Well, not really a creature reference. The Piltdown man was a skull and jawbone claimed to have been found by Charles Dawson in 1912 in Piltdown, England. The brain case was rather human and the jaw apish. For years there was debate that this might be the missing link between ape and man or a hoax. In 1953, modern techniques proved that the brain case and jawbone were from different species proving the hoax.
("Rats in the Walls" "Dagon")