The Critical Angle: “How do they keep finding new dinosaurs?”



It’s a lot harder than you might think.

Jurassic World:  Fallen Kingdom releases in the United States today, but for the last few weeks, I’ve been contemplating a question that was posed by a friend.


“How Do They Keep Finding New Dinosaurs?”


It’s a question that I’ve heard and read many times throughout my life. People are skeptical when I say we know of 700 species of non-avian dinosaur (that’s dinosaurs that aren’t birds). I suspected this disbelief in both the number of dinosaurs and the continued discovery of new dinosaur species had to do with a lack of knowledge of the history of paleontology, and the monstrously long timespan during which dinosaurs were alive.

Non-avian dinosaurs were an extremely diverse group of animals that emerged around 230 million years ago and went extinct 66 million years ago. That’s a range of 164 million years, during which time they lived on every continent. It might seem like 700+ species is a lot, but there are over 10,000 species of bird alive today. And these 10,000 species of bird are not all the same species that existed 30 million years ago, nor 20, nor 10. The same is true of dinosaurs.

To illustrate the wide gaps between animals, consider Jurassic Park stars Brachiosaurus and Tyrannosaurus, two of the most famous dinosaurs.  Yet these animals would never have seen one another in real life. Brachiosaurus lived 150 million years ago, while Tyrannosaurus wouldn’t appear for another 83 million years. There was more time separating Brachiosaurus and Tyrannosaurus than there is separating Tyrannosaurus and you. And neither was around for much more than a million years or so.

It’s also important to understand that Brachiosaurus and Tyrannosaurus didn’t rule the whole Earth. Both were restricted to the western half of the United States. Tyrannosaurus rex lived in what is now South Dakota, North Dakota, Wyoming and Montana, along what was then an inland sea that vertically split North America down the middle. Who was the queen ruling over the eastern United States 67 million years ago? We don’t know. The sediments in that area didn’t preserve particularly well. Fossilization, in general, is a very rare phenomenon.

These are all factors in understanding just how much we don’t know. I also wanted to test out how frequently certain names came up. I suspected most people might be able to name somewhere between five and 20 dinosaurs, but that there would be a high overlap in the dinosaurs named and that the vast majority of animals would be from two specific geological formations: the Hell Creek Formation (best known for Tyrannosaurus rex) and the Morrison Formation (where Brachiosaurus altithorax appears).

So How Did the Survey Go?

Here’s the question I asked in full:

“How Many Dinosaurs Can You Name?

“Please name as many dinosaurs as you can. Don’t worry about spelling, or whether or not it’s actually a dinosaur (unless, of course, you know it’s not a dinosaur, in which case, please don’t spam). If you only know it as Spike from The Land Before Time, that’s acceptable.”

My hope with the phrasing was to leave it open-ended and unintimidating. At the same time, I knew I was opening myself up to interpretation. The first thing I had to do was to filter out non-dinosaurs. That was easy for responses like “Pteranodon,” but harder for things like “Stegadon.” Did the responder mean Stegosaurus or did they mean Stegodon, a genus of animal related to the elephant? I decided to play things conservatively, so that individual name went out. And for instances such as “Baby Sinclair,” I went with what dinosaur the program assigns the character – in this case, Megalosaurus. The Flintstones’ Dino is considered a fictional genera: the Snorkasaurus, so I also omitted those responses.

Overall, 52 genera of dinosaur were named by responders. However, when looking at dinosaurs that appeared across 20% or more of the responses, that number fell to 16.

Out of these 16 genera, 10 are found in either the Hell Creek or Morrison formations. The six outliers consist of Velociraptor, Dilophosaurus, Compsognathus, Iguanodon, Parasaurolophus, and Spinosaurus. It’s not hard to imagine how these outliers might have broken through, as most play memorable roles in either Jurassic Park or one of its sequels. Iguanodon was the second dinosaur ever discovered and has featured prominently in other media (such as Disney’s Dinosaur), and Parasaurolophus’ distinctive crest has made it a mainstay in dinosaur art.

But there’s something else that should be noted here. All of these genera are old discoveries, with all but Dilophosaurus pre-dating World War II (Dilophosaurus was first found in 1954, and was called a species of Megalosaurus until it was properly named in 1970). So not only are our most well-known dinosaurs from similar regions, they’re also some of the first discoveries, from when fossil-hunting became popular during the late 1800s through the first half of the 20th century.

Not only are our most well-known dinosaurs from similar regions, they’re also some of the first discoveries.

Instead of asking how we keep finding new dinosaurs, perhaps it’s better that we ask ourselves just how many things we don’t know about them and their marvelous world.

Below is the list of the 52 valid dinosaurs named in the survey responses. How many names do you recognize? How many are new to you?

Allosaurus, Ankylosaurus, Apatosaurus, Archaeopteryx, Baryonyx, Brachiosaurus, Brontosaurus, Camarasaurus, Carnotaurus, Centrosaurus, Compsognathus, Corythosaurus, Dakotaraptor, Deinonychus, Diabloceratops, Dilophosaurus, Diplodocus, Dromaeosaurus, Eoraptor, Herrerasaurus, Gallimimus, Giganotosaurus, Iguanodon, Kosmoceratops, Maiasaura, Majungasaurus, Megalosaurus, Microraptor, Nodosaurus, Ornithomimus, Pachycephalosaurus, Pachyrhinosaurus, Parasaurolophus, Pisanosaurus, Protoceratops, Seismosaurus, Spinosaurus, Stegosaurus, Styracosaurus, Suchomimus, Supersaurus, Therizinosaurus, Titanosaurus, Torosaurus, Triceratops, Troodon, Tuojiangosaurus, Tyrannosaurus, Utahceratops, Utahraptor, Velociraptor

The Critical Angle is a recurring feature that uses critical thinking and skepticism to analyze pop culture phenomena. Skepticism is an approach to evaluating claims that emphasizes evidence and applies the tools of science. Rather than repeating the same old assertions, we put them to the test.

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