SEARCH

SEARCH BY CITATION

Keywords:

  • Dinosauria;
  • Theropoda;
  • Megalosaurus;
  • Bathonian

Abstract

  1. Top of page
  2. Abstract
  3. Geological Setting
  4. Systematic Palaeontology
  5. Discussion
  6. Acknowledgments
  7. References

Abstract:  The lectotype of the Middle Jurassic theropod dinosaur Megalosaurus bucklandii, a right dentary, can be diagnosed on the basis of two unique characters: a longitudinal groove on the ventral part of the lateral surface of the dentary and a slit-like anterior Meckelian foramen. This taxon, the first dinosaur to be scientifically described, is therefore valid. Currently, however, no further material can be referred to this species with any certainty. Megalosaurus bucklandii occupies an uncertain systematic position but is not an abelisaurid or coelophysoid. Additionally, it does not possess the diagnostic dentary characters that are present in all known spinosauroids. Owing to this uncertainty, use of the family Megalosauridae should be discontinued until such time as its systematic position becomes clearer.

Megalosaurus is a theropod dinosaur from the Middle Jurassic of England. It is historically important as the first dinosaurian taxon to be recognised as reptilian and formally described in the scientific literature (Buckland 1824) as well as being one of the taxa upon which Richard Owen (1842) originally based the Dinosauria. The type species, Megalosaurus bucklandii, was erected by Mantell (1827) based on the collection of material from Stonesfield, Oxfordshire, UK that formed the basis for Buckland’s original description. Until recently Megalosaurus occupied a central position in studies of non-coelurosaurian theropods and was often proposed as a typical early ‘carnosaur’ in the older literature (e.g. von Huene 1926). The taxon is also important as it is a representative of the poorly known Middle Jurassic dinosaur fauna (Rauhut 2003; Holtz et al. 2004).

In the years following the description of the syntype series, material from a range of Middle Jurassic–Lower Cretaceous localities in England and northern France was unjustifiably referred to M. bucklandii, reaching an acme in Phillips (1871). Subsequently, the species was restricted to material from the type horizon, the Stonesfield Slate, by von Huene (1923). This material consists of numerous unassociated elements belonging to large theropods and representing much of the skeleton (Buckland 1824; Phillips 1871). Cladistic analyses (Holtz 1994, 2000) have found the taxon to be a basal tetanuran and one of a succession of outgroups to a more derived clade comprising allosauroids and coelurosaurs. The analysis of Holtz et al. (2004) found Megalosaurus to be a spinosauroid related to Poekilopleuron and Torvosaurus. Allain and Chure (2002), however, proposed that multiple taxa were represented in the large theropod material from the Stonesfield Slate, an observation confirmed by Day and Barrett (2004). It was suggested that the taxon should be restricted to the lectotype dentary (OUMNH J.13505) and it was recommended that Megalosaurus, as formerly considered, should not be included in cladistic analyses as such analyses would be utilising a chimera (Allain and Chure, 2002). The latter authors also failed to find diagnostic features of the dentary and thus considered Megalosaurus to be a nomen dubium.

In order for the fairly abundant and well-preserved Middle Jurassic theropod record of Britain to be of use to palaeontologists, a degree of taxonomic stability must be achieved. Re-evaluation of the lectotype of M. bucklandii suggests that the taxon can be diagnosed, but its phylogenetic position within Theropoda remains uncertain.

Institutional abbreviations.  BMNH, Natural History Museum, London; BYU, Brigham Young University Museum of Geology, Provo; FMNH, Field Museum of Natural History, Chicago; MNHN, Muséum National d’Histoire Naturelle, Paris; OUMNH, Oxford University Museum of Natural History, Oxford; UCMP, University of California Museum of Paleontology, Berkeley; UMNH VP, University of Utah Museum of Natural History, Salt Lake City.

Geological Setting

  1. Top of page
  2. Abstract
  3. Geological Setting
  4. Systematic Palaeontology
  5. Discussion
  6. Acknowledgments
  7. References

The lectotype and paralectotype series, and much of the referred material, was recovered from the Stonesfield Slate. This is a recurrent lithological facies that occurs at three levels within the Taynton Limestone Formation. It consists of beds of laminated calcareous sandstone that are restricted to the vicinity of the village of Stonesfield, Oxfordshire (Boneham and Wyatt 1993). The Taynton Limestone Formation pertains to the Procerites progracilis (ammonite) Zone, which is thought to have been deposited in the lower part of the middle Bathonian (Torrens 1980). The Stonesfield Slate has produced one of the most diverse Middle Jurassic vertebrate faunas known, including the remains of turtles, crocodilians, pterosaurs, dinosaurs, pliosaurs, ichthyosaurs and cynodonts (Benton and Spencer 1995).

Systematic Palaeontology

  1. Top of page
  2. Abstract
  3. Geological Setting
  4. Systematic Palaeontology
  5. Discussion
  6. Acknowledgments
  7. References

DINOSAURIA Owen, 1842 THEROPODA Marsh, 1881 Incertae sedis

Genus MEGALOSAURUS Buckland and Conybeare, inBuckland 1824

Type species. Megalosaurus bucklandiiMantell, 1827.

Diagnosis.  As for the type species, M. bucklandii.

Remarks.  The generic name Megalosaurus was first used in Parkinson (1822, p. 298) but this publication did not include a description, definition or any indication of types as required for the name to be available under Article 12 of the International Code of Zoological Nomenclature (International Commission on Zoological Nomenclature 1999). Buckland (1824, p. 391) proposed the name accompanied by the explanation, ‘In consideration therefore of the enormous magnitude which this saurian attains, I have ventured, in concurrence with my friend and fellow-labourer, the Rev. W. Conybeare, to assign to it the name of Megalosaurus’. This was accompanied by a detailed description including figures and is thus taken as the original source for the name.

Megalosaurus bucklandiiMantell, 1827 Text-figures 1–2

image

Figure TEXT-FIG. 1..  Interpretive drawing of lectotype right dentary (OUMNH J.13505) of Megalosaurus bucklandii from the Taynton Limestone Formation of Stonesfield, Oxfordshire, UK. A, medial and B, lateral views; idp, interdental plates; mg, Meckelian groove; mf, Meckelian foramen; mfo, Mecklian fossa; nvf, neurovascular foramina. Light grey represents tooth; medium grey, areas restored in plaster; dark grey, broken surface. Scale bar represents 100 mm.

Download figure to PowerPoint

image

Figure TEXT-FIG. 2..  Photographs of OUMNH J.13505 in A, medial (with magnification of Meckelian foramina × 2), B, dorsal and C, lateral views; pdg, paradental groove. Scale bar represents 100 mm.

Download figure to PowerPoint

1826 Megalosaurus conybeari Ritgen, p. 354 (nomen nudum).

1827 Megalosaurus bucklandii Mantell, p. 67, pl. 18, fig. 2; pl. 19, figs 1, 8, 12, 14–16.

1832 Megalosaurus bucklandi von Meyer, p. 110.

Lectotype.  OUMNH J.13505, a partial right dentary. OUMNH J. 13505b and 13505c, blocks of matrix containing the impressions of the lateral and medial sides of the dentary respectively and fragments of the superficial layers of the bone.

Locality and horizon.  Unknown horizon within the Taynton Limestone Formation, middle Bathonian Procerites progracilis (ammonite) Zone, Stonesfield, Oxfordshire, UK.

Previous diagnosis.  Twelve to thirteen teeth in maxilla and dentary, tooth carinae positioned anteriorly and posteriorly, not obliquely. Dentary straight, with symphysial facet. Vertebrae short; scapula large, with anterior expansion of middle part of blade; humerus stout; pubis with small distal thickening, extensive symphysis, no foot; ischium down-curved posteriorly; femur massive, lesser trochanter placed well down shaft; tibia stout, 83 per cent of femur length (after Waldman 1974, p. 326).

Revised diagnosis.  Theropod dinosaur with the following autapomorphic features of the dentary: 13–14 teeth, a longitudinal groove in the ventral part of the lateral surface and a slit-like foramen anterior to the termination of the Meckelian groove.

Remarks.  The binomen Megalosaurus conybearei was used by Ritgen (1826) but not accompanied by any description, diagnosis or indication as required under Article 12 of the International Code of Zoological Nomenclature (International Commission on Zoological Nomenclature 1999) and is thus a nomen nudum. Megalosaurus bucklandii was used by Mantell (1827) in a publication including descriptions and figures of the syntype material. This spelling of the species epithet was used subsequently by only a few early authors (e.g. Mantell 1833; Eudes-Deslongchamps 1838) prior to Molnar et al. (1990) who incorrectly attributed the name to Ritgen (1826). Since that time it has been used as the presumed valid name in a handful of publications. Megalosaurus bucklandi was proposed by von Meyer (1832) and this spelling has been used by the vast majority of subsequent authors. Nevertheless it is an objective junior synonym of M. bucklandiiMantell, 1827.

The lectotype appeared in the collections of the Oxford Anatomy School at Christchurch College in 1797. The School’s minute book for 24 October 1797 records this entry: ‘Large jaw bone with two serrated teeth, in calc schistus from Stonesfield, purchased for 10s 6d’ (Günther 1925, p. 191). At this time the collection was being built by Dr (later Sir) Christopher Pegge, the Reader in Anatomy. Buckland was friendly with Dr Pegge but even if he had not been he would surely have known the collection as he was also a fellow of Christchurch.

The original syntype series of Megalosaurus bucklandii includes the various isolated, unassociated elements mentioned and figured by Mantell (1827) following the material originally attributed to this taxon by Buckland (1824), including: dorsal (OUMNH J. 13577) and caudal (OUMNH J. 13579) vertebrae, a sacrum (OUMNH J.13576), a right ilium (OUMNH J.29881: misidentified as a coracoid), a pubis (OUMNH J. 13563: misidentified as a fibula), an ischium (OUMNH J.13565: misidentified as a clavicle), a right femur (OUMNH J.13561), a metatarsal (OUMNH J. 13572), and two ribs (OUMNH J.13580, J.29792). Unfortunately, other material included in the original description (including a tooth and some fragments of bone) cannot be reliably identified among the OUMNH collections. Molnar et al. (1990) formally proposed designation of the dentary (OUMNH J.13505) as the lectotype, rendering the rest of the syntype series paralectotypes. However, as none of the paralectotypes can be convincingly referred to the same taxon as the lectotype dentary we follow Allain and Chure (2002) in restricting the hypodigm of Megalosaurus bucklandii to the lectotype pending the discovery of additional comparable material.

Description.  The type right dentary, OUMNH J.13505 is almost complete though missing much of the delicate portion posterior to the opening of the Meckelian fossa. The lateral and medial surfaces have been restored in part as indicated in Text-figure 1: however, there is no indication of damage in the figures of Buckland (1824, pl. 40, fig. 2) or Owen (1857, pl. 11, fig. 2). It is straight in dorsal view, unlike the medially curving dentary of Allosaurus (UMNH VP 9366). In lateral view it has a slightly sinuous ventral margin, being weakly convex anteriorly and weakly concave posteriorly, and a weakly convex dorsal margin, both of which are usual for carnivorous theropods.

Eleven alveoli are preserved, although more were certainly present. Waldman (1974) estimated that 12–13 teeth would have been present in the complete dentary based on comparison with Allosaurus. However, 13 teeth are present in the type of Dubreuillosaurus valesdunensis (MNHN 1998–13) with only ten positioned anterior to the position of the break in OUMNH J.13505. As such it is likely that more teeth, perhaps 14, were originally present in the latter specimen. The alveoli have transversely compressed oval outlines in dorsal view except for the anteriormost alveolus, which is small and subcircular. The fourth alveolus is the largest, having the greatest anteroposterior length. The third and fifth alveoli appear to have greater transverse widths (Text-fig. 2B): however, this is the result of resorption of the medial walls of the alveoli to accommodate replacement teeth and does not reflect their original dimensions. Although it is largest, the fourth alveolus is not transversely expanded. In coelophysoids (Dilophosaurus, UCMP 37303) and spinosauroids (Baryonyx, BMNH R9951; Dubreuillosaurus, MNHN 1998–13; Eustreptospondylus, OUMNH J.13558; Magnosaurus, OUMNH J.12143/1a–b; and Torvosaurus, BYU 2003) the third alveolus is the largest, and in these taxa the lateral wall of the dentary swells laterally to accommodate the enlarged alveolus. In OUMNH J.13505 the dentary is transversely expanded between the third and sixth alveoli but this is a much more gentle expansion and is subequal on both sides of the tooth row.

The interdental plates are poorly preserved but were probably subpentagonal in outline, with vertical, subparallel sides basally, but becoming pointed towards the apex. This shape is common among theropods, although some of the interdental plates of abelisaurids (Majungatholus, FMNH PR 2100) have a rectangular outline. In OUMNH J.13505 the interdental plates posterior to the fifth and sixth tooth positions respectively have the appearance of having rectangular outlines. However, at this level both the lateral wall of the dentary and the interdental plates are broken dorsally and the shape of the interdental plates cannot be assessed with certainty. On the basis of the shapes of more anteriorly and posteriorly positioned interdental plates these plates were probably subpentagonal and not square in outline. The interdental plates of Megalosaurus are unfused and do not have the rugose medial surfaces that are present in abelisaurids (Carrano et al. 2002).

The paradental groove for the dental artery separates the medial faces of the interdental plates from the medial wall of the dentary. It is open dorsally, defining a distinct gap between those two structures anteriorly until the fifth interdental plate where it becomes closed, allowing the two structures to contact one another. In most other Jurassic theropod taxa the groove is either open for the entire length (Allosaurus, UMNH VP 9366; Dilophosaurus, UCMP 37303; Magnosaurus, OUMNH J.12143/1a–b) or closed for the entire length (Torvosaurus, BYU 2003) of the dentary. However, in ‘Megalosaurushesperis (BMNH R332) and Dubreuillosaurus valesdunensis (MNHN 1998–13) the situation is similar to that in OUMNH J.13505. This character should be treated cautiously as it may be the result of post-burial plastic deformation of the element: however, it appears to be present in both left and right elements of ‘Megalosaurushesperis (BMNH R332).

The medial wall of the dentary beneath the interdental places is relatively flat. Anteriorly, there is no evidence of a definite symphysial area, though this region has been slightly abraded. Only the anterior part of the Meckelian fossa is preserved. The Meckelian groove continues along the ventral part of the medial surface from the anterior and anterodorsal bounds of the fossa, paralleling the ventral margin of the element. Posteriorly it is broad and indistinct, housing two finer, more distinct and slightly sinuous grooves. Anterior to the level of the sixth alveolus it becomes narrow and more distinct, terminating at the level of the posterior margin of the third alveolus. Ventral to this termination an oval foramen is present. Anterior to the termination a distinct, slit-like, opening is present that may be a second foramen (Text-fig. 2A). Two such foramina are present in most Jurassic theropods in which this region is preserved [Allosaurus, UMNH VP 9366; Ceratosaurus, UMNH VP 5278; Dubreuillosaurus, MNHN 1998–13; Eustreptospondylus, OUMNH J.13558; Magnosaurus, OUMNH J.12143/1a–b); Monolophosaurus (Zhao and Currie 1993); and Sinraptor (Currie and Zhao 1993)], although it is possible that only one is present in Dilophosaurus (UCMP 37303). The presence of only a single foramen is a feature shared with some abelisaurids (e.g. Majungatholus, FMNH PR 2100) and the Rhaetian taxon ‘Zanclodoncambrensis (BMNH R2912). None of the listed taxa possesses an anterior foramen that is dorsoventrally compressed.

A number of subcircular foramina are present with a random distribution in the anterior parts of the lateral and ventral surfaces of the dentary. A further four are widely spaced in a longitudinal row posterior to these and just dorsal to mid-height on the lateral surface (Text-fig. 2). They open dorsolaterally and are anteroposteriorly long ovals in shape. In common with Allosaurus (UMNH VP 9366) these are not set in a lateral groove, as are at least some in Ceratosaurus (UMNH VP 5278), Dilophosaurus (UCMP 37303), Dubreuillosaurus (MNHN 1998–13), Eustreptospondylus (OUMNH J13558), Magnosaurus (OUMNH J.12143/1a–b), Majungatholus (FMNH PR 2100), Monolophosaurus (N. Smith, pers. comm. 2006), Sinraptor (Currie and Zhao 1993; Gao 1999), Torvosaurus (BYU 2003). The dorsal part of the lateral wall is damaged and restored but only in places, giving it an unnatural jagged appearance. Parts have also been restored centrally and in the ventral part posteriorly. A longitudinal groove is present near the ventral margin and parallel to it (Text-fig. 1A). This has not been observed in any other non-avian theropod dinosaur.

Only one fully-erupted tooth is present, in the sixth alveolus. Partially erupted teeth are present in alveoli 3, 5 and 8, and replacement teeth are visible between the interdental plates adjacent to the fourth, fifth, sixth, eighth and ninth alveoli. The teeth are recurved, transversely compressed and serrated as is generally typical of theropods. They are almost symmetrical: the posterior carina, which continues to the base of the tooth, is positioned on the midline and the anterior carina, continuing about one-third of the way down the tooth, is only slightly laterally deflected basally. ‘Blood grooves’, fine grooves continuing onto the crown from between the serrations, are not present. Gentle transverse wrinkles continuing around the side of the crown and slightly upturned towards the carinae anteriorly and posteriorly are distinct laterally but only weak medially.

Discussion

  1. Top of page
  2. Abstract
  3. Geological Setting
  4. Systematic Palaeontology
  5. Discussion
  6. Acknowledgments
  7. References

The lectotype of Megalosaurus bears two potential apomorphies (contra Allain and Chure 2002) and is distinct from all other Jurassic theropods for which the dentary is known.

A second dentary from the type locality and horizon of Megalosaurus bucklandii was reported and figured in medial view by Owen (1857, pl. 12, figs 1–3) and mentioned again by Owen (1883). This specimen formed a part of the Duke of Marlborough’s collection at Blenheim Palace. Attempts to relocate this specimen have proved unsuccessful thus far. Although at least some of the other large theropod elements from the Stonesfield Slate almost certainly belonged to the same taxon as OUMNH J.13505, no records of association between the material exist. As there is evidence for more than one large theropod taxon in the Stonesfield fauna (Allain and Chure 2002; Day and Barrett 2004) none of these elements can be referred to M. bucklandii with any certainty.

Megalosaurus bucklandii shares features with a range of theropods from different taxonomic groupings. The distributions of these characters have not yet been assessed in numerical phylogenetic analyses. It does not possess an enlarged third dentary tooth, a character found by Rauhut (2003) to be a synapomorphy of Neotheropoda (under ACCTRAN optimisation) with subsequent loss in the clade comprising Ceratosauria and Tetanurae and redevelopment in Spinosauroidea. It also lacks rugose medial surfaces of the interdental plates, which have been found to be a synapomorphy of the Abelisauridae (Carrano et al. 2002). Consequently, Megalosaurus bucklandii is probably a member of the clade comprising Ceratosauria and Tetanurae, but lies outside Abelisauridae. There is currently no positive evidence on which to refer M. bucklandii to Spinosauroidea and the characteristic morphology of the dentary that is present in all known spinosauroids is absent in Megalosaurus. This conclusion differs from that of Holtz et al. (2004), whose phylogenetic analysis found Megalosaurus to be a spinosauroid. However, the latter placement probably relates to the inclusion of data from Stonesfield theropod elements that cannot confidently be referred to this taxon (see Allain and Chure 2002).

Various taxa have been referred to the Megalosauridae Huxley, 1869, including Chilantaisaurus tashuikouensis (Hu 1964), Gasosaurus (Dong and Tang 1985), ‘Szechuanosauruszigongensis (Gao 1993) and Poekilopleuron (Allain 2002). However, dentaries are not known in any of these taxa. Some recent authors have used the family Megalosauridae to refer to basal members of the Spinosauroidea. These include Holtz et al. (2004), who referred Megalosaurus bucklandii, Afrovenator, Eustreptospondylus, Piatnitzkysaurus, Poekilopleuron, Dubreuillosaurus (as ‘unnamed eustreptospondyline’) and Torvosaurus to this clade, and Allain (2002) who included Dubreuillosaurus, Torvosaurus, Afrovenator and Eustreptospondylus in Megalosauridae. Since Megalosaurus has not been shown to share any characters of systematic significance with spinosauroids it is recommended that this practice, as well as the practice of referring to any other taxa as ‘megalosaurid’ be discontinued until further information on the systematic position of Megalosaurus is revealed.

Acknowledgments

  1. Top of page
  2. Abstract
  3. Geological Setting
  4. Systematic Palaeontology
  5. Discussion
  6. Acknowledgments
  7. References

Acknowledgements.  We thank the following for access to specimens in their care: Mike Getty (UMNH VP), Pat Holdroyd (UCMP), Rod Scheetz (BYU), Sandra Chapman (BMNH) and, particularly, Paul Jeffery (OUMNH). RBJB thanks the Natural Environment Research Council (studentship number: NER/S/A/2005/13488) for funding his PhD research.

References

  1. Top of page
  2. Abstract
  3. Geological Setting
  4. Systematic Palaeontology
  5. Discussion
  6. Acknowledgments
  7. References
  • ALLAIN, R. 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, 548563.
  • ALLAIN, R. and CHURE, D. J. 2002. Poekilopleuron bucklandii, the theropod dinosaur from the Middle Jurassic (Bathonian) of Normandy. Palaeontology, 45, 11071121.
  • BENTON, M. J. and SPENCER, P. S. 1995. Fossil reptiles of Great Britain. Chapman and Hall, London, 386 pp.
  • BONEHAM, B. F. W. and WYATT, R. J. 1993. The stratigraphical position of the Middle Jurassic (Bathonian) Stonesfield Slate of Stonesfield, Oxfordshire, UK. Proceedings of the Geologists’ Association, 104, 123136.
  • BUCKLAND, W. 1824. Notice on the Megalosaurus or great fossil lizard of Stonesfield. Transactions of the Geological Society of London, 21, 390397, pls 40–44.
  • CARRANO, M. T., SAMPSON, S. D. and FORSTER, C. A. 2002. The osteology of Masiakasaurus knopfleri, a small abelisauroid (Dinosauria: Theropoda) from the Late Cretaceous of Madagascar. Journal of Vertebrate Paleontology, 22, 510534.
  • CURRIE, P. J. and ZHAO XI-JIN 1993. A new carnosaur (Dinosauria: Theropoda) from the Jurassic of Xinjiang, People’s Republic of China. Canadian Journal of Earth Sciences, 30, 20372081.
  • DAY, J. J. and BARRETT, P. M. 2004. Material referred to Megalosaurus (Dinosauria: Theropoda) from the Middle Jurassic of Stonesfield, Oxfordshire, England: one taxon or two? Proceedings of the Geologists’ Association, 115, 359366.
  • DONG ZHI-MING and TANG ZI-LU 1985. A new mid-Jurassic theropod (Gasosaurus constructus gen. et sp. nov. from Dashanpu, Zigong, Sichuan Province, China. Vertebrata PalAsiatica, 23, 7883, pls 1–2. [In Chinese, English abstract].
  • EUDES-DESLONGCHAMPS, J.-A. 1838. Mémoire sur le Poekilopleuron bucklandii, grand saurien fossile, intermédiare entre les crocodiles et les lézards. Mémoire de la Societé Linnéenne du Normandie, 6, 37146.
  • GAO YU-HUI 1993. A new species of Szechuanosaurus from the Middle Jurassic of Dashanpu, Zigong, Sichuan. Vertebrata PalAsiatica, 31, 308314, pls 1–3. [In Chinese, English abstract].
  • GAO, YU-HUI 1999. A complete carnosaur skeleton from Zigong, Sichuan. Yangchuanosaurus hepingensis. Sichuan Science and Technology Press, Chengdu, 80 pp., 20 pls. [In Chinese, English summary].
  • GÜNTHER, A. E. 1925. Early science in Oxford. Volume 3, the biological sciences. Part 2, the biological collections. Oxford University Press, Oxford, 564 pp.
  • HOLTZ, T. R. Jr 1994. The phylogenetic position of the Tyrannosauridae: implications for theropod systematics. Journal of Paleontology, 68, 11001117.
  • HOLTZ, T. R. JR 2000. A new phylogeny of the carnivorous dinosaurs. 5–61. In PÉREZ-MORENO, B. P., HOLTZ, T., SANZ, J.-L. and MORATALLA, J. J. (eds). Aspects of theropod paleobiology. Gaia, 15, 403 pp.
  • HOLTZ, T. R. JR, MOLNAR, R. E. and CURRIE, P. J. 2004. Basal Tetanurae. 71–110. In WEISHAMPEL, D. B., DODSON, P. and OSMÓLSKA, H. (eds). The Dinosauria. Second edition. University of California Press, Berkeley, CA, 861 pp.
  • HU SHOW-YUNG 1964. Carnosaurian remains from Alashan, Inner Mongolia. Vertebrata PalAsiatica, 8, 4263. pls 1–2. [In Chinese, English summary].
  • HUENE, F. von 1923. Carnivorous Saurischia in Europe since the Triassic. Geological Society of America, Bulletin, 34, 449458.
  • HUENE, F. VON 1926. The carnivorous Saurischia in the Jura and Cretaceous formations, principally in Europe. Revista del Museo de La Plata, 29, 35167.
  • HUXLEY, T. H. 1869. On the upper jaw of Megalosaurus. Quarterly Journal of the Geological Society of London, 25, 311314.
  • INTERNATIONAL COMMISSION ON ZOOLOGICAL NOMENCLATURE 1999. International Code of Zoological Nomenclature. Fourth Edition. International Trust for Zoological Nomenclature, London, 306 pp.
  • MANTELL, G. A. 1827. Illustrations of the geology of Sussex: a general view of the geological relations of the south-eastern part of England, with figures and descriptions of the fossils of Tilgate forest. Lupton Relfe, London. xii + 92 pp., 20 pls.
  • MANTELL, G. A. 1833. The geology of the south-east of England. Longman, London, 415 pp., 7 pls.
  • MARSH, O. C. 1881. Principal characters of American Jurassic dinosaurs. Part V. American Journal of Science, Series 3, 21, 417423.
  • MEYER, H. von 1832. Paläologica zur Geschichte der Erde. Siegmund Schmerber Verlag, Frankfurt-am-Main, 560 pp.
  • MOLNAR, R. E., KURZANOV, S. M. and DONG ZHI-MING 1990. Carnosauria. 169–209. In WEISHAMPEL, D. B., DODSON, P. and OSMOLSKA, H. (eds). The Dinosauria. University of California Press, Berkeley, CA, 733 pp.
  • OWEN, R. 1842. Report on British fossil reptiles. Part II. Reports of the British Association for the Advancement of Science, 11, 60204.
  • OWEN, R. 1857. Monograph on the Fossil Reptilia of the Wealden Formations. Part III. Dinosauria (Megalosaurus). Palaeontographical Society Monographs, 34, 126, pls 1–12.
  • OWEN, R. 1883. On the skull of Megalosaurus. Quarterly Journal of the Geological Society of London, 39, 334347.
  • PARKINSON, J. 1822. Outlines of oryctology: an introduction to the study of fossil organic remains. Sherwood, Neely and Jones, London, 346 pp.
  • PHILLIPS, J. 1871. Geology of Oxford and the valley of the Thames. Clarendon Press, Oxford, 523 pp, 17 pls.
  • RAUHUT, O. W. M. 2003. The interrelationships and evolution of basal theropod dinosaurs. Special Papers in Palaeontology, 69, 1213.
  • RITGEN, F. A. von 1826. Versuchte Herstellung einiger Becken urweltlichter Thiere. Nova Acta Academiae Caesarea Leopoldino-Carolinae Germanicae Naturae Curiosorum, 13, 331358.
  • TORRENS, H. S. 1980. Bathonian correlation chart. 21–44. In COPE, J. C. W. (ed). A correlation of Jurassic rocks in the British Isles,Part 2. Special Reports of the Geological Society of London, 15, 109 pp.
  • WALDMAN, M. 1974. Megalosaurids from the Bajocian (Middle Jurassic) of Dorset. Palaeontology, 17, 325339.
  • ZHAO XI-JIN and CURRIE, P. J. 1993. A large crested theropod from the Jurassic of Xinjiang, People’s Republic of China. Canadian Journal of Earth Sciences, 30, 20272036.