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RE: Feduccia et al: No Evidence Fossil Feathers Are Really Feathers
Hmmm... not only does Feduccia re-classify microraptors as birds, but he
also re-classifies psittacosaurs as ornithopods. Maybe he read Butler's
paper... (Guffaw guffaw.)
I'm also not sure what the presence of scales in the forearm of
_Pelecanimimus_ adds to this 'debate'. Birds have scales on their feet, so
why is this a big deal?
And somebody has just GOT TO explain to Feduccia the distinction between
"ancestor" and "sister taxon". I think even the most hard-headed
paleontologist recognizes that an ancestor cannot give rise to a descendent
that lived 25 million years earlier.
Feduccia, A., Lingham-Soliar, T., and Hinchliffe, J.R. (2005). Do feathered
dinosaurs exist? Testing the hypothesis on neontological and paleontological
evidence. J. Morphology (in press).
Abstract. "The origin of birds and avian flight from within the archosaurian
radiation has been among the most contentious issues in paleobiology.
Although there is general agreement that birds are related to theropod
dinosaurs at some level, debate centers on whether birds are derived
directly from highly derived theropods, the current dogma, or from an
earlier common ancestor lacking suites of derived anatomical characters.
Recent discoveries from the Early Cretaceous of China have highlighted the
debate, with claims of the discovery of all stages of feather evolution and
ancestral birds (theropod dinosaurs), although the deposits are at least 25
million years younger than those containing the earliest known bird
_Archaeopteryx_. In the first part of the study we examine the fossil
evidence relating to alleged feather progenitors, commonly referred to as
protofeathers, in these putative ancestors of birds. Our findings show no
evidence for the existence of protofeathers and consequently no evidence in
support of the follicular theory of the morphogenesis of the feather.
Rather, based on histological studies of the integument of modern reptiles,
which show complex patterns of the collagen fibers of the dermis, we
conclude that protofeathers are probably the remains of collagenous fiber
meshworks that reinforced the dinosaur integument. These meshworks of the
skin frequently formed aberrant patterns resembling feathers as a
consequence of decomposition. Our findings also draw support from new
paleontological evidence. We describe integumental structures, very similar
to protofeathers, preserved within the rib area of a _Psittacosaurus_
specimen from Nanjing, China, an ornithopod dinosaur unconnected with the
ancestry of birds. These integumental structures show a strong resemblance
to the collagenous fiber systems in the dermis of many animals. We also
report the presence of scales in the forearm of the theropod ornithomimid
(bird mimic) dinosaur, _Pelecanimimus_, from Spain. In the second part of
the study we examine evidence relating to the most critical character
thought to link birds to derived theropods, a tridactyl hand composed of
digits 1-2-3. We maintain the evidence supports interpretation of bird wing
digit identity as 2,3,4, which appears different from that in theropod
dinosaurs. The phylogenetic significance of Chinese microraptors is also
discussed, with respect to bird origins and flight origins. We suggest that
a possible solution to the disparate data is that Aves plus bird-like
maniraptoran theropods (e.g., microraptors and others) may be a separate
clade, distinctive from the main lineage of Theropoda, a remnant of the
early avian radiation, exhibiting all stages of flight and flightlessness."