D e p a r t m e n t o f O r g a n i s m a l B i o l o g y a n d A n a t o m y , a n d C o m m i t t e e o n E v o l u t i o n a r y B i o l o g y , U n i v e r s i t y o f C h i c a g o , 1 0 2 7 E a s t 5 7 t h S t r e e t , C h i c a g o , I l l . 6 0 6 3 7 , U S A
The “great debate” over bird origins may never have transpired had the now-famous furcula-bearing, feathered dinosaurs from Asia surfaced when the beds in which they were interred were first discovered in the 1920s. Compelling fossil evidence is now to hand that places birds as a specialized clade within theropod dinosaurs. Major insights include a more seamless fossil record linking birds and non-avian dinosaurs, clear evidence of an early pre-avian origin for feathers and other features previously known only among birds, together with an underscoring of the importance of miniaturization for the evolution of powered flight and a broadening of the functional scenarios for how powered bird flight was first achieved [Acta Zoologica Sinica50(6): 991 -1001, 2004].