“Thin plate lizard”
Late Cretaceous, 80.5 million years ago
Elasmosaurus was a plesiosaur that could grow up to 46 feet in length – half of that length being neck! When first discovered in 1868, the prominent paleontologist Edward Drinker Cope mistook its attenuated neck for a tail, placing its head on its rear end. Cope’s professional rival, Othniel Charles Marsh, ridiculed him for this error, marking the scientific community’s first usage of “butthead” in peer review.