In 1868, Edward Draker Cope received a shipment of bones from Kansas that looked promising. It was probably something yet unidentified in America, and he wanted to be the first to publish it. Rushing to beat his rivals to the punch, Cope published this restoration of the elasmosaurus platyurus in the American Philosophical Society journal.
In this original restoration, Cope put the animal's skull on the right, giving it a short neck and a long tail.
Shortly after the reconstruction was published, Cope's rival, O.C. Marsh noticed that the skull had likely been placed on the wrong end of the skeleton. He contacted fellow paleontologist Joseph Leidy who confirmed the mistake.
Cope quickly published a corrected version of the drawing with the skull on the left, giving the creature a longer neck and shorter tail.
Cope tried to purchase all copies of American Philosophical Society that contained the incorrect version, but the damage to his reputation was done. And his rivalry with Marsh would only intensify.