Coelophysoidea
Encyclopedia
Coelophysoids were common dinosaur
s of 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.
Well-known 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.
-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 the Dilophosauridae
has traditionally been included in Coelophysoidea, studies published in the late 2000s suggested that they may actually be more closely related to the tetanurans
.
The cladogram
below was recovered in a study by Martin D. Ezcurra and Gilles Cuny, 2007.
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...
s of the Late 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...
and Early 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...
periods. They were widespread geographically, probably living on all continents. Coelophysoids were all slender, carnivorous
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
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
Feathered dinosaurs
The realization that dinosaurs are closely related to birds raised the obvious possibility of feathered dinosaurs. Fossils of Archaeopteryx include well-preserved feathers, but it was not until the early 1990s that clearly non-avialan dinosaur fossils were discovered with preserved feathers...
. Some species may have lived in packs, as inferred from sites where numerous individuals have been found together.
Well-known examples of coelophysoids include Coelophysis
Coelophysis
Coelophysis , meaning "hollow form" in reference to its hollow bones , is one of the earliest known genera of dinosaur...
, Procompsognathus
Procompsognathus
Procompsognathus is a genus of small theropod dinosaur that lived during the late Triassic period , about 210 million years ago. Procompsognathus was named by Eberhard Fraas in 1913. He named the type species, P...
and Liliensternus
Liliensternus
Liliensternus was a genus of coelophysoid dinosaur from the Late Triassic period, about 205 Ma.Liliensternus was originally named in 1934 by Friedrich von Huene as a second species of Halticosaurus, H. liliensterni, the specific name honouring the German amateur paleontologist, Dr...
. Most dinosaurs formerly referred to as being in the dubious taxon "Podokesauridae" are now classified as coelophysoids.
Classification
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 premaxillaPremaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....
-maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...
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
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...
(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 the Dilophosauridae
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...
has traditionally been included in Coelophysoidea, studies published in the late 2000s suggested that they may actually be more closely related to the tetanurans
Tetanurae
Tetanurae, or "stiff tails", is a clade that includes most theropod dinosaurs, as well as birds. Tetanurans first appear during the early or middle Jurassic Period.-Definition:...
.
Taxonomy
- Superfamily Coelophysoidea
- ?DolichosuchusDolichosuchusDolichosuchus is the name given to a genus of dinosaur from the Triassic. It was originally classified in the disused family Hallopodidae, but has been reclassified as a coelophysoid. A single fossil was found in Germany. Since only one bone was discovered, the genus is considered a nomen dubium...
- ?GojirasaurusGojirasaurusGojirasaurus is a dubious genus of dinosaur named after the giant monster movie character Gojira . It was discovered in the Bull Canyon Formation...
- LiliensternusLiliensternusLiliensternus was a genus of coelophysoid dinosaur from the Late Triassic period, about 205 Ma.Liliensternus was originally named in 1934 by Friedrich von Huene as a second species of Halticosaurus, H. liliensterni, the specific name honouring the German amateur paleontologist, Dr...
- LophostropheusLophostropheusLophostropheus was a genus of coelophysoid dinosaur from the Rhaetian-Hettangian stage border Moon-Airel Formation of Normandy, France. It is based on a partial skeleton first described in 1966 as a specimen of Halticosaurus...
- ?SarcosaurusSarcosaurusSarcosaurus is a genus of theropod dinosaur, either a coelophysoid or a basal ceratosaur, roughly 3.5 meters long. It lived during the Sinemurian stage of the Early Jurassic, about 194 million years ago....
- Family CoelophysidaeCoelophysidaeThe Coelophysidae are a family of primitive carnivorous theropod dinosaurs. Most species were relatively small in size. The family flourished in the Late Triassic and Early Jurassic periods....
- PodokesaurusPodokesaurusPodokesaurus was a small carnivorous dinosaur of the Early Jurassic Period , and as such is one of the earliest known dinosaurs to inhabit the eastern United States . The small, bipedal carnivore was about 90 cm long and 0.3 m tall...
- ProcompsognathusProcompsognathusProcompsognathus is a genus of small theropod dinosaur that lived during the late Triassic period , about 210 million years ago. Procompsognathus was named by Eberhard Fraas in 1913. He named the type species, P...
- ?PterospondylusPterospondylusPterospondylus is a dubious genus of theropod dinosaur from the Late Triassic. It was a coelophysoid theropod which lived in what is now Germany . The type species, Pterospondylus trielbae, was described by Jaekel in 1913-14 for a single back vertebra...
- SegisaurusSegisaurusSegisaurus is a genus of small coelophysoid theropod dinosaur, that measured approximately 1 metre in length. The only known specimen was discovered in 1933 in early Jurassic strata in Tsegi Canyon, Arizona, for which it was named. Segisaurus is the only dinosaur to have ever been excavated from...
- Subfamily Coelophysinae
- CamposaurusCamposaurusCamposaurus is a coelophysoid dinosaur genus from the Late Triassic of North America. With fossils dating back to the early to middle Norian stage, it is the oldest known neotheropod. It is known from partial lower leg bones, holotype UCMP 34498, and other fragmentary material...
- CoelophysisCoelophysisCoelophysis , meaning "hollow form" in reference to its hollow bones , is one of the earliest known genera of dinosaur...
- MegapnosaurusMegapnosaurusMegapnosaurus was a dinosaur of the theropod family Coelophysidae, formerly called Syntarsus , living during the Early Jurassic. It was renamed by American entomologist Dr. Michael Ivie , Polish Australian Dr...
- Camposaurus
- Podokesaurus
- ?Family Halticosauridae
- ?Subfamily Halticosaurinae
- ?HalticosaurusHalticosaurusHalticosaurus is a genus of theropod dinosaur from the Late Triassic period . It was a coelophysoid found in the Middle Stubensandstein formation of what is present-day Germany...
- ?Halticosaurus
- ?Subfamily Halticosaurinae
- ?Dolichosuchus
The cladogram
Cladogram
A cladogram is a diagram used in cladistics which shows ancestral relations between organisms, to represent the evolutionary tree of life. Although traditionally such cladograms were generated largely on the basis of morphological characters, DNA and RNA sequencing data and computational...
below was recovered in a study by Martin D. Ezcurra and Gilles Cuny, 2007.
External links
- Coelophysoidea and Podokesauridae at DinoData.