Ronald Orenstein wrote-
I can't wait to see what Feduccia et al will say about this one. Will it be (choose one):
1. The structures are collagenous fibers (despite the fact that the paper was discussed with Peter Stettenheim, who ought to know a feather when he sees one)
2. Sinornithosaurus is a bird
3. The authors have committed a fraud.
I'd say "2" is his best bet. If he can make Caudipteryx a bird, Sinornithosaurus (which is very similar to Archaeopteryx) should be no problem. Just ignore cladistic analyses, find the many bird-like characters also seen in other eumaniraptorans (and ignore that last fact) and credit Sinornithosaurus with bird-like characters that it actually lacks, and there you go: instant bird. Of course we are all ignoring the highly probable option 4- Bird feathers were washed on top of the Sinornithosaurus holotype, so the feathers are simply associated incorrectly. I should have known! ;-)