Overview
- University of Chicago researchers report in Science that Edmontosaurus annectens fossils from east-central Wyoming preserve external anatomy as wafer-thin clay templates rather than soft tissue.
- The specimens reveal a fleshy crest along the neck and back, a continuous tail spike row, small pebble-like scales, and wedge-shaped, flat-bottomed hooves on the hind toes.
- The hooves constitute the earliest documented hooves in a land vertebrate and make Edmontosaurus the first confirmed hooved reptile.
- A proposed sequence of drought desiccation followed by flash-flood burial produced a biofilm that drew clay onto carcasses, with microbes hardening the layer; analyses found no tissue structures or DNA.
- Hospital and micro-CT scans, thin sections, and X-ray spectroscopy underpinned digital reconstructions validated against matching fossil footprints, while fieldwork mapped a localized Wyoming 'mummy zone' for further study.