Megalosauridae

Megalosaurids
Temporal range: MiddleLate Jurassic, 170–145 Ma Possible Berriasian-Valanginian record
Skeletal mount of Torvosaurus tanneri, Museum of Ancient Life
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Clade: Saurischia
Clade: Theropoda
Clade: Megalosauria
Family: Megalosauridae
Huxley, 1869
Type species
Megalosaurus bucklandii
Mantell, 1827
Subgroups
Synonyms
  • Torvosauridae Jensen, 1985
  • Eustreptospondylidae Paul, 1988
  • Streptospondylidae Kurzanov 1989

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.[1] 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.[2]

The defining megalosaurid, Megalosaurus bucklandii, was first named and described in 1824 by William Buckland after multiple finds in Stonesfield, Oxfordshire, UK. Megalosaurus was the first formally described dinosaur and was the basis for the establishment of the clade Dinosauria. It is also one of the largest known Middle Jurassic carnivorous dinosaurs, with the best-preserved femur at 805 mm and a proposed body mass of around 943 kg.[3] Megalosauridae has mainly been recognized as a European group of dinosaurs, based on fossils found in France and the UK, but fossils show that the group is also found in North America, Africa, South America and possibly Asia.[4][5][6]

The family Megalosauridae was first defined by Thomas Huxley in 1869, yet it has been contested throughout history due to its role as a "waste-basket" for many partially described dinosaurs or unidentified remains.[7] In the early years of paleontology, most large theropods were grouped together and up to 48 species were included in the clade Megalosauria, the basal clade of Megalosauridae. Over time, most of these taxa were placed in other clades and the parameters of Megalosauridae were narrowed significantly. However, some controversy remains over whether Megalosauridae should be considered its own distinct group, and dinosaurs in this family remain some of the most problematic taxa in all Dinosauria.[5][7] Some paleontologists, such as Paul Sereno in 2005, have disregarded the group due to its shaky foundation and lack of clarified phylogeny. However, recent research by Carrano, Benson, and Sampson has systematically analyzed all basal tetanurans and determined that Megalosauridae should exist as its own family. They have been generally closely related to the family Spinosauridae.

  1. ^ 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. doi:10.1111/j.1096-3642.2009.00569.x.
  2. ^ Cite error: The named reference :3 was invoked but never defined (see the help page).
  3. ^ Allain, Ronan (2002). "Discovery of megalosaur (Dinosauria, Theropoda) in the middle Bathonian of Normandy (France) and its implications for the phylogeny of basal tetanurae". Journal of Vertebrate Paleontology. 22 (3): 548–563. doi:10.1671/0272-4634(2002)022[0548:DOMDTI]2.0.CO;2. S2CID 85751613.
  4. ^ Rayfield, E.J. (2011). "Structural performance of tetanuran theropod skulls, with emphasis on the Megalosauridae, Spinosauridae and Carcharodontosauridae". Studies on Fossil Tetrapods. Special Papers in Palaeontology.
  5. ^ a b Serrano-Martinez, Alejandro (February 2015). "New theropod remains from the Tiourarén Formation (?Middle Jurassic, Niger) and their bearing on the dental evolution in basal tetanurans". Proceedings of the Geologists' Association. 126: 107–118. doi:10.1016/j.pgeola.2014.10.005.
  6. ^ Soto, Matías; Toriño, Pablo; Perea, Daniel (March 2020). "A large sized megalosaurid (Theropoda, Tetanurae) from the late Jurassic of Uruguay and Tanzania". Journal of South American Earth Sciences. 98: 102458. Bibcode:2020JSAES..9802458S. doi:10.1016/j.jsames.2019.102458. S2CID 213672502.
  7. ^ a b Benson, R.B.J. (2008). "The taxonomic status of Megalosaurus bucklandii (Dinosauria, Theropoda) from the Middle Jurassic of Oxfordshire, UK". Palaeontology. 51 (2): 419–424. doi:10.1111/j.1475-4983.2008.00751.x.