Coelophysis
Coelophysis (gr. "hollow form") is a genus represented by four species of coelophysid theropod dinosaur, which lived at the end of the Triassic period and in the early Jurassic, approximately 203 to 196 million years ago, from the Norian to the Pliensbachian in North America and Africa. Its generic name comes from the ancient Greek κοιλος/koilos which means "hollow" and φυσις/physis "shape". The type species, C. bauri, was described by Edward Drinker Cope in 1889. The name Rioarribasaurus is synonymous with Coelophysis. Other dinosaurs, such as Podokesaurus and Megapnosaurus, are considered synonymous with Coelophysis. Thus, the genus would be made up of the following species, Coelophysis bauri, the type species, Coelophysis rhodesiensis, originally Megapnosaurus "Syntarsus" rhodesiensis, Coelophysis kayentakatae, originally Megapnosaurus kayentakatae, and Coelophysis holyokensis, originally Podokesaurus holyokensis.
Description
C. bauri is the best known early dinosaur with a large number of complete skeletons. Its body had a graceful constitution and measured from 2.5 to 3 meters in length, reaching a meter in height at the hip. Paul in 1988 estimated the weight of the gracile form at 15 kilograms, and that of the robust form at 20 kilograms. This slender and agile bipedal carnivorous runner that lived in North America and its fossil records have been found in Arizona and in New Mexico, in the United States. Two forms of coelophysis were identified, one robust and the other gracile; at first they were considered to be two different species, but paleontologists later concluded that they were males and females of the same species, C. bauri.
Coelophysis was a slender animal in general appearance and possibly a swift runner. Despite being an early dinosaur, the evolution of theropod body shape had come a long way compared to earlier creatures like the Herrerasaurus and the Eoraptor. The torso of Coelophysis conforms to the basic theropod body shape, but the pectoral girdle shows some interesting special features in C. bauri had a furcula, the earliest known example in a dinosaur. Coelophysis also retains the ancestral condition of having four digits in the hand. It had only three functional digits, the fourth embedded in the flesh of the hand.
Coelophysis had narrow hips, forelimbs adapted for grasping, and narrow feet. Its neck and tail were long and slender. The pelvis and hindlimbs of C. bauri also have small variations from the theropod body plan. It has the open socket and straight ankle joint that define the Dinosauria. The hind limb ended in a three-toed foot, with a raised hallux. The tail had an unusual structure in the prezygapophyseal joints of its vertebrae, which formed a semi-rigid lattice, apparently allowing the tail to move only up or down. This by acting as a rudder or counterweight may have helped when the animal was maneuvering at high speed.
Coelophysishad a long, narrow head of approximately 270 millimeters, with large forward-facing eyes that gave it stereoscopic vision and, as a result, excellent depth perception. Rinehart et al. in 2004 they described the complete sclerotic ring found for a C. juvenile bauri, specimen NMMNH P-4200, and compared it with scleral ring data from reptiles and birds and concluded that Coelophysis was a diurnal predator oriented sight. The study found that the vision of Coelophysis was superior to the vision of most lizards, and comparable to that of modern birds of prey. The eyes of Coelophysis seem to be closest to those of eagles and hawks, with a high power of accommodation. The data also suggested poor night vision, which would mean that this dinosaur had a round rather than a divided pupil.
Coelophysis had an elongated snout with large windows that helped reduce the weight of the skull, while narrow bone struts preserved the skull's structural integrity. Its mouth was crowned with a large number of curved teeth, with serrated edges on the leading and trailing edges, which shows that it ate meat, probably small animals, such as the lizards that were found alongside them. it is possible that this small dinosaur lived in large herds, allowing it to hunt larger animals. The neck had a pronounced sigmoid curve, similar to that of many modern birds, which acted like a spring, giving its bite great speed.
Diagnostic Features
According to Ezcurra in 2007, and Bristowe and Raath in 2004, Coelophysis can be distinguished based on the following characteristics: the absence of a compensated rostral process of the maxilla, the quadrate being strongly caudal. a small external mandibular fenestra, which is 9–10% of the mandibular length, and the anteroposterior length of the ventral lacrimal process is greater than 30% of its height. Several paleontologists consider Coelophysis bauri to be the same dinosaur as Coelophysis rhodesiensis, formerly "Syntarsus", alternatively "Megapnosaurus", however, this has been refuted by Downs in 2000 who concluded that C. bauri differs from C. rhodesiensis in cervical length, proximal and distal hindlimb proportions, and proximal caudal vertebral anatomy. Tykoski and Rowe in 2004 concluded that C. bauri differs from C. rhodesiensis in that it lacks a pit at the base of the nasal process of the premaxilla. and Bristowe and Raath in 2004 concluded that C. bauri differs from C. rhodesiensis in having a longer maxillary tooth row.
A C. rhodesiensis it can be diagnosed by the elongation of its antorbital window to 40 percent of the skull length and by a ventral extension of the lacrimal that overlaps the jugal and reaches the alveolar margin in a condition unlike that of any other archosaur. This diagnosis was later corrected. It is significant that these characters were described from disarticulated material, because the length of the antorbital window depends on the position of the lacrimal being correctly interpreted; this interpretation also renders the maxillary row of the tooth entirely in front of the orbit, in contrast to other ceratosaurs. In addition to being one of the oldest dinosaurs that the presence of feathers has been suggested.
A C. kayetakatae, recognized by a crest on the nasolacrimals and fibula-to-calcaneus fusion in adults. The crest is similar to that of Dilophosaurus and this, together with the fact that inhabited the same territory in the Kayenta formation, has led to the belief that C. kayentakatae could have been a young Dilophosaurus. However, the skeleton type of C. kayentakatae is an adult that is more than half the size of the juvenile Dilophosaurus skeleton.
Coelophysis is a good example of how dinosaurs spread across the globe from their ancestral habitat, which was possibly South America. This small predator had the same basic features found in early dinosaurs, and its occurrence in [Africa and the southwestern US indicates that it migrated across the continents, which were then joined together at Pangea. There is differentiation at the species level between the African and North American specimens, they support the theories of migration and adaptation.
Discovery and research
Coelophysis was discovered in 1881 by David Baldwin, an amateur fossil collector working for E. D. Cope, in Triassic strata of the Chinle Formation in northwestern New Mexico, southwestern United States. Early in 1887 Cope referred the collected specimens to two new species, C. bauri and C. longicollis to the genus Coelurus named by O. C. Marsh in 1879. Later, during the same 1887, Cope reassigned the material to yet another genus, Tanystropheus. Two years later, Cope corrected his classification after noticing the differences in the vertebrae and named the genus Coelophysis with C. bauri as type species and C. longicollis refers to it, which was named after Georg Baur, a comparative anatomist whose ideas were similar to Cope's. The name Coelophysis comes from the Greek κοιλος / koilos, meaning 'hollow,' and φυσις / physis, meaning 'form', hence "hollow form& #3. 4; which is a reference to his hollow vertebrae. In 1947, George Whitaker, Edwin H. Colbert's assistant, at Ghost Ranch New Mexico, found a "bed of bones" substantial amount of Coelophysis fossils, close to the original find. American Museum of Natural History paleontologist Edwin H. Colbert conducted a comprehensive survey of all fossils found to that date and assigned them to Coelophysis. The Ghost Ranch specimens were so numerous, including many well-preserved and fully articulated specimens, that one of these has become the diagnostic, or type specimen for the entire genus, replacing the poorly preserved original specimen.
The poorly preserved early fossils do not give a complete idea of the animal's appearance. Over time, more fossils of this dinosaur have been found than any other. Thousands of Coelophysis fossils, including "bone beds," collection of many fossils of the same species in one location like those found at Ghost Ranch More than 100 Coelophysis fossil skeletons have been found in Arizona, New Mexico, and perhaps Utah. Adults and juveniles were discovered together and there are two types of adults, "robust" and "gracile" - these two forms can represent males and females of the same species.
This large concentration of specimens in one place suggests that they died at the same time in a catastrophic event. The remains found in this site lead one to believe that they were swept away by a flash flood in a mountainous area, in fact the petrified trees of the Petrified Forest National Park in Arizona were caused by a similar event. The oldest strata where Coelophysis has been discovered is the Carnian up to the Norian of the Late Triassic. Edwin H. Colbert has suggested that the ichnogenus Grallator must have been left by a Coelophysis.
Coelophysis (Syntarsus) rhodesiensis was named by Raath in 1969. Its type specimen is QG/1, a partial skeleton, and it is a three-dimensional body fossil. Its type locality is the Kwengula Stream, Southcote Farm, which occurs on a Hetangian-Sinemurian terrestrial sandstone in the Forest Sandstone Formation of Zimbabwe. It is known from at least 30 specimens from Forest Sandstone, North Matabebeland, Zimbabwe and the Upper Elliot Formation Cape Province, South Africa. The name initially given, Syntarsus, by Raath in 1969, is concerned. Piotr Węgrzynowicz of the Muzeum Ewolucji Instytutu Zoologii PAN in Warsaw discovered that the name Syntarsus had already been used for a colydiine beetle described in 1869, they proposed the name Megapnosaurus for the genus. Some paleontologists disagree with the name Megapnosaurus, which comes from the Greek μεγα = "great", απνοος = "apnea", "death", σαυρος = "lizard", considering it synonymous with Coelophysis. As early as 2004, Raath co-authored two papers in which "Syntarsus", Raath continues using the old invalid name which is taken as a more modern synonym of Coelophysis. Munyikwa and Raath in 1999, described a partial skull as "Syntarsus" (Megapnosaurus), which was tentatively reidentified as Dracovenator by Yates in 2005. Bristowe and Raath in 2004 used a partially articulated juvenile skull to demonstrate the nostril identified by Raath in 1977 it was closed in life, Raath article to the palatal backwards, and that his reconstruction of the lacrimal-jugal joint is inaccurate. They also confirmed the hyoids identified by Raath to be fuzes.
Coelophysis (Syntarsus) kayentakatae was named by Rowe in 1989. Its type specimen is MNA V2623, a partial skeleton. Its type locality is Rock Head North, and it was found in a Sinemurian-Pliensbachian dated terrestrial sandstone in the Kayenta Formation of Arizona. In 2005 Tykoski found C. Kayetakatae seemed to be more closely related to Segisaurus than to C. bauri or C. rhodesiensis. C. kayentakatae known from 16 adults and subadults has a small crest and marks an evolutionary step towards large coelophysids, such as Dilophosaurus.
The only known fossils of Coelophysis holyokesis were discovered in 1911 near Mount Holyoke College by professor of geology and geography, Mignon Talbot, who named it Podokesaurus holyokesis that same day. year. The fossil record suggests it may be a species of Coelophysis and not a separate genus, but the few records were consumed by fire and all that remains are plaster casts in the American Museum of Natural History, in New York.
Classification
Coelophysis is a distinct genus-level taxonomic unit composed of two species, C. bauri and C. rhodesiensis, the latter formerly classified as the genus Megapnosaurus. Two additional species originally described, C. longicollis and C. willistoni, are now considered synonyms of C. bauri. C. rhodesiensis is probably part of this generic complex, and is known from the Jurassic of southern Africa. A third possible species is Coelophysis kayentakatae, formerly referred to the genus Megapnosaurus. There is no clear consensus on this point.
In the early 1990s, there was debate about the diagnostic characteristics of the first specimens collected, compared to the Coelophysis material excavated at the Ghost Ranch quarry. Some paleontologists opined that the original specimens were not diagnostic beyond themselves, and therefore that the name C. bauri could not be applied to any other specimen. Therefore, they applied a different name, Rioarribasaurus, to the samples from the Ghost Ranch quarry.
Since the many well-preserved specimens from Ghost Ranch were used as Coelophysis in most scientific literature, the use of Rioarribasaurus would have been highly inconvenient for researchers, so it was requested that the type specimen of Coelophysis be transferred from the poorly preserved original specimen to one of the well-preserved Ghost Ranch specimens. This would make Rioarribasaurus a definite synonym of Coelophysis, specifically a more modern objective synonym. In the end, the International Commission on Zoological Nomenclature voted to make one of Ghost's samples Ranch to be the actual specimen type for Coelophysis and get rid of the name Rioarribasaurus entirely, declaring it to be a nomen rejectum or "rejected name", thus resolving the confusion. The name Coelophysis therefore became a nomen conservandum, "conserved name".
In a situation that affects many dinosaur taxa, some more recently discovered fossils were originally classified as new genera, but may be species of Coelophysis. For example, Professor Mignon Talbot's discovery in 1911, which she named Podokesaurus holyokensis, has long been considered related to Coelophysis, and some modern scientists consider that Podokesaurus is a synonym of Coelophysis. Another specimen from the Portland Formation of the Hartford Basin, now in the Boston Museum of Science, has also been referred to Coelophysis. This specimen consists of sandstone casts of a pubis, tibia, three ribs, and a possible vertebra, and likely originated from a quarry in Middletown, Connecticut. However, both the type specimen of Podokesaurus and the Middletown specimen are now considered indeterminate theropods.
Sullivan and Lucas in 1999 submitted a specimen of Cope's original material of Coleophysis, AMNH 2706, to what they thought was a recently discovered theropod, Eucoelophysis. However, subsequent studies have shown that Eucoelophysis has been misidentified as actually a primitive, non-dinosaur ornithodean closely related to Silesaurus.
The genus "Syntarsus" it was named by Raath in 1969 for the type species Syntarsus rhodesiensis of Africa, and later applied to the Syntarsus kayentakatae of North America. It was renamed Megapnosaurus by the American entomologist Dr. Michael Ivie of the Montana State University of Bozeman), the Polish Australian Dr. Adam Ślipiński and the Polish Dr. Piotr Węgrzynowicz of the Muzeum Ewolucji Instytutu Zoologii PAN in Warsaw the three scientists who discovered that the name of the genus Syntarsus was already taken for a collidine beetle described in 1869. Many paleontologists did not like the name Megapnosaurus, partly because taxonomists are expected to allow the original authors of a name will correct any errors in their work. Raath was aware of the homonymy between the dinosaur "Syntarsus" and the Syntarsus beetle, but the group that published Megapnosaurus believed that Raath was deceased and therefore could not correct his mistake, and proceeded accordingly. Mortimer in 2012 noted that "palaeontologists might have reacted more positively if the replacement name, Megapnosaurus, had not been a funny, which translates as " large dead lizard ". Yates (2005) analyzed Coelophysis and Megapnosaurus and concluded that the two genera are almost identical, and suggested that Megapnosaurus was possibly a synonym of Coelophysis. was a more modern synonym of Coelophysis. Megapnosaurus was considered by Paul in 1988 and Downs in 2000 to be congeneric with Coelophysis. Later, in 1993, Paul suggested that Coelophysis should be placed in Megapnosaurus, then known as "Syntarsus", to avoid the aforementioned taxonomic confusion. Downs in 2000 examined Camposaurus and concluded that it was a more modern synonym of Coelophysis, due to its similarity to some of the Ghost Ranch Coelophysis specimens. However, a reassessment of the Camposaurus holotype by Martin Ezcurra and Stephen Brusatte published in 2011 revealed a pair of autapomorphies in the holotype, indicating that Camposaurus arizonensis was not synonymous with C. bauri, although it was a close relative of C. rhodesensis.
Phylogeny
Theropod cladogram based on phylogenetic analysis by Sues et al., 2011
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Paleobiology
Food
The teeth of Coelophysis were typical of predatory dinosaurs, blade-shaped, recurved, sharp, and serrated with fine serrations on the leading and trailing edges. Its dentition shows that it was carnivorous, probably preying on small lizard-like animals that were discovered with them. It may also have hunted in packs to attack larger prey. C. bauri has approximately 26 teeth in the maxillary bone of the upper jaw and 27 teeth in the dentary bone of the lower jaw. Carpenter in 2002 examined the biomechanics of theropod forelimbs and attempted to assess their utility in predation.. He concluded that the forelimb of Coelophysis was flexible and had a good range of motion, but its bone structure suggested that it was comparatively weak. The forelimbs and small "weak" of this genus suggested that Coelophysis preyed on animals that were substantially smaller than itself. Rinehart et al. agreed that Coelophysis was a "fast-moving, small-game hunter". Carpenter also identified three distinct patterns of use of theropod forelimbs and noted that Coelophysis was a "combination entrap-cling" compared to other dinosaurs that were "cling on" or "long arms to catch".
It has been suggested that C. bauri was a cannibalistic species, based on presumed juvenile specimens found "within" from the abdominal cavities of some Ghost Ranch specimens. However, Robert J. Gay showed in 2002 that these specimens were misinterpreted. Several specimens of "Coelophysis juveniles" they were actually small crurotarsan reptiles like Hesperosuchus. Gay's position was supported in a 2006 study by Nesbitt et al.. In 2009, new evidence of cannibalism came out to light when further preparation of the previously excavated matrix revealed regurgitated material in and around the mouth of NMMNH P-44551 specimen. This material included fragments of teeth and jaw bones that Rinehart et al. considered "morphologically identical" to a juvenile Coelophysis.
In 2010, Gay examined the bones of juveniles found within the thoracic cavity of AMNH 7224, and calculated that the total volume of these bones was 17 times greater than the estimated maximum stomach volume of the juvenile. specimen of Coelophysis. Gay observed that the total volume would be even greater if one considers that there would be meat on these bones. This analysis also noted the absence of dental markings on the bones as would be expected from defatting and the absence of pitting expected from stomach acids. Finally Gay demonstrated that the supposed cannibalized juvenile bones were stratigraphically deposited below the largest animal that supposedly cannibalized them. Taken together, these data suggest that the Coelophysisel specimen AMNH 7224 was not a cannibal and that the bones of the juvenile and adult specimens were found in their final position as a result of coincidental overlapping. of individuals of different sizes".
Pack Behavior
The discovery of more than 1,000 Coelophysis specimens at the Whitaker Quarry at Ghost Ranch has suggested gregarious behavior to researchers such as Schwartz and Gillette. There is a tendency to see this large congregation of animals as evidence of large herds of Coelophysis roaming the earth. There is no direct evidence of herds, the deposits only indicate that large numbers of Coelophysis, along with other Triassic animals, they were buried together. Some of the evidence from the taphonomy of the site indicates that these animals may have gathered to feed or drink from a depleted water hole or to feed on a spawning migration of fish, then buried in a catastrophic flood or drought..
With 30 specimens of C. rhodesiensis found together in Zimbabwe some paleontologists have suggested that Coelophysis was in fact gregarious. Again, there is no evidence of herd behavior in this case and it has also been suggested that these animals were also victims of flash floods, as it appears to have been a common occurrence during this period at that location.
Development and sexual dimorphism
Rinehart in 2009 evaluated the ontogenic growth of this genus using data collected from the length of its upper leg bone, the femur, and concluded that Coelophysis juveniles grew rapidly, especially during the first year of life. Coelophysis probably reached sexual maturity between the second and third year of life and reached full size, just over 3 meters long, in its eighth year. This study identified four distinct growth stages: 1 year, 2 years, 4 years, and +7 years. It was also thought that, as soon as they were born, they would be able to fend for themselves.
Two "morphotypes" of Coelophysis, a more gracile form as in specimen AMNH 7223, and a slightly more robust form, as in specimens AMNH 7224 and NMMNH P-42200. Skeletal proportions were different between these two forms. The gracile form has a longer skull, longer neck, shorter forelimbs, and has sacral neural spines that are fused. The stout form has a shorter skull, shorter neck, longer forelimbs, and unfused sacral neural spines. Historically, it has been argued that this represents some kind of dimorphism in the Coelophysis population. probably sexual dimorphism. Raath agreed that dimorphism in Coelophysis is evidenced by the size and structure of the forelimb. Rinehart et al. studied 15 individuals, and agreed that two morphotypes were present, even in juvenile specimens, and suggested that sexual dimorphism was present early in life, before sexual maturity. Rinehart concluded that the gracile form was female and the stocky form was male based on differences in the sacral vertebrae of the gracile form, which allowed for greater flexibility for egg laying. Further support for this position was provided by a analysis showing that each morphotype comprised 50% of the population, as would be expected at a 50/50 sex ratio.
However, more recent research has found that C. bauri and C. rhodesiensis had highly variable growth between individuals, with some specimens being larger in their immature phase than smaller adults when fully mature. This indicates that the presumed presence of distinct morphotypes is simply the result of individual variation. This highly variable growth was likely ancestral to dinosaurs but later lost, and may have given early dinosaurs an evolutionary advantage in surviving harsh environmental challenges.
Playback
By compiling and analyzing a database of nearly three dozen birds and reptiles, and comparing it to existing data on the anatomy of Coelophysis Rinehart et al. in 2009 he drew the following conclusions. It was estimated that the average Coelophysis egg was 31-33.5 mm in its smallest diameter, and that each female would lay between 24-26 eggs in each clutch. Fossil remains suggest that some parental care was necessary to nurture the relatively small hatchlings during the first year of life, when they reached 1.5 meters in length by the end of their first growth stage. C. bauri invested as much energy in reproduction as other extinct reptiles of its approximate size.
Paleopathology
In a 2001 study by Bruce Rothschild and other paleontologists, 14 foot bones referred to Coelophysis were examined for signs of stress fracture, but found none. C. rhodesiensis, healed fractures of the tibia and metatarsal have been observed but are very rare. The supporting pads of the second "sacral" in a specimen of Syntarsus rhodesiensis they showed signs of fluctuating asymmetry. Fluctuating asymmetry results from developmental disturbances and is more common in populations under stress and thus can be informative about the quality of conditions in which a dinosaur lived.
Paleoecology
Distribution
Samples of Coelophysis have been recovered from the Ghost Ranch Quarry, Whitaker, in the Chinle Formation in New Mexico, and the Petrified Forest Member of the Chinle Formation in Arizona and New Mexico. At Ghost Ranch, Coelophysis was discovered in sediments deposited during the Late Triassic Norian stage, which have been dated to approximately 203 million years ago. In the Petrified Forest Member of the Chinle Formation, this genus was discovered in strata that also come from the Norian stage.
C. rhodesiensis has been recovered from the Upper Elliott Formation in the Cape and Free State Province of South Africa, as well as from the Chitake River bone quarry in the Forest Sandstone Formation in Zimbabwe.
Coelophysis kayentakatae is known from the Kayenta Formation, Rock Head, Willow Springs, Arizona, USA. It has been conjectured that this formation was deposited during the Sinemurian to Pliensbachian stages of the lower Jurassic period, that is, between 196 to 183 million years ago, approximately.
The fossil of C. holyokensis consists of a split rock found by Talbot and his sister Elly in a mound near the university.The mound consists of material deposited by ice and likely originates from the Portland Formation in Massachusetts. Originally it was believed that Podokesaurus lived during the Late Triassic Period, which was later disproven. Podokesaurus was discovered in sediments deposited during the Pliensbachian to Toarcian in the early Jurassic Period, approximately 190 and 174 million years ago.
Wildlife and habitat
Ghost Ranch was located near the equator 200 million years ago, and had a warm climate of mononic climate with strong seasonal precipitation. The Hayden quarry, a new excavation site in Ghost Ranch, New Mexico, has produced a diverse collection of fossil material that includes the first less advanced dinosaur and dinosaur test of the same period of time. The discovery indicates that the two groups lived together during the early three phase period 235 million years ago.
Therrien and Fastovsky in 2001 examined the paleoenvironment of Coelophysis and other early theropods from the Petrified Forest National Park in Arizona, and determined that this genus lived during the Late Triassic in an environment that consisted of plains alluvial areas marked by distinct dry and wet seasons. There was great competition during drier times, when animals fought for water in drying riverbeds. Archosaurs contemporaneous with Coelophysis in the Chinle Formation were the crurotarsal Revueltosaurus; the phytosaur Leptosuchus, Paleorhinus, Machaeroprosopus, Redondasaurus and possibly Rutiodon; various aetosaurids, including Acaenasuchus, Desmatosuchus, Paratypothorax, Stagonolepis, and Typothorax; the crocodilemorphs Hesperosuchus, and Parrishia; the rauisuchians Shuvosaurus, Effigia, Poposaurus, Postosuchus, and possibly Saurosuchus;the silesaurid Eucoelophysis; and the dinosaurs Chindesaurus, Camposaurus, Daemonosaurus, and Gojirasaurus. Coelophysis also lived with the archosaurimorphs Crosbysaurus, Tanytrachelos, Tecovasaurus, Trilophosaurus, and Vancleavea ; among other amniotes Acallosuchus, Colognathus, Kraterokheirodon, Placerias, and Uatchitodon; the amphibiansApachesaurus, andKoskinonodon; the fish Acrodu s, Lonchidion, Phoebodus, Reticulodus, Xenacanthus, Chinlea, Arganodus, Australosomus, Lasalichthyes, and Turseodus.
The Upper Elliot Formation is believed to have been a former floodplain. Fossils of the prosauropod dinosaur Massospondylus and Ignavusaurus have been recovered from the same formation, which boasts the world's most diverse fauna of early Jurassic ornithischian dinosaurs, including Abrictosaurus, Fabrosaurus, Heterodontosaurus and Lesothosaurus, among others. The Forest Sandstone Formation was a paleoenvironment with protosuchid crocodiles, sphenodonts, the Massospondylus dinosaur, and the indeterminate remains of a prosauropod. Paul in 1988 noted that C. rhodesiensis lived among the dunes and oases of the desert and hunted juvenile and adult prosauropods.
In the Kayenta Formation, vertebrates are known from both fossil body parts and footprints. Known vertebrates include hybodont sharks, indeterminate bony fishes, lungfishes, salamanders, the frog Prosalirus, the caecilian Eocaecilia, the turtle Kayentachelys i>, a sphenodont reptile, lizards, various primitive crocodylomorphs including Calsoyasuchus, Eopneumatosuchus, Kayentasuchus and Protosuchus), the pterosaur Rhamphinion, various theropods such as Dilophosaurus, Kayentavenator and the so-called "Shake N Bake theropod", the sauropodomorph Sarahsaurus, a heterodontosaurid, the armored dinosaurs Scelidosaurus and Scutellosaurus, the tritylodontid synapsids Dinnebiton, Kayentatherium and Oligokyphus, morganucodontids, the possible true mammal Dinnetherium, and a haramid mammal. Most of these finds come from the vicinity of Gold Spring, Arizona. The other vertebrate fossils consist of coprolites and the tracks of therapsids, lizard-like animals, and various types of dinosaurs.
Taphonomy
The multitude of specimens deposited so close at Ghost Ranch were likely the result of a flash flood, which washed away large numbers of Coelophysis and buried them quickly and at the same time. In fact, it appears that such flooding was common during this period of Earth's history, and in fact the Petrified Forest of nearby Arizona is the result of a log jam of preserved tree trunks that became trapped in a of those floods. Whitaker's quarry at Ghost Ranch is considered a monotaxonomic site because it contains multiple individuals of a single taxon. The quality of preservation and the ontogenic range, ages, of the specimens helped make Coelophysis one of the best-known genera. In 2009, Rinehart et al. observed that in In one case Coelophysis specimens were "washed to a low topographic level containing a small pond, where they probably drowned and were buried by a flood phenomenon from a nearby river". The 30 specimens of C. rhodesiensis found together in Zimbabwe were also likely the result of a flash flood, which washed away a large number of Coelophysis and buried them quickly and simultaneously as well.
The Kayenta Formation, in northeastern Arizona. The Kayenta Formation is part of the Glen Canyon Group group that includes formations not only from northern Arizona but also from southeastern Utah, western Colorado, and northwestern New Mexico. This is mainly composed of two facies, one dominated by silty depositions and the other dominated by sandstones. The siltstone facies occurs in most of Arizona, while the sandstone facies occurs in areas of Arizona, Utah, Colorado, and New Mexico. The formation was deposited mainly by rivers, with the siltstone facies being the slowest part of the fluvial system. Deposition of the Kayenta Formation was terminated by the encroaching field of dunes that would become the Navajo Sandstone.
Technology
Edwin H. Colbert has suggested that theropod tracks referring to the ichnogenus Grallator, located in the Connecticut River valley through Connecticut and Massachusetts, may have been made by Coelophysis. The tracks are from the Late Triassic to Early Jurassic in the Newark Supergroup. They clearly show the digits II III and IV but not I or V. That condition is rare for prints of its age. The digits were supposed to be stubby and ineffective, not touching the ground when the dinosaur was walking or running. David B. Weishampel and L. Young more recently concluded that they were from an unidentified primitive saurischian similar to Coelophysis. Skeletal remains similar to Coelophysis have also been found in the valley., which supports the idea that a species similar to Coelophysis is responsible for the tracks.
The dinosaur footprints most commonly attributed to C. rhodesiensis were discovered in Rhodesia in 1915. These footprints were discovered in the Nyamandhlovu Sandstone Formation, in red Aeolian sandstone that was deposited in the Late Triassic approximately 235 to 201 million years ago.
In popular culture
Coelophysis was the second dinosaur in space, following Maiasaura specimen STS-51-F. A Coelophysis skull from the Museum Carnegie's Natural History was aboard the space shuttle STS-89 mission STS-89 when it left the atmosphere on January 22, 1998. It was also taken to the Mir space station before being returned to Earth.
Being over 100 years old, Coelophysis is one of the best-known dinosaurs in literature. It was designated as the official state fossil of New Mexico, and is now the logo of the New Mexico Museum of Natural History. Coelophysis bauri also became a New Mexico state fossil in 1981.
Coelophysis also appeared in the first episode of the BBC series Walking with Dinosaurs where, along with other extinct species, they were recreated using CGI animation and animatronics.
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