An interesting example of the re-evolution of features once lost, arises in the case of the pangaloon. Its body is covered in scales, but these are not the conventional reptilian scales that were possessed by its archosaurian ancestors 200 million years ago. These scales are actually plates of keratin. The original scales were retained as the archosaur evolved into the primitive coelurosaur dinosaur. Then, as the ancestral coelurosaur developed and evolved into the arbrosaur, many of its scales evolved into insulating feathers.