Saturday, April 7, 2012

Yutyrannus - Not Feathers

http://blogs.scientificamerican.com/tetrapod-zoology/2012/04/04/giant-feathered-tyrannosaurs/
"As usual, the main gee-whiz points about Yutyrannus are already being widely discussed. We’ve known for a while (since the publication of Dilong paradoxus in 2004) that at least some tyrannosauroids possess stage 1 feathers (Xu et al. 2004). That is, filamentous integumentary structures that seem to be evolutionary precursors to the true, complex feathers that evolved elsewhere within coelurosaurian theropods. Yutyrannus is another feathery/filamenty tyrannosauroid, but it’s remarkable in being huge – it’s about 9 m long, meaning that here is the first GIANT feathery/filamenty tyrannosauroid."

http://en.wikipedia.org/wiki/Feather
"Feather evolution was broken down into the following stages by Xu and Guo in 2009:1. Single filament2. Multiple filaments joined at their base. 3. Multiple filaments joined at their base to a central filament4. Multiple filaments along the length of a central filament5. Multiple filaments arising from the edge of a membranous structure6. Pennaceous feather with vane of barbs and barbules and central rachis7. Pennaceous feather with an asymmetrical rachis8. Undifferentiated vane with central rachis"


Notice the unsupported part:
"Yutyrannus is another feathery/filamenty tyrannosauroid."

Yutyrannus is in no way "feathery". 

If people believed that birds were descended from pigs, they would call these pig bristles, "protofeathers":



But that is the sort of thing they claim now, in regard to the "filaments" (bristles) found on dinosaurs.



http://www.mcorriss.com/Prum_&_Brush_2002.pdf
"Darwinian  approaches to the  origin  of feathers, exemplified by Bock (1965),  have hypothesized a microevolutionary and functional continuum between  feathers and a hypothesized  antecedent structure (usually an elongate scale). Feathers, however, are hierarchically complex  assemblages of numerous evolutionary novelties—the feather follicle, tubular feather germ, feather branched structure,  interacting differentiated barbules—that have no homolog in any antecedent structures (Brush  1993, 1996, 2000; Prum  1999).
Genuine evolutionary novelties are distinct from simple microevolutionary changes in that they are qualitatively or categorically different from any antecedent or homonomous structure (Nitecki  1990; Mu¨ ller and  Wagner  1991; Raff 1996)."

So there is as much connection between pig bristles and feathers as there is between dinosaur "filaments" and feathers. In both cases, all the intermediates (all the "hierarchically complex  assemblages of numerous evolutionary novelties") are missing.
In one case, it would be a jump from pig bristle right to feather.
In the other case, it is a jump from dinosaur "filament" right to feather.

More from Darren Naish:
http://blogs.scientificamerican.com/tetrapod-zoology/2012/04/04/giant-feathered-tyrannosaurs/
"I must confess to being somewhat sceptical of the tyrannosauroid identification for Yutyrannus. I reviewed this paper (to those who don’t know: I did my PhD thesis on basal tyrannosauroids), and noted immediately that Yutyrannus actually resembles carcharodontosaurian allosauroids in some respects."

Porcupine with multi-coloured bristles:




https://upload.wikimedia.org/wikipedia/commons/thumb/f/f1/Stekelvarken_Aiguilles_Porc-%C3%A9pic.jpg/330px-Stekelvarken_Aiguilles_Porc-%C3%A9pic.jpg


https://web.archive.org/web/20120417134949/http://www.xinglida.net/pdf/Xu_et_al_2012_Yutyrannus.pdf
Filamentous integumentary structures are preserved in all three specimens. Those preserved in ZCDM V5000 are evidently associated with the posterior caudal vertebrae. As preserved, they are parallel to each other and form an angle of about 30u with the long axis of the tail. The filaments are at least 15 cm long. They are too densely packed for it to be possible to determine whether they are elongate broad filamentous feathers (EBFFs) like those seen in the therizinosauroid Beipiaosaurus, slender monofilaments, or compound filamentous structures. Those of ZCDM V5001 are near the pelvis and pes. They are filamentous structures, but morphological details are not preserved


11 comments:

  1. Notice the wording:
    "That is, filamentous integumentary structures that seem to be evolutionary precursors to the true, complex feathers that evolved elsewhere within coelurosaurian theropods."

    These are certainly not feathers. They are "filaments". But to those who believe that birds evolved from dinosaurs, these filaments SEEM to be "evolutionary precursors". That is what they wish to believe, even though there is no evidence of that

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  2. From Darren Naish:
    http://blogs.scientificamerican.com/tetrapod-zoology/2012/04/04/giant-feathered-tyrannosaurs/
    "I must confess to being somewhat sceptical of the tyrannosauroid identification for Yutyrannus. I reviewed this paper (to those who don’t know: I did my PhD thesis on basal tyrannosauroids), and noted immediately that Yutyrannus actually resembles carcharodontosaurian allosauroids in some respects."

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  3. There's been much discussion about this image on Talkrational.org and I was wondering what your thoughts were on it:

    http://i61.photobucket.com/albums/h44/arachnophilia/EvC/digits.jpg

    the ornithischian Heterodontosaurus
    B: the early theropod Herrerasaurus
    C: the neotheropod Coelophysis
    D: the tetanuran Allosaurus
    E: the coelurosaur Ornitholestes
    F: the Jurassic avialae Archaeopteryx
    G: the cretaceous enantiornithe Sinornis
    H: the wing of an Opisthocomus (hoatzin) hatchling
    I: the wing of the adult chicken Gallus

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  4. Man in Space, I have already dealt with this.

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  5. That, of course, begs the question why the diagram needs to be "dealt with" if your theory is correct.

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  6. David MarjanovićJuly 19, 2012 at 5:49 AM

    Pig bristles are ordinary mammalian hairs. They have very little in common with the more quill-like stage I feathers of Yutyrannus. Look at them a bit more closely.

    BTW, if I may ask, what did you do your doctorate in? Mine was on the phylogeny of tetrapods in the wide sense with special emphasis of the origin of the modern amphibians (Salientia, Caudata, Gymnophionomorpha, Albanerpetontidae).

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  7. You say pig bristles have very little in common with the Yutyrannus bristles. What do they have in common?

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  8. Concerning who I am, I prefer not to divulge. When personal info about me has come out I have received death threats against my family members by name.

    Since you are in the mainstream you do not experience this. Am I right?

    ReplyDelete
    Replies
    1. I've followed your blog closely and haven't seen a single death threat on it. You wouldn't be lying would you?

      Delete
    2. I do not post them. If you have followed the blog closely do you have a contribution?

      Delete
  9. David MarjanovićJuly 20, 2012 at 3:18 AM

    You say pig bristles have very little in common with the Yutyrannus bristles. What do they have in common?

    Gross shape.

    Since you are in the mainstream you do not experience this. Am I right?

    I would, if I had a blog that American creationists would read, for example. Prof. Myers of the U of Minnesota (Morris) gets death threats all the time.

    I asked because you call yourself a doctor, yet seem to know rather too little biology to have done a doctorate in that field.

    ReplyDelete