Eucoelophysis

Last updated

Eucoelophysis
Temporal range: Late Triassic, 228–208  Ma
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Family: Silesauridae
Clade: Sulcimentisauria
Genus: Eucoelophysis
Species:
E. baldwini
Binomial name
Eucoelophysis baldwini
Sullivan & Lucas, 1999

Eucoelophysis (meaning "true hollow form") is a genus of silesaurid dinosauriform from the Late Triassic (Norian) period Chinle Formation of New Mexico. It was assumed to be a coelophysid upon description, [1] but a study by Nesbitt et al. found that it was actually a close relative of Silesaurus , [2] [3] which was independently supported by Ezcurra (2006), who found it to be the sister group to Dinosauria, and Silesaurus as the next most basal taxon. [4]

However, the relationships of Silesaurus are uncertain. Dzik found it to be a basal dinosauriform (the group of archosaurs from which the dinosaurs evolved), but did not rule out the possibility that it represents a primitive ornithischian. [5]

Related Research Articles

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

Coelophysis 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 from the Carnian and Rhaetian faunal stages in what is now the southwestern United States. Megapnosaurus was once considered a species within this genus, but this interpretation has been challenged since 2017 and the genus Megapnosaurus is now considered valid.

<i>Revueltosaurus</i> Extinct genus of reptiles

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. It was 1 meter long.

<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.

Technosaurus is an extinct genus of Late Triassic silesaurid dinosauriform, from the Late Triassic Cooper Canyon Formation of Texas, United States.

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.

<i>Lewisuchus</i> Extinct genus of reptiles

Lewisuchus is a genus of archosaur that lived during the Late Triassic. As a silesaurid dinosauriform, it was a member of the group of reptiles most commonly considered to be the closest relatives of dinosaurs. Lewisuchus was about 1 metre (3.3 ft) long. Fossils have been found in the Chañares Formation of Argentina. It exhibited osteoderms along its back.

<i>Nyasasaurus</i> Extinct genus of reptiles

Nyasasaurus is an extinct genus of avemetatarsalian archosaur from the putatively Middle Triassic Manda Formation of Tanzania that may be the earliest known dinosaur. The type species Nyasasaurus parringtoni was first described in 1956 in the doctoral thesis of English paleontologist Alan J. Charig, but it was not formally described until 2013.

<i>Teleocrater</i> Extinct genus of reptiles

Teleocrater is a genus of avemetatarsalian archosaur from the Middle Triassic Manda Formation of Tanzania. The name was coined by English paleontologist Alan Charig in his 1956 doctoral dissertation, but was only formally published in 2017 by Sterling Nesbitt and colleagues. The genus contains the type and only species T. rhadinus. Uncertainty over the affinities of Teleocrater have persisted since Charig's initial publication; they were not resolved until Nesbitt et al. performed a phylogenetic analysis. They found that Teleocrater is most closely related to the similarly enigmatic Yarasuchus, Dongusuchus, and Spondylosoma in a group that was named the Aphanosauria. Aphanosauria was found to be the sister group of the Ornithodira, the group containing dinosaurs and pterosaurs.

<i>Silesaurus</i> Extinct genus of reptiles

Silesaurus is a genus of silesaurid dinosauriform from the Late Triassic, of what is now Poland.

<span class="mw-page-title-main">Dinosauromorpha</span> Clade of reptiles

Dinosauromorpha is a clade of avemetatarsalian archosaurs that includes the Dinosauria (dinosaurs) and some of their close relatives. It was originally defined to include dinosauriforms and lagerpetids, with later formulations specifically excluding pterosaurs from the group. Birds are the only dinosauromorphs which survive to the present day.

<i>Dromomeron</i> Extinct genus of reptiles

Dromomeron is a genus of lagerpetid avemetatarsalian which lived around 220 to 211.9 ± 0.7 million years ago. The genus contains species known from Late Triassic-age rocks of the Southwestern United States and northwestern Argentina. It is described as most closely related to the earlier Lagerpeton of Argentina, but was found among remains of true dinosaurs like Chindesaurus, indicating that the first dinosaurs did not immediately replace related groups.

Sterling Nesbitt is an American paleontologist best known for his work on the origin and early evolutionary patterns of archosaurs. He is currently an associate professor at Virginia Tech in the Department of Geosciences.

The Chinle Formation is an extensive geological unit in the southwestern United States, preserving a very diverse fauna of Late Triassic animals and plants. This is a list of fossilized organisms recovered from the formation.

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

Asilisaurus ; from Swahili, asili, and Greek, σαυρος is an extinct genus of silesaurid archosaur. The type species is Asilisaurus kongwe.Asilisaurus fossils were uncovered in the Manda Beds of Tanzania and date back to the middle Ladinian-early Carnian, making it one of the oldest known members of the Avemetatarsalia. It was the first non-dinosaurian dinosauriform recovered from Africa. The discovery of Asilisaurus has provided evidence for a rapid diversification of avemetatarsalians during the Middle Triassic, with the diversification of archosaurs during this time previously only documented in pseudosuchians.

<span class="mw-page-title-main">Silesauridae</span> Extinct family of dinosaur-like reptiles

Silesauridae is an extinct family of Triassic dinosauriforms. It is most commonly considered to be a clade of non-dinosaur dinosauriforms, and the sister group of dinosaurs. Some studies have instead suggested that most or all silesaurids comprised an early diverging clade or a paraphyletic grade within ornithischian dinosaurs. Silesaurids have a consistent general body plan, with a fairly long neck and legs and possibly quadrupedal habits, but most silesaurids are heavily fragmentary nonetheless. Furthermore, they occupied a variety of ecological niches, with early silesaurids being carnivorous and later taxa having adaptations for specialized herbivory. As indicated by the contents of referred coprolites, Silesaurus may have been insectivorous, feeding selectively on small beetles and other arthropods.

<i>Diodorus scytobrachion</i> Extinct species of reptile

Diodorus is a genus of silesaurid dinosauromorph that lived during the Late Triassic of what is now Morroco. Fossils were discovered in the Timezgadiouine Formation of the Argana Basin, and were used to name the new genus and species Diodorus scytobrachion. The genus name honours Diodorus, a legendary king of the Berber people, and Diodorus Siculus, a 1st-century historian, while the specific name is ancient Greek for "leathery arm". The holotype specimen is a partial dentary bone, and assigned specimens include isolated teeth, two humeri, a metatarsal, and femur.

<span class="mw-page-title-main">Manda Formation</span>

The Manda Formation is a Middle Triassic (Anisian?) or possibly Late Triassic (Carnian?) geologic formation in Tanzania. It preserves fossils of many terrestrial vertebrates from the Triassic, including some of the earliest dinosauromorph archosaurs. The formation is often considered to be Anisian in age according to general tetrapod biochronology hypotheses and correlations to the Cynognathus Assemblage Zone of South Africa. However, some recent studies cast doubt to this age, suggesting that parts deposits may actually be younger (Carnian) in age.

<span class="mw-page-title-main">Epipophyses</span> Bony projections of neck vertebrae in certain reptiles

Epipophyses are bony projections of the cervical vertebrae found in archosauromorphs, particularly dinosaurs. These paired processes sit above the postzygapophyses on the rear of the vertebral neural arch. Their morphology is variable and ranges from small, simple, hill-like elevations to large, complex, winglike projections. Epipophyses provided large attachment areas for several neck muscles; large epipophyses are therefore indicative of a strong neck musculature.

Martín Dário Ezcurra is an Argentinian born palaeontologist naming many extinct genera such as Aerotitan, Lophostropheus and Powellvenator.

References

  1. Sullivan, R.M. and Lucas, S.G. (1999). "Eucoelophysis baldwini, a new theropod dinosaur from the Upper Triassic of New Mexico, and the status of the original types of Coelophysis". Journal of Vertebrate Paleontology 19(1): 81-90.
  2. Nesbitt, S.J., Irmis, R.B., and Parker, W.G. (2005). "A critical review of the Triassic North American dinosaur record." In Kellner, A.W.A., Henriques, D.D.R., & Rodrigues, T. (eds.), II Congresso Latino-Americano de Paleontologia de Vertebrados, Boletim de Resumos. Rio de Janeiro: Museum Nacional/UFRJ, 139.
  3. Nesbitt, S. J., R. B. Irmis, and W. G. Parker. (2007). "A critical re-evaluation of the Late Triassic dinosaur taxa of North America." Journal of Systematic Palaeontology, 5:209-243.
  4. Ezcurra, M.D. (2006). "A review of the systematic position of the dinosauriform archosaur Eucoelophysis baldwini Sullivan & Lucas, 1999 from the Upper Triassic of New Mexico, USA." Geodiversitas, 28(4):649-684.
  5. Dzik, J. (2003). "A beaked herbivorous archosaur with dinosaur affinities from the early Late Triassic of Poland." Journal of Vertebrate Paleontology, 23(3): 556-574.