Edmontosaurus mummy SMF R 4036

The Edmontosaurus mummy SMF R 4036, nicknamed the Senckenberg mummy or Edmond, is an exceptionally well-preserved dinosaur fossil in the collection of the Senckenberg Museum (SMF) in Frankfurt am Main, Germany. It was found in 1910 in Wyoming, United States, in rocks of the Lance Formation that date to the late Maastrichtian, close to the Cretaceous–Paleogene extinction event 66 million years ago. The mummy is ascribed to the species Edmontosaurus annectens (originally Trachodon), a member of the Hadrosauridae ("duck-billed dinosaurs"). It comprises a nearly complete skeleton that was found wrapped in skin impressions, a rare case of preservation for which the term dinosaur mummy has been used. The fingers of the right hand are wrapped in a mitten-like envelope of skin impressions, initially interpreted as a paddle unsuited for terrestrial locomotion, thereby reinforcing the now outdated hypothesis that hadrosaurs were aquatic. The impression of a horny beak is also preserved with this specimen. Plant remains found in the body cavity were interpreted as stomach contents, indicating a diet of terrestrial plants. It is now believed that this plant material was washed into the body cavity of the carcass.

It is assumed that the individual died during a drought, in or near a riverbed. Subsequently, the carcass would have dried out before being carried away by a sudden flood and been buried rapidly. Sand filled the body cavity, preserving the three-dimensional shape of the body, and a biofilm (bacterial mat) on the skin formed a thin crust of clay that preserved the shape of the skin in positive relief (protruding up from the surface). The mummy was found by fossil hunter Charles Hazelius Sternberg and his sons, who sold their numerous finds to museums in North America and Europe. It is one of the best preserved hadrosaurid mummies and the second to be discovered, after the first such mummy was discovered by the Sternbergs in the same region two years earlier.