The "Ancestor of All Dinosaurs" Might Have Had
Feathers Dinofuzz (Updated)
See below for an update about the quote from Witmer's paper, "Fuzzy origins for feathers," on Caudipteryx, a fossil (which was a bird, not a dinosaur) that did have true pennaceous feathers.
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. 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, which states:
Here we report an exceptionally preserved skeleton of a juvenile megalosauroid, Sciurumimus albersdoerferi n. gen., n. sp., from the Late Jurassic of Germany, which preserves a filamentous plumage at the tail base and on parts of the body. These structures are identical to the type 1 feathers that have been reported in some ornithischians, the basal tyrannosaur Dilong, the basal therizinosauroid Beipiaosaurus, and, probably, in the basal coelurosaur Sinosauropteryx.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":
(Oliver W. M. Rauhut, Christian Foth, Helmut Tischlinger, and Mark A. Norell, "Exceptionally preserved juvenile megalosauroid theropod dinosaur with filamentous integument from the Late Jurassic of Germany," Proceedings of the National Academy of Sciences (2012))
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 Dilong.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. The truth comes out later in the paper:
(Lawrence M. Witmer, "Fuzzy origins for feathers," Nature, Vol. 458:293-295 (March 19, 2009). Note: See my update below for an explanation of why Caudipteryx is irrelevant to understanding this fossil.)
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.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."
Even if this fossil did have feathers, it's still not clear how that would imply "all dinosaurs" might have had feathers. 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. But this specimen itself is only about 150 million years old -- far later than the time period in which dinosaurs themselves originated. 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.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.
(Michael Balter, "Pint-Sized Predator Rattles the Dinosaur Family Tree," Science, Vol. 331: 134 (January 14, 2011) (emphasis added))
I've received a couple of nasty e-mails (and comments, which had to be rejected because they violated our civility policy) because of a blog that pointed out that the quote from the "Fuzzy origins for feathers" paper I offered was incomplete. The full quote is as follows:
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 Dilong.Critics are upset because initially I used ellipses and omitted the part that stated that dinofuzz is "evident in some theropods such as Caudipteryx that have true pennaceous feathers." So why did I omit that? Is it because I was trying to hide the comment about Caudipteryx's true feathers? No! It's because the new fossil find discussed in the article, Sciurumimus albersdoerferi, is being compared to Sinosauropteryx, Beipiaosaurus, and Dilong, but NOT Caudipteryx. So Caudipteryx is irrelevant to a discussion of Sciurumimus albersdoerferi. And it turns out that Sinosauropteryx, Beipiaosaurus, and Dilong, did NOT have feathers; they had dinofuzz.
(Lawrence M. Witmer, "Fuzzy origins for feathers," Nature, Vol. 458:293-295 (March 19, 2009))
Now am I trying to hide the fact Caudipteryx had true feathers? Of course not. In fact, I've discussed Caudipteryx here on Evolution News & Views before at pages including:
- Is the Latest "Feathered Dinosaur" Actually a Secondarily Flightless Bird?
- Of Whale and Feather Evolution: Nature's Two Macroevolutionary Lumps of Coal
So yes, Caudipteryx did have true pennaceous feathers, but as those links above discuss, a number of scientists have argued that Caudipteryx wasn't a dinosaur, but was a bird -- a secondarily flightless bird that had lost its ability to fly. In fact, a pretty impressive list of mainstream scientific authorities have argued Caudipteryx was NOT a dinosaur at all, but was simply a bird. These authorities include: Alan Feduccia, Theagarten Lingham-Soliar, J. Richard Hinchliffe, Storrs L. Olson, Terry D. Jones, James O. Farlow, John A. Ruben, Donald M. Henderson, Willem J. Hillenius, Peter Wellnhofer, Teresa Maryaska, Halszka Osm�lska, H. M. Wolsan, Frances C. James, and John A. Pourtless. So Caudipteryx not a good example of an uncontested feathered dinosaur.
So my reasons for omitting Caudipteryx weren't, in fact, nefarious. Rather, (1) Caudipteryx is irrelevant to a discussion of this new fossil find, Sciurumimus albersdoerferi, which is the topic of my post; and (2) as I've discussed many times before on Evolution News & Views, it's not helpful for those making a case for feathered dinosaurs, and there are strong authorities who don't even think it was a feathered dinosaurs.
In any case, to avoid confusion, speculation, and more nasty e-mails, I've now restored the full quote from Witmer's article. I do wonder why critics get so mad at me for omitting an irrelevant part of a quote, and give a free pass to the news media when it claims a dinosaur fossil had feathers, even though the fossil didn't. Selective outrage? You be the judge.
[1.] Alan Feduccia, Theagarten Lingham-Soliar, and J. Richard Hinchliffe, "Do Feathered Dinosaurs Exist? Testing the Hypothesis on Neontological and Paleontological Evidence," Journal of Morphology, Vol. 266:125-166, 2005.
[3.] Terry D. Jones, James O. Farlow, John A. Ruben, Donald M. Henderson, & Willem J. Hillenius, "Cursoriality in bipedal archosaurs," Nature, Vol. 406:716-718, August 17, 2000
[4.] P. Wellnhofer P. 2004. The plumage of Archaeopteryx: feathers of a dinosaur? In: Currie PJ, Koppelhus EB, Martin AS, Wright JL, editors. Feathered dragons: studies on the transition from dinosaurs to birds. Bloomington: Indiana University Press. p 282-300.
[5.] Maryanska T, Osmolska H, Wolsan HM. 2002. Avialan status for Oviraptorosauria. Acta Palaeontol Pol 47:97-116.
[6.] James FC, Pourtless JA. 2005. Review of: feathered dragons: studies on the transition from dinosaurs to birds. Auk 122:714- 716; Frances C. James and John A. Pourtless IV, "Cladistics and the Origin of Birds: A Review and Two New Analyses," The Ornithological Monographs, Vol. 66:1-78, April 30, 2009.