Parasaurolophus

Parasaurolophus in all its glory!

Based as much upon skin impressions and mummies of other hadrosaurs:

1. Basically every mummified duck-billed dinosaur has unusual skin structures projecting dorsally on the spinal ridge. Corythosaurus (another lambeosaurine) preserves a skin frill. Other mummies display serrated ridges, however, they are more distantly related than Parasaurolophus is to Corythosaurus, so i picked helmet-dude's frill.

2. There actually ARE skin impressions for Parasaurolophus walkeri, they indicate small dorsal body scales, and then smaller side scales (as in Leonardo too). Belly scales were so small in Leonardo that they would seem non-existant from a few feet away.

3. Leonardo (Brachylophosaurus mummy) preserves large cheek scales, possibly indicative of bright colours on the living animal.

4. A Maiasaura individual (male?) was discovered with a throat pouch (dewlap). Makes sense to me that if hadrosaurs were display creatures, males would have gone overboard with impressing the lady-dinos.

5. Leonardo's beak also rises higher on the upper jaw than previously thought (note the higher ridge on midline of upper jaw).