1) Transitional fossil 
Aurornis is an extinct genus of theropod dinosaurs from the Jurassic period of China. The genus Aurornis contains a single known species, Aurornis xui iː. Aurornis xui may be the most basal (`primitive`) avialan dinosaur known to date, and it is one of the earliest avialans found to date. The fossil evidence for the animal pre-dates that of the.....