The Big Dinosaur Podcast

Episode 47 is all about Megalosaurus, a carnivore and one of the three dinosaurs to comprise the original group Dinosauria.

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In this episode, we discuss:

• The dinosaur of the day: Megalosaurus, whose name means “Great Lizard”
• Comes from the late Middle Jurassic of Oxfordshire, England, though fossils from other areas have also been called Megalosaurus
• One Megalosaurus bone, the lower part of a femur, was found in 1676 and described by Robert Plot, a chemistry professor at the University of Oxford and first curator of the Ashmolean Museum, as the thighbone of a Roman war elephant, but later thought it came from a giant human (as mentioned in Bible); bone is lost, but the illustration was so detailed it’s been identified as Megalosaurus
• Plot published a description and illustration (first illustration of a dinosaur published)
• The first scientific name was from the 1700s, by Richard Brookes, who called it Scrotum humanum (not a valid name now)
• First non-avian dinosaur to be validly named, named in 1824
• Type species is Megalosaurus bucklandii, named in 1827
• In 1815, John Kidd reported on the find of bones in at the Stonesfield quarry, where the Megalosaurus femur was found, of giant tetrapods, which William Buckland, professor of geology at the University of Oxford and dean of Christ Church, acquired
• Buckland was an interesting fellow, who apparently had a pet bear he liked to dress in academic robes, he had a table made with dinosaur droppings that people admired without realizing what they were, and he liked to eat whatever he could try, including panthers, crocodiles and toasted mice (he said mole and blue-bottle fly tasted the worst)
• French comparative anatomist Georges Cuvier visited Buckland in 1818 and said they came from a giant lizard-like creature
• Buckland and his friend William Conybeare studied the fossils and Conybeare said they were from a “Huge Lizard” (1821)
• In 1822 James Parkinson, a physician, announced the name Megalosaurus and illustrated one of the teeth (said it was 40 ft long and 8 ft tall)
• Buckland kept studying Megalosaurus in 1823, and his wife Mary Morland drew the bones (basis for illustrating lithographies); Buckland formally announced Megalosaurus in 1824
• William Buckland formally described the first dinosaur in his paper “Notice on the Megalosaurusor great Fossil Lizard of Stonesfield”, published in 1824 in the Geological Society of London
• Buckland did not provide a specific name (common in the early nineteenth century–genus was more important than species name)
• At the time, there were orthodox Christians who had a problem with the existence of Megalosaurus (held that suffering and death only came from Original Sin, which didn’t make sense with a carnivorous creature that lived before humans); some people said Megalosaurus was originally a peaceful vegetarian, but Buckland said it helped end animal suffering by preying on old and sick animals
• Ferdinand von Ritgengave named the species Megalosaurus conybeari in 1826, but not many people used that name
• In 1827, Gideon Mantell named it Megalosaurus bucklandii
• Buckland thought Megalosaurus was quadrupedal and an amphibian that looked like a giant lizard (though he did understand based on the thighbone that it would have been more upright than sprawled)
• The idea that Megalosaurus and carnivorous dinosaurs in general were quadrupedal was challenged in 1859 with Compsognathus, and then in 1870 with Eustreptospondylus; after, John Philips made the first display of a theropod skeleton in Oxford, arranging Megalosaurus bones as bipedal
• Megalosaurus and two other genera were used to name Dinosauria in 1842 (by Richard Owen)
• The other two dinosaurs that inspired Dinosauria were Iguanodon and Hylaeosaurus
• Owen directed a model made for the Crystal Palace
• Benjamin Waterhouse Hawkins was commissioned to build Megalosaurus in 1852 for the Crystal Palace Park; it had a hump on the shoulders and the model helped the public in England be aware that ancient reptiles lived
• For a long time after being discovered, Megalosaurus was seen as the typical large carnivorous dinosaur, and it became a wastebasket taxon (lots of dinosaurs assigned the genus, but that changed in the 20th century, when scientists started restricting Megalosaurus to fossils found in England, from the Jurassic period
• Any fossils found that weren’t enough to name a new genus (usually of single teeth), were classified as Megalosaurus; at one point had the most species of any non-avian dinosaur genus (lots of them have been re-classified)
• Examples of the wastebasket taxon being used (all based on a single tooth) include Megalosaurus cloacinus, Megalosaurus insignis, Megalosaurus meriani
• Dinosaurs that were originally Megalosaurus include Duriavenator, Eustreptospondylus, Magnosaurus, Metriacanthosaurus, Dilophosaurus, Carcharodontosaurus
• Lots of other examples too
• More than 50 species have been classified under the genus Megalosaurus, when dinosaurs were not well known, and even in the 20th century when more was known
• Megalosaurus has a lot of synonyms, mostly because of the way it was spelled in papers. In 1913, one author added a “u” and made the synonym Megalousaurus; in 1926 another paper misspelled Megalosaurus 4 times, creating 4 new synonyms “Megalasaurus,” “Megolosaurus,” Megalosaurns” and “Magalosausus”; this happened again in 1964, when the “g” was accidentally replaced with a “q” to make “Meqalosaurus”
• Ronan Allain and Dan Chure said in the late 20th/early21st century that the fossils found in the same quarry as Megalosaurus may be multiple types of dinosaurs. Some researchers said there were no distinguishing characteristics between Megalosaurus and other relatives, making Megalosaurus a nomen dubium, but in 2008 Roger Benson and colleagues analyzed Megalosaurus and identified distinguishing characteristics in the lower jaw
• Characteristics include a wide longitudinal groove on the outer surface on the dentary, the third tooth socket not being enlarged, tall interdental plates that reinforce the teeth
• No complete skeletons have been found, but Benson published a detailed study of known bones in 2010
• No complete skeleton has been found of Megalosaurus
• First researchers thought Megalosaurus was a giant lizard 20 m long; Richard Own in 1842 said it was 9 m long and was quadrupedal; nowadays thought to be 23 ft or 7 m long, weighing 1.1 tonnes, bipedal with a long tail for balance
• Up to 30 ft long (9m), 10 ft (3 m ) tall, weighed about 1 ton
• Also short forelimbs, large head, lots of muscle, and long curved teeth
• Bipedal, long tail, long hindlimbs with three forward-facing toes, short forelimbs with three digits each
• Large, long head with dagger like teeth
• Not much known about the skull, but lower jaw was probably narrow
• Probably apex predator
• May have hunted stegosaurs and sauropods (early descriptions have it hunting Iguanodon, though Iguanodon actually lived much later)
• May have killed sauropods, may have been a scavenger
• Bleak House, Charles Dicken’s serial novel published between 1852 and 1853 is one of the first dinosaur references in literature. He wrote “As much mud in the streets as if the waters had but newly retired from the face of the earth, and it would not be wonderful to meet a Megalosaurus, forty feet long or so, waddling like an elephantine lizard up Holborn Hill.”
• Buckland’s son, Franklin Trevelyan Buckland came up with the idea that dinosaurs gave rise to dragon myths
• Benjamin Waterhouse Hawkins’ Megalosaurus is still around (though the glasshouse burned down in 1936)
• Around the same time Benjamin Waterhouse Hawkins built the Megalosaurus statue, Edouard Riou drew the famous image of Megalosaurus and Iguanodon in a vicious battle (very inaccurate, esp. since Iguanodon was an herbivore)
• Earl Sinclair from the TV show Dinosaurs is a Megalosaurus
• Megalosaurus was a theropod and a tetanuran
• Tenanurae means “stiff tails” and is a clade that includes more theropods
• Appeared in the early or middle Jurassic
• Clade was named in 1986 by Jacques Gauthier
• Includes all theropods more closely related to modern birds than Ceratosaurus
• Fun Fact: The paper that described the holotype of Tyrannosaurus rex also described another dinosaur called Dynamosaurus imperiosus, which were later determined to be the same species. T-rex was written earlier in the paper making it the official name of the species, otherwise we would be walking around saying D-imperiosus