This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Back in 2009 my book The Great Dinosaur Discoveries (Naish 2009; University of California Press in the US; A&C Black in the UK) was published. If you're read the book and like it, please remember that you can help me out by posting reviews on amazon (go here for the amazon.co.uk version). The following section is an excerpt from one of the early parts of the book - the part that introduces the section on 19th Century discoveries. It might include some very familiar material (sorry about that) but, if you haven't read the book already, here it is in what might be a novel sort of compilation.
In 1842, the trailblazing British scientist Richard Owen announced the discovery of the dinosaurs to great acclaim. He described them as immense animals with thick limb bones and strong, reinforced hips. They were the "most perfect modifications of the Reptilian type", and "must have played the most conspicuous parts, in their respective characters as devourers of animals and feeders upon vegetables, that this world has ever witnessed in oviparous and cold-blooded creatures".
Two decades earlier, scientists already knew of the existence of gigantic sea reptiles in the distant past, but by the time of Owen’s publication, clues were emerging that equally impressive reptiles had lived on land as well. The first of these “dinosaurs-to-be” was a huge carnivore, discovered in an English rock known as the Stonesfield Slate, and published by William Buckland in 1824 under the name Megalosaurus. Buckland imagined it to be a fearsome predatory lizard with a total body length of 18–21 m (60–70 ft).
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A second “dinosaur-to-be” was found by Gideon Mantell, a medical doctor and amateur fossil collector from the small market town of Lewes in East Sussex, in southern England. Mantell built up an impressive collection of fossils from his neighborhood over the years, first publishing on them in 1822. However, the fact that he lived outside the socio-political center of 19th-century England counted against him, despite his best efforts to make his way in London scientific circles. By the early 1820s, Mantell had obtained several unusual fossil teeth that came from the Tilgate Grit (now known to be Lower Cretaceous in age), and in 1825 he named Iguanodon for these remains. Since the teeth resembled those of iguanas, he regarded Iguanodon as lizard-like but enormous in size, its length perhaps exceeding 30 m (100 ft).
A third “dinosaur-to-be” was, like Iguanodon, also from the county of East Sussex. The specimen was uncovered by workmen and blasted into fragments that Mantell later managed to fit together, and in 1833 he named it Hylaeosaurus. It is a big armored reptile with large conical spines arranged on the neck and shoulders, and has remained poorly known. Certainly it has never become as familiar to the public as Megalosaurus or Iguanodon.
Owen’s Dinosauria
Megalosaurus, Iguanodon, and Hylaeosaurus were all remarkable discoveries, but these creatures were not regarded as close relatives until 1842, when Owen proposed that they be united in a new group, which he called the Dinosauria. He argued that dinosaurs—the name means “fearfully great lizards”—resembled large modern land mammals such as elephants and rhinos in their terrestrial habits, reinforced hip regions, and massive, elephantine limbs. However, it was simply a coincidence that the three species known at this point shared a special reinforced pelvic region*: more recent discoveries have shown that this feature is not a defining character of dinosaurs as once was thought. Interestingly, despite emphasizing their size, Owen also inadvertently “downsized” the dinosaurs. For example, he suggested that Megalosaurus and Iguanodon were both about 9 m (30 ft) long.
* This isn't entirely accurate but results from an editorial compromise.
Moreover, discoveries made during the 1860s showed that dinosaurs were not all elephantine monsters, but also included small species. The bird-like anatomy of the small dinosaurs Hypsilophodon (from England) and Compsognathus (from Germany) enabled Thomas Huxley—“Darwin’s bulldog”—to propose an affinity between dinosaurs and birds. Archaeopteryx, named from Germany in 1861, demonstrated that birds themselves lived alongside dinosaurs.
Owen’s views on dinosaurs became more familiar to the public than did those of his colleagues Buckland and Mantell because life-sized models of “Owenian dinosaurs” were created for a special exhibition of extinct animals—known as the Dinosaur Court—that opened in the grounds of the Crystal Palace, London, in 1854. The Crystal Palace Company had initially approached Mantell, but he had turned them down.
Global dimensions
Dinosaur fossil in North America were first reported during the 1850s. In 1855, geologist Ferdinand Vandiveer Hayden collected fossil teeth from the Cretaceous badlands of what is now Montana. On his return to Philadelphia in 1856 he passed them to palaeontologist Joseph Leidy. Although dinosaur tracks were discovered in the Connecticut Valley decades earlier, and described by the Reverend Edward Hitchcock in 1836, they were thought at the time to be bird tracks. The teeth collected by Hayden were therefore seen as the first North American dinosaur remains (see pp.32-33). They indicated that dinosaurs with similarities to Iguanodon and Megalosaurus awaited discovery on the continent. This was confirmed in 1858, when Hadrosaurus—the first duck-billed dinosaur to be found—was discovered in New Jersey. It was clearly related to Iguanodon, yet its bones suggested a kangaroo-like body. Iguanodon was itself to be re-imagined entirely, due to the discovery of several specimens at Bernissart in Belgium in 1878. Having studied the new skeletons, Belgian palaeontologist Louis Dollo showed that Iguanodon was shaped more like a giant kangaroo than the quadrupedal, lizard- or rhino-like animal originally pictured by Mantell and Owen.
By the end of the century, dinosaurs had become reasonably well known as a fascinating and diverse group of animals. In North America, stegosaurs were discovered in the 1870s and the giant horned dinosaur Triceratops was named during the 1880s. Sauropods, which had first been discovered during the 1840s in England but had remained enigmatic and mysterious, now became better understood, thanks to the naming of Camarasaurus from Colorado, in 1877. This was followed soon after by many other Late Jurassic relatives. It was clear that a golden age of discovery had begun.
For previous Tet Zoo articles on The Great Dinosaur Discoveries, and on Iguanodon, Megalosaurus and other historical dinosaur discoveries, see...
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Naish, D. 2009. The Great Dinosaur Discoveries. University of California Press, Berkeley.