Coelophysoidea

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Coelophysoids
Temporal range: Late Triassic-Early Jurassic, 228–183  Ma
Coelophysis bauri mount.jpg
Mounted skeleton of Coelophysis bauri , Cleveland Museum of Natural History
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Neotheropoda
Superfamily: Coelophysoidea
Nopcsa, 1928
Type species
Coelurus bauri
Cope, 1887
Subgroups
Synonyms
  • Podokesauroidea Huene, 1914

Coelophysoidea is an extinct clade of theropod dinosaurs common during the Late Triassic and Early Jurassic periods. They were widespread geographically, probably living on all continents. Coelophysoids were all slender, carnivorous forms with a superficial similarity to the coelurosaurs, with which they were formerly classified, and some species had delicate cranial crests. Sizes range from about 1 to 6 m in length. It is unknown what kind of external covering coelophysoids had, and various artists have portrayed them as either scaly or feathered. Some species may have lived in packs, as inferred from sites where numerous individuals have been found together.

Contents

Examples of coelophysoids include Coelophysis , Procompsognathus and Liliensternus . Most dinosaurs formerly referred to as being in the dubious taxon "Podokesauridae" are now classified as coelophysoids. The family Coelophysidae, which is contained within Coelophysoidea, flourished in the Late Triassic and Early Jurassic periods, and has been found on numerous continents. Many members of Coelophysidae are characterized by long, slender skulls and light skeletons built for speed. [1] One member genus, Coelophysis , displays the earliest known furcula in a dinosaur. [2]

History of Study

Under cladistic analysis, Coelophysidae was first defined by Paul Sereno in 1998 as the most recent common ancestor of Coelophysis bauri and Procompsognathus triassicus , and all of that common ancestor's descendants. [1] However, Tykoski (2005) has advocated for the definition to change to include the additional taxa of "Syntarsus" kayentakatae and Segisaurus halli . [3] Coelophysidae is part of the superfamily Coelophysoidea, which in turn is a subset of the larger Neotheropoda clade. [1] As part of Coelophysoidea, Coelophysidae is often placed as sister to the Dilophosauridae family, however, the monophyly of this clade has often been disputed. [1] The older term "Podokesauridae", named 14 years prior to Coelophysidae (which would normally grant it priority), is now usually ignored, since its type specimen was destroyed in a fire and can no longer be compared to new finds. [4]

Anatomy

Skull diagrams of various coelophysoids Coelophysidae.png
Skull diagrams of various coelophysoids

Despite their very early occurrence in the fossil record, coelophysoids have a number of derived features that separate them from primitive (basal) theropods. Among the most prominent of these derived features (apomorphies) is the way the upper jaw bones are connected (the premaxilla-maxilla articulation), which is flexible with a deep gap between the teeth in the two bones. A major source of disagreement among theropod experts is whether or not coelophysoids shared a more recent common ancestor with Ceratosauria (sensu stricto) than the ceratosaurs did with other theropods. Most recent analyses indicate the latter, that Coelophysoidea does not form a natural group with the ceratosaurians. Similarly, while Dilophosaurus and similar theropods have traditionally been classified as coelophysoids, several studies published in the late 2000s suggested that they may actually be more closely related to the tetanurans. [5]

Coelophysids are characterized by slender, skinny builds and long, narrow skulls with large fenestrae to allow for a lighter skull. [6] They are fairly primitive theropods, and so have fairly basal characteristics, such as hollow air sacs in the cervical vertebrae and obligate bipedalism. [6] 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. [2]

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). [7] [8] [9]

Classification

Coelophysoids are classifed as basal neotheropods that lie outside of Averostra. [10]

Cladogram from Ezcurra et al. 2020: [10]

Theropoda  
Coelophysis, restored with speculative feathers, compared to a human Coelophysis size.jpg
Coelophysis, restored with speculative feathers, compared to a human
A life reconstruction of an Early Jurassic ecosystem, with several coelophysoids in the foreground Ciechocinek Formation Reconstruction.jpg
A life reconstruction of an Early Jurassic ecosystem, with several coelophysoids in the foreground

The cladogram below was recovered in a study by Matthew T. Carrano, John R. Hutchinson and Scott D. Sampson, 2005. [11]

Coelophysoidea

The cladogram below was recovered in a study by Ezcurra et al. (2020). [10]

Coelophysoidea

Paleoecology

Life reconstruction of several coelophysoids in their environment Coelophysids and Peteinosaurus.jpg
Life reconstruction of several coelophysoids in their environment

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. [12] Procompsognathus triassicus was discovered in Germany, and Camposaurus arizonensis is from Arizona in North America. [13] [14] No coelophysid fossils were known from Asia until the discovery of Panguraptor lufengensis in 2014 in the Yunnan Province of China. [15] The genus Coelophysis has been found in North America, South Africa, and Zimbabwe. [16]

See also

Related Research Articles

<i>Coelophysis</i> Genus of theropod dinosaurs from the late Triassic

Coelophysis is a genus of coelophysid theropod dinosaur that lived approximately 215 to 208.5 million years ago during the Late Triassic period from the middle to late Norian age in what is now the southwestern United States. Megapnosaurus was once considered to be a species within this genus, but this interpretation has been challenged since 2017 and the genus Megapnosaurus is now considered valid.

<i>Procompsognathus</i> Extinct genus of dinosaurs

Procompsognathus is an extinct genus of coelophysid theropod dinosaur that lived approximately 210 million years ago during the later part of the Triassic Period, in what is now Germany. Procompsognathus was a small-sized, lightly built, ground-dwelling, bipedal carnivore, that could grow up to 1 m (3.3 ft) long.

<i>Saltriovenator</i> Extinct genus of dinosaurs

Saltriovenator is a genus of ceratosaurian dinosaur that lived during the Sinemurian stage of the Early Jurassic in what is now Italy. The type and only species is Saltriovenator zanellai; in the past, the species had been known under the informal name "saltriosaur". Although a full skeleton has not yet been discovered, Saltriovenator is thought to have been a large, bipedal carnivore similar to Ceratosaurus.

<i>Segisaurus</i> Extinct genus of dinosaurs

Segisaurus is a genus of small coelophysid theropod dinosaur, that measured approximately 1 metre in length. The only known specimen was discovered in early Jurassic strata in Tsegi Canyon, Arizona, for which it was named. Segisaurus is the only dinosaur to have ever been excavated from the area.

<i>Gojirasaurus</i> Extinct genus of dinosaurs

Gojirasaurus is a potentially dubious genus of coelophysoid theropod dinosaur named after the giant monster movie character Godzilla.

Podokesaurus is a genus of coelophysoid dinosaur that lived in what is now the eastern United States during the Early Jurassic Period. The first fossil was discovered by the geologist Mignon Talbot near Mount Holyoke, Massachusetts, in 1910. The specimen was fragmentary, preserving much of the body, limbs, and tail. In 1911, Talbot described and named the new genus and species Podokesaurus holyokensis based on it. The full name can be translated as "swift-footed lizard of Holyoke". This discovery made Talbot the first woman to find and describe a non-bird dinosaur. The holotype fossil was recognized as significant and was studied by other researchers, but was lost when the building it was kept in burned down in 1917; no unequivocal Podokesaurus specimens have since been discovered. It was made state dinosaur of Massachusetts in 2022.

<i>Sarcosaurus</i> Extinct genus of dinosaurs

"Sarcosaurus" is a genus of basal neotheropod dinosaur, roughly 3.5 metres (11 ft) long. It lived in what is now England and maybe Ireland and Scotland during the Hettangian-Sinemurian stages of the Early Jurassic, about 199-196 million years ago. "Sarcosaurus" is one of the earliest known Jurassic theropods, and one of only a handful of theropod genera from this time period. Along with "Dracoraptor hanigani" it is one of the two described neotheropods from the lowermost Jurassic of the United Kingdom.

<i>Sinosaurus</i> Genus of dinosaurs

Sinosaurus is an extinct genus of theropod dinosaur which lived during the Early Jurassic Period. It was a bipedal carnivore approximately 5.5 metres (18 ft) in length and 300 kilograms (660 lb) in body mass. Fossils of the animal were found at the Lufeng Formation, in the Yunnan Province of China.

<i>Zupaysaurus</i> Extinct genus of dinosaurs

Zupaysaurus is an extinct genus of early theropod dinosaur living during the Norian stage of the Late Triassic in what is now Argentina. Fossils of the dinosaur were found in the Los Colorados Formation of the Ischigualasto-Villa Unión Basin in northwestern Argentina. Although a full skeleton has not yet been discovered, Zupaysaurus can be considered a bipedal predator, up to 4 metres (13 ft) long. It may have had two parallel crests running the length of its snout.

<i>Camposaurus</i> Extinct genus of dinosaurs

Camposaurus is a coelophysid dinosaur genus from the Norian stage of the Late Triassic period of North America. The pertinent fossil remains date back to the early to middle Norian stage, and is widely regarded as the oldest known neotheropod.

Lophostropheus is an extinct genus of coelophysoid theropod dinosaur that lived approximately 205.6 to 196.5 million years ago during the boundary between the Late Triassic Period and the Early Jurassic Period, in what is now Normandy, France. Lophostropheus is one of the few dinosaurs that may have survived the Triassic–Jurassic extinction event.

<i>Tawa hallae</i> Extinct species of dinosaur

Tawa is a genus of possible basal theropod dinosaurs from the Late Triassic period. The fossil remains of Tawa hallae, the type and only species were found in the Hayden Quarry of Ghost Ranch, New Mexico, US. Its discovery alongside the relatives of Coelophysis and Herrerasaurus supports the hypothesis that the earliest dinosaurs arose in Gondwana during the early Late Triassic period in what is now South America, and radiated from there around the globe. The specific name honours Ruth Hall, founder of the Ghost Ranch Museum of Paleontology.

Kayentavenator is a genus of small carnivorous tetanuran dinosaur that lived during the Early Jurassic Period; fossils were recovered from the Kayenta Formation of northeastern Arizona and were described in 2010.

<i>Daemonosaurus</i> Genus of reptiles (fossil)

Daemonosaurus is an extinct genus of possible theropod dinosaur from the Late Triassic of New Mexico. The only known fossil is a skull and neck fragments from deposits of the latest Triassic Chinle Formation at Ghost Ranch. Daemonosaurus was an unusual dinosaur with a short skull and large, fang-like teeth. It lived alongside early neotheropods such as Coelophysis, which would have been among the most common dinosaurs by the end of the Triassic. However, Daemonosaurus retains several plesiomorphic ("primitive") traits of the snout, and it likely lies outside the clade Neotheropoda. It may be considered a late-surviving basal theropod or non-theropod basal saurischian, possibly allied to other early predatory dinosaurs such as herrerasaurids or Tawa.

<i>Megapnosaurus</i> Extinct genus of dinosaur

Megapnosaurus is an extinct genus of coelophysid theropod dinosaur that lived approximately 188 million years ago during the early part of the Jurassic Period in what is now Africa. The species was a small to medium-sized, lightly built, ground-dwelling, bipedal carnivore, that could grow up to 2.2 m (7.2 ft) long and weigh up to 13 kg (29 lb). It was originally given the genus name Syntarsus, but that name was later determined to be preoccupied by a beetle. The species was subsequently given a new genus name, Megapnosaurus, by Ivie, Ślipiński & Węgrzynowicz in 2001. Some studies have classified it as a species within the genus Coelophysis, but this interpretation has been challenged by more subsequent studies and the genus Megapnosaurus is now considered valid.

<i>Coelophysis</i>? <i>kayentakatae</i> Extinct species of dinosaur

Coelophysis? kayentakatae is an extinct species of neotheropod dinosaur that lived approximately 200–196 million years ago during the early part of the Jurassic Period in what is now the southwestern United States. It was originally named Syntarsus kayentakatae, but the genus Syntarsus was found to be preoccupied by a Colydiine beetle, so it was moved to the genus Megapnosaurus, and then to Coelophysis. A recent reassessment suggests that this species may require a new genus name.

Panguraptor is a genus of coelophysid theropod dinosaur known from fossils discovered in Lower Jurassic rocks of southern China. The type and only known species is Panguraptor lufengensis. The generic name refers to the deity Pangu but also to the supercontinent Pangaea for which in a geological context the same characters are used: 盘古. Raptor means "seizer", "robber" in Latin. The specific name is a reference to the Lufeng Formation. The holotype specimen was recovered on 12 October 2007 from the Lufeng Formation of Yunnan, which is noted for sauropodomorph fossils. It was described in 2014 by You Hai-Lu and colleagues.

<span class="mw-page-title-main">Timeline of coelophysoid research</span>

This timeline of coelophysoid research is a chronological listing of events in the history of paleontology focused on the coelophysoids, a group of primitive theropod dinosaurs that were among Earth's dominant predators during the Late Triassic and Early Jurassic epochs. Although formally trained scientists didn't discover coelophysoid fossils until the late 19th century, Native Americans of the modern southwestern United States may have already encountered their fossils. Navajo creation mythology describes the early Earth as being inhabited by a variety of different kinds of monsters who hunted humans for food. These monsters were killed by storms and the heroic Monster Slayers, leaving behind their bones. As these tales were told in New Mexico not far from bonebeds of Coelophysis, this dinosaur's remains may have been among the fossil remains that inspired the story.

Lepidus is a genus of extinct theropod from the Upper Triassic of the United States. It lived in the Otis Chalk localities of the Dockum Group in Texas, around 223 million years ago.

<i>Lucianovenator</i> Extinct genus of dinosaurs

Lucianovenator is an extinct genus of coelophysid theropod dinosaur which lived in Argentina during the Triassic. The genus name Lucianovenator translates to "Luciano's hunter", in reference to Don Luciano Leyes, who first reported the remains. The species name bonoi refers to Tulio del Bono, a local scientific authority who collaborated on the describers' research. It is one of the few neotheropods known from South America.

References

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  2. 1 2 Rinehart, L.F.; Lucas, S.G.; Hunt, A.P. (2007). "Furculae in the Late Triassic theropod dinosaur Coelophysis bauri". Paläontologische Zeitschrift. 81 (2): 174–180. doi:10.1007/BF02988391.
  3. Tykoski, Ronald S. (2005). Anatomy, Ontogeny, and Phylogeny of Coelophysoid Theropods (PhD). University of Texas at Austin.
  4. Sereno, P. (1999). "Taxon Search: Coelophysidae Archived 2007-10-07 at the Wayback Machine ". Accessed 2009-09-02.
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Sources