Neotheropoda

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Neotheropods
Temporal range:
Late Triassic Present, 228–0  Ma
Coelophysis mount NHM2.jpg
Cast of a Coelophysis bauri skeleton
House sparrow04.jpg
A female house sparrow (Passer domesticus)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Neotheropoda
Bakker, 1986
Subgroups
Synonyms
  • Avepoda Paul, 2002
  • EutheropodaNovas, Haro & Canale, 2003

Neotheropoda (meaning "new theropods") is a clade that includes coelophysoids and more advanced theropod dinosaurs, and is the only group of theropods that survived the Triassic–Jurassic extinction event. All neotheropods became extinct by the end of the Early Jurassic except for Averostra.

Classification

Neotheropoda was named by Robert T. Bakker in 1986 as a group including the relatively derived theropod subgroups Ceratosauria and Tetanurae, and excluding coelophysoids. [1] However, most later researchers have used it to denote a broader group. Neotheropoda was first defined as a clade by Paul Sereno in 1998 as Coelophysis plus modern birds, which includes almost all theropods except the most primitive species. [2] Dilophosauridae was formerly considered a small clade within Neotheropoda, but was later considered to be paraphyletic. [3]

The following family tree illustrates a synthesis of the relationships of the early theropod groups compiled by Hendrickx et al. in 2015. [4]

Theropoda

This second cladogram is based on the redescription of Dilophosaurus by Marsh and Rowe (2020). [3]

Theropoda

This third cladogram is based on the larger analysis in the description of Pendraig milnerae by Spiekman et al. 2021: [5]

Theropoda

Related Research Articles

<i>Dilophosaurus</i> Genus of theropod dinosaur from Early Jurassic

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.

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

Eoraptor is a genus of small, lightly built, basal sauropodomorph dinosaur. One of the earliest-known dinosaurs and one of the earliest members of the sauropod family, it lived approximately 231 to 228 million years ago, during the Late Triassic in Western Gondwana, in the region that is now northwestern Argentina. The type and only species, Eoraptor lunensis, was first described in 1993, and is known from an almost complete and well-preserved skeleton and several fragmentary ones. Eoraptor had multiple tooth shapes, which suggests that it was omnivorous. Eoraptor was 1.5 feet (0.46 m) tall and 3 feet (0.91 m) long.

Cryolophosaurus is a genus of large theropod dinosaur known from only a single species Cryolophosaurus ellioti, from the early Jurassic of Antarctica. It was one of the largest theropods of the Early Jurassic, with the subadult being estimated to have reached 6–7 metres (20–23 ft) long and weighed 350–465 kilograms (772–1,025 lb).

<span class="mw-page-title-main">Ceratosauria</span> Extinct clade of dinosaurs

Ceratosaurs are members of the clade Ceratosauria, a group of dinosaurs defined as all theropods sharing a more recent common ancestor with Ceratosaurus than with birds. The oldest known ceratosaur, Saltriovenator, dates to the earliest part of the Jurassic, around 199 million years ago. Ceratosauria includes three major clades: Ceratosauridae, Noasauridae, and Abelisauridae, found primarily in the Southern Hemisphere. Originally, Ceratosauria included the above dinosaurs plus the Late Triassic to Early Jurassic Coelophysoidea and Dilophosauridae, implying a much earlier divergence of ceratosaurs from other theropods. However, most recent studies have shown that coelophysoids and dilophosaurids do not form a natural group with other ceratosaurs, and are excluded from this group.

<span class="mw-page-title-main">Tetanurae</span> Clade containing most theropod dinosaurs

Tetanurae is a clade that includes most theropod dinosaurs, including megalosauroids, allosauroids, tyrannosauroids, ornithomimosaurs, compsognathids and maniraptorans. Tetanurans are defined as all theropods more closely related to modern birds than to Ceratosaurus and contain the majority of predatory dinosaur diversity. Tetanurae likely diverged from its sister group, Ceratosauria, during the late Triassic. Tetanurae first appeared in the fossil record by the Early Jurassic about 190 mya and by the Middle Jurassic had become globally distributed.

<span class="mw-page-title-main">Coelophysoidea</span> Extinct superfamily of dinosaurs

Coelophysoidea were common dinosaurs 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.

<span class="mw-page-title-main">Megalosauridae</span> Extinct family of dinosaurs

Megalosauridae is a monophyletic family of carnivorous theropod dinosaurs within the group Megalosauroidea. Appearing in the Middle Jurassic, megalosaurids were among the first major radiation of large theropod dinosaurs. They were a relatively primitive group of basal tetanurans containing two main subfamilies, Megalosaurinae and Afrovenatorinae, along with the basal genus Eustreptospondylus, an unresolved taxon which differs from both subfamilies.

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

Liliensternus is an extinct genus of basal neotheropod dinosaur that lived approximately 210 million years ago during the latter part of the Triassic Period in what is now Germany. Liliensternus was a moderate-sized, bipedal, ground-dwelling carnivore, that could grow up to 5.15 m (16.9 ft) long. It is the best represented Triassic theropod from Europe and one of the largest known.

<span class="mw-page-title-main">Coelophysidae</span> Extinct family of dinosaurs

Coelophysidae is 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, and has been found on numerous continents. Many members of Coelophysidae are characterized by long, slender skulls and light skeletons built for speed. One member genus, Coelophysis, displays the earliest known furcula in a dinosaur.

<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>Terrestrisuchus</i> Genus of terrestrial crocodylomorph

Terrestrisuchus is an extinct genus of very small early crocodylomorph that was about 76 centimetres (30 in) long. Fossils have been found in Wales and Southern England and date from near the very end of the Late Triassic during the Rhaetian, and it is known by type and only known species T. gracilis. Terrestrisuchus was a long-legged, active predator that lived entirely on land, unlike modern crocodilians. It inhabited a chain of tropical, low-lying islands that made up southern Britain, along with similarly small-sized dinosaurs and abundant rhynchocephalians. Numerous fossils of Terrestrisuchus are known from fissures in limestone karst which made up the islands it lived on, which formed caverns and sinkholes that preserved the remains of Terrestrisuchus and other island-living reptiles.

<span class="mw-page-title-main">Averostra</span> Clade of dinosaurs

Averostra, or "bird snouts", is a clade that includes most theropod dinosaurs, namely Ceratosauria and Tetanurae, and represent the only group of post-Early Jurassic theropods. Both survived into the Cretaceous period. When the Cretaceous–Paleogene extinction event occurred, ceratosaurians, megaraptorans an incertae sedis group within Tetanurae, and two groups of tetanurans within the clade Coelurosauria, the Tyrannosauroidea and Maniraptoriformes, were still extant. Only one subgroup of Maniraptoriformes, Aves, survived the extinction event and persisted to the present day.

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

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.

<span class="mw-page-title-main">Angela Milner</span> British paleontologist (1947–2021)

Angela Cheryl Milner was a British paleontologist who, in 1986 alongside Alan Charig, described the dinosaur Baryonyx.

<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.

The Avon Fissure Fill, also known as the Bristol Fissure Fill or Tytherington Fissure Fill, is a fissure fill in Avon, England which dates variously from the Norian and Rhaetian stages of the Late Triassic, or possibly as late as the Hettangian stage of the Early Jurassic. The fissure fill at Avon was a sinkhole formed by the dissolution of Lower Carboniferous limestones.

<span class="mw-page-title-main">Pant-y-Ffynnon Quarry</span> Stone quarry in Wales

Pant-y-Ffynnon Quarry is a stone quarry in the Vale of Glamorgan, Wales, around 3 kilometers east of Cowbridge. It contains fissure fill deposits dating to the Late Triassic (Rhaetian), hosted within karsts of Carboniferous aged limestone, primarily the Friars Point Limestone Formation. Remains of numerous small vertebrates, notably archosaurs, are known from the fissure fills in the quarry, similar to other Late Triassic-Early Jurassic fissure fill deposits known from Southwest England and southern Wales.

<span class="mw-page-title-main">Palaeontology in Wales</span> Overview of palaeontology in Wales

Palaeontology in Wales is palaeontological research occurring in Wales.

References

  1. Bakker, R.T. 1986. The Dinosaur Heresies . William Morrow, New York. 481 pp.
  2. Sereno, 1998. A rationale for phylogenetic definitions, with application to the higher-level taxonomy of Dinosauria. Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen. 210, 41-83.
  3. 1 2 Marsh, Adam D.; Rowe, Timothy B. (2020). "A comprehensive anatomical and phylogenetic evaluation of Dilophosaurus wetherilli (Dinosauria, Theropoda) with descriptions of new specimens from the Kayenta Formation of northern Arizona". Journal of Paleontology. 94: 1–103. doi: 10.1017/jpa.2020.14 . S2CID   220601744.
  4. Hendrickx, C., Hartman, S.A., & Mateus, O. (2015). An Overview of Non- Avian Theropod Discoveries and Classification. PalArch’s Journal of Vertebrate Palaeontology, 12(1): 1-73.
  5. Spiekman SN, Ezcurra MD, Butler RJ, Fraser NC, Maidment SC (2021). "Pendraig milnerae, a new small-sized coelophysoid theropod from the Late Triassic of Wales". Royal Society Open Science. 8 (10): Article ID 210915. doi: 10.1098/rsos.210915 . PMC   8493203 . PMID   34754500.