Even though the first dinosaurs was thought to have emerged some 245 million years ago, dinosaurs with feathers have been dated to only 180 million years ago. Yet, the story does not end there.
Feathers, it seems, did not originate with the dinosaurs. According to a recent study, they may have evolved in another group.
The pterosaurs, a closely related but separate group of “ruling reptiles” (or archosaurs, a group that, incidentally, also includes birds and crocodiles), also had feathers.
inputs from britanica