Feather Evolution Proved?

Another claim of feather evolution was reported in PNAS.¹  Creationists have long claimed that the evolution of feathers from reptilian scales is an intractable problem for Darwinists (example: 1994 article from Creation magazine).  Does the paper provide incontrovertible proof that feathers had evolved in dinosaurs before birds took flight in the air?
    Beipiaosaurus, a therizinopod theropod, discovered in the Liaoning province of China, was announced in 1999.  The latest paper by the discoverer Xing Xu discusses a new feather type found in a second specimen.  Xing Xu claims that all the intermediate steps in feather evolution predicted in a 1999 model by R. O. Prum (Natural History Museum, University of Kansas)²  have now been filled in: “Although the EBFFs [elongated broad filamentous feathers] in the basal therizinosaur Beipiaosaurus differ from the predicted stage I morphology in some features, such as their somewhat planar form, their discovery nevertheless documents an unbranched feather morphology in nonavian theropods and thus completes the array of fossil evidence for the morphological series predicted by the developmental models.”
    Summaries of the paper can be found on Live Science and the BBC News.  One of the main points Xu et al made was that these “integumentary structures” could never have been used for flight.  Beipiaosaurus was 7 feet long, after all, and some therizionsaurs reached 40 feet.  Also, the feather impressions were found only along the head, neck, torso and tail.  He proposed instead that they were used for mating displays.
    Speculations about the origin of feathers go way back (10/30/2002).  Thomas Huxley in the 1800s speculated about the origin of birds from dinosaurs.  The story has become more complex than a simple line from one to the other.  A bewildering array of specimens defies any neat, uncontroversial classification.
Update 01/22/2009: After this entry was posted, news of another “feathered dinosaur” was found on National Geographic News.  This specimen, Anchiornis huxleyii (named for Thomas Huxley who first suggested a dinosaur-to-bird link), is the smallest of all.  The purported feathers on this specimen, which cover the body and head, are apparently too indistinct to classify.  Its long forearms suggests that it was capable of flying or gliding.  Its estimated age seems close to that of Archaeopteryx.  Xing Xu’s paper calls it a “maniraptoran dinosaur” but whether the maniraptorans should be called “dinosaurs” at all seems open to revision.³   

1.  Xing Xu, Xiaoting Zheng and Hailu You, “A new feather type in a nonavian theropod and the early evolution of feathers,” Proceedings of the National Academy of Sciences, PNAS January 20, 2009 vol. 106 no. 3 832-834, doi: 10.1073/pnas.0810055106.
2.  Abstract available from PubMed.
3.  The maniraptoran clade, which includes the true birds, was invented in 1986.  Maniraptorans typically have long forearms (like bird wings) and are so classified by the arbitrary rule “all dinosaurs closer to modern birds than to the ornithomimids.”  Since the grouping includes many extinct species known only from skeletal features, some with faint “feather-like impressions,” and scientists disagree on the salient characteristics among mosaics of traits, the placement of this or that fossil in the group, or the status of the group itself, appears subjective.

Here at CEH, we respect empirical evidence and believe in following the evidence where it leads.  There are some strange aspects to this story, however, that should lead any observer to avoid jumping to conclusions. 

1. The only “feathered” dinosaur specimens come from the Liaoning Province of China.  Therizinopods from North America do not have the integumentary structures.  The rebuttal is that the fossils from Liaoning have exceptional preservation.  But so do other areas in the world, like Germany (see the important 03/15/2006 entry).  Why are none found elsewhere?
2. The “Feathered dinosaur” fossils all come from the Yixian formation in China and all began surfacing in the 1990s.  Archaeopteryx has been known since the time of Darwin.  And why is the same scientist, Xing Xu, so personally involved in these revelations?  A diversity of independent discoverers would be healthy.
3. China has strong motivation to find spectacular fossils.  Workers in the fossil quarries know that spectacular finds bring more money.
4. Western evolutionists have strong motivation to link dinosaurs with birds.  Recall the rush to judgment National Geographic made over Archaeoraptor that embarrassed them when it was found by Xing Xu to be a hoax.
5. The word feather is being used carelessly.  These are elongated fibers, if anything – nothing like the pennate feathers on birds with closed vanes, linked by a complex interlocking system of barbs and barbules.
6. The phylogeny of Beipiaosaurus and other therizinopods is controversial.  Every once in awhile the family tree gets rearranged.
7. The presumed feathers could be artifacts of the fossilization process at Liaoning.  Some have proposed they are flayed fibers of skin collagen.
8. The earliest-claimed “feathered dinosaur” Sinosauropteryx remains controversial (see the pro-Darwinist Wikipedia entry).  Scientists are not sure if the “feathers” are flayed collagen and where this species fits in the evolutionary tree (05/23/2007, 01/09/2008).
9. The integumentary structures had nothing to do with flight.  They probably did not provide insulation, either.  It is not clear what “evolutionary advantage” they played, if anything.  The hypothesis that they were used for mating displays is just that – a hypothesis.  How can one test it on an extinct animal?
10. Original papers on these feathered-dinosaur claims usually describe them as “protofeathers” or “integumentary structures” leaving some doubt about what they really were.  The ones with unambiguous feathers are arguably true birds, not dinosaurs.
11. The only other part of the world with well-preserved feathers is Germany, where Archaeopteryx was found.  This was a true bird capable of powered flight.  It possessed asymmetrical, pennaceous feathers.  Archaeopteryx, furthermore, is placed earlier than the so-called feathered dinosaurs.
12. Artist reconstructions tend to get carried away with exaggerating the integumentary structures to look like feathers.  Judge from the fossils, not from the artwork.
13. Of the 21 “feathered dinosaur” species listed by Wikipedia, all have problems either in classification or in identifying the integumentary structures as feathers.  Their list includes Velociraptor but the only evidence is the putative instance of quill knobs on one specimen (see 09/22/2007).  A careful reading of the article shows only inference based on evolutionary thinking: “The fact that the ancestors of Velociraptor were feathered and possibly capable of flight long suggested to paleontologists that Velociraptor bore feathers as well, since even flightless birds today retain most of their feathers.”  The article also entertains the possibility that they were secondarily flightless.  Their list also includes Juravenator, which had only scales, not feathers (see Mr. Dinofeather Xing Xu himself waffle about this in the 03/15/2006 entry).
14. Some of the “feathered dinosaurs” on the list may have devolved from birds and become flightless, like the kiwi is believed to have become secondarily flightless.  This has been proposed for Epidexipteryx, for example (see 10/22/2008), and Caudipteryx.
15. A careful look at the list shows that feathers are inferred among many of them – this, again, based on evolutionary assumptions.  “Inferred” feathers are imaginary feathers (06/13/2007, 07/09/2008).  We must go with the actual feathers found on specimens that are clear of hoax suspicions.  The ones marked with “pennaceous feathers” (not “pennaceous feathers inferred,” as with Velociraptor) are arguably all birds that could fly or, as in the case of Caudipteryx, lost the ability to fly.
16. Are there really 21 distinct species on the Wikipedia list, or is this a manufactured classification based on evolutionary assumptions?  How much overlap is there?  Sinocalliopteryx, for instance, is described as a larger version of Huaxiagnathus.  Some had no feathers at all but were only inferred to have feathers based on their presumed evolutionary position.  As with human evolution, where fossils could be reclassified as clearly human (Neanderthal) or clearly ape (Lucy), an outside observer could reclassify all the members as either birds or reptiles.  The presence of a consensus among doctrinaire Darwinists does not necessarily correlate with truth.
17. Placing the known specimens into an evolutionary sequence is a human activity that does not derive objectively from the bones themselves (see 10/06/2004).
18. Where are the skeptics?  Science thrives on controversy.  Skeptics of dinosaur-to-bird evolution like Alan Feduccia (10/10/2005) and Storrs Olson rarely get a hearing in the Darwin Chorus.  When their views are mentioned at all, it is usually just to drown them out with the chorus.  Remember Storrs Olson said in 2001, “They want to see feathers . . . so they see feathers.  This is simply an exercise in wishful thinking” (03/13/2001).  That doesn’t make for good press in the newspapers.

01/25/2008).  This gets comical real fast (click the Tweety bird).
    Without the “evolutionary thinking” that has become the mind-altering drug of choice among today’s paleontologists, we would simply recognize that our present world is impoverished of many complex and interesting animals that once lived on this planet.  There would not be this insatiable lust to link them into trees to honor their idol, Charles Darwin.  However the activity makes them feel good, it is a hallucination, not an observation.