1) Among all living creatures, only birds have feathers. The discovery of a single isolated feather in the mid 19th century in Late Jurassic rocks of Bavaria was enough to demonstrate the remote ancestry of birds (approximately 150 million years ago). The discovery of the skeleton of Archaeopteryx in the same area in 1861 confirmed the idea of a feathered ancestor of birds, but little else in the skeleton appeared related to living birds.

2) Ji et al now describe two small theropod dinosaurs from geological beds in the Liaoning province of China, the age of the beds disputed but apparently Late Jurassic/Early Cretaceous (about 145 million years ago). These theropods have down-like and vaned barbed feathers on the body, arms, legs, and tail. But these animals were clearly not birds, and they were clearly not capable of flight.

3) If these are true feathers -- and the evidence indicates they are indeed true feathers -- we are forced to revise our idea of the association of feathers with the animals we call birds.

4) By admitting that plumage did not first spring full-blown on the wings of Archaeopteryx, we are free to examine how feathers evolved in the first place.

5) The evolution of carnivorous dinosaurs through basal (relatively "primitive") *coelurosaurs into birds shows some unmistakable trends in the morphology of wishbones, breastbones, hollow bones, long arms, hands, etc.

6) Padian concludes: "The work of Ji et al should lay to rest any remaining doubts that birds evolved from small coelurosaurian dinosaurs. These new discoveries will excite the public and scientists alike by showing that down-like and later vaned body feathers evolved before flight feathers, and that a full complement of feathers was present in coelurosaurs before birds were invented."

QY: Kevin Padian <kpadian@socrates.berkeley.edu>
QY: Philip J. Currie <pcurrie@mcd.gov.ab.ca>
(Nature 25 Jun 98 393:729,753) (Science-Week 17 Jul 98)