We now have enough fossils of feathered dinosaurs to fill entire museums. These specimens have beautifully recorded the history of feather evolution but Ryan McKellar from the University of Alberta has found another narrator for that tale: amber.
Amber is actually fossilised tree resin, and some of it contains feathers dropped by dinosaurs. McKellar, working with Phillip Currie, studied beautiful cache of 11 such pieces that had been recovered from Grassy Lake, Canada many years earlier. “These were chance finds when we were preparing the amber to look for insects,” says Currie. “About half a dozen specimens were in my "research to do" specimen cabinet when Ryan ran across some more in his work.”
These 70-million-year old specimens hail from the late Cretaceous period and they are far more diverse than other amber-trapped feathers from the same period. It’s impossible to say who the feathers came from but given that some of them are far simpler than anything seen in known birds, McKellar suspects that they came from other types of dinosaur instead. After all, such species are far more common in Alberta’s fossil beds than true birds are.
Together, the amber feathers encompass the entire evolutionary history of feathers in four different stages, from simple filaments to flight-capable plumes. “It fleshes out a framework that was already evident from the feathered dinosaurs, although the preservation is far more spectacular in terms of detailed preservation and even colours,” says Currie. The slideshow below shows the various types.