Megalosaurus: The Original Dinosaur

An Artist reconstruction of Buckland’s great lizard
Image Credit: LadyofHats Mariana Ruiz,

There is no group of extinct life that enthrals the minds of the general public quite like dinosaurs. All palaeontologists both current and aspiring can claim to have at least been partially inspired by reading books and watching documentaries about dinosaurs, and from seeing their fossils and reconstructions in the many museums throughout the globe. Some dinosaurs have received vast amounts of media attention; the great Tyrannosaurus Rex; the three-horned Triceratops; and the long necked Brachiosaurus to name a few. However there is one dinosaur that can claim to be perhaps the most important of them all. Megalosaurus bucklandii is not as well-known as these other dinosaurs, which is quite surprising to me. However this medium-large sized theropod from the mid-Jurassic has every claim to live long in the history books.

Megalosaurus was the first dinosaur to be properly and scientifically described and the first animal to be referred to as a “dinosaur”. The first Megalosaurus fossils were discovered in the village of Stonesfield in Oxfordshire, England in the 18th century. These fossils came from a Mid-Jurassic (170-150 Million years old) deposit known as the “Stonesfield Slate”, a deposit that has also preserved the remains of other dinosaurs, pterosaurs, insects and plants of the time. The Megalosaurus fossils, originally described under the interesting name of Scrotum humanum, which was not formerly accepted by any scientific body, were passed on in 1824 to the geologist William Buckland, who in collaboration with the anatomist Georges Cuvier, identified the animal as a large extinct reptile. This animal was given the name Megalosaurus bucklandii, meaning “Buckland’s great lizard”. It was almost 20 years later in 1842 that Megalosaurus was referred to by Sir Richard Owen as a “dinosaur”. This discovery was quite unlike any living animal and captured the imagination of the Victorian public, with Megalosaurus making an appearance in the Charles Dickens novel Bleak House. This made it one of the first (but certainly not the last!) dinosaurs to appear in mainstream popular media.

A fossilised lower jaw and tooth of Megalosaurus. This jaw is one of the more iconic dinosaur fossils.
Image Credit: Wikimedia Commons,,_Megalosaurus_jaw.jpg

Most of the Megalosaurus specimens that these early Victorian geologists had to go on were incomplete, with the only finds being a lower jaw, upper jaw, some teeth and a few thigh and leg bones. In addition this was really the first time anyone had attempted to reconstruct dinosaurs from their bones. So the Victorian scientists could only make educated guesses as to what this animal was like. While they knew, based on its tooth anatomy, that it was related to reptiles the first reconstructions of Megalosaurus were very different to what we believe today. Basing its design on modern lizards Megalosaurus was reconstructed as a massive, sluggish four legged animal, with its tail dragging along the ground and possessing a big hump on its shoulders. This interpretation can be seen in all its glory at the Crystal Palace Park in London. Unveiled in 1851 it is displayed stalking a group of equally lizard like Iguanodon, also inaccurate as Iguanodon would appear almost 40 million years after Megalosaurus (to name one inaccuracy!). It was only when further theropod remains were found a few decades later that a more accurate picture of Megalosaurus became clear. However during this time the Megalosaurus species was known as a “wastebasket taxon” where any newly discovered large theropod remains were all haphazardly lumped into the Megalosaur group, like somebody chucking different types of cutlery into the same drawer. Also the animal was portrayed, like other bipedal dinosaurs at the time, standing upright like a Kangaroo. This would only change nearly a whole century later, where research in the 1960s and 1970s led to all bipedal dinosaurs’ posture being altered to the more horizontally balanced forms seen today, where the head and body were counterbalanced by a long, lofted tail.

The Megalosaurus model at Crystal Palace park. This model, first revealed in 1851, shows us what Victorian Scientists thought it looked like.
Image Credit: Chris Sampson,

Whilst Megalosaurus has a long and important story about its discovery, and how it changed scientific thinking forever, what was this dinosaur actually like when it was alive? Well, Megalosaurus belonged to a group of theropods known as the Megalosauridae. This group were the main land predators of the early to mid-Jurassic period, dominating the landscape until their numbers declined during the late Jurassic 150 million years ago. Megalosaurus had many of the features that are typical of theropod dinosaurs; big hind legs, saurischian (lizard-like) hips, arms ending in non-pronated wrists, sharp claws and robust jaws filled with razor sharp teeth suitable for cutting and biting into the flesh of its prey. The powerful legs of Megalosaurus would have enabled it to reach speeds of up to 20 miles per hour, equivalent to a modern day Grizzly Bear and easily fast enough to chase down its prey. Once caught Megalosaurus would have attacked its prey with a powerful bite, its skull built for heavy impact by having a framework of slightly loose bones that, through flexing on impact were able to absorb the forces involved in biting and holding large struggling prey. Reaching up to nine metres long, three metres tall and weighing nearly one and a half tonnes it was the undisputed top predator of mid-Jurassic England, hunting large herbivorous dinosaurs, such as the long necked sauropod Cetiosaurus. However it would have needed to be an unfussy eater. During the Mid Jurassic, the UK was broken up into small islands, with Megalosaurus probably swimming from island to island and combing the beaches for any food it could find, including any marine reptiles, crabs and pterosaurs that had been beached. It is also possible, like a lot of other theropods, that Megalosaurus could have been at least partially feathered. Evidence for this comes from another megalosaurid called Sciurumimus. Found in the Late Jurassic of Germany this juvenile megalosaur was found preserved with a filamentous coating of feathers. While this isn’t direct evidence of feathers on Megalosaurus the fact that it is present on a close relative means that it is likely that it too possessed a similar coating, making it look a bit less like a scaly lizard and a bit more like a fluffy carnivorous bird. This new finding, put forward in a 2014 study by Rauhut et. al., would certainly have startled William Buckland, Richard Owen and the other Victorian scientists that first named this remarkable beast a “dinosaur”.

So, just as the 2008 film “Iron Man” was the start of the Marvel Cinematic Universe, and the Benz Patent Motor Car was the origin of today’s cars, the discovery of Megalosaurus was the genesis of dinosaur research. While T-Rex and others get the spotlight nowadays without this first description and reconstruction of this Mid-Jurassic Megalosaur from Oxford, dinosaurs would not have captured the public imagination in quite the way that they have. The field of palaeontology would perhaps have never evolved into the science it is today, and who knows, in that world I may have become an archaeologist!

References/Further Reading

Rauhut et al 2014 paper about feather filaments in the Megalosaur Sciurumimus

Rauhut, O. W. M., et al. (2012). “Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany.” Proceedings of the National Academy of Sciences 109(29): 11746-11751.

The Friends of Crystal Palace Dinosaurs page on the Megalosaurus model at Crystal Palace park, including comparisons with how the Victorian scientists thought it looked and behaved compared with modern interpretations

“Megalosaurus”, Friends of Crystal Palace Dinosaurs,

More Information on Megalosaurus and other animals of the Stonesfield slate from the Oxford University Museum of Natural History website

“The Oxfordshire Dinosaurs”, Oxford University Museum of Natural History,

One thought on “Megalosaurus: The Original Dinosaur

  1. reader11 15th Nov 2019 / 4:22 pm

    Imagine being a feared predator for ~20 mil years, and then some time later you’re called “scrotum humanum” lol

    Would have loved to see some images, but pretty well written stuff anyways ❤

    Liked by 1 person

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