Magnosaurus Huene, 1932

Rauhut, Oliver W. M., 2003, The interrelationships and evolution of basal theropod dinosaurs, Special papers in palaeontology 69, pp. 1-213 : 20

Magnosaurus Huene, 1932

Included taxa. Magnosaurus nethercombensis ( Huene, 1923) ; Magnosaurus oxoniensis ( Walker, 1964) .

Temporal range. Bajocian-Callovian.

Occurrence. Inferior Oolite, Dorset; Middle Oxford Clay, Oxfordshire, England.

Diagnosis. Lateral nutrient foramina placed in a shallow longitudinal groove with a subrectangular crosssection on posterior part of dentary; squamosal with lateral flange on the rim of the infratemporal fenestra.

Remarks. The taxon Magnosaurus nethercombensis was originally described by Huene (1923, see also Huene 1926 «) as a new species of Megalosaurus , based on a pair of dentaries and fragmentary associated postcrania from the Bajocian of Dorset. Magnosaurus oxoniensis is based on a partial skull (Text-flg. 5c) and postcranial skeleton from the Callovian Oxford Clay of Oxfordshire, which was named Eustreptospondylus oxoniensis by Walker (1964).

Although comparisons are limited by the fragmentary nature of the remains of Magnosaurus nethercombensis , this taxon and Eustreptospondylus oxoniensis share several characters unseen in other Middle Jurassic theropods, including a slight dorsoventral and transverse expansion of the anterior part of the dentary, the presence of a significantly enlarged third dentary tooth, and the probable synapomorphy of a shallow, longitudinal groove with a rectangular cross-section on the dentary. Since all the other skeletal elements preserved in both species are, furthermore, almost indistinguishable, Eustreptospondylus oxoniensis Walker, 1964 , can be referred to the genus Magnosaurus Huene, 1932 . The stratigraphical separation of the two type specimens, and slight differences in the proximal extent of the pubic apron indicate that M. nethercombensis and M. oxoniensis should be tentatively regarded as different species. Since all character codings are identical in the two species, they can be treated as a single OTU.