Overview
- Two Edmontosaurus annectens from east-central Wyoming preserve continuous external anatomy as sub-millimeter clay templates rather than original soft tissue.
- The adult shows wedge-shaped, flat-bottomed caps on the three hind toes, representing the earliest hooves in a land vertebrate and the first documented in a reptile.
- The juvenile retains a complete fleshy outline with a tall midline crest, while the adult preserves a full tail spike row, pebble-like scales, and wrinkles indicating thin skin.
- Analyses using CT imaging, electron microscopy, X-ray spectroscopy, and 3D fitting to contemporaneous footprints support the reconstructions and reveal no detectable organics in the clay layer.
- Researchers mapped a compact Lance Formation locality known as the ‘mummy zone’ and infer drought desiccation, flash-flood burial, and microbial biofilms as the preservation pathway, with additional fieldwork planned.