Coelophysidae
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Coelophysidae is a family of primitive carnivorous
theropod Theropoda (; ), whose members are known as theropods, is a dinosaur clade that is characterized by hollow bones and three toes and claws on each limb. Theropods are generally classed as a group of saurischian dinosaurs. They were ancestrally c ...
dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...
s. Most species were relatively small in size. The family flourished in the
Late Triassic The Late Triassic is the third and final epoch of the Triassic Period in the geologic time scale, spanning the time between Ma and Ma (million years ago). It is preceded by the Middle Triassic Epoch and followed by the Early Jurassic Epoch. ...
and
Early Jurassic The Early Jurassic Epoch (geology), Epoch (in chronostratigraphy corresponding to the Lower Jurassic series (stratigraphy), Series) is the earliest of three epochs of the Jurassic Period. The Early Jurassic starts immediately after the Triassic-J ...
periods, and has been found on numerous continents. Many members of Coelophysidae are characterized by long, slender skulls and light skeletons built for speed. One member genus, ''
Coelophysis ''Coelophysis'' ( traditionally; or , as heard more commonly in recent decades) is an extinct genus of coelophysid theropod dinosaur that lived approximately 228 to 201.3 million years ago during the latter part of the Triassic Period fro ...
'', displays the earliest known
furcula The (Latin for "little fork") or wishbone is a forked bone found in most birds and some species of non-avian dinosaurs, and is formed by the fusion of the two pink clavicles. In birds, its primary function is in the strengthening of the thoracic ...
in a dinosaur. Under
cladistic Cladistics (; ) is an approach to biological classification in which organisms are categorized in groups ("clades") based on hypotheses of most recent common ancestry. The evidence for hypothesized relationships is typically shared derived char ...
analysis, Coelophysidae was first defined by
Paul Sereno Paul Callistus Sereno (born October 11, 1957) is a professor of paleontology at the University of Chicago and a National Geographic "explorer-in-residence" who has discovered several new dinosaur species on several continents, including at sites ...
in 1998 as the most recent common ancestor of ''
Coelophysis bauri ''Coelophysis'' ( traditionally; or , as heard more commonly in recent decades) is an extinct genus of coelophysid theropod dinosaur that lived approximately 228 to 201.3 million years ago during the latter part of the Triassic Period fro ...
'' and '' Procompsognathus triassicus'', and all of that common ancestor's descendants. However, Tykoski (2005) has advocated for the definition to change to include the additional taxa of "Syntarsus" ''kayentakatae'' and '' Segisaurus halli''. Coelophysidae is part of the superfamily Coelophysoidea, which in turn is a subset of the larger
Neotheropoda Neotheropoda (meaning "new theropods") is a clade that includes coelophysoids and more advanced theropod dinosaurs, and is the only group of theropods that survived the Triassic–Jurassic extinction event. All neotheropods became extinct by the ...
clade. As part of Coelophysoidea, Coelophysidae is often placed as sister to the Dilophosauridae family, however, the monophyly of this clade has often been disputed. The older term "Podokesauridae", named 14 years prior to Coelophysidae (which would normally grant it priority), is now usually ignored, since its
type specimen In biology, a type is a particular specimen (or in some cases a group of specimens) of an organism to which the scientific name of that organism is formally attached. In other words, a type is an example that serves to anchor or centralizes th ...
was destroyed in a fire and can no longer be compared to new finds.Sereno, P. (1999).
Taxon Search: Coelophysidae
". Accessed 2009-09-02.


Classification


Characteristics

Coelophysids are characterized by slender, skinny builds and long, narrow skulls with large
fenestra A fenestra (fenestration; plural fenestrae or fenestrations) is any small opening or pore, commonly used as a term in the biological sciences. It is the Latin word for "window", and is used in various fields to describe a pore in an anatomical st ...
e to allow for a lighter skull. They are fairly primitive theropods, and so have fairly basal characteristics, such as hollow air sacs in the cervical vertebrae and obligate bipedalism. Their slender builds allowed them to be fast and agile runners. All known members of Coelophysidae are carnivores. One species, ''Coelophysis bauri'' has the oldest known furcula (wishbone) of any dinosaur. It has also been speculated that some species within Coelophysidae, namely ''Coelophysis bauri'', displayed cannibalism, although the fossil evidence behind these claims has been heavily debated (Rinehart et al., 2009; Gay, 2002; Gay, 2010).


Phylogenetics

Coelophysidae is part of the larger superfamily of Coelophysoidea, which contains Dilophosauridae, '' Liliensternus'', and '' Zupaysaurus'' in addition to Coelophysidae. Coelophysoidea, in turn, is part of the larger clade of Neotheropoda. Of the two major families within Coelophysoidea, Dilophosauridae and Coelophysidae, Coelophysidae is considered to be more basal. The
cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...
below was recovered in a study by Matthew T. Carrano, John R. Hutchinson and Scott D. Sampson, 2005. The cladogram below follows the topology from a 2011 analysis by paleontologists Martin D. Ezcurra and Stephen L. Brusatte, modified with additional data by You Hai-Lu and colleagues in 2014. This cladogram follows the 2017 analysis by Ezcurra, with added results of the Martinez & Apaldetti analysis from their description of ''Lucianovenator''.


Biogeography

Fossils of members of Coelophysidae have been found across many continents, including North America, South America, Europe, Asia, and Africa. '' Powellvenator podocitus'' was discovered in Northwestern Argentina. '' Procompsognathus triassicus'' was discovered in Germany, and '' Camposaurus arizonensis'' is from Arizona in North America. No coelophysid fossils were known from Asia until the discovery of '' Panguraptor lufengensis'' in 2014 in the Yunnan Province of China. The genus ''Coelophysis'' has been found in North America, South Africa, and Zimbabwe.


See also

* Timeline of coelophysoid research * Coelophysoidea *
Coelophysis bauri ''Coelophysis'' ( traditionally; or , as heard more commonly in recent decades) is an extinct genus of coelophysid theropod dinosaur that lived approximately 228 to 201.3 million years ago during the latter part of the Triassic Period fro ...


References

{{Taxonbar, from=Q868185 * Late Triassic dinosaurs Early Jurassic dinosaurs Prehistoric dinosaur families Late Triassic first appearances Early Jurassic extinctions