Duck-billed dinosaur fleshy midline and hooves reveal terrestrial clay-template "mummification".

Abstract

Two "mummies" of the end-Cretaceous duck-billed dinosaur <i>Edmontosaurus annectens</i> preserve a fleshy crest over the neck and trunk, an interdigitating spike row over the hips and tail, and hooves capping the toes of the hind feet. A battery of tests showed that all of the fossilized integument (skin, spike, and hoof) are preserved as a thin (less than 1 millimeter) clay template that formed on the surface of a buried carcass during decay before the loss of all soft tissues and organic compounds. Unlike the underlying permineralized skeletal bone, the integument renderings of these "dinosaur mummies" are preserved as a thin external clay mask, a templating process documented previously only in anoxic marine settings.