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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.
In 1926, he named the tooth species Megalosaurus lydekkeri for a specimen, BMNH 41352, from the Lower Lias (Lower Jurassic) of England that Richard Lydekker had first described in 1888.von Huene, F. (1926). The carnivorous Saurischia in the Jura and Cretaceous formations, principally in Europe. Revista del Museo de La Plata 29:35-167.Lydekker, R. (1888). Catalogue of the Fossil Reptilia and Amphibia in the British Museum (Natural History). Part I. Containing the Orders Ornithosauria, Crocodilia, Dinosauria, Squamata, Rhynchocephalia, and Proterosauria. British Museum (Natural History):London, 309 p. Finally, in 1932, he created the genus Magnosaurus for M. nethercombensis, referred M. lydekkeri to it, and created a third species, M. woodwardi, for the genus. M. woodwardi was based on a tibia (BMNH R.3542) from the Lower Lias, which he simultaneously and accidentally also named Sarcosaurus;von Huene, F. (1932). Die fossile Reptil-Ordnung Saurischia, ihre Entwicklung und Geschichte. Monographien zur Geologie und Palaeontologie 1(4) German in 1956 the latter name was given priority by von Huene. Even more confusing, in the same 1932 publication von Huene renamed Sarcosaurus woodi into Magnosaurus woodi.
Until the 1990s, the genus had been ignored as a species of Megalosaurus.Waldman, M. (1974). "Megalosaurids from the Bajocian (Middle Jurassic) of Dorset". Palaeontology 17(2):325-339. However, with growing concern over what exactly is constituted by Megalosaurus, Magnosaurus has been generally separated as its own genus.Molnar, R.E., Kurzanov, S.M., and Dong, Z. (1990). "Carnosauria". In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.), The Dinosauria. University of California Press:Berkeley and Los Angeles, p. 169-209. Rauhut, O.W.M. (2003). "The Interrelationships and Evolution of Basal Theropod Dinosaurs." Special Papers in Palaeontology 69. The Palaeontological Association:London, 213 p.Holtz Jr., T.R., Molnar, R.E., and Currie, P.J. (2004). "Basal Tetanurae". In: Weishampel, D.B., Dodson, P., and Osmólska, H. (eds.), The Dinosauria (second edition). Berkeley: University of California Press:Berkeley, p. 71-110. Also, there are morphological differences: for example, possible Megalosaurus tibiae are compressed at the far end, unlike those of Magnosaurus. Rauhut (2003) considered it and Eustreptospondylus to be the same genus, because the two share a similarly expanded front tip of the dentary and enlarged third dentary tooth. He therefore renamed Eustreptospondylus oxoniensis a Magnosaurus oxoniensis but this has not been generally followed. Reviews have found it to most likely be a basal tetanuran, probably a Megalosauridae.Paul, G.S. (1988). Predatory Dinosaurs of the World. Simon & Schuster:New York, 464 p. A detailed redescription by Roger Benson in 2010 concluded Magnosaurus was valid taxon, a megalosaurid megalosauroid, and at about 175 million years old the oldest certain known member of the Tetanurae.
The type species of Eustreptospondylus, Megalosaurus and Sarcosaurus are also sometimes assigned to Magnosaurus. In such cases the combinations are:
Species
Magnosaurus is known from many species, most of were originally named as a different genus.Weishampel, D.B.; Dodson, P.; Osmolska, H. (eds.). "The Dinosauria: Second Edition". Berkeley: University of California Press, p 99. .
Description
Because the remains are sparse and fragmentary, most details about its anatomical features are unknown. It would have been a carnivore of moderate size for a dinosaur. The most similar animals to it would probably be Eustreptospondylus, Dubreuillosaurus, and Afrovenator. Paul (1988) roughly estimated the mass of the type individual as around , which would correspond to a length of roughly , judging by his estimates for the sizes of other theropods. Benson however, in 2010 gave a higher estimation of about half a tonne; the animal would have stood at over a metre at the hip.
Classification
The phylogenetic position of Magnosaurus according to Carrano et al. (2012) is shown by this cladogram:M.T. Carrano, R.B.J. Benson, and S.D. Sampson, 2012, "The phylogeny of Tetanurae (Dinosauria: Theropoda)", Journal of Systematic Palaeontology 10(2): 211-300
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