Temporal range: 166–Middle Jurassic Ma
A restoration of Megalosaurus bucklandii
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sauropsida
clade: Dinosauria
Suborder: Theropoda
Family: Megalosauridae
Subfamily: Megalosaurinae
Genus: Megalosaurus
Buckland, 1824
Species: M. bucklandii
Type species
Megalosaurus bucklandii
Buckland, 1824
  • Megalosaurus phllipsi, Welles, Powell & Pickering, 1995
  • Gressylosaurus Lapparent, 1967

Megalosaurus (Meaning “Mega Lizard”) (Buckland, 1824) was a large theropod dinosaur of the Megalosauridae family and was the first non-avian dinosaur skeleton ever described. It was discovered by William Buckland in the 1820s, and recognized as a huge reptile. However, Richard Plot wrote a scientific paper on the bottom of this dinosaur's femur, which he called "Scrotum humanum" (in reference to its lower femur, which somewhat resembled a scrotum) in 1627, nearly two centuries and 7 years before. The discovery of Megalosaurus changed the way scientists looked at Earth's past forever, since they then realized that humans weren't the first creatures to walk on this planet. The discovery of the fossils also challenged the widely held religious beliefs of biblical Christianity common at the time. For a long time, every giant theropod founded in Europe (or even North America) was considered a species of Megalosaurus. It was one of the original trio that Richard Owen proposed to call the Dinosaurian in 1842, along with Iguanodon and Hylaeosaurus.


250px-Megalosaurus, World Museum Liverpool

Megalosaurus Skeleton

Megalosaurus was a larger theropod for its day, reaching between 23 and 30 feet (7 to 9 meters) long, and weighing 1.5 to 2 tons, it one of the largest predator in its area of occurrence. A femur even suggests a size of 11.36 m and 4.6 tonnes. It had somewhat short, but strong arms with sharp, hooklike claws on three fingers, perfectly designed for gripping onto prey and slashing at it. It also had long, powerful hindlegs, good for chasing down prey. Its tail, like most other theropods, was built to help balance it while moving. It had a long, narrow skull with sharp, bladelike teeth for slicing through the flesh of other creatures.

But, its bite wasn't weaker than Allosaurus's, despite the skull being much more flattened. That's because it had a very thick, neck, helping the predator to bite its prey with great force. Its tail is very heavy and stiff, helping Megalosaurus to balance; it presents half of the Megalosaurus's weight. It was a close relative of the larger Torvosaurus of North America. Megalosaurus for a long time was thought to have been a carnosaur, but closer analysis of the bones proved it was its own genus. The newer version of Megalosaurus looks much different than the old-fashioned version of dinosaurs, which looked like large, lumbering lizards instead of large, upright, birdlike reptiles. It used to be pictured looking closely like a large Komodo Dragon, walking on four stout, sprawled legs with its tail dragging on the ground.

Megalo Parker femur

Parker coll. femur, an exceptionally large specimen of Megalosaurus.


Megalosaurus crystal palace email

Old-Fashioned Megalosaurus Statue

Megalosaurus may have been the first dinosaur to be described in the scientific literature. Part of a bone was recovered from the Taynton Limestone Formation of Stonesfield limestone quarry, Oxfordshire in 1676. Sir Thomas Pennyson gave the fragment to Robert Plot, Professor of Chemistry at the University of Oxford and first curator of the Ashmolean Museum, who published a description and illustration in his Natural History of Oxfordshire in 1676. It was the first illustration of a dinosaur bone published. Plot correctly identified the bone as the lower extremity of the thighbone or femur of a large animal and he recognized that it was too large to belong to any species known to be living in England. He therefore at first concluded it to be the thighbone of a Roman war elephant and later that of a giant human, such as those mentioned in the Bible. The bone has since been lost, but the illustration is detailed enough that some have since identified it as that of Megalosaurus.


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 testicles". 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. 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".

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Evolution of Megalosaurus changes throughout paleontologic history.

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 Media[]


Old-fashioned Megalosaurus fights old-fashioned Iguanodon

Megalosaurus is not really too popular of a dinosaur in TV shows or documentaries, but it's quite famous in the paleontology world and in most books listing dinosaurs and video games:

  • It was mentioned several times in Robert T. Bakker's book, The Dinosaur Heresies, and is shown killing an ancient crocodile, and also is shown with its jaw bone compared to an early mammal called Megazostrodon.
  • It's also listed in a book called The Ultimate Book of Dinosaurs, where they talk about the theropod and give a general description of it, and another one called Dino Wars, where they compare its deadliness to other dinosaurs. In England, there are parks with statues of the old-fashioned Megalosaurus created by Benjamin Waterhouse Hawkins by Buckingham Palace.
  • When dinosaurs ruled the earth megalosaurus

    Megalosaurus in When Dinosaurs ruled the Earth.

    Megalosaurus is the type of species that Earl Sinclair from Jim Henson's Dinosaurs is.
  • Megalosaurus also appears in the anime series, Dinosaur King, as a rare golden rainbow Dinosaur, which is uniquely aggressive.
  • It was seen as a Rod Puppet in Dinosaur! with Walter Cronkite “Tale of a Tooth”.
  • It also appears in Dino Hunter: Deadly Shore in its' old inaccurate lizard-like form.
  • Megalosaurus JW

    Megalosaurus in Jurassic World: The Game

    It also appears in ARK: Survival Evolved.
  • Megalosaurus is in Jurassic World: Alive. The Megalosaurus is a rare dinosaur, and features a Rajasaur-like build.
  • A single Megalosaurus, though not explicitly named in-game, appears in Dinosaur Adventure 3D, fighting a Stegosaurus in the latter's associated cutscene. However, the two dinosaurs would've never encountered each other in real life, as Megalosaurus lived in Europe, while Stegosaurus lived in North America.
  • In When Dinosaurs Ruled the Earth, a quadrupedal Megalosaurus exists, Which is similar to the one as a quadruped. Some think the Creature in the Film looks more like a quadruped Tyrannosaurus rex. Since it resembles The Beast From 20,000 Fathoms from 1953. Including Planet of Dinosaurs several years later.
  • Megalosaurus even appeared on Dinosaur Train “Dinosaurs A to Z”.
  • Megalosaurus was featured on a few episodes of the A&E Documentary Dinosaur! With Walter Cronkite.
  • Megalosaurus appeard in the two-part British documentary Dinosaur Britain on ITV that tells the story about the many types of dinosaurs that once ruled Great Britain.