When immersing yourself into the world of paleontology, you may notice that a few odd “themes” pop up every now and then. For example, if you were to open the index of a dinosaur encyclopedia, you may notice that one of the most frequently referenced dinosaurs is the theropod Megalosaurus. So much so, that in some books it is even mentioned more than Tyrannosaurus. While Megalosaurus holds the title for the first named dinosaur species, there isn’t much else that’s special about it. Even the remains attributed to it are fragmented and incomplete. So why the abundance of references? Well, it is not due its scientific significance, but rather from the history behind the use of the name “Megalosaurus.”
Because Megalosaurus is the first named dinosaur, it’s been typecast amongst paleontologists as the “average” theropod dinosaur. This designation would lead to Megalosaurus becoming a “wastebasket taxon,” meaning that it became the go-to name for classifying any newly found species. For about 150 years, whenever paleontologists found the remains of a mid-sized theropod that could not be identified as distinct, they assigned it to be a sub-species of Megalosaurus. While this classification initially made sense as a way to identify new finds as theropods, it soon devolved into a confusing mess as more and more dinosaurs were assigned to the Megalosaurus moniker. In total, hundreds of specimens from five continents and spanning 100 million years of geologic time were assigned as sub-species of Megalosaurus. To make it clear, it’s not possible for a single species to have been found in locations across the globe and over such a long period of time.
More recently, many of the specimens identified as Megalosaurus have been reassigned to other dinosaurs. As you can imagine, keeping track of all the dinosaurs that were, at some point, named Megalosaurus can be difficult. Luckily, I have compiled a list of these dinosaurs and have tried to break it down into clear tiers with a definitive tally on Megalosaurus species. Without further ado, let’s get into it!
The Actual Megalosaurus
- M. Bucklandii: In the present, only the one species of Megalosaurus – the original Megalosaurus bucklandii from Britain – is recognized as valid.
Originally Named Megalosaurus, Reassigned to an Existing Species:
- Afrovenator: This one is a little confusing. In 1956, paleontologists accidentally listed a specimen of Megalosaurus saharicus as Megalosaurus africanus. In 1994, paleontologist Paul Sereno named a new theropod genus Afrovenator africanus. This created some confusion regarding the relationship between the two genera: simply, they are not the same dinosaur.
- Allosaurus: One of the most famous and common dinosaurs known to science, Allosaurus fossils were recognized as Megalosaurus on multiple occasions.
- Ceratosaurus: A mid-sized horned theropod from the Jurassic of North America.
- Daspletosaurus: Originally named Deinodon horridus, this set of teeth was later identified as belonging to a mid-sized tyrannosaurid, either Daspletosaurus or Gorgosaurus.
- Gorgosaurus: See # 5.
- Plateosaurus: A Triassic prosauropod and one of the best-known dinosaurs that has been assigned to Megalosaurus on numerous occasions.
- Poekilopleuron: One of earliest known dinosaurs and the proud owner of a confusing history revolved around constant naming and renaming.
- Streptospondylus: Mid-sized theropod from the Jurassic of France.
- Struthiomimus: Well-known ornithomimid genus from the Late Cretaceous of North America.
- Torvosaurus: In 1988, paleontologist Gregory S. Paul attempted to rename the Jurassic theropod Torvosaurus tanneri into Megalosaurus tanneri, albeit with no success. Additionally, two Megalosaurus species, one from Tanzania and the other Portugal, likely represent Torvosaurus fossils.
The Dubious Dinos:
- Gresslyosaurus: A Swiss prosauropod that likely represents another species.
- “Megalosaurus” cloacinus: Archosaur tooth from Germany.
- “Megalosaurus” dapukaensis: Unpublished theropod remains from Tibet.
- “Megalosaurus” monasterii: Theropod tooth initially named after the ray-finned fish Saurocephalus.
- “Megalosaurus” pannoniensis: Tooth belonging to a theropod from the Cretaceous of Austria.
- Megalosaurus phillipsi: A theropod from England that may be Megalosaurus bucklandii, though its validity is debatable.
- “Megalosaurus” tibetensis: Unpublished theropod remains from Tibet.
- “Prodeinodon”: Like Megalosaurus, Prodeinodon represents another wastebasket taxon
- Valdoraptor: A possible ornithomimid from England.
Named Megalosaurus, Became a new Species of Dinosaur:
- Betasuchus: Possibly a rare European abelisaurid and the only dinosaur from The Netherlands.
- Carcharodontosaurus: One of the largest theropod species known to science.
- Dilophosaurus: The infamous frilled venom-spitting dinosaur from Jurassic Park (that couldn’t actually spit venom and didn’t have nearly as impressive a frill).
- Duriavenator: Close relative of Megalosaurus
- Erectopus: A little-known allosaurid species from France.
- Majungasaurus: One of three cannibal dinosaurs and my personal favorite.
- Magnosaurus: Fragmentary Jurassic theropod that has had three separate species be assigned to Megalosaurus.
- Metriacanthosaurus: Mid-sized English theropod species.
- Proceratosaurus: A crested theropod and one of the earliest known tyrannosaurids.
Named Megalosaurus, But Wasn’t Even a Dinosaur to Begin With:
- Dakosaurus: A specially adapted marine crocodile from the Jurassic of Germany.
Goodness, that was a long list. I’m going to need a bit of a rest after this one.
Honestly, I find it kind of ridiculous that so many specimens got assigned to the Megalosaurus moniker. If you were a paleontologist and had the freedom to name a dinosaur whatever you wanted, why stick to the one that has been taken over 30 times before? Why not name it something like…Dynamoterror? Oh wait, that’s taken? Hmm…how about Tyrannotitan? Nope, it’s taken too. Maybe naming dinosaurs is harder than I thought. Guess I’ll have to name my mid-sized basal theropod Megalosaurus too when the time comes…
I do not take credit for any images found in this article.
Header image of Megalosaurus courtesy of Mark Witton, found at his blog here
Plateosaurus courtesy of Raul Martin, found here
Dilophosaurus courtesy of Juan Carlos Alonso, found here
Dakosaurus courtesy of Julio Lacerda, found here
- “Megalosaurus.” Wikipedia, Wikimedia Foundation, 31 Mar. 2021, en.wikipedia.org/wiki/Megalosaurus.
- Molina-Pérez Rubén, et al. Dinosaur Facts and Figures: the Theropods and Other Dinosauriformes. Princeton University Press, 2019.
- Prothero, Donald R. Story of the Dinosaurs in 25 Discoveries: Amazing Fossils and the People Who Found Them. Columbia University Press, 2021.