Saturday, February 4, 2012

* Dinosaurs did not have wing-like arms

I could hardly have put it better than the following:
http://scienceblogs.com/tetrapodzool..._they_dont.php
Quote:
The fact that long remiges have now been documented in oviraptorosaurs, dromaeosaurids and other maniraptorans shows that feathered arms essentially the same as those present in basal birds evolved somewhere round about the base of the oviraptorosaur + paravian clade, and there is no evidence that wing-like arms were present in more basal coelurosaurs, nor in other theropods, or other dinosaurs, or other archosaurs.
The dino to bird folks do not specify their imagined lineage. But they have some belief that coelurosaur dinosaurs evolved into Paraves and those Paraves evolved into modern birds. But it leaves open when in that lineage "wing-like arms" appeared.
Naish asserts that "feathered arms essentially the same as those present in basal birds evolved somewhere round about the base of the oviraptorosaur + paravian clade".
He then says that "there is no evidence that wing-like arms were present in more basal coelurosaurs, nor in other theropods, or other dinosaurs, or other archosaurs."
In other words, concerning wing arms, there is no connection whatsoever between dinos and paraves/oviraptors.

http://www.ivpp.cas.cn/qt/papers/201403/P020140314389417822583.pdf
Page 9/10
The relative length and diameter of the humerus in several theropod taxa. We use
the ratios of humeral length to femoral length, and humeral diameter to femoral diameter, as
indicators of forelimb length and robustness. Relative to the femur, the humerus is
significantly longer and thicker in basal paravians than in non-paravian theropods, derived
dromaeosaurids and troodontids (the relatively short and slender forelimbs in the last two
groups are secondarily evolved according to the current phylogenetic analysis).
Page 28/29
The discovery of Xiaotingia further demonstrates that many features
previously regarded as distinctively avialan actually characterize the
more inclusive Paraves. For example, proportionally long and robust
forelimbs are optimized in our analysis as a primitive character state
for the Paraves (see Supplementary Information). The significant
lengthening and thickening of the forelimbs indicates a dramatic shift
in forelimb function at the base of the Paraves, which might be related
to the appearance of a degree of aerodynamic capability. This hypothesis
is consistent with the presence of flight feathers with asymmetrical
vanes in both basal avialans and basal deinonychosaurs6,23

23 comments:

  1. Someone will notice that Naish has included "archosaurs" in the list. This is an exaggeration.
    He has overlooked pterosaurs.
    It is considered that pterosaurs were archosaurs. But obviously pterosaurs had "wing-like arms". They had wings and they used them to fly!

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  2. Bats, like Pterosaurs, also have a wing arm and wing membrane. A wing membrane birds do not have.

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  3. Why would Nature reinvent the wheel?

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  4. How did Nature reinvent the wheel?

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    Replies
    1. You have a flying creature in pterosaurs with a wing arm and a wing membrane and no feathers.

      You have a flying creature in a bat with a wing arm and a wing membrane and no feathers.

      And you have a flying creature in a bird with feathers and no wing membrane.

      It seems like Nature has to go through a whole lot of rigamorole for a Pterosaur to sprout feathers, lose the membrane and maintain flight capability when it wouldn't have to do any of that if it developed into a bat instead.

      Even looking at the wing structure do you see the long digits that you see in Pterosaurs and bats in birds?

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    2. A pterosaur does not have to "sprout" feathers. The fibers in the pterosaur wing are the basis of feathers. You really have not read the posts about the fibers have you?

      I also cover the subject of the change in the fingers from pterosaur to bird.

      I suggest you acquaint yourself with the material on this site.

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    3. I have read them. fibers to feathers seems far less parsimonious than membrane to membrane.

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    4. I am proposing the origin and development of birds from pterosaurs.
      If you wish to analyze bats I suggest you set up a blog on that. When you do, please let me know and I will be delighted to comment on your posts in your blog.

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    5. I am suggesting you are overlooking a very important piece to your ideas.

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    6. If you wish to include your thoughts about that in your blog then I will be delighted to respond. As things stand bats are not part of what I am proposing. May I suggest you stop wasting our time here on this?

      Delete
  5. Holy Pterror, did you check out the posts that analyze the fibers within the pterosaur wing. Those fibers are the basis of feathers when the skin membrane is lost.
    I want to make sure you understand that. Do you?

    You can use the search function to find all the material.

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  6. An interesting paper regarding bats, pterosaurs and birds that have seemingly overlooked

    http://onlinelibrary.wiley.com/doi/10.1111/j.1420-9101.2006.01285.x/full

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  7. Here is an interesting quote from the article:
    "Mesozoic birds at least are more similar in their morphospace occupation to nonavian theropods than they are to pterosaurs."

    How do you interpret that?

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    Replies
    1. As strong support that bats developed from pterosaurs and not birds.

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  8. Why do you say it supports the idea that birds did not evolve from pterosaurs?

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    Replies
    1. Because you would expect them to share a more similar morphospace occupation with pterosaurs than they do with nonavian theropods. But these articles are mainly written from a dino to bird viewpoint anyway, so I'm not sure we should lend much credence to them.

      What I would lend credence to is the idea that it takes Nature far less effort to develop a bat wing out of a pterosaur wing than it does to create a bird wing from a pterosaur wing.

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    2. What non-avian theropods does the study include? In other words, what do they mean by "nonavian theropods".

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    3. I don't know and don't care. I am proposing the origin and development of bats from pterosaurs.

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    4. You were the one who presented us with the article.
      Why do you keep wasting our time?
      Set up your own blog.

      Delete
  9. While we wait for Holy Pterror to respond, here is a question for folks. Have you followed my posts sufficiently to immediately be suspicious when you see the phrase "nonavian theropod" in an article?
    Do you know what is coming?

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  10. The "nonavian theropods" in the article are all after the oviraptor/paraves point. (In other words they are not dinosaurs - not even close to dinosaurs).
    This is EXACTLY the con game I have pointed out again and again and again.

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  11. http://www.yale.edu/eeb/prum/pdf/Prum_n_Brush_2002.pdf
    "In conclusion, the morphological and
    molecular developmental details shared by
    avian feather and scales support homology
    between these structures at the level of the
    placode. The morphology and development
    of all subsequent structures within the feather
    are evolutionary novelties that have no homologs
    in avian or reptilian scales."

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  12. http://www.yale.edu/eeb/prum/pdf/Prum_n_Brush_2002.pdf
    "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"

    ReplyDelete