Gojirasaurus | |
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Scale and skeletal diagram | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Clade: | Dinosauria |
Clade: | Saurischia |
Clade: | Theropoda |
Genus: | † Gojirasaurus Carpenter, 1997 |
Species: | †G. quayi |
Binomial name | |
†Gojirasaurus quayi Carpenter, 1997 | |
Synonyms | |
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Gojirasaurus (meaning "Godzilla lizard") [1] is a genus of "coelophysoid" theropod dinosaur from the Late Triassic of New Mexico. It is named after the giant monster movie character Godzilla (Hepburn: Gojira), and contains a single species, Gojirasaurus quayi.
Gojirasaurus quayi was described and named by Kenneth Carpenter in 1997 based on a partial skeleton, the holotype specimen UCM 47221, from Quay County, New Mexico. The holotype is an assortment of various postcranial bones, including a right scapula, right pubis, left tibia, left metatarsal V, [2] four vertebral centra, a neural arch, and fragments of ribs and gastralia. [1] In addition, a single large serrated tooth is associated with the postcranial material. The holotype is housed in the collections of the University of Colorado Museum of Natural History, in Boulder, Colorado. [1]
The specimen hails from purplish-grey mudstones of the Bull Canyon Formation (sometimes called the Cooper Canyon Formation), a major fossiliferous component of the Dockum Group in eastern New Mexico. In particular, it was found at a site in the vicinity of Revuelto Creek, the type locality for the Revueltian "faunachron". [3] The Revueltian is a biostratigraphic unit roughly equivalent to the mid-late Norian stage of the Triassic Period, approximately 215–207 million years ago. [4] The Revuelto Creek fossils were deposited in the earlier part of the Revueltian, close to around 212 million years ago. [5]
Though it would not be formally named until 1997, the fossils of Gojirasaurus were frequently mentioned through the 1980s and 1990s, as a robust Coelophysis-like theropod from Revuelto Creek. [6] [7] Among these preliminary accounts is a short description by Parrish & Carpenter (1986). [8] In 1994, an unpublished thesis by Adrian Hunt attempted to name the Revuelto Creek theropod as "Revueltoraptor lucasi". Hunt's conception of the species included not just UCM 47221, but also numerous theropod-like fossils stored at the NMMNH (New Mexico Museum of Natural History and Science). As a name, "Revueltoraptor lucasi" was never formally published, and later evaluations recognized that most of Hunt's additional fossils are likely from Shuvosaurus rather than theropods. [1]
The generic name Gojirasaurus is derived from the name of the giant Japanese movie monster "Gojira" (Godzilla) and the Greek word "sauros" (σαυρος) meaning "lizard"; [9] thus, "Godzilla lizard". Carpenter (1997) selected "Gojira" in reference to the relatively large size of this theropod, which exceeded that of its Triassic counterparts. The specific name quayi, is a reference to Quay County. [1]
Gojirasaurus is one of the largest theropods known from the Triassic Period, with an estimate total length of 5.5–6 metres (18–20 ft) long and a weight of at least 150 kilograms (330 lb). [1] [10] Benson et al. (2018) estimated that it weighed around 190 kilograms (420 lb), only exceeded by Herrerasaurus among Triassic carnivorous dinosaurs. [11] Carpenter (1997) pointed to features of the pelvis and ankle suggesting that this was an immature individual, and could therefore have grown to even a larger size in maturity. [1] Christopher T. Griffin (2019) and Griffin and Nesbitt (2020) confirmed that Gojirasaurus possessed features indicative of ontogenetic immaturity. [2] [12]
According to Nesbitt et al. (2007), Gojirasaurus can be distinguished based on the fact that its tibia is more robust than that of its relative Coelophysis . Rauhut (2003) attempted to diagnose this genus based on the fact that the mid/posterior dorsal vertebrae had taller neural spines than those observed in other coelophysoids. [13]
Griffin (2019) followed Nesbitt (2007)'s diagnosis on Gojirasaurus and distinguishes it from Megapnosaurus and Dilophosaurus based on several characteristics of metatarsal V. [2]
Parrish and Carpenter (1986) drew similarities between UCM 47221 and "Halticosaurus liliensterni", a large German theropod now known as Liliensternus . Both were assigned to the family "Procompsognathidae", though the authors acknowledged that family names in use at the time were provisional and likely to be obsolete in the future. [8] Conversely, Hunt (1994) and Hunt et al. (1998) [14] argued that the specimen is a herrerasaurid, alongside various other fossils from the Late Triassic of North America. [15] [16] The formal naming and description of Gojirasaurus by Carpenter (1997) firmly classified it within Coelophysoidea. Many traits were comparable to Coelophysis, Dilophosaurus, and particularly Liliensternus. [1]
Various phylogenetic analyses in the 2000s supported coelophysoid affinities for Gojirasaurus, close to or among the smaller Coelophysidae rather than with Dilophosaurus. [13] [17] [18] [19] [20] Many studies noted that its remains are too fragmentary for further elaboration. Starting with Yates (2005), the monophyly of Coelophysoidea has been brought into question, with Dilophosaurus resolving as more closely related to averostrans (non-coelophysoid theropods). [18] In some analyses, Gojirasaurus maintains its position among the coelophysids, [18] but other studies instead bring it over to the lineage leading to Dilophosaurus and averostrans. [21] [22] [23]
A persistent question regarding Gojirasaurus quayi is how much of its fossil material actually belongs to one species. [15] Gojirasaurus coexisted with Shuvosaurus, an unusual reptile with a toothless beak and bipedal stance. Though previously regarded as an aberrant dinosaur, by 2007 most specialists agreed that Shuvosaurus was actually more closely related to crocodilians, and that its dinosaur-like traits are merely convergent. [24] According to Nesbitt et al. (2007), some components of UCM 47221, such as the tibia and pubis, are clearly coelophysoid in form and distinct from Shuvosaurus. [15] However, other parts of the skeleton, such as the scapula and vertebrae, are not readily distinguishable from Shuvosaurus. [15] The serrated tooth could be from any number of large carnivorous archosaurs which inhabited the area. [15]
Even the assuredly coelophysoid components of the skeleton have few unambiguous unique features. For example, the robust tibia is similar to Coelophysis-like fossils which Padian (1986) described from Petrified Forest National Park in Arizona, only differing in size. [25] [15] [16] Several studies regard Gojirasaurus as a "metataxon": a collection of fossils for which assignment to a single species can neither be proven nor disproven. [13] [15] Nevertheless, Gojirasaurus persists in the scientific literature as a useful example of a large Triassic coelophysoid, validity notwithstanding. [11] [2] [12]
Gojirasaurus's assignment to the Coelophysoidea would suggest that it was a bipedal, terrestrial, actively mobile carnivore.
The Revuelto Creek area preserves a diverse fauna of both terrestrial and aquatic animals from the Bull Canyon Formation. [6] [8] [7] [26] On land, herbivorous pseudosuchians are quite common, including the shuvosaurid Shuvosaurus inexpectatus , [26] the aetosaurs Typothorax coccinarum , [7] [26] Paratypothorax , [7] and Rioarribasuchus , [27] and the small aetosauriform Revueltosaurus callenderi . [28] Both Shuvosaurus and Revueltosaurus have previously been misidentified as dinosaurs. [7] [26]
Among terrestrial carnivores, Gojirasaurus was joined by at least a few other true dinosaurus. Bull Canyon dinosaur fragments are sometimes identified as coelophysids, herrerasaurids, [26] and/or Chindesaurus , [7] but most are too fragmentary to assess in great detail. [15] [2] [5] Lepidosauromorphs, crocodylomorphs, and large carnivorous "rauisuchians" are also represented by rare fragments. [26] Particularly robust archosauromorph limb fragments, previously thought to be from a late-surviving rhynchosaur (" Otischalkia "), [7] [26] are probably from malerisaurine azendohsaurids instead. [29] The early turtle Chinlechelys tenertesta is a notable component of the terrestrial fauna. [30] [31]
Phytosaur fossils are common at Revuelto Creek. One particularly impressive phytosaur skull was initially referred to "Rutiodon" (Smilosuchus) gregorii , [6] [8] and later to "Arribasuchus" buceros. [7] It and other Bull Canyon phytosaur remains most likely belong to a species of Machaeroprosopus (Pseudopalatus). [26] [32] Small metoposaurid amphibians, sometimes identified as " Apachesaurus gregorii ", [7] [26] frequent the area alongside larger metoposaurids. [6] [26] Various fish inhabited the waterways: arganodontid lungfish, coelacanths ( Quayia zideki ), and actinopterygians. [6] [26]
Dilophosaurus is a genus of theropod dinosaurs that lived in what is now North America during the Early Jurassic, about 186 million years ago. Three skeletons were discovered in northern Arizona in 1940, and the two best preserved were collected in 1942. The most complete specimen became the holotype of a new species in the genus Megalosaurus, named M. wetherilli by Samuel P. Welles in 1954. Welles found a larger skeleton belonging to the same species in 1964. Realizing it bore crests on its skull, he assigned the species to the new genus Dilophosaurus in 1970, as Dilophosaurus wetherilli. The genus name means "two-crested lizard", and the species name honors John Wetherill, a Navajo councilor. Further specimens have since been found, including an infant. Fossil footprints have also been attributed to the animal, including resting traces. Another species, Dilophosaurus sinensis from China, was named in 1993, but was later found to belong to the genus Sinosaurus.
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.
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.
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.
Effigia was an extinct genus of shuvosaurid known from the Late Triassic of New Mexico, south-western USA. With a bipedal stance, long neck, and a toothless beaked skull, Effigia and other shuvosaurids bore a resemblance to the ornithomimid dinosaurs of the Cretaceous Period. However, shuvosaurids were not dinosaurs, but were instead a specialized family of poposauroid pseudosuchians, meaning that their closest living relatives are crocodilians.
Revueltosaurus is an extinct genus of suchian pseudosuchian from Late Triassic deposits of New Mexico, Arizona and North Carolina, United States. Many specimens, mostly teeth, have been assigned to Revueltosaurus over the years. Currently, three species are included in this genus, all of which were originally thought to represent monospecific genera of basal ornithischian dinosaurs. Revueltosaurus was about 1 meter long.
Shuvosaurus is a genus of beaked, bipedal poposauroid pseudosuchian from the Late Triassic of western Texas. Despite superficially resembling a theropod dinosaur, especially the ostrich-like ornithomimids, it is instead more closely related to living crocodilians than to dinosaurs. Shuvosaurus is known by the type and only species S. inexpectatus, and is closely related to the very similar Effigia within the clade Shuvosauridae. Shuvosaurus was originally described from a restored skull and very few fragmentary postcranial bones as a probable ornithomimosaur, or at least a very ornithomimosaur-like early theropod. The true pseudosuchian affinities of Shuvosaurus were only recognised after the discovery of Effigia linked the skull of Shuvosaurus with similar poposauroid skeletal remains found in the same quarry.
Chindesaurus is an extinct genus of basal saurischian dinosaur from the Late Triassic of the southwestern United States. It is known from a single species, C. bryansmalli, based on a partial skeleton recovered from Petrified Forest National Park in Arizona. The original specimen was nicknamed "Gertie", and generated much publicity for the park upon its discovery in 1984 and airlift out of the park in 1985. Other fragmentary referred specimens have been found in Late Triassic sediments throughout Arizona, New Mexico, and Texas, but these may not belong to the genus. Chindesaurus was a bipedal carnivore, approximately as large as a wolf.
The Chinle Formation is an Upper Triassic continental geological formation of fluvial, lacustrine, and palustrine to eolian deposits spread across the U.S. states of Nevada, Utah, northern Arizona, western New Mexico, and western Colorado. In New Mexico, it is often raised to the status of a geological group, the Chinle Group. Some authors have controversially considered the Chinle to be synonymous to the Dockum Group of eastern Colorado and New Mexico, western Texas, the Oklahoma panhandle, and southwestern Kansas. The Chinle Formation is part of the Colorado Plateau, Basin and Range, and the southern section of the Interior Plains. A probable separate depositional basin within the Chinle is found in northwestern Colorado and northeastern Utah. The southern portion of the Chinle reaches a maximum thickness of a little over 520 meters (1,710 ft). Typically, the Chinle rests unconformably on the Moenkopi Formation.
Spinosuchus is an extinct genus of trilophosaurid allokotosaur from the Late Triassic of Texas, southern United States. It has been assigned to a variety of groups over its history, from coelophysid dinosaur to pseudosuchian to uncertain theropod dinosaur and to Proterosuchidae. This uncertainty is not unusual, given that it was only known from a poorly preserved, wall-mounted, partial vertebral column of an animal that lived in a time of diverse, poorly known reptile groups. However, newly collected material and recent phylogenetic studies of early archosauromorphs suggest that it represents an advanced trilophosaurid very closely related to Trilophosaurus.
The Cooper Canyon Formation is a geological formation of Norian age in Texas. It is one of several formations encompassed by the Dockum Group.
Machaeroprosopus is an extinct genus of mystriosuchin leptosuchomorph phytosaur from the Late Triassic of the southwestern United States. M. validus, once thought to be the type species of Machaeroprosopus, was named in 1916 on the basis of three complete skulls from Chinle Formation, Arizona. The skulls have been lost since the 1950s, and a line drawing in the original 1916 description is the only visual record of the specimen. Another species, M. andersoni, was named in 1922 from New Mexico, and the species M. adamanensis, M. gregorii, M. lithodendrorum, M. tenuis, and M. zunii were named in 1930. Most species have been reassigned to the genera Smilosuchus, Rutiodon, or Phytosaurus. Until recently, M. validus was considered to be the only species that has not been reassigned. Thus, Machaeroprosopus was considered to be a nomen dubium or "doubtful name" because of the lack of diagnostic specimens that can support its distinction from other phytosaur genera. However, a taxonomic revision of Machaeroprosopus, conducted by Parker et al. in 2013, revealed that UW 3807, the holotype of M. validus, is not the holotype of Machaeroprosopus, while the species Machaeroprosopus buceros, Machaeroprosopus being a replacement name, with a fixed type species, for Metarhinus, is the combinatio nova of the type species of the genu: Belodon buceros. Therefore, the name Pseudopalatus must be considered a junior synonym of Machaeroprosopus, and all species of the former must be reassigned to the latter. This revised taxonomy was already accepted in several studies, including Stocker and Butler (2013). Stocker and Butler (2013) also treated M. andersoni as a valid species, and not a junior synonym of Machaeroprosopus buceros as was previously suggested by Long and Murry (1995).
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.
Eodromaeus is an extinct genus of probable basal theropod dinosaurs from the Late Triassic of Argentina. Like many other of the earliest-known dinosaurs, it hails from the Carnian-age Ischigualasto Formation, within the Ischigualasto-Villa Unión Basin of northwestern Argentina. Upon its discovery, it was argued to be one of the oldest true theropods, supplanting its contemporary Eoraptor, which was reinterpreted as a basal sauropodomorph.
The Bull Canyon Formation is a geological formation of Late Triassic (Norian) age in eastern New Mexico and the Texas Panhandle. It is one of several formations encompassed by the Dockum Group.
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).
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.
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.
Robert Joseph Gay is an American Paleontologist known for his work in the Chinle and Kayenta Formations in the southwest United States. He is known for the discovery of the first occurrence of Crosbysaurus from Utah, as well as his studies of cannibalism in Coelophysis and sexual dimorphism in Dilophosaurus. Since 2014, Gay has taken high school students to the Chinle of Comb Ridge, Utah, and he is currently making new discoveries there. In December 2017, he and coauthors Xavier A. Jenkins of Arizona State University and John R. Foster of the Museum of Moab formally published their study on the oldest known dinosaur from Utah, a neotheropod that is likely an animal similar to Coelophysis. Robert Gay is currently the Education Director at the Colorado Canyons Association.