Feathers are
an unmistakable trait of birds, and the relative
lack of fossils showing the origin and evolution
of feathers has driven much of the debate over
bird origins. A turkey-sized dinosaur named Sinosauropteryx
and another find dubbed

Protarchaeopteryx,
were described by Ji Qiang and Ji Shu'an of the
National Geological Museum of China in two reports
. These fossils were found in Liaoning province
in strata dating to the late Jurassic or early
Cretaceous. Sinosauropteryx has fringed elements
along its backbone and body surface which may
be feather precursors. It does, however, have
many differences with birds and probably is related
to the theropod Compsognathus. This finding may
be either a maniraptoran theropod or possibly
a bird, but a full description of its anatomy
still awaits publication . Hou and colleagues
(1995) have reported the finding of Confuciusornis
sanctus, a pigeon-sized specimen from a formation
in northeastern China dated to the Jurassic-Cretaceous
boundary. This species may have lived before Archaeopteryx,
but exhibits the hindlimbs and retroverted pubis
similar to Archaeopteryx. The skeleton also has
unfused carpal elements and long fingers with
long, curved claws (Hou et al, 1995). There also
exist avian-like contour feathers, which could
indicate endothermic physiology.