In 1868, Edward Drinker Cope incorrectly restored the type specimen of Elasmosaurus platyurus, by placing the skull at the end of the animal's tail. His error haunted him the rest of his career. In examining the scientific literature and popular science literature available to Cope prior to 1868, as well as taking note of the extent of knowledge which I suggest his professional colleagues shared with him concerning plesiosaurs, it seems impossible that he should have incorrectly restored the fossil. I further suggest that he made this error more than once, even after his mistake was pointed out to him.
“Mr. Conybeare has justly remarked how difficult it is to determine the number of the cervical vertebrae in a Plesiosaur, owing to the gradual transition in their lateral appendages from the condition of hatchet-shaped laminae to the ordinary elongated form of ribs.”
—Richard Owen
“A Description of a Specimen of Plesiosaurus Macrocephalus, Conybeare,” 1840
“It is this apparent adaptation of the parts to the articulation of chevron bones which has led me to consider the vertebrae under consideration as caudals, otherwise from their resemblance to the cervical vertebrae of Plesiosaurus pachyomus, as represented by Prof. Owen, I should have viewed them as belonging to the cervical series.”
—Joseph Leidy, writing on Discosaurus vestutus in
“Cretaceous Reptiles of the United States,” 1865
“It is the least able contribution to paleontology that we remember …it contains no science.”
—Thomas Huxley
Review of Leidy's “Cretaceous Reptiles of the United States”
Geological Magazine, 1868
“Elasmosaurus platyurus …The anatomical characters of the different regions of the vertebral column …are decidedly Plesiosaurian. Prof. Cope has described the skeleton in a reversed position to the true one and in that view has represented it in a restored condition …”
—Joseph Leidy
“Communication to the Academy of Natural Sciences of Philadelphia”
March 8, 1870
