small theropods, although this classification has been abolished...
(incl. Aves)
- †Allosauroidea
- †Cruxicheiros
Popular tetanurans
Many popular dinosaurs are tetanurans, including AllosaurusAllosaurus
Allosaurus is a genus of large theropod dinosaur that lived 155 to 150 million years ago during the late Jurassic period . The name Allosaurus means "different lizard". It is derived from the Greek /allos and /sauros...
, Oviraptor
Oviraptor
Oviraptor is a genus of small Mongolian theropod dinosaur, first discovered by the paleontologist Roy Chapman Andrews, and first described by Henry Fairfield Osborn, in 1924...
, Spinosaurus
Spinosaurus
Spinosaurus is a genus of theropod dinosaur which lived in what is now North Africa, from the lower Albian to lower Cenomanian stages of the Cretaceous period, about 112 to 97 million years ago. This genus was first known from Egyptian remains discovered in 1912 and described by German...
, Tyrannosaurus
Tyrannosaurus
Tyrannosaurus meaning "tyrant," and sauros meaning "lizard") is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex , commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other...
, Velociraptor
Velociraptor
Velociraptor is a genus of dromaeosaurid theropod dinosaur that existed approximately 75 to 71 million years ago during the later part of the Cretaceous Period. Two species are currently recognized, although others have been assigned in the past. The type species is V. mongoliensis; fossils...
, as well as the ancient bird Archaeopteryx
Archaeopteryx
Archaeopteryx , sometimes referred to by its German name Urvogel , is a genus of theropod dinosaur that is closely related to birds. The name derives from the Ancient Greek meaning "ancient", and , meaning "feather" or "wing"...
and all species of modern birds. The first Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
dinosaur to be named was Megalosaurus bucklandii
Megalosaurus
Megalosaurus is a genus of large meat-eating theropod dinosaurs of the Middle Jurassic period of Europe...
, a basal
Basal (phylogenetics)
In phylogenetics, a basal clade is the earliest clade to branch in a larger clade; it appears at the base of a cladogram.A basal group forms an outgroup to the rest of the clade, such as in the following example:...
tetanuran.