Megalosaurus (meaning "Great Lizard") is a genus of large meat-eating theropod dinosaurs of the Middle Jurassic period (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 the late Middle Jurassic of the Oxfordshire.
The earliest possible fossils of the genus came from the Taynton Limestone Formation. One of these was the lower part of a femur, discovered in the 17th century. It was originally described by Robert Plot as a thighbone of a Roman war elephant, and then as a biblical giant. The first scientific name given for it, in the 18th century, was Scrotum humanum, created by Richard Brookes as a caption; however, this is not considered valid today.
Megalosaurus was, in 1824, the first genus of non-avian dinosaur to be validly named. The type species is Megalosaurus bucklandii, named in 1827. In 1842, Megalosaurus was one of three genera on which Richard Owen based his Dinosauria. On Owen's directions a model was made as one of the Crystal Palace Dinosaurs, which greatly increased the public interest for prehistoric reptiles. Subsequently, over fifty other species would be classified under the genus, originally because dinosaurs were not well known, but even during the 20th century after many dinosaurs had been discovered. Today it is understood these additional species were not 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 of twenty metres length. In 1842, Owen concluded that it was no longer than nine metres, standing on upright legs. He still thought it was a quadruped, though. Modern scientists, by comparing Megalosaurus with its direct relatives in the Megalosauridae, were able to obtain a more accurate picture. Megalosaurus was about seven metres long, weighing about 1.1 tonnes. 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.
Description[]
Size comparison (human in blue, lectotype in pink, largest specimen in red)
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', 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' 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.
Modern reconstructions[]
Restoration of Megalosaurus, with a mostly hypothetical head
In fact, Megalosaurus did have a relatively large head and the teeth were clearly that of a carnivore. However, the long tail would have balanced the body and head and so Megalosaurus is now restored as a bipedal beast—like all other theropods—about 9 meters in length. The structure of the cervical vertebrae suggests that its neck would have been very flexible. To support its weight of around one ton, the legs were large and muscular. Like all theropods, it had three forward facing toes and a single reversed one. Although they had not reached the minuscule size of later theropods like Tyrannosaurus, the fore limbs of Megalosaurus were small and probably had three or four digits.
Living in what is now Europe, during the Jurassic Period (181 to 169 million years ago), Megalosaurus may have hunted stegosaurs and sauropods. Repeated descriptions of Megalosaurus hunting Iguanodon (another of the earliest dinosaurs named) through the forests that then covered the continent are probably inaccurate, because Iguanodon skeletons are found in much younger Early Cretaceous formations. No fossils assignable to Megalosaurus have been discovered in Africa, contrary to some outdated dinosaur books.
Although Megalosaurus was a powerful carnivore and could probably have attacked even the largest sauropods, it is also likely that it gained some of its food by scavenging. That is not to detract from its prowess as a hunter (Tyrannosaurus probably did much the same). Efficiency was necessary to feed such a large body.
There is a good descriptive display of Megalosaurus and of the history of discovery, in the Oxford University Museum of Natural History.
Discovery[]
1854 reconstruction in Crystal Palace Park guided by Richard Owen presents Megalosaurus as a quadruped; modern reconstructions make it bipedal, like most theropods
Possible Megalosaurus tooth OU 1328
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".
"Scrotum humanum"[]
The cover of Robert Plot's Natural History of Oxfordshire, 1677 (right). Plot's illustration of the lower extremity of a Megalosaurus femur (left).
Megalosaurus was the first dinosaur to be described in the scientific literature. Part of a bone was recovered from a limestone quarry at Cornwell near Chipping Norton, Oxfordshire, England in 1676. The fragment was sent to Robert Plot, Professor of Chemistry at the University of Oxford and first curator of the Ashmolean Museum, who published a description in his Natural History of Oxfordshire in 1677. He correctly identified the bone as the lower extremity of the femur of a large animal and he recognized that it was too large to belong to any known species. He therefore concluded it to be the thigh bone of a giant human, such as those mentioned in the Bible. The bone has since been lost but the illustration is detailed enough to identify it clearly as the femur of a Megalosaurus.[1]
The Cornwell bone was described again by Richard Brookes in 1763. He called it "Scrotum humanum," while comparing its appearance to a pair of human testicles. The label was not considered to be a proper Linnaean "name" for the animal in question at the time, and was not used in subsequent literature. Technically, though, the name was published after the advent of binomial nomenclature, and so if it was truly intended to represent the erection of a new genus it would have priority over Megalosaurus. However, the rules of the ICZN state that if a name falls into disuse for 50 years after publication, it is no longer in competition for priority. Therefore, the name Scrotum humanum would be a nomen oblitum, or "forgotten name" even if it had been a valid genus to begin with.[2]
Buckland's research[]
Engraving from William Buckland's "Notice on the Megalosaurus or great Fossil Lizard of Stonesfield", 1824. Caption reads "anterior extremity of the right lower jaw of the Megalosaurus from Stonesfield near Oxford".
More discoveries were made, starting in 1815, again at the Stonesfield quarry (currently considered part of the Taynton Limestone Formation, dating to the mid-Bathonian stage of the Jurassic Period).[3] They were acquired by William Buckland, Professor of Geology at the University of Oxford and dean of Christ Church. He did not know to what animal the bones belonged but, in 1818, after the Napoleonic Wars, the French comparative anatomist Georges Cuvier visited Buckland in Oxford and realised that the bones belonged to a giant lizard-like creature. Buckland then published descriptions of the bones in Transactions of the Geological Society, in 1824 (Physician James Parkinson had described them in an article in 1822).
By 1824, Buckland had a piece of a lower jaw with teeth, some vertebrae, and fragments of pelvis, scapula and hind limbs, probably not all from the same individual. Buckland identified the organism as being a giant animal related to the Sauria (lizards) and he placed it in the new genus Megalosaurus, estimating the animal to be 12 m long in life.[4] In 1826, Ferdinand von Ritgen gave this dinosaur a complete binomial, Megalosaurus conybeari, which was not used by later authors and is now considered a nomen oblitum. A year later, in 1827, Gideon Mantell included Megalosaurus in his geological survey of southeastern England, and assigned the species its current binomial name, Megalosaurus bucklandii.[5] It would not be until 1842 that Richard Owen coined the term 'dinosaur'.
Megalosaurus vertebra - OUMNH.
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 1997, a famous group of fossilised footprints (ichnites) was found in a limestone quarry at Ardley, 20 km Northeast of Oxford, England. 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 Oxford University Museum of Natural History.
Early reconstructions[]
Reconstruction of Megalosaurus and Pterodactylus by Samuel Griswold Goodrich from 1859. This is typical of early reconstructions in presenting Megalosaurus as a quadruped; modern reconstructions make it bipedal.
Édouard Riou's 1863 depiction of herbivore Iguanodon battling Megalosaurus
Von Meyer's restoration of Megalosaurus from before 1897; showing it bipedal with long neural spines
In 1852, Benjamin Waterhouse Hawkins was commissioned to a build a model of Megalosaurus for the exhibition of dinosaurs at the Crystal Palace, which is still there to this day. Early paleontologists, never having seen such a creature before, reconstructed it like the dragons of popular mythology, with a huge head and walking on all fours. It was not until the middle of the nineteenth century, when other theropods began to be discovered in North America, that a more accurate picture was developed. Some confusion still exists, for at one time (before classification of dinosaurs became the serious business it is today), all theropods from Europe were given the title Megalosaurus. Since then, these have mostly been reclassified but older papers can still cause confusion. For further confusion, the most reproduced anatomy diagram of a Megalosaurus' skeleton was produced before any vertebrae had been recovered. While drawing it, Friedrich von Huene of the University of Tübingen, Germany, instead used the backbones of Altispinax, a mysterious big theropod known from high-spined dorsal vertebrae and at times classified as a spinosaur. Hence, many later drawings, based on his original, show Megalosaurus with a deep spinal ridge or even a small sail, like that of Spinosaurus.
Classification[]
| Megalosauroidea |
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Inaccurate attributions[]
At one time, Megalosaurus was a 'wastebasket genus', used to classify many different kinds of large theropods. Dilophosaurus, Eustreptospondylus, and Metriacanthosaurus were all initially believed to be species of Megalosaurus. In recent years, the genus has been subject to extensive reconsideration and most of the extraneous species have been removed.
Paleoecology[]
Founded in the Taynton Limestone and Chipping Norton Limestone formations in England, Megalosaurus lived in the tropical climes of Europe around 165 million years ago during the Middle Jurassic period, roaming forests in search of prey. The formations were home to various species of fish, mammals and marine reptiles. The close association of Megalosaurus fossils and marine deposits suggests that it occasionally fed on dead plesiosaurs and other carrion washed up on the shore.[6] Other dinosaur remains are scarce, but include the sauropod Cetiosaurus, small tyrannosauroid Proceratosaurus, and fellow megalosaurid Duriavenator. Other possible Megalosaurus species have been found in the El Mers Group in Morocco and the Lourinhã Formation in Portugal.
JPInstitute.com Description[]
Megalosaurus was the first dinosaur ever named. Megalosaurus was found in England in the year 1822 by a geologist named William Buckland. He found the teeth and knew it was from a really big animal. The word 'dinosaur' did not yet exist. In fact, this dinosaur was a typical two legged meat-eater, but people back then knew so little about it that they thought it walked on four legs like a big lizard. It wasn't until 20 years later, in 1842, that Sir Richard Owen came up with the word 'dinosaur' to describe these spectacular fossil creatures which were being discovered.
Since so little of Megalosaurus was originally discovered, it was depicted as a large, quadrupedal lizard with a head like a crocodile. This image of the first dinosaurs lasted some years until more complete specimens were discovered.
Megalosaurus was a common carnivore of the Jurassic - species of this genus have been found on several continents. As common as it was, it exhibits only a few of the technical characteristics associated with other therapods.
Dinosaur Field Guide Description[]
Megalosaurus ("giant lizard") was the first Mesozoic dinosaur to be H named. For centuries, fragments of meat-eating dinosaurs had been found, but scientists thought these came from giant human beings (!) or elephants. Then around 1815, Reverend William Buckland, a scientist at the University of Oxford, came across the remains of a jawbone with teeth, leg bones, and other parts of a skeleton. The teeth reminded Buckland of those of the monitor lizards, meat-eating lizards of the modern world. But these teeth and bones came from a reptile far larger than any monitor lizard! In 1822, this new creature was given the name Megalosaurus. Buckland did not call his creature a dinosaur. That word would not be invented until 1842. No complete Megalosaurus skeleton has yet been found. However, we can compare the bones we have found to more complete theropods and see that Megalosaurus was a two-legged predator with short but powerful arms. It seems to have been the largest meat-eater on land in Europe during the Middle Jurassic Period.
Fun Facts[]
The book Bleak House by Charles Dickens (published in 1853) begins with the author imagining a 40-foot-long Megalosaurus "waddling like an elephantine lizard" up a muddy street in London.
Trivia[]
In the early days of paleontology, any meat-eating dinosaur fossils were considered to come from Megalosaurus however, as more and better skeletons were found, scientists realized how diverge the meat-eating dinosaurs truly were.
Gallery[]
Appearance in other media[]
Jurassic Park[]
- Megalosaurus is in the game, Jurassic World: The Game as a tournament dinosaur.
- Megalosaurus is in Jurassic World: Alive. The Megalosaurus is a rare dinosaur, and features a Rajasaur-like build.
 |
Read more Megalosaurus on Jurassic Park Wiki |
The Land Before Time[]
It appears in The Land Before Time: Dinosaur Q&A.
 |
non-canon only |
We're Back! A Dinosaur's Story[]
It appears in Your Pet Dinosaur: An Owner's Manual.
 |
Read more Megalosaurus on We’re Back A Dinosaur’s Story Wiki |
Links[]
References[]
- ↑ Template:Cite book
- ↑ Halstead, L.B. (1970). "Scrotum humanum Brookes 1763 - the first named dinosaur." Journal of Insignificant Research, 5: 14–15.
- ↑ Benson, R.B.J. (2009). "An assessment of variability in theropod dinosaur remains from the Bathonian (Middle Jurassic) of Stonesfield and New Park Quarry, UK and taxonomic implications for Megalosaurus bucklandii and Iliosuchus incognitus." Palaeontology, doi: 10.1111/j.1475-4983.2009.00884.x
- ↑ Buckland, W. (1824). "Notice on the Megalosaurus or great Fossil Lizard of Stonesfield." Transactions of the Geological Society of London, series 2, vol. 1: 390–396.
- ↑ Mantell, G. (1827). "Illustrations of the geology of Sussex: a general view of the geological relations of the southeastern part of England, with figures and descriptions of the fossils of Tilgate Forest."
- ↑ Cite error: Invalid
<ref>tag; no text was provided for refs named:0