page_title: Megalosauridae
section_title: Historical classification
hierarchical_section_title: Megalosauridae / Classification / Historical classification
caption_attribution_description: Original caption of the plate: The femur of the Megalosaurus; one fourth nat size. Fig. 1. Hinder surface.&#160;&#160;&#160;„&#160;&#160;&#160;2. Inner surface. From the Oolitic Slate, of Stonesfield, Oxfordshire. In the British Museum. Notes: Meaning of letters (according to description on Vol. I, p. 345): a&#160;=&#160;femoral head, b&#160;=&#160;groove between neck of femoral head and “great trochanter”, c&#160;=&#160;“great trochanter” (corresponds to the anterior or lesser trochanter of modern terminology), d&#160;=&#160;“inner trochanter” (corresponds to the 4th trochanter of modern terminology), e&#160;=&#160;inner condyle (medial condyle, Condylus medialis femoris), f&#160;=&#160;outer condyle (lateral condyle, Condylus lateralis femoris), g&#160;=&#160;“anterior or rotular interspace” (anterior intercondylar groove). The “Oolitic Slate, of Stonesfield” today is called Stonesfield Slate referred to the Taynton Limestone Formation which is of Middle Jurassic (middle Bathonian) age.&#91;1&#93; ↑ modern anatomical terms and stratigraphy according to Roger B. J. Benson (2010): A description of Megalosaurus bucklandii (Dinosauria: Theropoda) from the Bathonian of the UK and the relationships of Middle Jurassic theropods. Zoological Journal of the Linnean Society 158(4):&#160;882–935, doi:10.1111/j.1096-3642.2009.00569.x
context_page_description: Megalosauridae is a monophyletic family of carnivorous theropod dinosaurs within the group Megalosauroidea, closely related to the family Spinosauridae. Some members of this family include Megalosaurus, Torvosaurus, Eustreptospondylus, and Afrovenator. Appearing in the Middle Jurassic, megalosaurids were among the first major radiation of large theropod dinosaurs, although they became extinct by the end of the Jurassic period. They were a relatively primitive group of basal tetanurans containing two main subfamilies, Megalosaurinae and Afrovenatorinae, along with the basal genus Eustreptospondylus, an unresolved taxon which differs from both subfamilies.
  The defining megalosaurid is Megalosaurus bucklandii, first named and described in 1824 by William Buckland after multiple finds in Stonesfield, Oxfordshire, UK. Megalosaurus was the first formally described dinosaur and was the basis for the establishment of the clade Dinosauria. It is also one of the largest known Middle Jurassic carnivorous dinosaurs, with the best-preserved femur at 805 mm and a proposed body mass of around 943 kg.
context_section_description: From the family's inception, many specimens found in the field have been wrongly classified as megalosaurids. For example, most large carnivores found for about a century after the naming of Megalosaurus bucklandii were placed in Megalosauridae. Megalosaurus was the first paleontological finding of its kind when William Buckland discovered a giant femur and named it in 1824, predating even the term Dinosauria. When initially defined, the species M. bucklandii was anatomically based on various dissociated bones found in quarries around the village of Stonesfield, UK. Some of these early findings included a right dentary with a well-preserved tooth, ribs, pelvic bones, and sacral vertebrae. As early paleontologists and researchers found more dinosaur bones in the surrounding area, they attributed them all to M. bucklandii since it was the only named and described dinosaur at this point in history. Therefore, the species was initially described and classified by a mass of possibly unrelated characteristics.
  Modern paleontology first began to approach the problematic cladistic separation of Megalosauridae during the early 20th century. Fredrich von Huene separated carnivorous theropods, which had all been grouped into the broad category of megalosaurids, into two distinct families of larger, more giant sized and smaller, more lightly built theropods. These two groups were named Coelurosauria and Pachypodosauria respectively. Later on, Huene distinguished between carnivorous and herbivorous dinosaurs in Pachypodosauria, placing the meat-eaters in a new group Carnosauria.
  As more information was uncovered about basal theropods and phylogenetic characteristics, modern paleontologists began to question the proper naming for this group. In 2005 paleontologist Paul Sereno rejected the use of the clade Megalosauridae due to its ambiguous early history in favor of the name Torvosauridae. Today, it is accepted that megalosaurids existed at least as a group of basal tetanurans, due to the fact that they have more derived taxa than ceratosaurs and that the name Megalosauridae should represent this group. Megalosauridae also has priority over Torvosauridae under ICZN rules governing family names.
caption: Megalosaurus femur
exif: {"Image ImageWidth": "10032", "Image ImageLength": "9904", "Image BitsPerSample": "[8, 8, 8]", "Image Compression": "Uncompressed", "Image PhotometricInterpretation": "2", "Image Make": "i2s Digibook Scanner", "Image Model": "Suprascan A0 10000 RGB", "Image Orientation": "Horizontal (normal)", "Image SamplesPerPixel": "3", "Image XResolution": "800", "Image YResolution": "800", "Image PlanarConfiguration": "1", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop CS3 Windows", "Image DateTime": "2013:09:23 15:44:09", "Image ExifOffset": "320", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "458", "Thumbnail JPEGInterchangeFormatLength": "4547", "EXIF ColorSpace": "Uncalibrated", "EXIF ExifImageWidth": "2076", "EXIF ExifImageLength": "2801"}