Great resource for feather evolution.
http://people.eku.edu/ritchisong/feather_evolution.htm
I’m taking a brief interest in whether feathers evolved from scales or from hair.
It may depend on the type of feather, there are nine standard types. Perhaps Types 1-3 evolved from hair and types 8-9 from scales?
Not on that website are that hairs had developed at least as early as the upper Permian, before 251 Ma. That’s long before the first crocodile, pterosaur and dinosaur. http://onlinelibrary.wiley.com/doi/10.1111/let.12156/abstract
Hairs have been found on mammals, pterosaurs and ornithischian dinosaurs, but not on the theropod dinosaurs that led to birds. Scales have been found on fish, crocodiles and both ornithischian and saurischian dinosaurs but not on theropods or pterosaurs.
Also not on that website, Type 3 feathers (downy feathers) have now been found on an ornithischian dinosaur https://en.wikipedia.org/wiki/Kulindadromeus as well as the theropod dinosaurs and birds.
So what do you think? Is the evolution of the feather as murky as ever or is it starting to clear up?
