Megalosauroidea(meaning 'great/big lizard forms') is asuperfamily(orclade) oftetanurantheropoddinosaursthat lived from theMiddle Jurassicto theLate Cretaceousperiod. The group is defined asMegalosaurus bucklandiiand all taxa sharing a more recent common ancestor with it than withAllosaurus fragilisorPasser domesticus.[2]Members of the group includeSpinosaurus,Megalosaurus,andTorvosaurus.They are possibly paraphyletic in nature with respect toAllosauroidea.
| Megalosauroids Temporal range:Middle Jurassic-Late Cretaceous,Possible LateToarcianand LateSantonianrecords. PossibleCampanianand LateMaastrichtianrecords,[1]but this is likely erroneous.
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| Torvosaurusskeletal mount,Museum of Ancient Life | |
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| Spinosaurusskeletal mount,National Geographic Museum | |
Scientific classification
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Clade: | Dinosauria |
| Clade: | Saurischia |
| Clade: | Theropoda |
| Clade: | †Carnosauria(?) |
| Superfamily: | †Megalosauroidea Huxley,1889 |
| Type species | |
| †Megalosaurus bucklandii Mantell,1827
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| Subgroups | |
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| Synonyms | |
Classification
editThe nameSpinosauroideais sometimes used in place of Megalosauroidea. The superfamily Spinosauroidea was named in 1915 byErnst Stromer.It is a synonym of Megalosauroidea in almost all modern phylogenetic analyses, and it is therefore redundant. Spinosauroidea was defined as acladein 1998 byPaul Serenoas the node clade containing the common ancestor ofSpinosaurusandTorvosaurusand all its descendants. Thomas Holtz in 2004 defined a branch clade with the same name containing all species closer toSpinosaurusthan toPasserdomesticus.TheICZNholds 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 ofMegalosaurusas 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.[2]
The classification of megalosauroids follows a study by Benson in 2010. Note that several "wildcard"[2]taxa that are probably megalosauroids were excluded from the final tree, includingMagnosaurus,PiveteausaurusandStreptospondylus.[2]Later,MagnosaurusandStreptospondyluswere added in the final tree.[3]These are known from remains too fragmentary to be reliably classified.[2]Some of these 'wildcard' taxa, such asPoekilopleuronandMegaraptor,have been considered possible megalosauroids in the past, but the analysis found that they are more likelyallosauroids.[3]
| Megalosauroidea |
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Carrano, Benson & Sampson (2012) performed much largerphylogeneticanalysis of theTetanuraethat includes more taxa. They used the clade nameMegalosauria(Bonaparte, 1850) in their analysis and defined it as the node comprisingMegalosaurus,Spinosaurus,their most recent common ancestor, and all its descendants. Furthermore, a new megalosauroid familyPiatnitzkysauridaewas named to include all megalosauroids more closely related toPiatnitzkysaurusthan to eitherSpinosaurusorMegalosaurus.Within Megalosauridae a new subfamily was named,Afrovenatorinae,to include all megalosaurids more closely related toAfrovenatorthan toMegalosaurus.Unlike Bensonet al.,2010, they recoveredPoekilopleuronas an afrovenatorine, whileXuanhanosauruswas recovered as the basalmostmetriacanthosaurid.However, the position of these taxa is very unstable, and their exclusion from the analysis gave more resolved and stable cladogram.Streptospondyluswas also excluded to get more resolved Megalosauridae and Afrovenatorinae. The Chinese tetanuranLeshansauruswas included for the first time in a phylogenetic analysis, and was recovered as an afrovenatorine. BothChuandongocoelurusandMonolophosauruswere found to be just outsideOrionides.Thecladogrampresented here follows that study.[4]
| Tetanurae |
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In 2019, Rauhut and Pol describedAsfaltovenator vialidadi,a basal allosauroid displaying a mosaic of primitive and derived features seen withinTetanurae.Their phylogenetic analysis found traditional Megalosauroidea to represent a basalgradeof carnosaurs,paraphyleticwith respect toAllosauroidea.[5]
See also
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References
edit- ^Weishampel, David B.; Barrett, Paul M.; Coria, Rodolfo A.; Le Loeuff, Jean; Xing, Xu; Xijin, Zhao; Sanhi, Ashok; Gomani, Elizabeth M. P.; Noto, Christopher R. (2004). "Dinosaur Distribution". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka (eds.).The Dinosauria(2nd ed.). University of California Press. pp. 517–606.ISBN978-0-520-24209-8.JSTOR10.1525/j.ctt1pn61w.31.
- ^abcdeBenson, R.B.J. (2010)."A description ofMegalosaurus bucklandii(Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods ".Zoological Journal of the Linnean Society.158(4): 882–935.doi:10.1111/j.1096-3642.2009.00569.x.
- ^abBenson, R.B.J., Carrano, M.T and Brusatte, S.L. (2010). "A new clade of archaic large-bodied predatory dinosaurs (Theropoda: Allosauroidea) that survived to the latest Mesozoic".Naturwissenschaften.97(1): 71–78.Bibcode:2010NW.....97...71B.doi:10.1007/s00114-009-0614-x.PMID19826771.S2CID22646156.
{{cite journal}}:CS1 maint: multiple names: authors list (link)Supporting Information - ^Carrano, M. T.; Benson, R. B. J.; Sampson, S. D. (2012). "The phylogeny of Tetanurae (Dinosauria: Theropoda)".Journal of Systematic Palaeontology.10(2): 211–300.doi:10.1080/14772019.2011.630927.S2CID85354215.
- ^Rauhut, Oliver W. M.; Pol, Diego (2019-12-11)."Probable basal allosauroid from the early Middle Jurassic Cañadón Asfalto Formation of Argentina highlights phylogenetic uncertainty in tetanuran theropod dinosaurs".Scientific Reports.9(1): 18826.Bibcode:2019NatSR...918826R.doi:10.1038/s41598-019-53672-7.ISSN2045-2322.PMC6906444.PMID31827108.