Fuzzy thinking about fuzzy dinosaurs

A visual approximation.

Casey Luskin, the Discoveryless Institute’s resident attack chihuahua, is on a roll. This time he’s gone off on a tangent about a recent find of yet another dinosaur fossil with evidence of protofeathers, Sciurumimus albersdoerferi and dinosaur evolution in general.

Luskin: The media that loyally serve Big Science are at it again, overstating the finds of a scientific paper to promote an evolutionary icon. This time, the icon is feathered dinosaurs, representing the purported ancestral relationship between dinos and birds. (Luskin 2012)

Ah, if only. If only Mr. Luskin’s conspiratorial fantasy were true and the media was that on the ball. The fact of the matter is that defenders of science education like me often cringe at the mischaracterizations and overstatements that come out of the popular media regarding evolution. I am constantly shaking my head and yelling at the TV or radio “no, that’s not what that means at all”, or words to that effect.

I wish I had a nickel (because being underemployed I could really use the money) for every time a silly reporter, while talking about some fossil discovery, described it as “overthrowing everything we thought we knew about the evolution of X”.

That is absolute bollocks, 99% of the time.

Luskin: A recent article in Science News claims, “All dinosaurs may have had feathers,” because a newly discovered fossil dinosaur supposedly “sports long, fine plumage.” Looking at the find, however, shows that it’s nothing more than a classic example of what critics affectionately call “dinofuzz.” This is all-but-admitted in the technical paper, published in Proceedings of the National Academy of Sciences…

How quickly people become jaded. For over 160 years dinosaurs were universally thought to be covered with only scales and scutes like the skin of living reptiles and the feet of birds (Currie & Padian 1997, p. 669). It wasn’t until the discovery of Sinosauropteryx, a mere 16 years ago, that we had any knowledge of the “dinofuzz”, that Mr. Luskin dismisses so easily. Furthermore, this is one of the few examples of fossil protofeathers discovered outside of China. 

Sinosauropteryx

Sinosauropteryx protofeathers

Luskin: But of course these “type 1 feathers” aren’t really true birdlike feathers. As one paper in Nature noted, they are hairlike structures sometimes called “dinofuzz”:

And indeed, Tianyulong doesn’t have true pennaceous feathers. It has long filaments, very similar to what have been called “protofeathers” or, more non-committally, “dinofuzz.” These filaments … are also found in a range of other theropods that lack definitive feathers, such as the basal coelurosaur Sinosauropteryx, the therizinosauroid Beipiaosaurus and the basal tyrannosauroid Dilong.

The paper Mr. Luskin is quoting from here talks about the discovery of protofeather-like structures on a fossil of an ornithischian dinosaur Tianyulong. What is surprising about these structures is not the fact that they are not “true pennaceous feathers” is that they are any kind of feathers found on an ornithischian dinosaur. This is because it was previously thought that protofeathers/feathers were only to be found in saurischian dinosaurs and in fact only in one branch of the saurischians, the theropods.

Of course, I see an ellipsis (…) in his quote and whenever I see those three little dots in a quote given by creationists, warning lights go off in my brain. So let us put back what is missing in that ellipsis and see if it was anything pertinent (section replaced with ellipsis in bold): 

And indeed, Tianyulong doesn’t have true pennaceous feathers. It has long filaments, very similar to what have been called ‘protofeathers or, more non-committally, ‘dinofuzz’. These filaments are evident in some theropods such as Caudipteryx that have true pennaceous feathers, but are also found in a range of other theropods that lack definitive feathers, such as the basal coelurosaur Sinosauropteryx, the therizinosauroid Beipiaosaurus and the basal tyrannosauroid Dilong3,4,10. (Witmer 2009, p. 294, emphasis mine)

As you can see, what Mr. Luskin removed was a reference to Caudipteryx, a theropod dinosaur that had both “dinofuzz”—the significance of which he is trying to minimize throughout his article—and “true pennaceous feathers”. However, he did leave in the part about other theropods that lack “definitive feathers”.

It is almost as if he wants his readers to think that all dinosaurs with “dinofuzz” had only “dinofuzz” and doesn’t want them considering the possible implications of a dinosaur like Caudipteryx that had “dinofuzz” and true feathers.

Luskin: In other words, the fossil structures on this new dinosaur are being compared to those of species that “lack definitive feathers.” They are not “true pennaceous feathers,” but rather are best viewed as “filaments” or “dinofuzz.” So much for the claim that this was a feathered dinosaur. 

What is particularly galling is that for years creationists like Mr. Luskin have been demanding evidence for protofeathers in the fossil record and now that they are turning up, they’re dismissed as not “true birdlike feathers”.

Heads they win, tails you lose.

Misc. protofeathers trapped in amber.

See: Amber trapped dinosaur feathers at different stages in their evolution for details.

Luskin: The truth comes out later in the paper:

The protofeathers probably are monofilaments, because no branching patterns are visible in the well preserved, long filaments above the tail; apparent branching patterns in a few places probably are the result of compaction of these structures. Because of the state of preservation, it cannot be established if these structures were hollow.

Mr. Luskin writes as if careful, full, descriptions of the fossil material (stated in qualified terms) is something done reluctantly by paleontologists (this is a recurrent creationist fantasy).

By way of contrast, creationists, as we have seen, are anything but careful in the way they deal with quoting scientists. This time Mr. Luskin seems to have changed a comma into a period and lost the last part of a sentence the above paragraph.

Here is the paragraph restored:

The protofeathers probably are monofilaments, because no branching patterns are visible in the well-preserved, long filaments above the tail; apparent branching patterns in a few places probably are the result of compaction of these structures (16). Because of the state of preservation, it cannot be established if these structures were hollow, like the filaments found in other dinosaurs (3, 14). The thickness of these filaments is ~0.2 mm in the long filaments in the dorsal tail region and less in the shorter filaments at the tail flank, back, and belly of the animal; the filaments are comparable in size to the filamentous protofeathers found in Sinosauropteryx (14). (Rauhut et al. 2012, p. 4, emphasis mine).

Once more it seems as if Mr. Luskin did not want his readers to consider the fact that other dinosaurs have hollow, more feather-like, structures than those found in Sciurumimus.

In any event I suspect that even if this fossils did have full-blown feathers creationists would dismiss them demanding to see the “half-feathers” (something they would never define and would always insist has not been found despite the existence of miscellaneous fossil protofeathers).

Luskin: Likewise, the Science News piece admits at the bottom of the article: “Unlike modern feathers, these ‘protofeathers’ or ‘type 1 feathers’ look like simple strands of hair.”

Yes, it would be more surprising to find highly derived feather types in a such a basal theropod as Sciurumimus. The Science News article clearly states:

Researchers have found feathered dinosaurs before, but this one is more distantly related to birds than any previously discovered. (Rosen 2012, emphasis mine)

The PNAS paper spells this out more explicitly:

Sciurumimus albersdoerferi represents the phylogenetically most basal theropod that preserves direct evidence for feathers and helps close the gap between feathers reported in coelurosaurian theropods and filaments in ornithischian dinosaurs, further supporting the homology of these structures.

[...] The presence of type 1 feathers along the dorsal side of the tail, the ventral tail flank, and parts of the body in Sciurumimus show that the entire body of this animal was plumaged, as is the case in compsognathids (2). As a megalosaurid, Sciurumimus is the most basal theropod taxon yet reported with such integumentary structures and demonstrates that at least the juveniles of basal tetanurans had protofeathers. Sciurumimus thus helps bridge the considerable gap between basal ornithischians, for which monofilaments have been reported (4), and coelurosaurs, for which protofeathers [morphotype 1 (39)] or feathers generally seem to be present (2, 15, 40). (Rauhut et al. 2012, p. 1 and 5, emphasis mine)

Sciurumimus albersdoerferi

Luskin: Even if this fossil did have feathers, it’s still not clear how that would imply “all dinosaurs” might have had feathers.

It’s called inference Mr. Luskin. If protofeathers/feathers are found to be wide spread among very different types of dinosaurs, it becomes a plausible inference, rooted in evolutionary theory, that all or most dinosaurs had them.

Luskin: Because this dinosaur comes from a different group from the one that is said to have led to birds, researchers say it “suggests that the ancestor of all dinosaurs might have been a feathered animal.” That argument might add up if you make a bunch of evolutionary assumptions — namely common descent of all dinosaurs in the first place.

Scientist are not sitting around seriously considering whether common descent is true any more than they are considering whether matter is made up of atoms or whether germs cause disease.

At this point scientists do assume the common descent of not just dinosaurs but all living things because evolution is one of the most rigorously tested and best confirmed theories in science. Creationist claims not withstanding, there is no scientific controversy about this fact of evolution (a fact being what the late Stephen Jay Gould described as something “…confirmed to such a degree that it would be perverse to withhold provisional assent.”)(Gould 1994, p. 255).

See this link for more on Feathered dinosaurs.

Luskin: But this specimen itself is only about 150 million years old — far later than the time period in which dinosaurs themselves originated.

Now Mr. Luskin takes a hard turn from attempting to minimize the “dinofuzz” found on Sciurumimus and begins trying to smear dinosaur evolution in general.

Luskin: Dinosaurs are thought to have evolved before 230 million years ago, but as a different paper in Science admitted last year, the fossil record doesn’t document the evolution of major dinosaur groups:

Tracing the origins of the earliest dinosaurs has been a major challenge for paleontologists because there are no uncontested fossils from their earliest days on Earth. By the time Eoraptor and other undisputed early dinosaurs came on the scene about 230 million years ago, most researchers have concluded, dinosaurs had already evolved into three major lineages: ornithischians, which later gave rise to armored beasts like Stegosaurus and Ankylosaurus; sauropodomorphs, the lineage that led to giant plant eaters like Apatosaurus and Brachiosaurus; and the meat-eating theropods, such as T. rex and Allosaurus. (emphasis Mr. Luskin’s)

Mr. Luskin is at it once again. He boldfaced the first sentence to highlight what he wants his readers to consider, clearly fostering the idea that there is an unabridged, perhaps unbridgeable, gap in our knowledge, while leaving out significant context and de-emphasizing statements that point in a different direction.

First, there is the paragraph immediately preceding the one he quoted:

“The new specimens are remarkable,” says Sterling Nesbitt, a paleontologist at the University of Washington, Seattle. Michael Benton, a paleobiologist at the University of Bristol in the United Kingdom, adds that the fossils—which the discovery team has assigned to a new species called Eodromaeus murphiare “complete enough to add substantially to our knowledge” of early dinosaur evolution. (Balter 2011, emphasis mine)

Then the quote Mr. Luskin gave, immediately after the portion he chose to highlight, refers to Eoraptor and “other undisputed early dinosaurs” (emphasis mine), that have increased our understanding of the early days of dinosaurs.

In other words, the sentence Mr. Luskin highlighted was a historical digression giving the reader some context to understand how some of the new finds like Eoraptor and Eodromaeus are starting to fill in the gaps in our knowledge of early dinosaur evolution. Not some sort of admission that we remain hopelessly mired in ignorance.

Basal dinosaurs

Image sources: Eodromaeus (Martinez et al. 2011, p. 208) Eoraptor (Langer, 2004, p. 27) and Lesothosaurus (Norman et al. 2004, p. 329)

See: A Tale of Two Dinosaurs for more on creationist claims regarding early dinosaurs.

Regardless, even if we were so mired, it would lend absolutely no credence to the creationists magical “God did it” hypothesis.

Luskin: Rather than suggesting that all dinosaurs had feathers, this new megalosauroid with its “dinofuzz” suggests something very different: the fact that a group has dinofuzz doesn’t necessarily mean it was closely related, or ancestral, to birds. (emphasis original)

Mr. Luskin is partly correct here given that possession of “dinofuzz” or protofeathers is apparently a symplesiomorphy—an ancestral characteristic of all dinosaurs—so the possession this characteristic by itself is not indicative of a close relationship to birds.  However, the fact that all dinosaurs possessed these protofeather structures is still consistent with the hypothesis that birds are a subset of dinosaurs.

To determine which particular group of (non-avian) dinosaurs are most closely related to birds we must look at other less commonly shared characteristics (synapomorphies). We can look at certain Maniraptoran dinosaurs like Caudipteryx that share a host of anatomical details with early birds like Archaeopteryx, including, as is the case with Caudipteryx more bird-like pennaceous feathers.

As creationists are wont to do, Mr. Luskin is trying to cast doubt on evolution by focusing on, and attempting to call into question, a very narrow detail (protofeathers), while ignoring the larger context of the totality of evidence that flies in the face of his position.

Moreover he seems willing to use less than honest methods (the uses of out of context and altered quotations) to do so.

References

Balter, Michael (2011) “Pint-Sized Predator Rattles The Dinosaur Family Tree“; Science, 331:134

Currie, Philip J. & Padian, Kevin (Editors) (1997) Encyclopedia of Dinosaurs; Academic Press

Gould, Stephen Jay (1994)Evolution as Fact and Theory;In, Hen’s Teeth and Horse’s Toes, W. W. Norton & Company, pp. 253-262

Langer, Max C. (2004) “Basal Saurischia“, chapter 2 in Weishampel, David B. et al. (2004) The Dinosauria (2nd edition)

Luskin, Casey (2012) “The “Ancestor of All Dinosaurs” Might Have Had Feathers Dinofuzz“; Evolution News and Views(website), downloaded on 7-16-2012

Martinez, Ricardo N. et al. (2011) “A Basal Dinosaur from the Dawn of the Dinosaur Era in Southwestern Pangaea“, Science 331(6014): 206-210

Norman, David B. et al. (2004) “Basal Ornithischia“, chapter 14 in Weishampel, David B. et al. (2004) The Dinosauria (2nd edition)

Rauhut, Oliver W. M. et al. (2012) “Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany“, Proceedings of the National Academy of Sciences; published ahead of print July 2, 2012

Rosen, Meghan (2012) “All dinosaurs may have had feathers“; Science News (website), downloaded on 7-16-2012

Witmer, Lawrence M. (2009) “Fuzzy origins for feathers“; Nature, 458:293-295

Zheng, Xiao-Ting et al. (2009) “An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures“; Nature, 458:333-336

15 thoughts on “Fuzzy thinking about fuzzy dinosaurs

  1. Magnificent Troy. But you should summarize Prum’s theory about the four stages of feather evolution and how all four have been found in both fossils and amber.

  2. Luskin: Likewise, the Science News piece admits at the bottom of the article: “Unlike modern feathers, these ‘protofeathers’ or ‘type 1 feathers’ look like simple strands of hair.”

    Yes, it would be more surprising to find highly derived feather types in a such a basal theropod as Sciurumimus.

    So, this is another case, in which creationist want to see the proverbial Cambrian rabbit (in the sense of ‘something which would be a problem to evolutionary theory, like suddenly appearing modern feathers’) to accept evolution. :/

  3. It’s the first I’ve heard of Casey’s promotion. After years as DI’s attack gerbil it seems he’s made attack chihuahua. Congratulations Casey…keep up the, um, good work.

  4. Pingback: Why I Quit Arguing With Creationists « stand up for REAL science

  5. Pingback: Science Tidbits for July 17, 2012 « Teaching Sapiens

  6. Thanks so much for this post, Troy. I am one of the people who commented on Casey Luskin’s original post and pointed him to your criticism. In my research for the subsequent discussion that followed on ENV, I learned a lot more than I previously knew about feathered dinosaurs. That would not have happened without your efforts here.

    If you are interested in a broader discussion of feathers, I highly recommend Thor Hanson’s book, “Feathers: The Evolution of a Natural Miracle.” It is one of the best science books I have read in quite some time.

    Cheers-
    Jeremy

  7. Well, I got in some good digs at Casey on the feathered dinosaur thing. Then they posted a bunch of their own responses, insulted me, and closed all further comments.

    Tucked tail and ran. It’s possible they may open comments again after they return from their big tent revival meeting in California.

  8. Pingback: Carnival of Evolution 50: The Teaching Edition « Teaching Biology

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s