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Dinosaur Discoveries: A Series of Accidents and Coincidences

Updated: Sep 20, 2022

Harry T. Jones examines and contextualises the intriguing events that triggered monumental discoveries in the dinosaur world.

Palaeontology, the study of prehistoric life, is a discipline heavily shaped by accidents and coincidences. The very basis by which we know about prehistoric fauna and flora is via their fossils and traces, which are only preserved by a very specific set of conditions. Even if organisms do fossilise, it is a matter of coincidence whether they survive erosion and tectonic movement, and are accessibly exposed for us to accidentally stumble upon. In this article, we will explore some of the most significant dinosaur discoveries affected by accidents and coincidences. Allons-y!

Long in the Tooth – the Road to Iguanodon

In 1822, Mary Ann Mantell and her amateur palaeontologist husband, Dr Gideon Mantell, came across a group of relatively large teeth stuck in some rocks by the side of the road while on their way to Sussex. On the advice of fellow naturalist Georges Cuvier, Dr Mantell took the mysterious teeth to the Hunterian Museum, London, where he discovered the teeth resembled those of an iguana, but much larger, thanks to an iguana skeleton that, coincidentally, had recently been prepared. In 1825, Mantell subsequently assigned the teeth to a new genus: Iguanodon (meaning ‘iguana tooth’).

After investigating several isolated finds in the following years, Mantell finally came across more substantial Iguanodon evidence in 1834 when some workmen accidentally blew up a rock slab in a limestone quarry near Maidstone, Kent. Mantell designated the bones within the slab as Iguanodon, although this material was reassigned to the similar but lighter-built Mantellisaurus in 2012. Sir Richard Owen used Iguanodon (and two other genera) to coin the word ‘dinosaur’ in 1842.

An Explosive Mistake – the Lost Spinosaurus

In 1915, German palaeontologist Ernst Stromer named a new dinosaur based on a partial skeleton found in Egypt – Spinosaurus aegyptiacus. This large predator, dated to the Late Cretaceous, was noteworthy for its crocodile-like jaw and tall vertebral spines, indicative of a sail-like feature along its back. The material Stromer studied was the holotype: the specimen used to formally describe the species. Unfortunately, the holotype was accidentally destroyed in April 1944 when British aircraft inadvertently bombed the Munich museum where the specimen was housed during World War II.

Thankfully, Stromer’s son donated his father’s notes, sketches, and surviving photographs to the renovated museum in 1995, where these archives were unearthed again in 2000 and studied once more. Fragmentary Spinosaurus remains have since been discovered, with palaeontologist Nizar Ibrahim in particular paving the way, through chance encounters of his own, to a better understanding of this enigmatic predator.

Corpse Mine – the Exceptionally Preserved Nodosaur

A regular mining operation near Alberta, Canada, accidentally revealed the extraordinarily well-preserved remains of a dinosaur in 2011. The dinosaur was identified as a nodosaur, a group of herbivorous, armoured dinosaurs. This one lived some 110 million years ago in what is now western Canada. The recovered remains only represent the animal’s front half, from its snout to hips, but the 2.75-metre-long reassembled grey blocks are so well preserved that they bear individual scales! Bony armour plates called osteoderms coat its neck and back, and its shoulders are adorned with a pair of 20-inch-long spikes, most likely reinforcing its defence against predators.

Osteoderms are usually scattered as the animal’s body decays, but a specific set of circumstances allowed them to preserve as they appeared in life. When this nodosaur died, its body was swept out to sea, where it sank to the seafloor, back-first, and was engulfed in sediment. This rapid undersea burial allowed excellent 3D preservation of the animal (rather than a flattened fossil). The dinosaur was named in 2017 as the new species Borealopelta markmitchelli. Melanin pigment analysis even revealed that Borealopelta exhibited a reddish-brown colouration!

These are but a few examples of times when accident and coincidence have played a part in the discovery of dinosaurs. Similar situations will likely arise in future, revealing new insights into our planet’s prehistory. Maybe one day you’ll accidentally stumble across a new fossil, coincidentally exposed as you pass by…

Further reading:

1) Osterloff, E. (no date) Iguanodon: the teeth that led to a dinosaur discovery. Available at:

2) Osterloff, E. (no date) The search for the real Iguanodon. Available at:

3) Dinosaur Isle (no date) Iguanodon - Iguanodon bernissartensis and Mantellisaurus atherfieldensis. Available at:

4) Martignetti, E. (2020) Maidstone’s Iguanodon. Available at:

5) Smithsonian Magazine (no date) Rediscovering Spinosaurus, the Lost Dinosaur. Available at:

6) Greshko, M. (2017) The Amazing Dinosaur Found (Accidentally) by Miners in Canada. Available at:

7) Brown, C.M., Henderson, D.M., Vinther, J., Fletcher, I., Sistiaga, A., Herrera, J., and Summons, R.E. (2017) ‘An Exceptionally Preserved Three-Dimensional Armored Dinosaur Reveals Insights into Coloration and Cretaceous Predator-Prey Dynamics’, Current Biology, 27 (16), pp. 2514-2521. doi:

From SATNAV Issue 24, pages 8 and 9.

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