Megalosauroidea (meaning 'great/big lizard forms') is a

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

(or

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English ter ...

) of

tetanuran Tetanurae (/ˌtɛtəˈnjuːriː/ or "stiff tails") is a clade that includes most theropod dinosaurs, including megalosauroids, allosauroids, tyrannosauroids, ornithomimosaurs, compsognathids and maniraptorans (including birds). Tetanurans ar ...

theropod

dinosaur Dinosaurs are a diverse group of reptiles of the clade Dinosauria. They first appeared during the Triassic period, between 243 and 233.23 million years ago (mya), although the exact origin and timing of the evolution of dinosaurs is t ...

s that lived from the

Middle Jurassic The Middle Jurassic is the second Epoch (geology), epoch of the Jurassic Period (geology), Period. It lasted from about 174.1 to 163.5 million years ago. Fossils of land-dwelling animals, such as dinosaurs, from the Middle Jurassic are relatively ...

to the

Late Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', ...

period. The group is defined as ''

Megalosaurus bucklandii ''Megalosaurus'' (meaning "great lizard", from Greek , ', meaning 'big', 'tall' or 'great' and , ', meaning 'lizard') is an extinct genus of large carnivorous theropod dinosaurs of the Middle Jurassic period (Bathonian stage, 166 million years a ...

'' and all taxa sharing a more recent common ancestor with it than with ''

Allosaurus fragilis ''Allosaurus'' () is a genus of large carnosaurian theropod dinosaur that lived 155 to 145 million years ago during the Late Jurassic epoch ( Kimmeridgian to late Tithonian). The name "''Allosaurus''" means "different lizard" alludi ...

'' or ''

Passer domesticus The house sparrow (''Passer domesticus'') is a bird of the sparrow family Passeridae, found in most parts of the world. It is a small bird that has a typical length of and a mass of . Females and young birds are coloured pale brown and grey, an ...

''. Members of the group include ''

Spinosaurus ''Spinosaurus'' (; ) is a genus of spinosaurid dinosaur that lived in what now is North Africa during the Cenomanian to upper Turonian stages of the Late Cretaceous period, about 99 to 93.5 million years ago. The genus was known first f ...

'', ''

Megalosaurus ''Megalosaurus'' (meaning "great lizard", from Greek , ', meaning 'big', 'tall' or 'great' and , ', meaning 'lizard') is an extinct genus of large carnivorous theropod dinosaurs of the Middle Jurassic period (Bathonian stage, 166 million years ...

'', and ''

Torvosaurus ''Torvosaurus'' () is a genus of carnivorous megalosaurid theropod dinosaur that lived approximately 165 to 148 million years ago during the late Middle and Late Jurassic period (Callovian to Tithonian stages) in what is now Colorado, Portuga ...

''. They are possibly paraphyletic in nature.

Classification

The name Spinosauroidea is sometimes used in place of Megalosauroidea. The superfamily Spinosauroidea was named in 1915 by

Ernst Stromer Ernst Freiherr Stromer von Reichenbach (12 June 1871 in Nürnberg – 18 December 1952 in Erlangen) was a German paleontologist. He is best remembered for his expedition to Egypt, during which the first known remains of ''Spinosaurus'' we ...

. It is a synonym of Megalosauroidea in almost all modern phylogenetic analyses, and it is therefore redundant. Spinosauroidea was defined as a

in 1998 by

Paul Sereno Paul Callistus Sereno (born October 11, 1957) is a professor of paleontology at the University of Chicago and a National Geographic "explorer-in-residence" who has discovered several new dinosaur species on several continents, including at si ...

as the node clade containing the common ancestor of ''Spinosaurus'' and ''Torvosaurus'' and all its descendants. Thomas Holtz in 2004 defined a branch clade with the same name containing all species closer to ''Spinosaurus'' than to ''

Passer ''Passer'' is a genus of sparrows, also known as the true sparrows. The genus contains 28 species and includes the house sparrow and the Eurasian tree sparrow, two of the most common birds in the world. They are small birds with thick bills for ...

domesticus''. The

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the I ...

holds that even clade names (which do not yet have any governing body) should be replaced if having a traditional taxon suffix and being synonyms of ranked taxa at or below the superfamily level. The seniority of Megalosauroidea was not followed in most paleontological literature during the 1990s and early 2000s. A series of papers supporting the validity of ''

'' as a genus, the relationships of megalosauroids, and the placement of "spinosauroids" among them, published between 2008 and 2010 argued that Megalosauroidea was in fact the valid name for the group. The classification of megalosauroids follows a study by Benson in 2010. Note that several "wildcard" taxa that are probably megalosauroids were excluded from the final tree, including ''

Magnosaurus ''Magnosaurus'' (meaning 'large lizard') was a genus of theropod dinosaur from the Middle Jurassic of England. It is based on fragmentary remains and has often been confused with or included in ''Megalosaurus''. History and taxonomy In 1923, Fr ...

'', ''

Piveteausaurus ''Piveteausaurus'' (meaning " Jean Piveteau's lizard") is a genus of theropod dinosaur known from a partial skull discovered in the Middle Jurassic Marnes de Dives formation of Calvados, in northern France and lived about 164.7-161.2 million yea ...

'' and ''

Streptospondylus ''Streptospondylus'' (meaning "reversed vertebra") is a genus of tetanuran theropod dinosaur known from the Late Jurassic period of France, 161 million years ago. It was a medium-sized predator with an estimated length of 6 meters (19.5&nb ...

''. Later, ''

'' and ''Streptospondylus'' were added in the final tree.Supporting Information
/ref> These are known from remains too fragmentary to be reliably classified. Some of these 'wildcard' taxa, such as ''

Poekilopleuron ''Poekilopleuron'' (meaning "varied ribs") is a genus of tetanuran dinosaur, which lived during the middle Bathonian of the Jurassic, about 168 to 166 million years ago. The genus has been used under many different spelling variants, although on ...

'' and ''

Megaraptor ''Megaraptor'' () is a genus of large theropod dinosaur that lived in the ages of the Late Cretaceous. Its fossils have been discovered in the Patagonian Portezuelo Formation of Argentina, South America. Initially thought to have been a giant dr ...

'', have been considered possible megalosauroids in the past, but the analysis found that they are more likely

allosauroid Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Metriacanthosauridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae. Allosauroids, alongside the family Megalosauroidea, were among ...

s. Carrano, Benson & Sampson (2012) performed much larger

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups ...

analysis of the

Tetanurae Tetanurae (/ˌtɛtəˈnjuːriː/ or "stiff tails") is a clade that includes most theropod dinosaurs, including megalosauroids, allosauroids, tyrannosauroids, ornithomimosaurs, compsognathids and maniraptorans (including birds). Tetanurans ar ...

that includes more taxa. They used the clade name Megalosauria (Bonaparte, 1850) in their analysis and defined it as the node comprising ''Megalosaurus'', ''Spinosaurus'', their most recent common ancestor, and all its descendants. Furthermore, a new megalosauroid family Piatnitzkysauridae was named to include all megalosauroids more closely related to ''Piatnitzkysaurus'' than to either ''Spinosaurus'' or ''Megalosaurus''. Within Megalosauridae a new subfamily was named,

Afrovenatorinae 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 ...

, to include all megalosaurids more closely related to ''Afrovenator'' than to ''Megalosaurus''. Unlike Benson ''et al.'', 2010, they recovered ''

'' as an afrovenatorine, while '' Xuanhanosaurus'' was recovered as the basalmost metriacanthosaurid. However, the position of these taxa is very unstable, and their exclusion from the analysis gave more resolved and stable cladogram. ''

'' was also excluded to get more resolved Megalosauridae and Afrovenatorinae. The Chinese tetanuran ''

Leshansaurus ''Leshansaurus'' is a genus of theropod dinosaur from the Late Jurassic Shaximiao Formation of what is now China. It was described in 2009 by a team of Chinese paleontologists. The type species is ''Leshansaurus qianweiensis''. Fossils of ''Lesh ...

'' was included for the first time in a phylogenetic analysis, and was recovered as an afrovenatorine. Both ''

Chuandongocoelurus ''Chuandongocoelurus'' ( ) is a genus of carnivorous tetanuran theropod dinosaur from the Jurassic of China. Discovery and naming The type species ''Chuandongocoelurus primitivus'' was first described and named by Chinese paleontologist H ...

'' and '' Monolophosaurus'' were found to be just outside

Orionides Orionides is a clade of tetanuran theropod dinosaurs from the Middle Jurassic to the Present. The clade includes most theropod dinosaurs, including birds. Relationships Although many phylogenetic analyses found basal tetanurans that were outs ...

. The

cladogram A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to ...

presented here follows that study. In 2019, Rauhut and Pol described ''

Asfaltovenator vialidadi ''Asfaltovenator'' (meaning "Cañadón Asfalto Formation hunter" after the fossil formation in which its fossils were found) is a genus of possibly allosauroid dinosaur from the Lower Jurassic Cañadón Asfalto Formation from Chubut Province, Ar ...

'', a basal allosauroid displaying a mosaic of primitive and derived features seen within

. Their phylogenetic analysis found traditional Megalosauroidea to represent a basal

grade Grade most commonly refers to: * Grade (education), a measurement of a student's performance * Grade, the number of the year a student has reached in a given educational stage * Grade (slope), the steepness of a slope Grade or grading may also ref ...

of carnosaurs,

paraphyletic In taxonomy, a group is paraphyletic if it consists of the group's last common ancestor and most of its descendants, excluding a few monophyletic subgroups. The group is said to be paraphyletic ''with respect to'' the excluded subgroups. In ...

with respect to

Allosauroidea Allosauroidea is a superfamily or clade of theropod dinosaurs which contains four families — the Metriacanthosauridae, Allosauridae, Carcharodontosauridae, and Neovenatoridae. Allosauroids, alongside the family Megalosauroidea, were amo ...

References

{{Taxonbar, from=Q132202 Fossil taxa described in 1889 Bajocian first appearances Cenomanian extinctions

Classification

See also

References