melanosomes

Fossil pigments, feathers, skin impressions, and living relatives suggest many dinosaurs were more colorful than old museum models.

Paleontologists don't guess. When they reconstruct a dinosaur, they work from fossilized bones to muscle attachment scars to preserved skin impressions to microscopic pigment organelles locked in ancient feathers. The process is more constrained than most people realize — and more surprising. Some dinosaurs' actual colors are now known with genuine scientific confidence.