The Fossilized Skin Impressions of an Edmontosaurus

Shortly after death, a dinosaur's body is broken down fairly rapidly and decomposition begins in earnest. Because of this, both softer internal and external parts rarely last long enough to leave evidence of their existence in the fossil record.

But in rare and ideal preservation circumstances, an animal's integuments (e.g. skin or feathers) are immediately pressed against a mineral substrate that quickly hardens and eventually fossilizes, leaving an exact impression of the outside of a recently deceased dinosaur. Skin impressions—like the beautiful specimens offered here—provide valuable insights into the exact appearance of Edmontosaurus, a herbivorous hadrosaurid ("duck-billed") dinosaur that hasn't seen the light of day in over 66 million years.

This fossilized dermal impression was found associated with an Edmontosaurus skeleton, with the natural cast and mold (positive and negative) from different areas of the same individual.