Magnosaurus

*Magnosaurus nethercombensis*

***Magnosaurus*** (meaning 'large lizard') was a genus of basal tetanuran theropod dinosaurfrom the Middle Jurassic of England. It is based on fragmentary remains and has often been confused with or included in *Megalosaurus*.

## Description

Because the remains are sparse and fragmentary, most details about its anatomical features are unknown. It would have been a bipedal 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 175 kg (386 lb), which would correspond to a length of roughly four metres (13.1 ft), 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.

## History and Taxonomy

In 1923, Friedrich von Huene named *Megalosaurus nethercombensis* from a partial skeleton (OUM J12143) from the Aalenian-Bajocian-age Middle Jurassic Inferior Oolite, found in the nineteenth century by W. Parker near Nethercomb, north of Sherborne, in Dorset, England. The material included partial dentaries, dorsal and caudal vertebrae, a partial ilium, a partial right pubis, internal casts of the femora, and tibiae, from a possibly juvenile individual. Huene interpreted it as a more primitive species of *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 Lydekkerhad first described in 1888. 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 andrewsi*; 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*. However, with growing concern over what exactly is constituted by *Megalosaurus*, *Magnosaurus*has been generally separated as its own genus. 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 megalosaurid. A detailed redescription by Roger Benson in 2010 concluded *Magnosaurus* was valid taxon, a megalosauridmegalosauroid, and at about 175 million years old the oldest certain known member of the Tetanurae.

### Species

*Magnosaurus* is known from many species, most of were originally named as a different genus.

* *Magnosaurus nethercombensis* (Huene, 1923) Huene, 1932 = *Megalosaurus nethercombensis* Huene, 1923
* *Magnosaurus lydekkeri* (Huene, 1926) Huene, 1932 *(nomen dubium)* = *Megalosaurus lydekkeri* Huene, 1926
* *Magnosaurus woodwardi* Huene, 1932 *(nomen dubium)* = *Sarcosaurus andrewsi*Huene, 1932 = *Megalosaurus woodwardi*(Huene, 1932)

The type species of *Eustreptospondylus*, *Megalosaurus* and *Sarcosaurus* are also sometimes assigned to *Magnosaurus*. In such cases the combinations are:

* *Magnosaurus woodi* (Andrews, 1921) = *Sarcosaurus woodi* Andrews, 1921
* *Magnosaurus oxoniensis* (Walker, 1964) Rahut, 2003 = *Eustreptospondylus oxoniensis*Walker, 1964
* *Magnosaurus bucklandi* (Meyer, 1832) Weishampel *et al.*, 2004 = lapsus calami, *Megalosaurus bucklandi* Meyer, 1832 = *Megalosaurus bucklandii* Mantell, 1827

## Classification

The phylogenetic position of Magnosaurus according to Carrano et al. (2012) is shown by this cladogram:

## JPInstitute.com Description

Magnosaurus was a smaller version of Megalosaurus, a large meat-eater. Both dinosaurs lived in England, but Magnosaurus lived millions of years before its larger relative. In fact, some scientists think that Magnosaurus is just an early Megalosaurus.

There is still discussion as to whether Magnosaurus should be considered a species of Megalosaurus. However, careful study has found several distinctions, notably in the thickness of the teeth.

## Links

https://web.archive.org/web/20030813080123/http://www.jpinstitute.com/dinopedia/dinocards/dc\_magno.html
https://web.archive.org/web/20080705164729/http://kids.yahoo.com/dinosaurs/322--Magnosaurus