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Megalosaurus (meaning "great lizard", from Ancient Greek μέγας, megas, meaning 'big', 'tall' or 'great' and σαῦρος, sauros, meaning 'lizard') is an extinct genus of large carnivorous theropod of the Middle Jurassic Epoch (Bathonian stage, 166 million years ago) of southern England. Although fossils from other areas have been assigned to the genus, the only certain remains of Megalosaurus come from Oxfordshire and date to the late Middle Jurassic.
The earliest remains of Megalosaurus were described in the 17th century, and were initially interpreted as the remains of elephants or giants. Megalosaurus was named in 1824 by William Buckland, becoming the first genus of (non-avian) dinosaur to be validly named. The type species is M. bucklandii, named in 1827 by Gideon Mantell, after Buckland. In 1842, Megalosaurus was one of three genera on which Richard Owen based his Dinosauria, along with Iguanodon and Hylaeosaurus. On Owen's directions a model was made as one of the Crystal Palace Dinosaurs, which greatly increased the public interest for prehistoric reptiles. Over 50 other species would eventually be classified under the genus; at first, this was because so few types of dinosaur had been identified, but the practice continued even into the 20th century after many other dinosaurs had been discovered. Today it is understood that none of these additional species was directly related to M. bucklandii, which is the only true Megalosaurus species. Because a complete skeleton of it has never been found, much is still unclear about its build.
The first naturalists who investigated Megalosaurus mistook it for a gigantic lizard in length. In 1842, Owen concluded that it was no longer than . He still thought it was a quadruped, though. Modern scientists were able to obtain a more accurate picture, by comparing Megalosaurus with its direct relatives in the Megalosauridae. Megalosaurus was about long, weighing about . It was bipedal, walking on stout hindlimbs, its horizontal torso balanced by a horizontal tail. Its forelimbs were short, though very robust. Megalosaurus had a rather large head, equipped with long curved teeth. It was generally a robust and heavily muscled animal.
At the time Megalosaurus lived, Europe formed an island archipelago bounded by then narrow Atlantic Ocean and Tethys Ocean, with Megalosaurus inhabiting an island formed by the London–Brabant Massif, where it likely served as the apex predator of its ecosystem, coexisting with other dinosaurs like the large sauropod Cetiosaurus, Stegosauria, Ankylosauria, and heterodontosaurids.
OU 1328 was collected near Caswell, near Witney, Oxfordshire sometime during the 17th century and became the third dinosaur fossil to ever be illustrated,Gunther, R.T. (1945). Early Science in Oxford: Life and Letters of Edward Lhuyd, volume 14. Author:Oxford. after " Scrotum humanum" in 1677 and " Rutellum impicatum" in 1699.
It has also been argued that this possible Megalosaurus bone was given the very first species name ever applied to an extinct dinosaur. Plot's engraving of the Cornwell bone was again used in a book by Richard Brookes in 1763. Brookes, in a caption, called it " Scrotum humanum", apparently comparing its appearance to a pair of "human ". However, it is possible that the attribution of this name stemmed from illustrator error, not Richard Brookes. In 1970, paleontologist Lambert Beverly Halstead pointed out that the similarity of Scrotum humanum to a modern species name, a so-called Linnaean "binomen" that has two parts, was not a coincidence. Carl Linnaeus, the founder of modern taxonomy, had in the eighteenth century not merely devised a system for naming living creatures, but also for classifying geological objects. The book by Brookes was all about applying this latter system to curious stones found in England. According to Halstead, Brookes thus had deliberately used binomial nomenclature, and had in fact indicated the possible type specimen of a new biological genus. According to the rules of the International Code of Zoological Nomenclature (ICZN), the name Scrotum humanum in principle had priority over Megalosaurus because it was published first. That Brookes understood that the stone did not actually represent a pair of petrified testicles was irrelevant. Merely the fact that the name had not been used in subsequent literature meant that it could be removed from competition for priority, because the ICZN states that if a name has never been considered valid after 1899, it can be made a nomen oblitum, an invalid "forgotten name".
In 1993, after the death of Halstead, his friend William A.S. Sarjeant submitted a petition to the International Commission on Zoological Nomenclature to formally suppress the name Scrotum in favour of Megalosaurus. He wrote that the supposed junior synonym Megalosaurus bucklandii should be made a conserved name to ensure its priority. However, the Executive Secretary of the ICZN at the time, Philip K. Tubbs, did not consider the petition to be admissible, concluding that the term " Scrotum humanum", published merely as a label for an illustration, did not constitute the valid creation of a new name, and stated that there was no evidence it was ever intended as such. Furthermore, the partial femur was too incomplete to definitely be referred to Megalosaurus and not a different, contemporary theropod.
In the early nineteenth century, more discoveries were made. In 1815, John Kidd reported the find of bones of giant tetrapods, again at the Stonesfield quarry. The layers there are currently considered part of the Taynton Limestone Formation, dating to the mid-Bathonian stage of the Jurassic Period. The bones were apparently acquired by William Buckland, Professor of Geology at the University of Oxford and fellow of Corpus Christi. Buckland also studied a lower jaw, according to Gunther the one bought by Pegge. Buckland did not know to what animal the bones belonged but, in 1818, after the Napoleonic Wars, the French people comparative anatomist Georges Cuvier visited Buckland in Oxford and realized that they were those of a giant lizard-like creature. Buckland further studied the remains with Mary Buckland (later his wife), and his friend William Conybeare who in 1821 referred to them as the "Huge Lizard". In 1822 Buckland and Conybeare, in a joint article to be included in Cuvier's Ossemens, intended to provide scientific names for both gigantic lizard-like creatures known at the time: the remains found near Maastricht would be named Mosasaurus – then seen as a land-dwelling animal – while for the British lizard Conybeare had devised the name "Megalosaurus", from the Greek μέγας, megas, "large". That year a publication failed to occur, but the physician James Parkinson already in 1822 announced the name "Megalosaurus", illustrating one of the teeth and revealing the creature was 40 feet long and eight feet high. It is generally considered that the name in 1822 was still a nomen nudum ("naked name"). Buckland, urged on by an impatient Cuvier, continued to work on the subject during 1823. Mary Morland provide drawings of the bones, that were to be the basis of illustrating lithographies. Finally, on 20 February 1824, during the same meeting of the Geological Society of London in which Conybeare described a very complete specimen of Plesiosaurus, Buckland formally announced Megalosaurus. The descriptions of the bones in the Transactions of the Geological Society, in 1824, constitute a valid publication of the name. Megalosaurus was the first non-avian dinosaur genus named; the first of which the remains had with certainty been scientifically described was Streptospondylus, in 1808 by Cuvier.
By 1824, the material available to Buckland consisted of specimen OUM J13505, a piece of a right lower jaw with a single erupted tooth; OUM J13577, a posterior dorsal vertebra; OUM J13579, an anterior caudal vertebra; OUM J13576, a sacrum of five sacral vertebrae; OUM J13585, a cervical rib; OUM J13580, a rib; OUM J29881, an ilium of the pelvis, OUM J13563, a piece of the pubic bone; OUM J13565, a part of the ischium; OUM J13561, a thigh bone and OUM J13572, the lower part of a second metatarsal. As he himself was aware, these did not all belong to the same individual; only the sacrum was articulated. Because they represented several individuals, the described fossils formed a syntype series. By modern standards, from these a single specimen has to be selected to serve as the type specimen on which the name is based. In 1990, Ralph Molnar chose the famous dentary (front part of the lower jaw), OUM J13505, as such a lectotype.Molnar, R.E.; Seriozha M.K. & Dong Z. (1990). "Carnosauria" In: (2025). 9780520254084, University of California Press. ISBN 9780520254084 Because he was unaccustomed to the deep dinosaurian pelvis, much taller than with typical reptiles, Buckland misidentified several bones, interpreting the pubic bone as a fibula and mistaking the ischium for a clavicle. Buckland identified the organism as being a giant animal belonging to the Sauria – the Lizards, at the time seen as including the crocodiles - and he placed it in the new genus Megalosaurus, repeating an estimate by Cuvier that the largest pieces he described, indicated an animal 12 meters long in life.
The presumption that carnivorous dinosaurs, like Megalosaurus, were quadrupeds was first challenged by the find of Compsognathus in 1859. That, however, was a very small animal, the significance of which for gigantic forms could be denied. In 1870, near Oxford, the type specimen of Eustreptospondylus was discovered – the first reasonably intact skeleton of a large theropod. It was clearly bipedal. Shortly afterwards, John Phillips created the first public display of a theropod skeleton in Oxford, arranging the known Megalosaurus bones, held by recesses in cardboard sheets, in a more or less natural position. During the 1870s, discoveries of large theropods, like Allosaurus, confirmed that they were bipedal. The Oxford University Museum of Natural History display contains most of the specimens from the original description by Buckland.
Apart from the finds in the Taynton Limestone Formation, in 1939 Sidney Hugh Reynolds referred remains to Megalosaurus that had been found in the older Chipping Norton Limestone Formation dating from the early Bathonian, about 30 single teeth and bones. Though the age disparity makes it problematic to assume an identity with Megalosaurus bucklandii, in 2009 Benson could not establish any relevant anatomical differences with M. bucklandii among the remains found at one site, the New Park Quarry, and therefore affirmed the reference to that species. However, in another site, the Oakham Quarry, the material contained one bone, an ilium, that was clearly dissimilar.
Sometimes have been referred to Megalosaurus or to the ichnogenus Megalosauripus. In 1997, a famous group of fossilized footprints (ichnites) was found in a limestone quarry at Ardley, 20 kilometers northeast of Oxford. They were thought to have been made by Megalosaurus and possibly also some left by Cetiosaurus. There are replicas of some of these footprints, set across the lawn of the Oxford University Museum of Natural History. One track was of a theropod accelerating from walking to running. According to Benson, such referrals are unprovable, as the tracks show no traits unique to Megalosaurus. Certainly they should be limited to finds that are of the same age as Megalosaurus bucklandii. In 2024 five more sets of tracks were discovered at a nearby Bicester quarry, with one of them showing clear features of large tridactyl theropod feet distinctive of Megalosaurus.
Finds from sites outside England, especially in France, have in the nineteenth and twentieth century been referred to M. bucklandii. In 2010 Benson considered these as either clearly different or too fragmentary to establish an identity.
The lower jaw is rather robust. It is also straight in top view, without much expansion at the jaw tip, suggesting the lower jaws as a pair, the mandibula, were narrow. Several traits in 2008 identified as autapomorphies, later transpired to have been the result of damage. However, a unique combination of traits is present in the wide longitudinal groove on the outer side (shared with Torvosaurus), the small third dentary tooth and a vascular channel, below the row of interdental plates, that only is closed from the fifth tooth position onwards. The number of dentary teeth was probably 13 or 14, though the preserved damaged specimens show at most 11 tooth sockets. The interdental plates have smooth inner sides, whereas those of the maxilla are vertically grooved; the same combination is shown by Piatnitzkysaurus. The surangular has no bony shelf, or even ridge, on its outer side. There is laterally an oval opening present in front of the jaw joint, a foramen surangulare posterior, but a second foramen surangulare anterior to the front of it is lacking.
The Stonesfield Slate material contains no neck vertebrae; but a single broken anterior cervical vertebra is known from the New Park Quarry, specimen NHMUK PV R9674. The breakage reveals large internal air chambers. The vertebra is also otherwise heavily pneumatized, with large pleurocoels, pneumatic excavations, on its sides. The rear facet of the centrum is strongly concave. The neck ribs are short. The front dorsal vertebrae are slightly opisthocoelous, with convex front centrum facets and concave rear centrum facets. They are also deeply keeled, with the ridge on the underside representing about 50% of the total centrum height. The front dorsals perhaps have a pleurocoel above the diapophysis, the lower rib joint process. The rear dorsal vertebrae, according to Benson, are not pneumatized. They are slightly amphicoelous, with hollow centrum facets. They have secondary joint processes, forming a hyposphene–hypantrum complex, the hyposphene having a triangular transverse cross-section. The height of the dorsal spines of the rear dorsals is unknown, but a high spine on a tail vertebra of the New Park Quarry material, specimen NHMUK PV R9677, suggests the presence of a crest on the hip area. The spines of the five vertebrae of the sacrum form a supraneural plate, fused at the top. The undersides of the sacral vertebrae are rounded but the second sacral is keeled; normally it is the third or fourth sacral having a ridge. The sacral vertebrae seem not to be pneumatized but have excavations at their sides. The tail vertebrae are slightly amphicoelous, with hollow centrum facets on both the front and rear side. They have excavations at their sides and a longitudinal groove on the underside. The neural spines of the tail basis are transversely thin and tall, representing more than half of the total vertebral height.
The humerus is very robust with strongly expanded upper and lower ends. Humerus specimen OUMNH J.13575 has a length of 388 millimeters. Its shaft circumference equals about half of the total humerus length. The humerus head continues to the front and the rear into large bosses, together forming a massive bone plate. On the front outer side of the shaft a large triangular deltopectoral crest is present, the attachment for the Musculus pectoralis major and the Musculus deltoideus. It covers about the upper half of the shaft length, its apex positioned rather low. The ulna is extremely robust, for its absolute size more heavily built than with any other known member of the Tetanurae. The only known specimen, NHMUK PV OR 36585, has a length of 232 millimeters and a minimal shaft circumference of 142 millimeters. The ulna is straight in front view and has a large olecranon, the attachment process for the Musculus triceps brachii. Radius, wrist and hand are unknown.
In the pelvis, the ilium is long and low, with a convex upper profile. Its front blade is triangular and rather short; at the front end there is a small drooping point, separated by a notch from the pubic peduncle. The rear blade is roughly rectangular. The outer side of the ilium is concave, serving as an attachment surface for the Musculus iliofemoralis, the main thigh muscle. Above the hip joint, on this surface a low vertical ridge is present with conspicuous vertical grooves. The bottom of the rear blade is excavated by a narrow but deep trough forming a bony shelf for the attachment of the Musculus caudofemoralis brevis. The outer side of the rear blade does not match the inner side, which thus can be seen as a separate "medial blade" that in side view is visible in two places: in the corner between outer side and the ischial peduncle and as a small surface behind the extreme rear tip of the outer side of the rear blade. The pubic bone is straight. The pubic bones of both pelvis halves are connected via narrow bony skirts that originated at a rather high position on the rear side and continued downwards to a point low on the front side of the shaft. The ischium is S-shaped in side view, showing at the transition point between the two curvatures a rough boss on the outer side. On the front edge of the ischial shaft an obturator process is present in the form of a low ridge, at its top separated from the shaft by a notch. To below, this ridge continues into an exceptionally thick bony skirt at the inner rear side of the shaft, covering over half of its length. Towards the end of the shaft, this skirt gradually merges with it. The shaft eventually ends in a sizeable "foot" with a convex lower profile.
The thigh bone is straight in front view. Seen from the same direction its head is perpendicular to the shaft, seen from above it is orientated 20° to the front. The greater trochanter is relatively wide and separated from the robust lesser trochanter in front of it, by a fissure. At the front base of the lesser trochanter a low accessory trochanter is present. At the lower end of the thigh bone a distinct front, extensor, groove separates the . At the upper inner side of this groove a rough area is present continuing inwards into a longitudinal ridge, a typical megalosauroid trait. The shinbone, or tibia, is relatively straight, slightly curving inwards. To below, its shaft progressively flattens from front to rear, resulting in a generally oval cross-section. For about an eighth of its length the front lower end of the shaft is covered by a vertical branch of the Talus bone. Of the foot, only the second, third and fourth metatarsals are known, the bone elements that were connected to the three weight-bearing toes. They are straight and robust, showing ligament pits at their lower sides. The third metatarsal has no clear condyles at its lower end, resulting in a more flexible joint, allowing for a modicum of horizontal movement. The top inner side of the third metatarsal carries a unique ridge that fits into a groove along the top outer side of the second metatarsal, causing a tighter connection.
Various distinguishing traits of the lower jaw have been established. The longitudinal groove on the outer surface of the dentary is wide. The third tooth socket of the dentary is not enlarged. Seen from above, the dentary is straight without an expanded jaw tip. The interdental plates, reinforcing the teeth from behind, of the lower jaw are tall. Benson also concluded it would be most parsimonious to assume that the Stonesfield Slate material represents a single species. If so, several additional distinctive traits can be observed in other parts of the skeleton. The low vertical ridge on the outer side of the ilium, above the hip joint, shows parallel vertical grooves. The bony skirts between the shafts of the ischia are thick and touch each other forming an almost flat surface. There is a boss present on the lower outer side of the ischium shaft with a rough surface. The underside of the second sacral vertebra has an angular longitudinal keel. A ridge on the upper side of the third metatarsal connected to a groove in the side of the second metatarsal. The middle of the front edge of the scapula forms a thin crest.Carrano (2012) p. 236
In the late 20th century the new method of cladistics allowed for the first time to exactly calculate how closely various taxa were related to each other. In 2012, Matthew Carrano et al. showed that Megalosaurus was the sister species of Torvosaurus within the Megalosaurinae, giving this cladogram:Carrano (2012), p. 270
Benson in 2010 concluded from its size and common distribution that Megalosaurus was the apex predator of its habitat. He saw the absence of Cetiosaurus on the French Armorican Massif as an indication that Megalosaurus too did not live on that island and was limited to the London-Brabant Massif, a tectonic high that during this period formed an island landmass including parts of southern Britain and adjacent areas of northern France, the Netherlands, Belgium and western Germany, suggested to be comparable in size to Cuba with an area of around . It has been questioned why the dinosaurs of the island did not experience insular dwarfism, as would be expected for an island of this size. A possible explanation for this is that the island remained ecologically connected to the much larger landmass comprising northern Britain (the Scottish Massif), the Fennoscandian Shield and the now submerged region in the North Sea between them,Buffetaut, E., B. Gibout, I. Launois, and C. Delacroix. 2011. The sauropod dinosaur Cetiosaurus Owen in the Bathonian (Middle Jurassic) of the Ardennes (NE France): insular, but not dwarf. Carnets de Géologie CG2011/06:149–161. with the seaway across England being very shallow, and showing evidence of at times being temporarily transformed into lagoons and terrestrial environments during the Bathonian. Plant fossils from the Taynton Limestone Formation from which many Megalosaurus fossils originate, representing the nearshore vegetation are largely dominated by conifers (including the living family Araucariaceae and the extinct family Cheirolepidiaceae) as well as the extinct seed plant group Bennettitales, with other plants including ( Ctenis), ferns ( Phlebopteris, Coniopteris) Caytoniales, the living genus Ginkgo, and the seed ferns Pachypteris and Komlopteris, representing a probably seasonally dry coastal environment including .
In 1882, Henri-Émile Sauvage named remains found at Louppy-le-Château, teeth and vertebrae from the Early Cretaceous, Megalosaurus superbus, "the proud one". In 1923, this became the genus Erectopus. In 1884/1885, Wilhelm Barnim Dames, based on specimen UM 84, a tooth from the Early Cretaceous, named Megalosaurus dunkeri, the specific name honouring Wilhelm Dunker. In 1923, this was made a separate genus Altispinax. In 1885, Joseph Henri Ferdinand Douvillé renamed Dakosaurus gracilis Quenstedt 1885 into Megalosaurus gracilis. Today the renaming is generally rejected. In 1889, Richard Lydekker named Megalosaurus oweni, the specific name honouring Owen, based on a series of metatarsals from the Early Cretaceous, specimen BMNH R?2556?. In 1991, this was made a separate genus Valdoraptor. In 1892, Edward Drinker Cope renamed Ceratosaurus nasicornis Marsh 1884 into Megalosaurus nasicornis. This had been largely motivated by a desire to annoy his rival Othniel Charles Marsh and the name has found no acceptance. In 1896, Charles Jean Julien Depéret named Megalosaurus crenatissimus, "the much crenelated", based on remains from the Late Cretaceous found in Madagascar. In 1955 this was made a separate genus Majungasaurus. The generic name Laelaps, used by Cope to denote a theropod, had been preoccupied by a mite. Marsh had therefore provided the replacement name Dryptosaurus, but Henry Fairfield Osborn, a partisan of Cope, rejected this replacement and thus in 1898 renamed Laelaps aquilunguis Cope 1866 into Megalosaurus aquilunguis.
In 1910, Arthur Smith Woodward named Megalosaurus bradleyi based on a skull from the Middle Jurassic, the specific name honouring the collector F. Lewis Bradley. In 1926, this was made a separate genus Proceratosaurus. In 1920, Werner Janensch named Megalosaurus ingens, "the enormous", based on specimen MB R 1050, a 12 centimeter long tooth from German East Africa. It possibly represents a large member of the Carcharodontosauridae; Carrano e.a. saw it as an indeterminate member of the Tetanurae. M. ingens is now seen as a specimen of Torvosaurus. In 1923, von Huene renamed Poekilopleuron bucklandii Eudes-Deslongchamps 1838 into Megalosaurus poikilopleuron. Today, the genus Poekilopleuron is generally seen as valid. In the same publication, von Huene named two additional Megalosaurus species. The first was Megalosaurus parkeri, its specific name honouring William Kitchen Parker and based on a pelvis, leg bones and vertebrae from the Late Cretaceous. This was made the separate genus Metriacanthosaurus in 1964. The second was Megalosaurus nethercombensis, named after its provenance from Nethercombe and based on two dentaries, leg bones, a pelvis and vertebrae from the Middle Jurassic, which von Huene himself in 1932 made the separate genus Magnosaurus. In 1925, Depéret, based on two teeth from Algeria, named Megalosaurus saharicus. In 1931/1932 this was made the separate genus Carcharodontosaurus. In 1956 von Huene by mistake named the same species as Megalosaurus africanus, intending to base it on remains from Morocco but referring the Algerian teeth; this implies that M. africanus is a junior objective synonym of M. saharicus. In 1926, von Huene named Megalosaurus lydekkeri, its specific name honouring Richard Lydekker, based on NHMUK OR 41352, i.e. the same specimen that had already been made the holotype of M. woodwardi (Lydekker, 1909). This implies that M. lydekkeri is a junior objective synonym of M. woodwardi. It is likewise seen as a nomen dubium.
In the same publication von Huene named Megalosaurus terquemi based on three teeth found near Hettingen, its specific name honouring Olry Terquem. It is seen as a nomen dubium, the fossil material probably representing some member of the Phytosauria or some other archosaur.Carrano (2012), p. 260 In 1932, a work by von Huene mentioned a Megalosaurus (Magnosaurus) woodwardi, a synonym of Magnosaurus woodwardi named in the same book. Its type specimen is differing from the earlier Megalosaurus woodwardi (Lydekker, 1909), the two names are not synonyms. In 1954 Samuel Welles named Megalosaurus wetherilli. This species is exceptional in being based on a rather complete skeleton, found in Arizona, from the Early Jurassic. Its specific name honours John Wetherill. In 1970, Welles made this the separate genus Dilophosaurus. In 1955, Albert-Félix de Lapparent named Megalosaurus mersensis based on a series of 23 vertebrae found near Tizi n'Juillerh in a layer of the El Mers Formation of Morocco. This probably represents a member of the Mesosuchia.Carrano (2012), p. 259 In 1956, Alfred Sherwood Romer renamed Aggiosaurus nicaeensis Ambayrac 1913, based on a lower jaw found near Nice, on the authority of von Huene into Megalosaurus nicaeensis. Originally it had been considered to be some crocodilian; present opinion confirms this. In 1957, de Lapparent named Megalosaurus pombali based on three teeth found near Pombal in the Jurassic of Portugal. Today it is seen as a nomen dubium, an indeterminate member of the Theropoda.
In 1965, Oskar Kuhn renamed Zanclodon silesiacus Jaekel 1910 into Megalosaurus? silesiacus.Kuhn, O. (1965). "Saurischia (Supplementum 1)". In: It is a nomen dubium based on the tooth of some indeterminate predatory Triassic archosaur, found in Silesia, perhaps a theropod. In 1966, Guillermo del Corro named Megalosaurus inexpectatus, named "the unexpected" as it was discovered on a sauropod site with remains of Chubutisaurus, based on specimen MACN 18.172, a tooth found in Argentina. It might represent a member of the Carcharodontosauridae.Carrano (2012), p. 258 In 1970, Rodney Steel named two Megalosaurus species. Firstly, he renamed Iliosuchus incognitus Huene 1932 into Megalosaurus incognitus. Secondly, he renamed Nuthetes destructor Owen 1854 into Megalosaurus destructor. Both genera are today seen as not identical to Megalosaurus. Michael Waldman in 1974 renamed Sarcosaurus andrewsi Huene 1932 into Megalosaurus andrewsi. Indeed, Sarcosaurus andrewsi is today by some scientists not seen as directly related to the type species of Sarcosaurus: Sarcosaurus woodi. In the same publication Waldman named Megalosaurus hesperis, "the western one", based on skull fragments from the Middle Jurassic. In 2008 this was made the separate genus Duriavenator. Del Corro in 1974 named Megalosaurus chubutensis, based on specimen MACN 18.189, a tooth found in Chubut Province. It is a nomen dubium, a possible carcharodontosaurid, or a very large Abelisauridae.
In 1985, Zhao Xijin named two Megalosaurus species found in Tibet.Zhao X., "The Jurassic Reptilia". In: He had earlier mentioned these species in an unpublished dissertation of 1983, implying they initially were invalid nomina ex dissertatione. However, his 1985 publication did not contain descriptions so the names are still nomina nuda. The first species was Megalosaurus "dapukaensis", named for the Dapuka Group. It was, in the second edition of The Dinosauria, by mistake spelled as Megalosaurus cachuensis. The second species was Megalosaurus "tibetensis". In 1987/1988, Monique Vianey-Liaud renamed Massospondylus rawesi (Lydekker, 1890), based on specimen NHMUK R4190, a tooth from the Maastrichtian of India, into Megalosaurus rawesi. This is a nomen dubium, a possible member of the Abelisauridae. In 1988, Gregory S. Paul renamed Torvosaurus tanneri Galton & Jensen 1979 into Megalosaurus tanneri. The change has found no acceptance. In 1973, Anatoly Konstantinovich Rozhdestvensky had renamed Poekilopleuron schmidti Kiprijanow 1883 into a Megalosaurus sp. However, as it is formally impossible to change a named species into an unnamed one, George Olshevsky in 1991 used the combinatio nova Megalosaurus schmidti. It is a chimaera. In 1993, Ernst Probst and Raymund Windolf by mistake renamed Plateosaurus ornatus Huene 1905 into Megalosaurus ornatus by mentioning the latter name in a species list. (1993). 9783570023143, C. Bertelsmann Verlag. ISBN 9783570023143 This can be seen as a nomen vanum. The same publication listed the ichnospecies Megalosauropus teutonicus Kaever & Lapparent 1974 as a Megalosaurus teutonicus. In 1997, Windolf renamed Saurocephalus monasterii Münster 1846, based on a tooth found near Hannover, into Megalosaurus monasterii.Windolf, R., "Theropoden-Zähne aus dem Oberen Jura Niedersachsens". In: It is a nomen dubium, an indeterminate member of the Theropoda. In 1998, Peter Malcolm Galton renamed Zanclodon cambrensis Newton 1899, based on a left lower jaw, specimen BGS 6532 found at Bridgend, into ? Megalosaurus cambrensis because it was not a basal Sauropodomorpha. It is a senior synonym of Gressylosaurus cambrensis Olshevsky 1991. The specific name refers to Cambria, the Latin name of Wales. It probably represents a member of the Coelophysoidea, or some other predatory archosaur.
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