1. The Stegosaurus with a Brain in its Butt
When Stegosaurus was first discovered, in 1877, experts weren't used to the idea of elephant-sized lizards with bird-sized brains. That's why, in the late 19th century, the famous paleontologist Othniel C. Marsh broached the idea that a second brain resided in Stegosaurus' rump, which presumably helped to control the rear part of its body. Today, no one believes that Stegosaurus (or any dinosaur) had two brains, but it may well turn out that the cavity in this stegosaur's tail was used to store extra food (in the form of glycogen).
2. The Dino-Chicken that Ate Washington
The National Geographic Society doesn't put its institutional heft behind just any dinosaur find, which is why this august body was embarrassed to discover that the "Archaeoraptor" it prominently displayed in 1999 had actually been cobbled together out of two separate fossils. It seems that a Chinese adventurer was eager to supply the long-sought "missing link" between dinosaurs and birds, and fabricated the evidence out of the body of a chicken and the tail of a lizard--which he then said he'd found in 125-million-year-old rocks.
3. The Brachiosaurus from Beneath the Sea
When a dinosaur has a 40-foot-neck and a skull with the nasal openings on top, it's natural to speculate about what kind of environment it could possibly have lived in. For years, 19th-century paleontologists thought Brachiosaurus spent most of its life underwater and stuck its head out of the surface to breathe, like a human snorkeler. However, later research proved that a sauropod as massive as Brachiosaurus would have instantly suffocated from the water pressure, and this genus was relocated to land, where it properly belongs.
4. The Caterpillar that Killed the Dinosaurs
Caterpillars evolved during the late Cretaceous period, shortly before the dinosaurs went extinct. Coincidence, or something more sinister? A while back, scientists were semi-convinced by the theory that hordes of voracious caterpillars stripped ancient woodlands of their leaves, prompting the starvation of herbivorous dinosaurs (and of the carnivorous dinosaurs that fed on them). Death-by-caterpillar still has its adherents, but most experts believe dinosaurs were done in by a massive meteor impact--which somehow sounds more convincing!
5. The Elasmosaurus with its Head on its Tail
In 1868, one of the longest-running feuds in modern science got off to a rousing start when paleontologist Edward Drinker Cope reconstructed an Elasmosaurus skeleton with its head on its tail, rather than its neck (to be fair, no one had ever seen such a long-necked marine reptile before). According to legend, this error was quickly pointed out (in a not-very-friendly way) by Cope's rival, Othniel C. Marsh, the first shot in what came to be known as the late 19th century's "Bone Wars."
6. Hydrarchos, the Ruler of the Waves
The early 19th century witnessed the "Gold Rush" of paleontology, with biologists, anatomists, geologists, and just plain amateurs stumbling over themselves to unearth the latest spectacular fossils. The culmination of this trend was in 1845, when Albert Koch displayed a gigantic marine reptile he named Hydrarchos, which had actually been pieced together from the skeletal remains of Basilosaurus, a prehistoric whale. By the way, this creature's putative species name, "sillimani," refers not to its misguided perpetrator, but to the 19th century naturalist Benjamin Silliman.
7. The Oviraptor that Kidnapped its Own Eggs
When the first skeleton of Oviraptor was discovered in 1923, its skull lay only four inches away from a clutch of Protoceratops eggs, prompting paleontologist Henry Osborn to assign this dinosaur's name (Greek for "egg thief"). For years afterward, Oviraptor lingered in the popular imagination as a wily, hungry, none-too-nice gobbler of other species' young. The trouble is, it was later proved that those "Protoceratops" eggs were really Oviraptor eggs, and this misunderstood reptile was simply guarding its own brood!
8. The Iguanodon with a Horn on its Snout
Iguanodon was one of the first dinosaurs ever to be positively ID'd, so it's understandable that the baffled paleontologists of the early 19th century were unsure how to piece its bones together. The man wo discovered Iguanodon, Gideon Mantell, placed its thumb spike on the end of its snout, like the horn of a reptilian rhinoceros--and it took decades for experts to work out this ornithopod's posture. (For the record, Iguanodon is now believed to have been mostly quadrupedal, but capable of rearing up on its hind legs when necessary.)
9. The Plesiosaur that Lurks in Loch Ness
The most famous "photograph" of the Loch Ness Monster shows a reptilian creature with an unusually long neck, and the most famous reptilian creatures with unusually long necks were the marine reptiles known as plesiosaurs, which went extinct along with the dinosaurs 65 million years ago years ago. Today, some cryptozoologists (and many out-and-out pseudoscientists) continue to believe that a gigantic plesiosaur lives in Loch Ness, even though, for some reason, no one has ever been able to find convincing proof of the existence of this multi-ton behemoth.
10. The Hypsilophodon that Lived up a Tree
When it was discovered in 1849, Hypsilophodon went against the grain of accepted dinosaur anatomy: this ancient ornithopod was small, sleek and bipedal, rather than huge, quadrupedal and lumbering. Unable to process the data, paleontologists surmised that Hypsilophodon lived up in trees, like an oversized squirrel. However, in 1974, a detailed study of Hypsilophodon's body plan showed that it was no more capable of climbing an oak tree than a comparably sized dog.
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