 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
China’s Feathered Dinosaurs
Detail showing downy plumage along
backbone of Sinosauropteryx
CLOSE WINDOW
—well before the evolution of the modern avian flight apparatus—suggests that the role of feathers in
retaining body heat preceded their function in flight.
Sinosauropteryx retains several primitive features—such as very short arms—indicating that
it is the least bird-like of the theropod dinosaurs preserved in this ancient Chinese lake bed. Nevertheless,
its body is already covered with downy plumes that provide a glimpse of the earliest known stage in feather
evolution. Sinosauropteryx feathers are composed of fine filaments branching from hollow quills, rather like
down feathers in birds today.
Although individual feathers in Sinosauropteryx are hard to pick out, they all appear about the same size and
shape. This contrasts with feathers on the hand (remiges), tail (retrices), and body (contour) feathers that
evolved later in dinosaurs. These feathers can vary considerably in size and shape on different parts of the body.
And unlike Sinosauropteryx feathers, the filaments in “aerodynamic” feathers of living birds are tightly bound
together by tiny hooks, thus forming clean, sharp-edged outlines and broad, fixed, aerodynamic surfaces.