Open Paleo

Megalosauroidea

Fitzinger, 1843 Type genus Megalosaurus

Its genera lived 174.7–93.9 million years ago Middle Jurassic–Late Cretaceous

Megalosauroidea is a superfamily of basal tetanuran theropod dinosaurs that lived from the Middle Jurassic to the Late Cretaceous. It is defined as all taxa closer to Megalosaurus than to Allosaurus and modern birds (Benson, 2010) or, in the version of Carrano and colleagues (2012), than to Allosaurus and Tyrannosaurus, and it brings together the family Piatnitzkysauridae with the clade Megalosauria, which unites the megalosaurids and the spinosaurids. Its members range from large-bodied terrestrial predators such as Megalosaurus and Torvosaurus to the elongate-snouted, likely semiaquatic spinosaurids, including Spinosaurus. Some analyses recover the traditional megalosauroids as paraphyletic with respect to Allosauroidea rather than as a single natural group. The name Spinosauroidea is sometimes used for the same assemblage but is treated as a junior synonym in most modern work.

Under dispute

The monophyly of Megalosauroidea is contested. Most analyses recover it as a clade of Piatnitzkysauridae plus Megalosauria (Carrano and colleagues, 2012; Benson, 2010; Rauhut and colleagues, 2016), but Rauhut and Pol (2019) recover the traditional megalosauroids as a paraphyletic grade of successive outgroups to Allosauroidea within Carnosauria, and Zou and colleagues (2025) recover Piatnitzkysauridae outside Megalosauroidea as the sister group of Avetheropoda. Heavy homoplasy at the base of Tetanurae leaves these relationships weakly resolved.

Diagnosis

  1. U-shaped ventral process of the postorbital
  2. Chevrons whose proximal articular surface lacks distinct anterior and posterior facets
  3. Iliac pubic peduncle with a length-to-width ratio of about 1.3 to 1.4
  4. Anterior dorsal vertebrae with prominent ventral keels inset from the lateral surfaces
  5. Step-like ridge within the infrapostzygapophyseal fossa of the dorsal vertebrae
  6. Dorsal neural spines about 1.4 to 1.7 times the centrum height

Clades within Megalosauroidea

References

  1. Fitzinger, L. (1843). Systema Reptilium. Fasciculus Primus. Amblyglossae. 106 pp. Braumüller und Seidel.

    Listed the family as "Megalosauri", attributed to Meyer, from which the superfamily name takes its authorship by coordination.

    fitzinger1843a
  2. 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. Informa UK Limited. doi:10.1080/14772019.2011.630927

    Defined Megalosauroidea as all taxa closer to Megalosaurus than to Allosaurus or Tyrannosaurus.

    carrano2012a
  3. Rauhut, O. W. M.; Pol, D. (2019). Probable basal allosauroid from the early Middle Jurassic Cañadón Asfalto Formation of Argentina highlights phylogenetic uncertainty in tetanuran theropod dinosaurs. Scientific Reports 9(1). Springer Science and Business Media LLC. doi:10.1038/s41598-019-53672-7

    Recovered traditional megalosauroids as a paraphyletic grade outside Allosauroidea within Carnosauria.

    rauhut2019a
  4. Zou, Y.; Chen, L.; Wang, T.; Wang, G. F.; Zhang, W. G.; Zhang, X. Q.; Wang, Z. J.; Wu, X. C.; You, H. L. (2025). A new metriacanthosaurid theropod dinosaur from the Middle Jurassic of Yunnan Province, China. PeerJ 13: e19218. PeerJ. doi:10.7717/peerj.19218

    Recovered Piatnitzkysauridae outside Megalosauroidea in a new metriacanthosaurid phylogenetic analysis.

    zou2025a
  5. Benson, R. B. J. (2010). A description of Megalosaurus 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. Oxford University Press (OUP). doi:10.1111/j.1096-3642.2009.00569.x

    Defined Megalosauroidea as Megalosaurus bucklandii and all taxa closer to it than to Allosaurus fragilis or Passer domesticus, treating Spinosauroidea as a junior synonym.

    benson2010c
  6. Rauhut, O. M.; Hübner, T.; Lanser, K. (2016). A new megalosaurid theropod dinosaur from the late Middle Jurassic (Callovian) of north-western Germany: Implications for theropod evolution and faunal turnover in the Jurassic. Palaeontologia Electronica 19(2): 26A. Coquina Press. doi:10.26879/654

    Described Wiehenvenator, with a megalosauroid phylogeny that uses Eustreptospondylinae in place of Afrovenatorinae for priority.

    rauhut2016a