Science, Tech, Math › Animals & Nature 12 Famous Fossil Discoveries Share Flipboard Email Print Drow male/Wikimedia Commons/CC BY 4.0, 3.0, 2.5, 2.0, 1.0 Animals & Nature Dinosaurs Paleontologists Basics Carnivores Dinosaurs & Birds Herbivores Marine Reptiles Prehistoric Mammals Amphibians Birds Habitat Profiles Mammals Reptiles Wildlife Conservation Insects Marine Life Forestry Evolution View More By Bob Strauss Science Writer B.S., Cornell University Bob Strauss is a science writer and the author of several books, including "The Big Book of What, How and Why" and "A Field Guide to the Dinosaurs of North America." our editorial process Bob Strauss Updated August 15, 2019 As rare and impressive as they may be, not all dinosaur fossils are equally famous, or have had the same profound effect on paleontology and our understanding of life during the Mesozoic Era. 01 of 12 Megalosaurus (1676) Ghedoghedo/Wikimedia Commons/CC BY 3.0 When the partial femur of Megalosaurus was unearthed in England in 1676, a professor at Oxford University identified it as belonging to a human giant, as 17th-century theologists couldn't wrap their minds around the concept of huge, lumbering reptiles from a land before time. It took another 150 years (until 1824) for William Buckland to give this genus its distinctive name, and nearly 20 years after that for Megalosaurus to be conclusively identified as a dinosaur (by the famous paleontologist Richard Owen). 02 of 12 Mosasaurus (1764) Ghedoghedo/Wikimedia Commons/CC BY 3.0 For hundreds of years before the 18th century, central and western Europeans had been digging up strange-looking bones along lakebeds and riverbanks. What made the spectacular skeleton of the marine reptile Mosasaurus important was that it was the first fossil to be positively identified (by the naturalist Georges Cuvier) as belonging to an extinct species. From this point on, scientists realized they were dealing with creatures that lived, and died, millions of years before humans had even appeared on Earth. 03 of 12 Iguanodon (1820) Ronny Mg/Wikimedia Commons/CC BY 1.0 Iguanodon was only the second dinosaur after Megalosaurus to be given a formal genus name. More importantly, its numerous fossils (first investigated by Gideon Mantell in 1820) precipitated a heated debate among naturalists about whether or not these ancient reptiles even existed. Georges Cuvier and William Buckland laughed away the bones as belonging to a fish or rhinoceros, while Richard Owen pretty much hit the Cretaceous nail on the head, identifying Iguanodon as a true dinosaur. 04 of 12 Hadrosaurus (1858) andytang20/Flickr/CC BY 2.0 Hadrosaurus is more important for historical than for paleontological reasons. This was the first near-complete dinosaur fossil ever to be excavated in the United States, and one of the few to be discovered on the eastern seaboard (New Jersey, to be exact, where it's now the official state dinosaur) rather than in the west. Named by the American paleontologist Joseph Leidy, Hadrosaurus lent its moniker to a huge family of duck-billed dinosaurs — the hadrosaurs — but experts still debate whether the original "type fossil" merits its genus designation. 05 of 12 Archaeopteryx (1860-1862) Giles Watson/Flickr/CC BY 2.0 In 1860, Charles Darwin published his Earth-shaking treatise on evolution "On the Origin of Species." As luck would have it, the next couple of years saw a series of spectacular discoveries at the limestone deposits of Solnhofen, Germany that led to a complete, exquisitely preserved fossils of an ancient creature, Archaeopteryx, that seemed to be the perfect "missing link" between dinosaurs and birds. Since then, more convincing transitional forms (such as Sinosauropteryx) have been unearthed, but none have had as profound an impact as this pigeon-sized dino-bird. 06 of 12 Diplodocus (1877) Etemenanki3/Wikimedia Commons/CC BY 4.0 By a historical quirk, most of the dinosaur fossils unearthed in late 18th and early 19th century Europe belonged to relatively small ornithopods or slightly bigger theropods. The discovery of Diplodocus in western North America's Morrison Formation ushered in the age of giant sauropods, which have since captured the imagination of the public to a far greater extent than relatively prosaic dinosaurs like Megalosaurus and Iguanodon. It didn't hurt that the industrialist Andrew Carnegie donated casts of Diplodocus to natural history museums around the world. 07 of 12 Coelophysis (1947) James St. John/Wikimedia Commons/CC BY 2.0 Although Coelophysis was named in 1889 (by the famous paleontologist Edward Drinker Cope), this early dinosaur didn't make a splash in the popular imagination until 1947, when Edwin H. Colbert discovered innumerable Coelophysis skeletons tangled together at the Ghost Ranch fossil site in New Mexico. This discovery showed that at least some genera of small theropods traveled in vast herds — and that large populations of dinosaurs, meat-eaters and plant-eaters alike, were regularly drowned by flash floods. 08 of 12 Maiasaura (1975) Zissoudisctrucker/Wikimedia Commons/CC BY 4.0 Jack Horner may be best known as the inspiration for Sam Neill's character in "Jurassic Park," but in paleontology circles, he's famous for discovering the extensive nesting grounds of Maiasaura, a mid-sized hadrosaur that roamed the American West in vast herds. Taken together, the fossilized nests and well-preserved skeletons of baby, juvenile, and adult Maiasaura (located in Montana's Two Medicine Formation) show that at least some dinosaurs had active family lives and didn't necessarily abandon their young after they hatched. 09 of 12 Sinosauropteryx (1997) Sam / Olai Ose / Skjaervoy/Flickr/CC BY 2.0 The first of a spectacular series of "dino-bird" discoveries in China's Liaoning quarry, the well-preserved fossil of Sinosauropteryx betrays the unmistakable impression of primitive, hair-like feathers, the first time paleontologists had ever directly detected this feature on a dinosaur. Unexpectedly, an analysis of Sinosauropteryx's remains shows that it was only distantly related to another famous feathered dinosaur, Archaeopteryx, prompting paleontologists to revise their theories about how — and when — dinosaurs evolved into birds. 10 of 12 Brachylophosaurus (2000) Brenda/Wikimedia Commons/CC BY 2.0 Although "Leonardo" (as he was dubbed by the excavation team) wasn't the first specimen of Brachylophosaurus ever discovered, he was far and away the most spectacular. This near-complete, mummified, teenaged hadrosaur occasioned a new era of technology in paleontology, as researchers bombarded his fossil with high-powered X-rays and MRI scans in an attempt to piece together his internal anatomy (with mixed results). Many of these same techniques are now being applied to dinosaur fossils in far less pristine condition. 11 of 12 Asilisaurus (2010) Smokeybjb/Wikimedia Commons/CC BY 3.0 Not technically a dinosaur, but an archosaur (the family of reptiles from which dinosaurs evolved), Asilisaurus lived toward the beginning of the Triassic period, 240 million years ago. Why is this important? Well, Asilisaurus was as close to a dinosaur as you can get without actually being a dinosaur, meaning that true dinosaurs may have counted among its contemporaries. The trouble is, paleontologists had previously believed that the first true dinosaurs evolved 230 million years ago — so the discovery of Asilisaurus pushed back this timeline by 10 million years! 12 of 12 Yutyrannus (2012) Laika ac from USA/Wikimedia Commons/CC BY 2.0 If there's one thing Hollywood has taught us about Tyrannosaurus rex, it's that this dinosaur had green, scaly, lizard-like skin. Except maybe not: you see, Yutyrannus was also a tyrannosaur. But this early Cretaceous meat-eater, which lived in Asia over 50 million years before the North American T. rex, had a coat of feathers. What this implies is that all tyrannosaurs sported feathers at some stage of their life cycles, so it's possible that juvenile and teenage T. rex individuals (and maybe even adults) were as soft and downy as baby ducks!