Page 106 - The Transitional Form Dilemma

THE TRANSITIONAL-FORM DILEMMA

Feathers are complex structures. Their abrupt appearance in the bird fossil
record has been difficult to explain, mainly because no intermediate structures
are preserved in the related theropod taxa. 67
Therefore, even if a feathered dinosaur were found, it could never
be regarded as evidence that birds evolved from dinosaurs, because
bird feathers are unique structures, and no evidence suggests that they
evolved from anything else.
Also noteworthy is that all the fossils presented as “feathered di-
nosaurs” were found in China. Why have they all been unearthed in
China, and nowhere else in the world? Chinese fossil beds are capable
of preserving not just uncertain structures such as dino-fuzz, but bird
feathers as well. Feduccia also questions this:
One must explain also why all theropods and other dinosaurs discovered in
other deposits where integument is preserved exhibit no dino-fuzz, but true
reptilian skin, devoid of any featherlike material, and why typically Chinese
dromaeosaurs preserving dino-fuzz do not normally preserve feathers, when a
hardened rachis, if present, would be more easily preserved. 68

So what are all these so-called “feathered dinosaurs” found in
China? What is the true identity of these creatures portrayed as transi-
tional forms between reptiles and birds?
Feduccia explains that some of the animals portrayed as “feath-
ered dinosaurs” are extinct reptiles displaying dino-fuzz, and that oth-
ers are real birds:
There are clearly two different taphonomic phenomena in the early Cretaceous
lacustrine deposits of the Yixian and Jiufotang formations of China, one pre-
serving dino-fuzz filaments, as in the first discovered, so-called “feathered di-
nosaur” Sinosauropteryx (a compsognathid), and one preserving actual
avian feathers, as in the feathered dinosaurs that were featured on the cover of
Nature, but which turned out to be secondarily flightless birds. 69
In other words, all the fossils presented to the world as feathered
dinosaurs or dino-birds belong to either various flightless birds, like
today’s ostriches, or else to reptiles possessing the organic material
known as dino-fuzz, which has nothing to do with true bird feathers.

104