Original sentence: If these dinosaurs didn't have feathers, or feather-like structures, then feathers may have evolved at a later time, and been used for flight right from the start.It calls into question the theory that the first feathers evolved not for flight but for insulation, and that they made their first appearance in relatively early dinosaur lineages that later evolved into modern birds.This hypothesis puts Sinosauropteryx's claim as first known species with feather at stake and also the current theory of origin of feather itself