Tetanurae, or "stiff tails", is a
cladeA clade is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants.[The term "monophyletic group" is used in this article...]
that includes most theropod dinosaurs, as well as
birdBirds are winged, bipedal, endothermic , vertebrate animals that lay eggs. There are around 10,000 living species, making them the most numerous tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Birds range in size from the Bee Hummingbird to the ...
s. Tetanurans (or tetanurines) first appear during the early or middle
JurassicThe Jurassic is a geologic period and system that extends from about Ma to Ma, 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
Tetanurae meaning "stiff tails", was named by
Jacques GauthierJacques Armand Gauthier is a vertebrate paleontologist, comparative morphologist, and systematist, and one of the founders of the use of cladistics in biology....
on
cladisticCladistics is a form of biological systematics which classifies living organisms on the basis of shared ancestry...
grounds in 1986 for a large group of
theropodTheropods are a group of bipedal saurischian dinosaurs. Although they were primarily carnivorous, a number of theropod families evolved herbivory during the Cretaceous Period...
dinosaurs. Gauthier's paper was the first serious application of the science of
cladisticsCladistics is a form of biological systematics which classifies living organisms on the basis of shared ancestry...
to
vertebrate paleontologyVertebrate paleontology seeks 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
theropodsTheropods are a group of bipedal saurischian dinosaurs. Although they were primarily carnivorous, a number of theropod families evolved herbivory during the Cretaceous Period...
more closely related to modern birds than to
CeratosaurusCeratosaurus meaning 'horned lizard', in reference to the horn on its nose , was a large predatory dinosaur from the Late Jurassic Period , found in the Morrison Formation of North America, in Tanzania and Portugal...
(e.g.
PadianKevin 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
CarnosauriaCarnosauria 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
CoelurosauriaCoelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. It is a diverse group that includes tyrannosaurs, ornithomimosaurs, and maniraptors; Maniraptora includes birds, the only descendents of coelurosaurs alive today...
, although many of what he considered
carnosaursCarnosauria 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
coelurosaursCoelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. It is a diverse group that includes tyrannosaurs, ornithomimosaurs, and maniraptors; Maniraptora includes birds, the only descendents of coelurosaurs alive today...
or
basalIn 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 SerenoPaul Callistus Sereno is an American paleontologist who is the discoverer of several new dinosaur species on several continents...
(1999) named
Neotetanurae for the node joining
CarnosauriaCarnosauria 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
AllosauroideaAllosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Sinraptoridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae...
) and
CoelurosauriaCoelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. It is a diverse group that includes tyrannosaurs, ornithomimosaurs, and maniraptors; Maniraptora includes birds, the only descendents of coelurosaurs alive today...
, excluding other tetanurans such as
spinosauroidsSpinosauroidea is a superfamily of tetanuran theropod dinosaurs that lived from the Middle Jurassic to the Late Cretaceous period. It is likely that megalosaurs are a family within this group.- Systematics :...
. 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 was a large theropod dinosaur, with a bizarre crest on its head that looked like a Spanish comb...
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
dilophosauridsDilophosauridae 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 created 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
TriassicThe Triassic is a geologic period and system that extends from about 251 to 199 Ma . 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
cladeA clade is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants.[The term "monophyletic group" is used in this article...]
of advanced theropods together.
Large, predatory
spinosauridsSpinosauridae 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 JurassicThe Jurassic is a geologic period and system that extends from about Ma to Ma, 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 CretaceousThe Cretaceous , Latin language for "chalky", 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 on the Jurassic period and is followed by the Paleogene period of the...
, especially in
GondwanaGondwana , originally Gondwanaland, is the name given to a southern precursor-supercontinent. Its final joining occurred between ca. 570 and 510 Ma ago, joining East Gondwana to West Gondwana. It later separated from Laurasia 180- during the breakup of the Pangaea supercontinent that existed about...
, but seem to have died out before the end of the
CretaceousThe Cretaceous , Latin language for "chalky", 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 on the Jurassic period and is followed by the Paleogene period of the...
, possibly due to competition from
abelisauridAbelisauridae 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...
ceratosaursCeratosaurs 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
tyrannosauridTyrannosauridae 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...
coelurosaursCoelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. It is a diverse group that includes tyrannosaurs, ornithomimosaurs, and maniraptors; Maniraptora includes birds, the only descendents of coelurosaurs alive today...
. The diverse
coelurosaursCoelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs. It is a diverse group that includes tyrannosaurs, ornithomimosaurs, and maniraptors; Maniraptora includes birds, the only descendents of coelurosaurs alive today...
persisted until the end of the
Mesozoic EraThe Mesozoic Era is one of three geologic eras of the Phanerozoic eon. The division of time into eras dates back to Giovanni Arduino, in the 18th century, although his original name for the era now called the "Mesozoic" was "Secondary" The Mesozoic Era is one of three geologic eras of the...
, when all except for crown clade avians died out. Modern birds are the only living representatives of the clade Tetanurae.
Popular tetanurans
Many popular dinosaurs are tetanurans, including
AllosaurusAllosaurus is a genus of large theropod dinosaur that lived 155 to 145 million years ago, in the late Jurassic period . The name Allosaurus means "different lizard" and is derived from the Greek αλλος/allos and σαυρος/sauros...
,
OviraptorOviraptor is a genus of small Mongolian theropod dinosaur, first discovered by the legendary paleontologist Roy Chapman Andrews, and first described by Henry Fairfield Osborn, in 1924...
,
SpinosaurusSpinosaurus is a genus of theropod dinosaur which lived in what is now North Africa, sometime during the Albian and Cenomanian stages of the Cretaceous period, about 112 to 93.5 million years ago. This genus was first known from Egyptian remains discovered in the 1910s and described by...
,
TyrannosaurusTyrannosaurus was a genus of 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 tyrannosaurids...
,
VelociraptorVelociraptor is a genus of dromaeosaurid theropod dinosaur that existed approximately 75 to 71 mya during the later part of the Cretaceous Period. Only two species are currently recognized, although others have been assigned in the past. The type species is V...
, as well as the ancient bird
ArchaeopteryxArchaeopteryx, sometimes referred to by its German name Urvogel , is the earliest and most primitive bird known...
and all species of modern birds. The first
MesozoicThe Mesozoic Era is one of three geologic eras of the Phanerozoic eon. The division of time into eras dates back to Giovanni Arduino, in the 18th century, although his original name for the era now called the "Mesozoic" was "Secondary" The Mesozoic Era is one of three geologic eras of the...
dinosaur to be named was
Megalosaurus bucklandiiMegalosaurus is a genus of large meat-eating theropod dinosaurs of the Middle Jurassic period of Europe...
, a
basalIn 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.