The birds weren't the first. Plumage of various types - from simple fluff to complex structures that allow you to fly - appeared in dinosaurs.
And the perfectly preserved juvenile theropod of the Jurassic period, found in Germany, indicates that, possibly, all (!) Dinosaurs in general were covered with threadlike feathers to one degree or another.
For the first time, the fluffy lizard - theropod sinosauropteryx - was discovered in 1996. Since then, paleontologists have identified over 30 species of feathered dinosaurs. Most of them are coelurosaurs, that is, representatives of a highly diversified group of theropods, which includes formidable tyrannosaurs, and sickle-clawed Deinonychosaurs, and bizarre therizinosaurs, and birds.
There are, however, exceptions. Paleontologists have also found simple feathers along the spine of the Psittacosaurs and Tianyulongs, although these ornithischians appear to have had nothing to do with birds (contrary to their name). It was hypothesized that ranks of primitive proto-feathers were common among dinosaurs. The new discovery confirms this scandalous conclusion.
Theropod Sciurumimus albersdoerferi lived about 150 million years ago. Particularly remarkable is the fact that the dinosaur belongs to the superfamily Spinosauroidea (Megalosauroidea).
Photo: H. Tischlinger / Jura Museum Eichstätt
These were the archaic, toothed dinosaurs that stood at the base of the theropod family tree. They are a very long evolutionary distance from feathered dinosaurs and early birds. According to lead author Oliver Rauchut of the Ludwig Maximilian University (FRG), this means that simple feathers are a very ancient feature of dinosaurs. The filamentous formations that Sciurumimus is endowed with are very similar to the primitive structures of psittacosaurs, Tianyuluns and even pterosaurs - flying reptiles that were the closest relatives of dinosaurs. The widespread occurrence of this feature hints that the proto-feathers are as old as Dinosauria itself.
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Commentators agree that the fossilized beams are indeed very similar to fluff (more geochemical studies are needed to be sure), but, for example, Paul Barrett of the Natural History Museum in London (UK) considers the endowment of all dinosaurs with feathers speculation. It is possible that fluff appeared several times in the evolutionary history of this clade. More examples are needed among non-coelurosaur theropods, and even better among other groups.
Mr Rauchut advises looking in fine-grained sediments where there is a better chance of keeping feathers.