Sunday, October 16, 2011

Seriema

http://en.wikipedia.org/wiki/Seriema

The seriemas are the sole extant members of the small and ancient familyCariamidae, which is also the sole surviving family of the Cariamae. Once believed to be related to cranes, they have been placed by one recent study near the falconsparrots and passerines.[1] There are two species:
  • Red-legged Seriema, or Crested CariamaCariama cristata. This is found from eastern Brazil, to central Argentina. It is bigger and nests on the ground or in a bush or tree up to 3 m (9.8 ft) above the ground.
  • Black-legged SeriemaChunga burmeisteri. This is found in northwest Argentina and Paraguay. It nests in a tree.

The seriemas have an extensible second claw that is raised from the ground. This resembles the "sickle claw" of Velociraptor and its relatives.



325 comments:

  1. Reference concerning "sickle claw":
    http://en.wikipedia.org/wiki/Deinonychus
    "Despite being the most distinctive feature of Deinonychus, the shape and curvature of the sickle claw varies between specimens. The type specimen described by Ostrom in 1969 has a strongly curved sickle claw, while a newer specimen described in 1976 had a claw with much weaker curvature, more similar in profile with the 'normal' claws on the remaining toes.[25] Ostrom suggested that this difference in the size and shape of the sickle claws could be due to individual, sexual, or age-related variation, but admitted he could not be sure."

    Perhaps the "sickle claw" was present in some Dromaeosaurids and not in others.
    Possibly the modern birds that have a sickle claw developed from the Dromaeosaurids with sickle claws and that other modern birds developed from dromaeosaurids that did not have the sickle claw.

    ReplyDelete
  2. For reference:
    http://en.wikipedia.org/wiki/Deinonychus
    "Ostrom compared Deinonychus to the ostrich and cassowary. He noted that the bird species can inflict serious injury with the large claw on the second toe.[1]"

    ReplyDelete
  3. http://en.wikipedia.org/wiki/Cariamae
    "Cariamae is a suggested name for a group of primarily flightless birds that have been around for 63 million years. The group includes the families Cariamidae [eg. seriemas], Phorusrhacidae, Bathornithidae, Idiornithidae and Ameghinornithidae. Though traditionally considered as a suborder of the Gruiformes, based on both morphological and genetic studies[2] they may belong to a separate group of birds whose other living members would be the Falconidae, the Psittaciformes and the Passeriformes.[3]"

    The earliest known fossil belonging to this group is an isolated femur from the Cape Lamb Member of the Lopez de Bertodano Formation, Vega Island, Antarctica. This specimen, which dates to the late Cretaceous period about 65 million years ago, is identical to the femurs of modern seriemas, and belonged to a large bird about 1 metre (3.3 ft) tall. Because of its age and geographic location, this unnamed species may have been close to the ancestry of both cariamids and phorusrhacids.[4]

    ReplyDelete
  4. I couldn't find a link to email this to you directly, so I'll just post it here for you. I think this a pretty convincing diagram that truly shows just how similar pterosuars are to modern birds and their ancestors and relatives. I'm not sure how your critics can refute this, but I am sure they will try.

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

    A: the ornithischian Heterodontosaurus
    B: the early theropod Herrerasaurus
    C: the neotheropod Coelophysis
    D: the tetanuran Allosaurus
    E: the early maniraptoran 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
    J. adult Pterosaur

    ReplyDelete
  5. Holy Pterror, are you proposing that birds evolved from ornithischian dinosaurs?

    That would make more sense than saurischian dinosaurs, considering the hip structure.
    Even so a lineage from pterosaurs is more credible.

    (I have not made a big issue of the fact that the dino to bird enthusiats have picked the wrong kind of dinosaur).

    ReplyDelete
  6. Holy Pterror, if that series makes sense to you, perhaps you can explain the evolution from A. (an ornithischian dinosaur) to B. (a saurischian dinosaur).

    Is that the kind of lineage you are proposing?

    ReplyDelete
  7. I have asked people a number of times for the dino to bird lineage. Holy Pterror has shown a proposed lineage.
    But the lineage begins with a an ornithischian dinosaur evolving into a saurischian dinosaur in the second step.
    If that is not bad enough the saurischian hip structure in Step 2 then evolves back into the ornithischian hip structure in a later step.

    This is why I keep asking for the dino to bird lineage. Whenever someone gives such a lineage it is absurd.

    ReplyDelete
  8. Are pterosaurs saurischian, or ornithischian?

    Oh wait, they're neither. They're not even dinosaurs.

    I guess that makes your theory twice as absurd.

    ReplyDelete
  9. Anonymous, your comment makes no sense. Is it a attempt at humor?

    If you post again, could you include a made-up name please, to avoid confusion. Thanks.

    ReplyDelete
  10. I have proposed that Enantiornithes is on the line in all of the lineages I have presented (except the flightless birds).
    So it is good to see (in the drawing) that the hand structure for Enantiornithes* and for modern chicken** are nearly identical.

    Once again support for the ideas I am proposing.


    * G: the cretaceous enantiornithe Sinornis
    ** I: the wing of the adult chicken Gallus

    ReplyDelete
  11. So you think that the similarity between the "hand" structures of a primitive bird and a modern bird support your theory. Because that is what we would expect if one was ancestral to the other.

    Right?

    Now, let's think about this. If the similarity supports ancestry, what does LACK of similarity do?

    Obviously, provide support AGAINST ancestry.

    Now let's look at E and J.

    Hmm.

    Looks like your theory is busted.

    ReplyDelete
  12. Hmmn. No.
    Have you looked at the posts I have made on the subject of the pterosaur hand?
    Type in "hand" in the search box. There is a search box on the right side of every page.

    Also, if that series makes sense to you, perhaps you can explain the evolution from A. (an ornithischian dinosaur) to B. (a saurischian dinosaur)?
    And then back to an ornithiscian type hip structure.

    I am very interested in your input on that.

    ReplyDelete
  13. http://en.wikipedia.org/wiki/Ornithischia
    "The ornithischian pubis bone points downward and toward the tail (backwards), parallel with the ischium, with a forward-pointing process to support the abdomen. This makes a four-pronged pelvic structure. In contrast to this, the saurischian pubis points downward and toward the head (forwards), as in ancestral lizard types."

    ReplyDelete
  14. YUp, I did. Your posts on the pterosaur hand try to support some pretty unsupportable things. Like one bone being analogous to an entirely different one. You provide no support for those claims, so I guess we're supposed to take your word for it. Not gonna happen.

    Also, whether you think the pterosaur wing somehow (by improbable and inexplicable steps)led to the dromeosaur hand of not, the fact remains that its VASTLY DIFFERENT from it.

    If you think similarity is indicative of ancesrty, then you ALSO have to admit that lack of similarity is indicative of LACK of ancestry.

    You made your bed. Lie in it.

    ReplyDelete
  15. Oudenoida posted:
    "Like one bone being analogous to an entirely different one."

    Can you point us to what you are referring to please?

    And I am certainly not expecting anyone to take my word for anything. That is why I include references for the points I make.
    If you would include references for what you say then we could have a good discussion.

    ReplyDelete
  16. Here is your post on the pterosaur hand:

    http://pterosaurnet.blogspot.com/2010/11/pterosaur-hand.html

    Nothing but assertion. No references, no support. You post a crude DR%AWING of a pterosaur, then you just say the pteroid is the first finger and it is the 5th finger that's the wing finger.

    And the fact remains: Even if that was the case (and it's not, and I will post my reference for it as soon as you post yours), the 'hand' is STILL vastly different to the dromeosaur hand.

    Whether you think the pterosaur wing somehow (by improbable and inexplicable steps)led to the dromeosaur hand of not, the fact remains that its VASTLY DIFFERENT from it.

    If you think similarity is indicative of ancesrty, then you ALSO have to admit that lack of similarity is indicative of LACK of ancestry.


    You can't run away from that.

    ReplyDelete
  17. Oudenoida, that is one post of mine. I go into detail in the others.
    I suggest you review all the entries I have posted on the pterosaur hand. It is a very interesting subject.
    But it looks like you are not interested in actually looking into this.
    When you have something of substance to contribute I will respond to you.

    ReplyDelete
  18. Do you really think you can bluff your way out of this?

    That was the first post the search came up with. There are more. but in ALL ( A L L ) your other posts, you simply make unsupported assertions about how scientists "mislabeled" bones, and how one type of bone is actually another. NO evidence, not even an ARGUMENT to support that claim.

    Like here:

    http://pterosaurnet.blogspot.com/2010/12/pterosaur-wrist-3.html
    http://pterosaurnet.blogspot.com/2010/12/here-are-two-diagrams-that-show.html
    http://pterosaurnet.blogspot.com/2010/12/more-on-pterosaur-wrist.html
    http://pterosaurnet.blogspot.com/2010/12/pterosaur-wrist-4.html
    http://pterosaurnet.blogspot.com/2010/12/pterosaur-wrist-5.html
    http://pterosaurnet.blogspot.com/2010/12/primitive-bird-1st-metacarpal.html
    http://pterosaurnet.blogspot.com/2010/05/bird-and-pterosaur-carpus-2.html

    In each and every one of your posts, you repeat those unsupported claims about the pteroid and the 1st finger, with exactly ZERO evidence or support. You accuse scientists of "mislabeling" the bone, and you don't feel you need to justify that claim in any way.

    But if you think otherwise, please present ANY point in those posts, that can be used as EVIDENCE for such mislabeling, and for the pteroid being the thumb. Prove me wrong.

    But you won't, of course, because there isn't any. That's what another poster, DaveGodfrey, told you a while ago:

    http://pterosaurnet.blogspot.com/2010/10/questions.html

    "What is your peer-reviewed reference that pterosaurs have retained digit 1 as the pteroid bone? It is not quoted anywhere. You state that everyone's made this mistake many times, but you never actually provide any anatomical reason why we should agree with your diagnosis. What specimens have you studied that allow you to make this judgement"?

    You avoided answering back then, as you are avoiding now.

    You got nothing but empty assertions.

    And even with those, the hole you dug for yourself remains:

    If you think similarity is indicative of ancesrty, then you ALSO have to admit that lack of similarity is indicative of LACK of ancestry.

    And E and J are NOT similar.

    You made your bed. Lie on it.

    ReplyDelete
  19. Oudenoida, let's try to keep this discussion focused. Earlier you said:
    "Like one bone being analogous to an entirely different one."

    Can you point us to what you are referring to please?

    As a sidenote, you seem to be taking all this quite personally.

    ReplyDelete
  20. Read my previous posts. I mention it repeatedly. In summary, my question is identical to DaveGodfrey's question.

    "What is your peer-reviewed reference that pterosaurs have retained digit 1 as the pteroid bone? It is not quoted anywhere. You state that everyone's made this mistake many times, but you never actually provide any anatomical reason why we should agree with your diagnosis. What specimens have you studied that allow you to make this judgement"?

    But the FOCUS of the discussion, in case you forgot, is not that. It's THIS:


    If you think similarity is indicative of ancesrty, then you ALSO have to admit that lack of similarity is indicative of LACK of ancestry.

    And E and J are NOT similar.

    "As a sidenote, you seem to be taking all this quite personally"

    I have no idea what you mean by that. I am simply not cutting you the slack others have so far. Hope that's fine with you.

    ReplyDelete
  21. Here is a reference you did not list:
    http://pterosaurnet.blogspot.com/2010/05/continued-2.html

    "http://www.jstor.org/pss/50448
    "interpretation by Goldfuss (1831) of the pteroid as the first digit, or thumb, and thus the wing-finger as the fifth digit, sparked off a protracted debate"and
    "The nature of the pteroid, a rod-like bone projecting from the carpus in pterosaurs, has long been disputed. Three lines of evidence, morphological, developmental and histological, indicate that the pteroid is a true bone, rather than ossified cartilage. The origin of the pteroid is unclear: it may be a modified carpal, the first metacarpal, or a neomorph."

    ReplyDelete
  22. Oudenoida posted:
    "Read my previous posts. I mention it repeatedly."

    This is the kind of run-around that I am very familiar with.

    You posted earlier:
    "Like one bone being analogous to an entirely different one."

    My question to you is still:
    Can you point us to what you are referring to please?

    ReplyDelete
  23. "I have no idea what you mean by that. I am simply not cutting you the slack others have so far. Hope that's fine with you."

    This sounds like the kind of spin we saw with Harry Seeley.
    Perhaps it is the same person.
    Time will tell.

    ReplyDelete
  24. For reference:

    http://pterosaurnet.blogspot.com/2010/12/more-on-pterosaur-wrist.html

    "Here the first metacarpal is mislabeled as "lateral carpal".
    http://www.bioone.org/doi/abs/10.1671/0272-4634%282007%2927%5B881:AAFOTP%5D2.0.CO%3B2

    FIGURE 1. Exploded reconstruction of the left carpus of Istiodactylus latidens in dorsal view from Hankin and Watson (1914), showing the pteroid articulating with an upward directed fovea of the preaxial (= lateral) carpal.

    Note:
    When you study the drawings and pictures that I have provided you see that the "distal synacarpal" is actually the same shape as all 4 distal carpals fused.
    When the distal syncarpal is seen to include all 4 distal carpals, then we see that the bone that articulates with the syncarpal is shaped like a metacarpal (and not a carpal).
    And this arrangement of carpal, metacarpal and phalanx is of course the usual pattern."

    ReplyDelete
  25. I begin with the idea that the pteroid is the thumb.
    Then I review the other bones and see how they fit into the picture.
    And they fit in in a very straightforward way, resulting in an arrangement of carpal, metacarpal and phalanx which is of course the usual pattern.

    And then there is a very straightforward development into the hand structure of primitive birds.


    Could anyone present the evolution of the hand in the dino to bird model?
    Holy Pterror gave this:
    A: the ornithischian Heterodontosaurus
    B: the early theropod Herrerasaurus
    C: the neotheropod Coelophysis
    D: the tetanuran Allosaurus
    E: the early maniraptoran 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

    Does anyone disagree that that was the dino to bird hand evolution?

    ReplyDelete
  26. For reference:

    http://en.wikipedia.org/wiki/Pterosaur
    "The pterosaur wrist consists of two inner (proximal) and four outer (distal) carpals (wrist bones), excluding the pteroid bone, which may itself be a modified distal carpal. The proximal carpals are fused together into a "syncarpal" in mature specimens, while three [actually four] of the distal carpals fuse to form a distal syncarpal. The remaining distal carpal, [actually the thumb metacarpal] referred to here as the medial carpal, but which has also been termed the distal lateral, or pre-axial carpal, articulates on a vertically elongate biconvex facet on the anterior surface of the distal syncarpal. The medial carpal [actually thumb metacarpal] bears a deep concave fovea that opens anteriorly, ventrally and somewhat medially, within which the pteroid articulates.[16]"

    My modifications are in square brackets [ ].

    ReplyDelete
  27. Also: Pterosaur seems to not be able to address this point:

    Whether you think the pterosaur wing somehow (by improbable and inexplicable steps)led to the dromeosaur hand of not, the fact remains that its VASTLY DIFFERENT from it.

    If you think similarity is indicative of ancesrty, then you ALSO have to admit that lack of similarity is indicative of LACK of ancestry.

    And E and J are NOT similar.

    Can anyone help Pterosaur with this?

    ReplyDelete
  28. In other exciting news, your (already unsupported and implausible) "progression" has the fifth finger losing a phalanx as it becomes huge and elongated (only to suddenly disappear later, I wonder how that happened since according to your claims it would mean the wing membrane would disappear too), and the second finger losing and gaining and losing a phalanx like a yo-yo. Now add to that the first metacarpal becoming a carpal to become a metacarpal again, and a phalanx becoming a sesamoid and back to a phalanx....


    Cool story bro. :D

    ReplyDelete
  29. Oudenoida posted:
    "In other exciting news, your (already unsupported and implausible) "progression" has the fifth finger losing a phalanx as it becomes huge and elongated (only to suddenly disappear later, I wonder how that happened since according to your claims it would mean the wing membrane would disappear too), and the second finger losing and gaining and losing a phalanx like a yo-yo. Now add to that the first metacarpal becoming a carpal to become a metacarpal again, and a phalanx becoming a sesamoid and back to a phalanx...."

    Oudenoida, please explain why you say those things - with references to what I posted.
    Thanks.

    And do you agree with the finger evolution shown for the dino to bird listing presented earlier?
    Here it is:
    A: the ornithischian Heterodontosaurus
    B: the early theropod Herrerasaurus
    C: the neotheropod Coelophysis
    D: the tetanuran Allosaurus
    E: the early maniraptoran 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

    I want to see what you are comparing my proposal to.

    ReplyDelete
  30. "Whether you think the pterosaur wing somehow (by improbable and inexplicable steps)led to the dromeosaur hand of not, the fact remains that its VASTLY DIFFERENT from it."

    Actually it is not vastly different.
    Since modern birds do not have a 5th digit we see that in whatever lineage anyone proposes the 5th digit is lost.
    In the pterosaur to bird model the 5th digit is lost.

    Also what is your alternative lineage? Do you agree with the list given earlier?

    ReplyDelete
  31. "Actually it is not vastly different".

    Denying reality can't help you. Look at the pictures E and J. They ARE vastly different. One has this huge finger which essentially forms most of the wing, by providing an attachment for the wing membrane. If that is suddently, LOST, the animal loses flying ability altogether. Unless you claim a fully functional pterosaur wing became a fully functional 'flying dromeosaur' wing in one go, you HAVE to account for this implausible saltation.

    ReplyDelete
  32. Oudenoida posted:
    "Now add to that the first metacarpal becoming a carpal to become a metacarpal again,"

    Can you give a reference for this please?

    ReplyDelete
  33. Oudenoida posted:
    "a phalanx becoming a sesamoid and back to a phalanx.."

    Can you give a reference for this please?

    ReplyDelete
  34. Oudenoida do you agree with the finger evolution shown for the dino to bird listing presented earlier?
    Here it is:
    A: the ornithischian Heterodontosaurus
    B: the early theropod Herrerasaurus
    C: the neotheropod Coelophysis
    D: the tetanuran Allosaurus
    E: the early maniraptoran 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

    I want to see what you are comparing my proposal to

    ReplyDelete
  35. I just did. Your OWN POST a while ago. You said:

    "With the understanding of the "sesamoid" bone being the first phalanx of the thumb (and the pteroid being the second phalanx)"

    So the bone that looks like a sesamoid is actually a phalanx, according to you. And the pteroid is the second thumb phalanx, according to you.

    As for the metacarpal, there are about four or five posts of yours where you claim that the first metacarpal of pterosaurs has been "mislabeled" as a carpal. Like here:

    http://pterosaurnet.blogspot.com/2010/12/primitive-bird-1st-metacarpal.html

    Do I need to post them all again?

    So it's obvious that your theory needs a phalanx (pre-pterosaur) to morph into looking like a sesamoid (pterosaur) and then look like a phalanx again ('primitive bird').

    Also, you need a metacarpal (pre-pterosaur) to morph into looking like a carpal (pterosaur) and back into a metacarpal ('primitive bird'). That's the only way in which you can maintain the 1st digit number steady in your "progression".

    And in the meantime, the 5th digit STILL loses a phalanx while it grows enormous, only to disappear later (and the wing itself, apparently), while the 2nd digit STILL loses and gains and loses a phalanx like a yo-yo.

    Are you simply retracting what you have said? If so, fine. But be honest enough to admit it.


    Now:

    "with the finger evolution shown for the dino to bird listing presented earlier"?

    What exactly do you mean by "finger evolution shown for the dino to bird list"? Are you talking about the similarity, or are you proposing that this is the actual ancestor-descendant relationship from dinosaurs to birds?

    Sounds like it's exactly the kind of spin you would try.

    ReplyDelete
  36. Hahaha! I just noticed your previous post:

    "Holy Pterror, are you proposing that birds evolved from ornithischian dinosaurs?

    That would make more sense than saurischian dinosaurs, considering the hip structure.
    Even so a lineage from pterosaurs is more credible.

    (I have not made a big issue of the fact that the dino to bird enthusiats have picked the wrong kind of dinosaur)".

    You seem to have no concept of the consequences of what you post.

    So, they "picked the wrong kind f dinosaur", huh? Because it's just absurd that you can have an ornithischian descendant from a saurischian ancestor, right?

    How would you describe the pelvic girdle of PTEROSAURS, doctor?

    ReplyDelete
  37. Oudenoida posted:
    "What exactly do you mean by "finger evolution shown for the dino to bird list"? Are you talking about the similarity, or are you proposing that this is the actual ancestor-descendant relationship from dinosaurs to birds?"


    I am talking about this:
    http://i61.photobucket.com/albums/h44/arachnophilia/EvC/digits.jpg

    A: the ornithischian Heterodontosaurus
    B: the early theropod Herrerasaurus
    C: the neotheropod Coelophysis
    D: the tetanuran Allosaurus
    E: the early maniraptoran 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


    I am asking YOU if that is your proposed ancestor-descendant relationship from dinosaur hand to bird hand.
    If not, what is your proposal?

    ReplyDelete
  38. Also:

    "I am asking YOU if that is your proposed ancestor-descendant relationship from dinosaur hand to bird hand".

    Nice. You say "hand" there, to lure me into believing you mean an ancestor-descndant relationship similar in MORPHOLOGY to the HAND features posted on that list. But if I agree to it, you'll pretend you meant an ancestral relationship of the very SPECIESs mentioned, and start talking about ornithischian and saurischian PELVIS and other differences between them.


    And that's the kind of spin we're all familiar with.

    ReplyDelete
  39. That list shows a taxon with a backwards pointing hip structure, evolving into a taxon with a forward pointing hip structure and then evolving into a taxon with a backwards pointing hip structure.
    Does that represent your thinking?
    If not, what is your thinking? What is your dino to bird lineage?

    ReplyDelete
  40. For reference concerning pterosaur pelvic bones:
    http://pterosaurnet.blogspot.com/2010/05/pelvic-bones.html

    ReplyDelete
  41. Oudenoida posted:
    "Also, you need a metacarpal (pre-pterosaur) to morph into looking like a carpal (pterosaur) and back into a metacarpal ('primitive bird'). That's the only way in which you can maintain the 1st digit number steady in your "progression"."

    "morph into looking like a carpal".
    Are you making a joke? Or just trying to spin this?
    It was always a metacarpal.
    You are definitely looking like Harry Seeley. He would throw anything up against the wall to see if it would stick.

    How is Athens these days? Are you one of the rioters?

    ReplyDelete
  42. http://pterosaurnet.blogspot.com/2010/12/with-new-understanding-of-sesamoid-bone.html
    With the understanding of the "sesamoid" bone being the first phalanx of the thumb (and the pteroid being the second phalanx), the progression now can be seen as:

    Total progression
    2-3-4-4-5 Pterosaur ancestor
    2-2-3-4-4 Pterosaur
    2-3-4-x-x Primitive bird (maniraptors that are not modern birds)
    1-2-1-x-x Modern birds

    Note:
    If the sesamoid is not the first phalanx then the pteroid itself would be the first (and only) phalanx.
    This would make the pterosaur thumb structure the same as modern birds where the alula is the first (and only) thumb phalanx.

    The pteroid is either the first (and only ) phalanx or the second phalanx of the thumb.
    Either way, it fits within the development lineage I am proposing.

    ReplyDelete
  43. "Are you making a joke? Or just trying to spin this?
    It was always a metacarpal".

    You may claim "it was always a metacarpal", but that doesn't change the fact that the FORM of the metacarpal changes in that of a carpal bone, to later change back into a metacarpal.

    And it's even worse with the first phalanx, which turns into something looking like a SESAMOID, before turning BACK into looking like a phalanx.

    The plot thickens.

    "You are definitely looking like Harry Seeley. He would throw anything up against the wall to see if it would stick".

    Aaand the paranoid delusions kick in again.

    "How is Athens these days? Are you one of the rioters"?

    Oooh. Burn. So much for the serious, scholarly persona, huh?


    "The pteroid is either the first (and only ) phalanx or the second phalanx of the thumb.
    Either way, it fits within the development lineage I am proposing".

    And either has absolutely ZERO evidence to back it up. And both would make an anatomist laugh.

    ReplyDelete
  44. Oudenoida posted:
    "You may claim "it was always a metacarpal", but that doesn't change the fact that the FORM of the metacarpal changes in that of a carpal bone, to later change back into a metacarpal."

    Can you support that assertion concerning the FORM with a reference please? Do you have fossil pictures or drawings to support that?
    I am very interested.


    By the way I like the reference to Socrates - Ouden oida.

    ReplyDelete
  45. I have also added additional material to this post:
    http://pterosaurnet.blogspot.com/2010/12/more-on-pterosaur-wrist.html

    ReplyDelete
  46. For reference:
    http://pterosaurnet.blogspot.com/2010/12/primitive-bird-1st-metacarpal.html

    Here you can see the 1st metacarpal in the primitive bird* (diagram D) which corresponds to the 1st metacarpal I have been referring to in the pterosaur.


    *Deinonychus antirrhopus

    ReplyDelete
  47. Can anyone present us with any references/pictures/drawings concerning the digits of primitive birds (eg. dromaeosaurid)?

    This is the only one I have found so far*:
    http://www.pnas.org/content/96/9/5111/F3.large.jpg
    http://www.pnas.org/content/96/9/5111.full (figure 3)


    *Referred to in my post:
    http://pterosaurnet.blogspot.com/2010/12/primitive-bird-1st-metacarpal.html

    ReplyDelete
  48. And this one (left side):

    http://en.wikipedia.org/wiki/Deinonychus
    http://upload.wikimedia.org/wikipedia/commons/thumb/3/39/Archaeo-deinony_hands.svg/220px-Archaeo-deinony_hands.svg.png

    ReplyDelete
  49. "Can you support that assertion concerning the FORM with a reference please? Do you have fossil pictures or drawings to support that?
    I am very interested".

    Interesting. YOU make the claim that a bone universally defined as a carpal is actually a metacarpal, YOU accuse all scientists and experts dealing with pterosaur anatomy of "mislabeling" it, and somehow it's MY job to show that a carpal bone does not look like a metacarpal?

    You cannot shift the burden of proof here, Doc.

    However, I WILL help you get started in that, by providing a reference AND pictures as you request:

    http://bigcat.fhsu.edu/biology/cbennett/pteroid-articulation.html

    Yes, it's the SAME reference you have linked (and selectively quoted) in the past. Now look at those three pictures of carpals (A, B and C). Notice the size and shape, the multiple facets, similar to a typical carpal bone. In particular, notice WHERE the pteroid articulates (hover the mouse over the pictures). Not the fovea (as some had speculated) but at the SIDE. Nothing like a typical metacarpophalangeal joint (in case you wonder what THOSE look like as well, take a look at your knuckles).

    So, in shape, position of facets, form and function, the bone with which the pteroid articulates looks nothing like a metacarpal, and the joint looks nothing like a metacarpophalangeal joint.


    There you go. If you have any evidence to the contrary, please present it. I may have more to link to, but first you have to provide SOME support for your position.

    ReplyDelete
  50. "For reference:
    http://pterosaurnet.blogspot.com/2010/12/primitive-bird-1st-metacarpal.html

    Here you can see the 1st metacarpal in the primitive bird* (diagram D) which corresponds to the 1st metacarpal I have been referring to in the pterosaur".


    And as I explained, it looks NOTHING like the pterosaur carpal. It looks like a thick METAcarpal, with a diaphysis, two ends, a swivel and a condular articulation at each end.

    Compare it to the pictures of the carpals I linked to, their multiple facets including the fovea, their irregular shape and the position of the pteroid articulation.

    ReplyDelete
  51. Oudenoida posted:
    "Now look at those three pictures of carpals (A, B and C). Notice the size and shape, the multiple facets, similar to a typical carpal bone. In particular, notice WHERE the pteroid articulates (hover the mouse over the pictures). Not the fovea (as some had speculated) but at the SIDE."

    You are accepting the opinion of one researcher (Bennett). That is your right of course.
    I accept the more common-sense standard idea that the pteroid articulates within the fovea.

    Note the following:
    http://pterosaurnet.blogspot.com/2010/12/with-new-understanding-of-sesamoid-bone.html

    Concerning the sesamoid:
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1560000/?tool=pmcentrez
    We propose instead that the sesamoid in question was originally embedded in the tendon of a pteroid extensor or flexor muscle where it passed over the medial carpal, [actually metacarpal] and that it was pulled into the fovea after death in some specimens as a result of disarticulation of the [meta]carpal–pteroid joint.

    ReplyDelete
  52. For reference:
    http://scienceblogs.com/tetrapodzoology/2010/06/clubs_spurs_spikes_and_claws.php
    "A projecting structure termed the extensor process (or extensor attachment) is present between the carpal trochlea and the alular digit; it belongs to metacarpal I (also called the alular metacarpal), but this is hard to appreciate in modern birds because metacarpal I is fused imperceptibly into the carpometacarpus as mentioned above"

    ReplyDelete
  53. "I accept the more common-sense standard idea that the pteroid articulates within the fovea".

    "Common sense"? Really? Care to explain how it's "common sense"?

    And even if it was "common sense" that the fovea was a joint surface for the pteroid, you STILL have an extra articular surface on the SIDE to account for. Plus the other articular surfaces, and the general shape of the carpal which, as I explained, has no similarity to the diaphysis/epiphyses shape of a metacarpal.

    But it doesn't matter, because the pteroid DID NOT articulate with the fovea. See here:

    http://www.bioone.org/doi/abs/10.1671/0272-4634%282007%2927%5B881%3AAAFOTP%5D2.0.CO%3B2?journalCode=vrpa

    "Articulated specimens of a wide range of pterosaurs preserve a sesamoid associated with the tendon of M. flexorcarpi ulnaris in the fovea of the preaxial carpal. No specimen preserves the pteroid articulated in the fovea, and because the sesamoid articulated there, the pteroid could not. Therefore, both the traditional and alternative reconstructions, which are based on the assumption that the pteroid articulated in the fovea, are falsified. The preaxial carpal acted as a strut to increase the leverage of M. flexor carpi ulnaris for wrist extension. The pteroid articulated with the side of the carpal, was directed medially toward the shoulder, and could be extended and depressed to control the propatagium".

    And most importantly:

    http://bigcat.fhsu.edu/biology/cbennett/pteroid-errant.html

    "in October 2008 at the 68th Annual Meeting of the
    Society of Vertebrate Paleontology in Cleveland, Ohio, Dave Unwin acknowledged that the pteroid
    did not articulate in the distal fovea of the preaxial".

    So the author of the paper you linked to CHANGED HIS MIND.

    Let's see if you can be half the scientist he is and do the same.

    ReplyDelete
  54. http://www.bioone.org/doi/abs/10.1671/0272-4634%282007%2927%5B881%3AAAFOTP%5D2.0.CO%3B2?journalCode=vrpa
    "because the sesamoid articulated there, the pteroid could not."

    That is why I posted in my last post:
    Concerning the sesamoid:
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1560000/?tool=pmcentrez
    "We propose instead that the sesamoid in question was originally embedded in the tendon of a pteroid extensor or flexor muscle where it passed over the medial carpal, [actually metacarpal] and that it was pulled into the fovea after death in some specimens as a result of disarticulation of the [meta]carpal–pteroid joint."

    We could argue about this till the cows come home. And I do not think it even matters.
    The bottom line is that the pteroid articulates with the metacarpal (which some people consider to be a carpal).

    We are arguing about a very specific point related to the pterosaur to bird idea.
    What is your alternative?
    Please show us the dino to bird hand evolution at the same level of detail please.
    Then we can compare.

    ReplyDelete
  55. A summary of the pictures:
    Pterosaur:
    http://bigcat.fhsu.edu/biology/cbennett/carpals-Bring.jpg
    http://bigcat.fhsu.edu/biology/cbennett/fig5a.jpg
    v

    http://jeb.biologists.org/content/vol210/issue10/images/small/JEB000307F4.gif


    http://www.bioone.org/na101/home/literatum/publisher/bioone/journals/content/vrpa/2007/02724634-27.4/0272-4634%282007%2927%5B881%3Aaafotp%5D2.0.co%3B2/production/images/large/i0272-4634-27-4-881-f05.jpeg

    FIGURE 5. Photographs of A, the left (above) and right (below) carpal regions of Anhanguera santanae, AMNH 22555, in dorsal view, slightly disarticulated but in situ during preparation; B, the right preaxial carpal, Sesamoid A, and pteroid of Pteranodon sp. indet., YPM 2300, in dorsal or lateral view; and C, non-rticular (left) and articular (right) surfaces, respectively, of Sesamoid A of Pteranodon longiceps, YPM 1175. Abbreviations: art, articular surface for fovea; asp, articular surface for pteroid; ds, distal syncarpal; mciv, metacarpal IV; pc, preaxial carpal; ps, proximal syncarpal; pt, pteroid; r, radius; str, striations for attachment to its tendon; u, ulna; and sesA, Sesamoid A. Photograph of AMNH 22555 courtesy of P. Wellnhofer.

    http://www.bioone.org/na101/home/literatum/publisher/bioone/journals/content/vrpa/2007/02724634-27.4/0272-4634%282007%2927%5B881%3Aaafotp%5D2.0.co%3B2/production/images/medium/i0272-4634-27-4-881-f02.gif

    http://www.bioone.org/na101/home/literatum/publisher/bioone/journals/content/vrpa/2007/02724634-27.4/0272-4634%282007%2927%5B881%3Aaafotp%5D2.0.co%3B2/production/images/medium/i0272-4634-27-4-881-f01.gif


    Deinonychus antirrhopus:
    http://img253.imageshack.us/img253/3970/234h.jpg

    http://upload.wikimedia.org/wikipedia/commons/thumb/3/39/Archaeo-deinony_hands.svg/220px-Archaeo-deinony_hands.svg.png

    ReplyDelete
  56. I have put the pictures listed in the previous post here:
    http://pterosaurnet.blogspot.com/2010/12/pterosaur-wrist-5.html

    ReplyDelete
  57. http://pterosaurnet.blogspot.com/2010/12/primitive-bird-1st-metacarpal.html

    "Here you can see the 1st metacarpal in the primitive bird* (diagram D) which corresponds to the 1st metacarpal I have been referring to in the pterosaur"."
    http://img253.imageshack.us/img253/3970/234h.jpg

    Oudenoida posted:
    "And as I explained, it looks NOTHING like the pterosaur carpal. It looks like a thick METAcarpal, with a diaphysis, two ends, a swivel and a condular articulation at each end.
    Compare it to the pictures of the carpals I linked to, their multiple facets including the fovea, their irregular shape and the position of the pteroid articulation."


    The total of your objection is that the DRAWING (not an actual fossil) of a deinonychus metacarpal looks different TO YOU than the fossils of the pterosaur thumb metacarpal.

    Is your objection more than that?

    ReplyDelete
  58. Here is the pterosaur metacarpal (mislabeled a "lateral carpal"):
    http://www.bioone.org/na101/home/literatum/publisher/bioone/journals/content/vrpa/2007/02724634-27.4/0272-4634(2007)27%5B881:aafotp%5D2.0.co;2/production/images/medium/i0272-4634-27-4-881-f01.gif

    and here is the deinonychus metacarpal:
    http://img253.imageshack.us/img253/3970/234h.jpg

    These two DRAWINGS look similar to me.
    Is your objection based on more than this?

    ReplyDelete
  59. By the way, it is not to be expected that they will be exactly the same.
    The pterosaur metacarpal would have modified to work with the primitive bird alula. The pteroid developed into the alula.

    ReplyDelete
  60. I have presented a model of how a pterosaur hand could develop into a primitive bird hand.
    Could someone now present a model of how a dino hand could evolve into a primitive bird hand please?
    That would be great. Then we can compare them.

    ReplyDelete
  61. "We could argue about this till the cows come home. And I do not think it even matters".

    There's no point in arguing, doctor. It's over. The very AUTHOR of the article you used as evidence has admitted he was WRONG.

    The pteroid did not articulate with the fovea. But you're right, it does not matter. Because EITHER WAY, as I explained and showed in those pictures, that carpal bone looked NOTHING like a metacarpal.


    "The bottom line is that the pteroid articulates with the metacarpal (which some people consider to be a carpal)".

    Denying the truth won't help you, doctor. That bone is NOT a metacarpal. A phalanx does not articulate ON THE SIDE of a metacarpal. A metacarpal has a diaphyseal body and two ends, a base and a head. With joints at the end. It's NOTHING like those pictures, those pictures look like CARPAL bones, multi-faceted and irregular.

    Look at them again:

    http://bigcat.fhsu.edu/biology/cbennett/pteroid-articulation.html


    "We are arguing about a very specific point related to the pterosaur to bird idea.
    What is your alternative?
    Please show us the dino to bird hand evolution at the same level of detail please.
    Then we can compare".

    We have nothing to compare, doctor. I could argue that the dromeosaur hand came from the dragon hand, and I would STILL be less wrong than you. But if you really want to see a comparison, see below.


    "The total of your objection is that the DRAWING (not an actual fossil) of a deinonychus metacarpal looks different TO YOU than the fossils of the pterosaur thumb metacarpal.

    Is your objection more than that"?

    Playing dumb won't help you either. I did not post drawings of carpals, doctor. I posted PICTURES of FOSSILS. As for what a metacarpal ACTUALLY looks like, it's pretty basic knowlege. A google search can provide dozens of examples. But again, for a complete comparison, see below.

    On the other hand, you ADMIT that it is YOUR position that is based on two "DRAWINGS" that "look similar to you" (and you alone).

    Projection can't help you either.

    And since you want PICTURES of metacarpals, here you go:

    http://books.google.gr/books?id=01oUBEC9Nn4C&pg=PA97&lpg=PA97#v=onepage&q&f=false


    On page 97 of this lovely book, "The interrelationships and evolution of basal theropod dinosaurs", we see a PICTURE of a Deinonychus metacarpal. Notice that it has the structure all metacarpals have: A diaphyseal body, two ends with articulations. Nothing like those carpal pterosaur bones.

    But that's not all. You can compare that to the PICTURES of a dilophosaur and and allosaurus metacarpal below. As you can see, they are basically the same shape. In fact. the allosaurus 1st metacarpal is even more thick and bulky than the corresponding deinonychus one.

    And just in case you try to claim that we don't know because the Allosaurus bone is partial (we know you too well by now), here's anothe picture:

    http://www.nps.gov/museum/exhibits/dino/exb/metacarpals_dino11541a_exb.jpg


    So there's your 'comparison', doctor. As those pictures all show, the dromeosaur first metacarpal does not look at all like the pterosaur carpal (how could it? It's a METACARPAL), but looks quite similar to a basal theropod metacarpal.

    You can read more of that book for more similarities.

    I guess the cows are home, doctor.

    ReplyDelete
  62. Oudenoida, you are getting more and more desperate as this discussion continues. Just like Harry Seeley did as that discussion continued.

    As I said people argue any point till the cows come home. And I am not wasting time on your spin.

    And also as I said, it is not to be expected that they will be exactly the same.
    The pterosaur metacarpal would have modified to work with the primitive bird alula. The pteroid developed into the alula.

    You have posted:
    "We have nothing to compare, doctor."

    That says it all.

    ReplyDelete
  63. The allosaurus 1st metacarpal is more thick and bulky than the deinonychus one. (It is not "corresponding" since birds did not evolve from dinos).

    The pterosaur 1st metacarpal is more thick and bulky than the corresponding deinonychus one.

    And also as I said, it is not to be expected that they will be exactly the same.
    The pterosaur 1st metacarpal would have modified to work with the primitive bird alula. The pteroid developed into the alula.

    There is really no point in continuing to argue this.

    ReplyDelete
  64. Here is a question:
    If the pteroid articulated with the fovea of the 1st metacarpal, then could the sesamoid be over top of the junction point* providing leverage and/or protection?


    * Concerning the sesamoid:
    http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1560000/?tool=pmcentrez
    We propose instead that the sesamoid in question was originally embedded in the tendon of a pteroid extensor or flexor muscle where it passed over the medial carpal [metacarpal], and that it was pulled into the fovea after death in some specimens as a result of disarticulation of the [meta]carpal–pteroid joint.

    ReplyDelete
  65. Actually diagram D in this reference shows the sesamoid in that position.
    http://jeb.biologists.org/content/210/10/1663/F4.expansion

    ReplyDelete
  66. I have revised the proposed progression.
    I have removed the precursor to the pterosaur because it is not part of the theory I am proposing. Also I have put in some question marks.


    http://pterosaurnet.blogspot.com/2010/12/with-new-understanding-of-sesamoid-bone.html

    1-2?-3?-4?-4? Pterosaur
    2?-3?-4?-x-x Primitive bird (maniraptors that are not modern birds)
    1-2-1-x-x Modern bird

    ReplyDelete
  67. The precursor to the pterosaur is pretty important. What was the ancestral condition like? It appears that your idea requires reversals and wholesale changes (metacarpals turning into carpals, and back again). Pretending it doesn't exist isn't going to help you here. Nor is throwing a few question marks around. People who actually study the fossils in question don't think there's any question about how many phalanges pterosaurs, birds and the various theropods had.

    ReplyDelete
  68. Hello A Nonny Mouse.
    Concerning the precursor to the pterosaur: every theory begins at some point. Personally I think the pre-cursor was some kind of gliding warm-blooded creature. But I have not taken the time to analyze that part.

    What reversals are you talking about? Please specify. And compare the reversals (if any) that are in the dino to bird theory.

    Also what "metacarpals turning into carpals" are you talking about?

    If you know the exact, agreed-upon answers to the question marks I have added, please present them with references.
    That would be great.
    Is it:
    1-2-3-4-4 Pterosaur
    2-3-4-x-x Primitive bird (maniraptors that are not modern birds)
    1-2-1-x-x Modern bird

    ReplyDelete
  69. Some posters here think that I must continue arguing with them until they are satisfied. That will never end since they have their own personal opinion, that they will never give up.
    My goal is to present evidence that supports what I am saying.
    Once I have done that and responded to questions and objections, I have to draw the line on discussion. Else it will go on forever.
    If people are not satisfied, then so be it. That is also the way science works. Not everyone will agree.


    .

    ReplyDelete
  70. This probably goes without saying, but sometimes we overlook the obvious things.
    The pteroid digit (thumb) lost its claw because the claw would have ripped the membrane (propatagium) that it was controlling.

    ReplyDelete
  71. For reference:
    http://www.seaworld.org/animal-info/info-books/raptors/physical-characteristics.htm
    "The wings of many diurnal birds of prey have a vestigial claw located at the end of the thumb bone."

    ReplyDelete
  72. Could someone please give us some reference on the dino hand that evolved into the bird hand please?
    Was it like the Compsognathus or the Tyrannosaurus?
    If not, what taxa was it like?

    ReplyDelete
  73. For reference:
    http://www.seaworld.org/animal-info/info-books/raptors/physical-characteristics.htm
    "The wings of many diurnal birds of prey have a vestigial claw located at the end of the thumb bone."

    If that is so, then the modern bird pattern (of at least some taxa) is:
    2-2-1-x-x
    Is that correct?

    ReplyDelete
  74. Putting these ideas together we have the following:
    The pteroid lost its claw because it would have ripped the propatagium. But the claw structure is there in potential of course.
    In the primitive bird it re-emerged* since there was no concern about ripping a membrane.
    And in modern birds (at least in some taxa) it is still there as vestigial.

    This sounds like pretty standard evolution stuff.


    *This re-emergence could also be considered vestigial.

    ReplyDelete
  75. Sometimes we need to step back and take a larger perspective.
    Pterosaurs were flying. They had a hand structure that is almost identical to primitive and modern birds. We are arguing about ONE bone and how similar it is to another.

    On the other hand, dinosaurs were running around on the ground with tiny arms.

    ReplyDelete
  76. "Putting these ideas together we have the following:
    The pteroid lost its claw because it would have ripped the propatagium. But the claw structure is there in potential of course.
    In the primitive bird it re-emerged* since there was no concern about ripping a membrane.
    And in modern birds (at least in some taxa) it is still there as vestigial".


    IOW, the pterosaur 1st finger lost all its phalanges but one, that supposedly became the pteroid (here I am momentarily assuming that your absurdities about the carpal bone being a metacarpal are not what they are, that is complete nonsense).

    Then the finger regrew ALL its phalanges back, along with the claw, in the 'primitive bird' stage.

    Then it lost them all again, in the modern bird stage.

    And in the meantime, the second digit lost a phalanx in the pterosaur, to gain it again in the 'primitive bird', to lose it again.


    And the third digit lost a phalanx, then gained it back, then lost two.


    Yup, "pretty standard evolution stuff".

    :D

    ReplyDelete
  77. Oudenoida posted:
    "Then the finger regrew ALL its phalanges back, along with the claw, in the 'primitive bird' stage."

    Let's see if we can come to an agreement on how many phalanges we are talking about.

    I am saying that the pterosaur had a thumb made up of one phalanx (the pteroid bone) and one claw not expressed.

    From the references I see about the primitive bird thumb, it had one phalanx and one claw.

    Are you seeing this differently?

    ReplyDelete
  78. If anyone else would like to contribute, please do (if any one else is following this).

    ReplyDelete
  79. "And in the meantime, the second digit lost a phalanx in the pterosaur, to gain it again in the 'primitive bird', to lose it again."

    Since we do not know the ancestor of the pterosaur we are not in a position to say that the second digit lost a phalanx in the pterosaur.

    ReplyDelete
  80. "And the third digit lost a phalanx, then gained it back, then lost two."

    Since we do not know the ancestor of the pterosaur we are not in a position to say that the third digit lost a phalanx in the pterosaur.

    ReplyDelete
  81. As a general comment - it is becoming mainstream (if it is not already) that modern birds evolved from dromaeosauruds.
    I am agreeing with that idea.
    So any differences between dromaeosaurid and modern bird hands are the same problem (if it is a problem at all) for both theories.

    ReplyDelete
  82. As far as I can see, the only think to concern ourselves with, is the re-emergence of one phalanx on the thumb*, and one phalanx on the 2nd digit and one phalanx on the 3rd digit - in the development from the pterosaur to primitive bird.


    * the claw (which I have already discussed)

    ReplyDelete
  83. As far as I can see, the only thing to concern ourselves with, is the re-emergence of one phalanx on the thumb, and one phalanx on the 2nd digit and one phalanx on the 3rd digit - in the development from the pterosaur to primitive bird.

    This is based on the assumption that the progression is:
    1-2-3-4-4 Pterosaur
    2-3-4-x-x Primitive bird (maniraptors that are not modern birds)

    ReplyDelete
  84. Turning back to the issue about the pterosaur bone that I am saying is a thumb metacarpal and that others claim is a carpal.
    If that bone is a carpal then we should ask - what happened to the metacarpal? Did it just disappear?
    And how do you explain the pteroid? Is it the metacarpal? It does not look like a metacarpal.

    ReplyDelete
  85. Oudenoida gave us this reference:
    http://books.google.gr/books?id=01oUBEC9Nn4C&pg=PA97&lpg=PA97#v=onepage&q&f=false

    On page 98 there is an allosaurus hand. The metacarpal 1 (MC-I)* looks quite a bit like the bone that I am saying is the pterosaur 1st metacarpal.


    This all supports the idea that the pterosaur bone we are discussing is not a carpal (sometimes called a "medial carpal") but a metacarpal.

    ReplyDelete
  86. Also on page 98 there is a Dilophosaurus hand. The metacarpal 1 (Mc-I)* looks VERY similar to the bone that I am saying is the pterosaur 1st metacarpal.
    You can see for yourself.

    I have posted all the pictures I could on the post:
    http://pterosaurnet.blogspot.com/2010/12/pterosaur-wrist-5.html

    ReplyDelete
  87. Perhaps people have looked at the bone we have been discussing and come to see that it has the shape of a primitive thumb metacarpal.
    I do not expect people to acknowledge that.
    That is okay.

    I am now analyzing the role of the sesamoid. If anyone would like to contribute I welcome your input.
    At the moment I am working with the idea that the sesamoid sat over the junction of the metacarpal and the pteroid bone. There it would protect the joint like our kneecap protects our knee joint.
    I am also thinking that it would have strengthened the joint.
    When flying, the force on the propatagium would be very strong and might bend the joint backwards, which would be disastrous.
    I wonder if the sesamaoid would provide support to prevent that.

    Thoughts?

    ReplyDelete
  88. Is this relevant?
    http://en.wikipedia.org/wiki/Sesamoid_bone#Human_anatomy
    "In the hand — two sesamoid bones are commonly found in the distal portions of the first metacarpal bone (within the tendons of adductor pollicis and flexor pollicis brevis)."

    If this is relevant to the pterosaur hand, it is exactly what I have been suggesting and supports the idea that the bone we have been talking about is a metacarpal with a sesamoid at the distal end.

    Right?

    ReplyDelete
  89. Does this mean that you now see "a point in discussing this"? Because I needn't make long explanatory posts again, to have you delete them because you claim you've suddenly lost interest.

    Anyway, here goes.

    Like you said, anyone can see those pictures and judge for themselves. The deinonychus, dilophosaurus and allosaurus metacarpal are indeed very similar. NOT because they are thick and bulky (notice that the dilophosaur metacarpal is less "bulky" than the deinonychus one), but because they have the characteristic morphology of a metacarpal:

    http://books.google.gr/books?id=01oUBEC9Nn4C&pg=PA97&lpg=PA97#v=onepage&q&f=false

    A diaphyseal shaft, two ends where the articulation is. The proximal end connects to the carpus and the distal end articulates with the corresponding phalanx. That is how a meatacarpal looks like. Short or long, thin or thick, the morphology is shared in all three specimens, your "looks to me" claims notwithstanding.

    In contrast, let's look at the pterosaur carpal again:

    http://bigcat.fhsu.edu/biology/cbennett/carpals.jpg

    In all these samples you can get a clear picture of what the bone looks like. It has a flattened and irregular surface, with multiple facets, resembling something between a trapezium and a capitate (both human carpal bones). No central diaphyseal shaft, no epiphyseal joints at two ends.

    For more pictures, look here:

    http://www.bioone.org/na101/home/literatum/publisher/bioone/journals/content/vrpa/2007/02724634-27.4/0272-4634%282007%2927%5B881%3Aaafotp%5D2.0.co%3B2/production/images/large/i0272-4634-27-4-881-f03.jpeg

    http://www.bioone.org/na101/home/literatum/publisher/bioone/journals/content/vrpa/2007/02724634-27.4/0272-4634%282007%2927%5B881%3Aaafotp%5D2.0.co%3B2/production/images/medium/i0272-4634-27-4-881-f05.gif

    Where you can see other views of the bone, and distinguish its irregular shape and multiple articulation. Still "look like a metacarpal" to you?

    A great deal of people, all scientists and experts, have looked at those fossils over the years, doctor. Not ONE has ever thought of comparing that bone to a metacarpal. Doesn't that strike you as a bit odd, if you could supposedly spot a similarity from drawings?

    The truth is that there is no similarity, for the reasons I made clear in my description above. That claim is dead in the water.

    ReplyDelete
  90. As I have said, people can argue any point till the cows come home. That means nothing.

    Oudenoida you added one additional reference:
    http://www.bioone.org/na101/home/literatum/publisher/bioone/journals/content/vrpa/2007/02724634-27.4/0272-4634%282007%2927%5B881%3Aaafotp%5D2.0.co%3B2/production/images/large/i0272-4634-27-4-881-f03.jpeg

    Can you give us the article reference for this picture please?

    ReplyDelete
  91. I have added the new picture to the summary of pictures here:

    http://pterosaurnet.blogspot.com/2010/12/pterosaur-wrist-5.html

    ReplyDelete
  92. What I found interesting about the most recent picture from Oudenoida, is that the pteroid looks more like a phalanx than most drawings I have seen of it. It is often described as a rod rather than a finger.

    It looks like it is a phalanx that articulated with a metacarpal. In other words the usual pattern.

    The alternative is that the metacarpal disappeared and the pteroid is either a metacarpal (but does not look like a metacarpal at all) or a phalanx uniquely articulating directly with a carpal.

    ReplyDelete
  93. Why should I? To have you once again ignore me and say "it means nothing"?

    Either you're interested in understanding what metacarpals, carpals, and the pterosaur carpal look like, or you don't. If you do, then acknowledge and address my descriptions of the bones. If you don't, then drop the subject.

    As for the new pictures, in case you missed it, the pteroid is NOT articulated with the fovea of the carpal. That facet is clearly connected to the sesamoid, while the articular surface of the pteroid lies at the side.

    How many phalanges articulate to the SIDE of a metacarpal?

    ReplyDelete
  94. Time for you to move on Oudenoida.

    ReplyDelete
  95. I had posted:

    The alternative is that the metacarpal disappeared and the pteroid is either a metacarpal (but does not look like a metacarpal at all) or a phalanx uniquely articulating directly with a carpal.

    I should spell it out. These alternatives are not parsimonious at all.

    ReplyDelete
  96. Here is a question/observation.
    We know that a sesamoid is "commonly found in the distal portions of the first METACARPAL bone".* (As we see in the pterosaur).
    Is there any evidence of a sesamoid being at the distal end of the thumb CARPAL in any taxa? Is it commonly found there?


    * http://en.wikipedia.org/wiki/Sesamoid_bone#Human_anatomy
    "In the hand — two sesamoid bones are commonly found in the distal portions of the first metacarpal bone (within the tendons of adductor pollicis and flexor pollicis brevis)."

    ReplyDelete
  97. http://en.wikipedia.org/wiki/Metacarpophalangeal_joint
    The metacarpophalangeal joints (MCP) are of the condyloid kind, formed by the reception of the rounded heads of the metacarpal bones into shallow cavities on the proximal ends of the first phalanges, with the exception of that of the thumb, which presents more of the characters of a ginglymoid joint[1].

    http://en.wikipedia.org/wiki/Ginglymoid
    A hinge joint (ginglymus) is a bone joint in which the articular surfaces are molded to each other in such a manner as to permit motion only in one plane—backward and forward—the extent of motion at the same time being considerable.


    Everything lines up.
    The pteroid bone (phalanx) articulates with the first metacarpal as a hinge joint in the usual manner. The pteroid only could move "backward and forward" which is all that is required for the backward and forward movement of the propatagium.
    And the sesamoid is present, as is common at that joint.

    This is parsimonius.

    ReplyDelete
  98. Here is a video that shows the movement of a hinge joint:
    http://www.youtube.com/watch?v=BXoMa2bVC18&feature=autoplay&list=PLC2703AB3A7880325&lf=results_video&playnext=3

    It starts at 0:57.
    You can also see the sesamoid.

    ReplyDelete
  99. This picture is helpful:
    http://upload.wikimedia.org/wikipedia/commons/thumb/d/d0/Gray338.png/250px-Gray338.png

    I have posted this on the thread:
    http://pterosaurnet.blogspot.com/2010/12/pterosaur-wrist-5.html

    ReplyDelete
  100. Here is a question/observation.
    We know that a sesamoid is "commonly found in the distal portions of the first METACARPAL bone".* (As we see in the pterosaur).
    Is there any evidence of a sesamoid being at the distal end of the thumb CARPAL in any taxa? Is it commonly found there?


    * http://en.wikipedia.org/wiki/Sesamoid_bone#Human_anatomy
    "In the hand — two sesamoid bones are commonly found in the distal portions of the first metacarpal bone (within the tendons of adductor pollicis and flexor pollicis brevis)."


    Is there any evidence of a sesamoid being at the distal end of the thumb CARPAL in any taxa? Is it commonly found there?

    Can anyone answer this question?

    ReplyDelete
  101. Is there any evidence of a sesamoid being at the distal end of the thumb CARPAL in any taxa? Is it commonly found there?

    I have researched this question and have not found any reference to a sesamoid being at the distal end of the thumb CARPAL in any taxa. (If anyone has such evidence please give us the reference link).

    So if there is no evidence of that occurring in any taxon, then we are looking at a purported UNIQUE occurrence in the pterosaur hand. Just one more purported absolutely unique aspect - IF the bone we are discussing is a CARPAL.
    The simpler explanation (that does not require us to jump through hoops) is that the bone is a metacarpal. Then literally everything follows the STANDARD pattern.

    ReplyDelete
  102. Here is a pterosaur fossil:
    http://www.oceansofkansas.com/Pteranodon/FHSM/FHSM%20VP-2072Pteroid1.jpg

    This shows a new aspect of the pteroid. The pteroid is made of two phalanges.

    ReplyDelete
  103. Here is the progression I am proposing:

    2-2-3-4-4 Pterosaur
    2-3-4-x-x Primitive bird (maniraptors that are not modern birds)
    2-2-1-x-x Modern bird

    Fused pteroid phalanges:
    http://www.oceansofkansas.com/Pteranodon/FHSM/FHSM%20VP-2072Pteroid1.jpg

    http://www.oceansofkansas.com/Pteranodon/FHSM/FHSM%20VP-2183-3a.jpg

    ReplyDelete
  104. http://rspb.royalsocietypublishing.org/content/273/1582/119.full
    "The pteroid bone is a rod-like element found only in pterosaurs, the flying reptiles of the Mesozoic."

    We have been discussing a bone that is commonly labelled a "medial carpal".
    If it is a CARPAL then the pteroid cannot be explained.
    As the reference above says, it is an "element found only in pterosaurs".

    I have also shown that the placement of the sesamoid is also an oddity not found in any other taxa.

    We should be skeptical of any explanation that requires believing that the creature is unlike ALL other creatures that have ever existed. We should conclude that that explanation is probably not correct.

    ReplyDelete
  105. Oudenoida said...
    Perhaps in your mind "everything lines up": Not so in reality.

    Let's leave aside for a minute your most crucial problem (that, as I explained and showed, the pterosaur preaxial carpal bears NO SIMILARITY WHATSOEVER to the typical metacarpal form). Let's focus on your other claims.

    The sesamoids in the first human metacarpal are TWO, associated with specific TENDONS. You need to understand what sesamoids are and do better. Sesamoids do not just appear in metacarpals: they facilitate, strengthen and protect tendons throughout the body. Wiki says:
    "Sesamoids are found in locations where a tendon passes over a joint, such as the hand, knee, and foot. Functionally, they act to protect the tendon and to increase its mechanical effect. The presence of the sesamoid bone holds the tendon slightly farther away from the center of the joint and thus increases its moment arm. Sesamoid bones also prevent the tendon from flattening into the joint as tension increases and therefore also maintain a more consistent moment arm through a variety of possible tendon loads".

    So having a sesamoid is not an indication for a bone being a metacarpal. The patella is a sesamoid. The pisiform (a CARPAL bone, btw) is a sesamoid.

    On the first human metacarpal, the two sesamoids are small (no larger than lentils) and correspond to specific digit flexors. Now look at that sesamoid in the pictures I posted. What tendon did it connect to? A flexor for the pteroid? The sesamoid itself has nearly the same diameter as the pteroid! Where is that tendon? Where did it insert on the pteroid? What was its function, and why was such a strong muscle needed for such a slight movement in a slender bone? All these questions BY THEMSELVES make the idea unparsimonious.

    Now add to that the ACTUAL FACTS: In ALL ( A L L ) pterosaur fossils, whenever the sesamoid was found in an articulating position, that position was IN THE FOVEA. In ALL ( A L L ) pterosaur fossils, whenever the pteroid was found, it was NEVER in a position articulating with the fovea. See Bennet's paper.

    The pteroid did not articulate with the fovea, but at the SIDE of the carpal. There is no relation to a metacarpophalangeal joint whatsoever. And the presense of a large sesamoid articulating with the offset fovea of an irregular bone shows there was another powerful tendon working through that area.

    Even the author of the paper you often cite has admitted he was wrong about the pteroid articulating with the fovea. Time to let go, doctor.

    ALso, by postulating about "thumb carpals" you are assuming what you want to prove: that the preaxial carpal was somehow corresponding to the first column (1st metacarpal and phalanges). First of all, carpal bones do not always correspond and articulate with one specific metacarpal. not even the human trapezium does that; it connects to both the first and the second metacarpal. Secondly, nothing indicates that the preaxial carpal in pterosaurs had to be the one articulating with the first metacarpal. I could have migrated from a certral position, even in the proximal row.


    I honestly don't get why you insist on this whole pteroid being a phalanx business. Besides having to consider a carpal bone as a metacarpal, it creates all sorts of issues with having to gain and then lose phalanges on the second and third digit. Why not assume what the conventional theory says -that the pteroid was probably a neomorph- and that it got lost in later stages of your 'lineage'? It won't make your theory any less plausible than it already is. You still have to cope with the loss of the entire 4th finger that supports the wing membrane, plus all the other changes from pterosaurs to "primitive birds", but at least the other digits would line up correctly. and you wouldn't have to question the opinion of ALL scientists who ever studied the preaxial carpal, based on two pictures that "look similar to you".

    Think about it.

    ReplyDelete
  106. "Let's leave aside for a minute your most crucial problem (that, as I explained and showed, the pterosaur preaxial carpal bears NO SIMILARITY WHATSOEVER to the typical metacarpal form). Let's focus on your other claims."

    By expressing your opinion in capital letters it does not become any more credible.
    Let it go.

    ReplyDelete
  107. "it creates all sorts of issues with having to gain and then lose phalanges on the second and third digit."

    This is a joke I assume. That small amount of expressed or unexpressed phalanges occurs all the time.
    Are you saying that is unusual? If so, you need to study this a lot more.

    What you are doing is looking to absurdly exaggerate anything you can. It shows your case to be weak.
    You approach this in the way people argue politics. Not in a scientific way.

    ReplyDelete
  108. Oudenoida, is there any evidence of a sesamoid being at the distal end of the thumb CARPAL in any taxa? Is it commonly found there?

    ReplyDelete
  109. "Why not assume what the conventional theory says -that the pteroid was probably a neomorph- and that it got lost in later stages of your 'lineage'?"

    And while we are at it, let's assume it was placed there by fairies.

    Did you see my note above:
    Let me repeat it:

    http://rspb.royalsocietypublishing.org/content/273/1582/119.full
    "The pteroid bone is a rod-like element found only in pterosaurs, the flying reptiles of the Mesozoic."

    We have been discussing a bone that is commonly labelled a "medial carpal".
    If it is a CARPAL then the pteroid cannot be explained.
    As the reference above says, it is an "element found only in pterosaurs".

    I have also shown that the placement of the sesamoid is also an oddity not found in any other taxa.

    We should be skeptical of any explanation that requires believing that the creature is unlike ALL other creatures that have ever existed. We should conclude that that explanation is probably not correct.

    ReplyDelete
  110. "Where is that tendon? Where did it insert on the pteroid? What was its function, and why was such a strong muscle needed for such a slight movement in a slender bone?"

    Good questions.
    But we do know why it needed a hugely strong muscle.
    TO ALLOW THE PTEROID TO SUPPORT THE PROPATAGIUM AGAINST STRONG WIND FORCES IN FLIGHT.
    The pteroid not only moved the propatagium (backward and forward) but also supported it in flight.

    ReplyDelete
  111. This blog is intended to present the pterosaur to bird idea.
    If someone contributes something worthwhile I will respond.
    Otherwise I will simply continue my research and post the results.

    ReplyDelete
  112. http://www.ucmp.berkeley.edu/vertebrates/flight/pter.html
    "Pterosaurs also had a bone unique to their clade. It is called the pteroid bone, and it pointed from the pterosaur's wrist towards the shoulder, supporting part of the wing membrane. Such a novel structure is rare among vertebrates, and noteworthy; new bones are unusual structures to evolve — evolution usually co-opts bones from old functions and structures to new functions and structures rather than "reinventing the wheel."

    We should be skeptical of any explanation that requires believing that the creature is unlike ALL other creatures that have ever existed. We should conclude that that explanation is probably not correct.

    ReplyDelete
  113. If we assume that the pterosaur developed from a creature that had a thumb of two phalanges (which is the usual pattern), then we can see that what I am proposing is exactly the same pattern continued into the pterosaur.
    There was a metacarpal and two phalanges.

    This is parsimonious.

    ReplyDelete
  114. I have suggested that the pteroid is composed of the fusion of two phalanges. We can see that, from the fossils. And we can see that, in the abrupt bend of the pteroid bone where the two bones are fused at an angle.

    That started me wondering about the mechanics of bones fusing.
    Is that the result of the ossification of the ligament between the two bones?

    ReplyDelete
  115. I should mention that if people submit comments with childish insults they will not be posted.

    ReplyDelete
  116. I have suggested that the pteroid is composed of the fusion of two phalanges. We can see that, from the fossils. And we can see that, in the abrupt bend of the pteroid bone where the two bones are fused at an angle.

    That started me wondering about the mechanics of bones fusing.
    Is that the result of the ossification of the ligament between the two bones?

    Or does the fusion occur by the removal of the cartilage between the two bones and then the bones fuse directly with each other?

    ReplyDelete
  117. From what I can see, it looks like the bones fuse directly with each other - as we see in the fusing of bones in a human skull.
    It would be interesting and helpful to know what the unfused bones are like (before they fuse) in the chick embryo for the bird hand. I have not seen any material on that.
    If anyone can contribute on that please do.

    ReplyDelete
  118. This reference also has info on bird hands including ratites:
    http://scienceblogs.com/tetrapodzoology/2010/06/clubs_spurs_spikes_and_claws.php

    ReplyDelete
  119. http://www.species.net/Aves/Cassowary.html
    Apteria, eyelashes and a wing claw are present, but there is no alula (bastard wing), nor are there feathers under the wing.


    and

    http://www.netpets.org/birds/healthspa/vet/ratite.html
    The tip of the alula has become cornified to form a hook in the ostrich and rhea, wheras the distal phalanx of the emu and cassowary has become cornified to form a hook.

    ReplyDelete
  120. What makes us think that the pterosaur wing finger is not the index finger?
    Are there some specific fossils that lead us to rule out that possibility?

    Would the hand work for flying if the wing finger were the index finger?

    ReplyDelete
  121. Hold your arms out to your sides palms down. Visualize your index finger (digit 2) being quite long. Visualize a membrane being attached to this extended index finger and attaching to the body, for example at the hip.
    Where would your fingers 3, 4 and 5 be? Would they interfere with the membrane?

    This model of the pterosaur hand seems so natural and so workable that we should ask - what makes us think it was some other way?

    Are there specific fossils that rule this simple, natural model out?

    Could someone give us a reference to a fossil picture that would shed light on this question?

    ReplyDelete
  122. I should make it clear that the pterosaur to bird theory does not depend on the idea that the index finger is the wing finger.
    But it is a significant idea onto itself.
    And it also makes an almost seamless transition to the structure of the primitive bird hand.

    ReplyDelete
  123. I am hoping that someone can give us a picture of a fossil that relates to the question as to whether the index finger is the wing finger.
    I mean a picture of a fossil and not a drawing since a drawing can be made to represent anything.

    ReplyDelete
  124. "This model of the pterosaur hand seems so natural and so workable that we should ask - what makes us think it was some other way?"

    Every articulated fossil makes us think it was some other way. As do the trackways.

    How many specimens have you examined that leads you to think your alternative is remotely credible?

    Look at every fossil of an articulated pterosaur you have posted here, or seen elsewhere. The elongated finger is the fourth one along. There is no way on earth it could be the index finger. Footprints also show that the fourth finger is the one supporting the membrane.

    "I should make it clear that the pterosaur to bird theory does not depend on the idea that the index finger is the wing finger.
    But it is a significant idea onto itself."

    No. its a silly idea based on a total lack of evidence, and contradicted by the first pterosaur fossil found and described by Baron Cuvier.

    ReplyDelete
  125. A Nonny Mouse has not presented any fossil as I had asked for.
    Anyone else?

    ReplyDelete
  126. To visualize the index finger as wing finger extend your arms to your sides. Now lower your index finger. Notice that the 3rd, 4th and 5th fingers appear to be above the index finger.

    ReplyDelete
  127. As I mentioned in the post above if you lower your index finger then the 3rd, 4th and 5th fingers appear to be above the index finger. And that is what we see in every pterosaur fossil.
    If anyone can present a different fossil than that, please do.
    I am very interested.

    ReplyDelete
  128. Interesting video about how the pterosaur might have flown:
    http://www.youtube.com/watch?v=8WFmpEmmzOU
    Especially from 2:17

    And here is an ablatross flying:
    http://www.youtube.com/watch?v=1jNBTrHPVN4

    ReplyDelete
  129. So how did pterosaurs fly?
    Here is an entry on a blog that describes how one blogger sees it:

    http://whenpigsfly-returns.blogspot.com/2008/02/pterosaur-wings-as-i-understand-them.html

    What is interesting is he implies he has agreement from some of the main researchers in this field.

    But the method that he describes is with the palms facing up which seems quite odd.

    ReplyDelete
  130. No. It makes perfect sense given what we understand of the specimens. Specimens you have already seen pictures of, and yet completely misinterpreted time and time again. Specimens you have never actually looked at first hand and yet somehow you think you're qualified to rubbish the work of workers who have put the necessary work in, have gained a detailed understanding of animal anatomy and so on. I see no point in repeatedly rubbing your nose in it. The information is out there and very easy to find.

    Just for starters, there's a good discussion of the pterosaur hand here http://archosaurmusings.wordpress.com/2009/04/13/where-is-the-pterosaurian-5th-finger/

    This site show a picture of the trackway. You can clearly see the handprints. There's no way you'd have the index finger as the support for the membrane. Not just because the fingers would have interfered with it in your configuration.

    http://www.pterosaur.net/terrestrial_locomotion.php

    Now, what's your evidence for rejecting this information? So far it seems to be on a par with your "the metacarpal is actually a carpal"- i.e. completely absent

    ReplyDelete
  131. A Nonny Mouse, are you agreeing with the idea that the pterosaur flew with palms up? Do you think that is the mainstream idea?

    Also in the references you gave, there is nothing that contradicts what I am proposing.
    If you think there is something there that contradicts what I am saying, please copy and paste the material you think does that.

    ReplyDelete
  132. A Nonny Mouse posted:
    "So far it seems to be on a par with your 'the metacarpal is actually a carpal' "

    I do not know what you are referring to here.
    I am proposing that the bone which is commonly called a "medial carpal" is a metacarpal.

    Are you confused about that? Or are you referring to something else?

    Are others confused about this?

    ReplyDelete
  133. "Also in the references you gave, there is nothing that contradicts what I am proposing."

    Look at the fossils. The fossils themselves contradict what you are saying. You are wrong about the wing finger being the index finger.

    Reading Dave Hone's excellent post shows you to be wrong. The whole, detailed post lists several very good reasons why you are totally wrong.

    "In reptiles at least, digit IV is the biggest (the longest and also often the most robust) of the five digits. That makes it relatively easy to spot and adds another reference point as with the pollex (and furthermore V is typically the shorted and smallest). In terms of pterosaurs this is obviously a strong indicator that the wing finger is indeed digit IV since not only is it really big, but also digit III is similar to both digits I and II. It is therefore most parsimonious to assume that digit IV started as the biggest and got bigger, and III stayed the same size, than V became super sized and IV shrank to look like II and III."

    "In pterosaurs, the basic formula is one of 2-3-4-4-X (the X denotes there are none present) so it is easy to see how this more closely matches a pattern of I-IV than of II-V. When you add to that the fact that there is no ungual on the pterosaur digit IV and thus it originally would have had 5 phalanges and not 4, it becomes an even better match."

    "So if we add all of that together, we can be really pretty confident that the pterosaurian wing finger is indeed digit IV. It has the right number of phalanges, it is the biggest on the finger and we would expect V to be lost before I. If it were a digit V we would have to have had IV shrink in size, have different numbers of phalanges on pretty much every digit, have an odd reversal in digit I being lost first and have the digit V ungual change to look like the other phalanges. It’s pretty clear therefore which option we should pick!"

    It totally contradicts both your initial idea that the pterosaur wing finger is digit V and your new idea that it is digit II.

    "Or are you referring to something else?"

    Don't you recall suggesting that the large metacarpal in the third finger of the dromaeosaur hand was actually a carpal? You may well have changed your mind since then, but its another example of your ignorance of anatomy.

    ReplyDelete
  134. "A Nonny Mouse, are you agreeing with the idea that the pterosaur flew with palms up? Do you think that is the mainstream idea?"

    I see no evidence that contradicts this idea. Notice how in each pterosaur fossil that shows the articulated hand the fingers and claws face forwards. Which is not what you would see if the back of the hand were facing forwards in flight.

    Hold out your hands in front of you with the palms facing forwards and the fingers to the side. This is (roughly) how pterosaurs placed their hands on the ground. Rotate your arms at the shoulder and elbow to stretch your arms and hands out to the side. Do not move your wrist. Your palms will face upwards and forwards.

    ReplyDelete
  135. "Look at the fossils. The fossils themselves contradict what you are saying."

    Please present some links to fossils that contradict what I am saying. That would be great.

    ReplyDelete
  136. "Reading Dave Hone's excellent post shows you to be wrong. The whole, detailed post lists several very good reasons why you are totally wrong."

    All that Hone is doing is presenting the consensus opinion. He presents no evidence.

    ReplyDelete
  137. I posted:
    "A Nonny Mouse, are you agreeing with the idea that the pterosaur flew with palms up? Do you think that is the mainstream idea?"

    A Nonny Mouse posted:
    "I see no evidence that contradicts this idea. Notice how in each pterosaur fossil that shows the articulated hand the fingers and claws face forwards. Which is not what you would see if the back of the hand were facing forwards in flight."

    So you actually believe that the pterosaur flew with palms up?
    I thought that perhaps that was just some crazy idea of one particular blogger.

    Do others think that the pterosaur flew palms up?
    Do others think that that is the mainstream idea?

    ReplyDelete
  138. "Which is not what you would see if the back of the hand were facing forwards in flight."

    I am not claiming that the back of the hand was facing forwards in flight.
    Put your arms out to your sides, palms down (parallel to the floor)*. Now just lower your index finger a little bit. That is what I am proposing.
    And the membrane is attached to the index finger (which in the pterosaur is long).


    * Like you extended your arms when you pretended to be Superman when you were a kid.

    ReplyDelete
  139. By the way you can stop with the stupid insult of:
    "but its another example of your ignorance of anatomy."

    You are the one who believes in the magical appearance of a pteroid bone out of the blue, the idea that pterosaurs flew with their palms up, that your wing finger made a magical 180 degree turn and that a sesamoid appears at a carpal/metacarpal joint which is found in no other creature.

    I am not arguing these points again. But it is ludicrous for YOU to claim any superior knowledge of anatomy.

    ReplyDelete
  140. I need to say again that the pterosaur to bird theory does not depend on the idea of the wing finger being the index finger.
    But the index finger being the wing finger is so much more parsimonious, that it is an interesting idea on its own.
    With the index finger being the wing finger we do not need to believe that the wing finger was magically turned 180 degrees.
    It just bends like a completely normal joint.

    ReplyDelete
  141. "All that Hone is doing is presenting the consensus opinion. He presents no evidence."

    Actually he does. Read it again.

    "Please present some links to fossils that contradict what I am saying. That would be great."

    Look for them yourself. There's enough specimens out there that you should have seen by now. You shouldn't need spoonfeeding.

    "But the index finger being the wing finger is so much more parsimonious, that it is an interesting idea on its own.
    With the index finger being the wing finger we do not need to believe that the wing finger was magically turned 180 degrees."

    No, it is not more parsimonious at all. You don't have enough phalanges. You need to re-arrange the fingers completely - especially if you still think the pteroid is a finger (and why does it have a metacarpal that looks for all the world like a carpal? And what evidence do you have for it being made of two phalanges? No primitive pterosaur has two bones making up the pteroid, and if there's any evidence of fusion of phalanges in other animals I've never seen it.

    Pterosaur wing fingers have to be "double jointed" to fold upwards and back when the animal walked on the ground.

    "Put your arms out to your sides, palms down (parallel to the floor). Now just lower your index finger a little bit. That is what I am proposing.
    And the membrane is attached to the index finger (which in the pterosaur is long)."

    So why do all the other fingers face forwards in these fossils, rather than sideways as required in this scenario? Why, when counting outwards on the fossils is the index finger the one on the outside? Rather than the one on the inside as your scenario would require. If the palms face upwards and the ring finger out to the side it isn't rotated through 180 degrees. The inner fingers are curled towards the hand, and the index finger is outstretched. The joints go the other way in this finger. Have you never seen some-one who is double jointed?

    "By the way you can stop with the stupid insult of:
    "but its another example of your ignorance of anatomy.""

    Its not an insult. Its an accurate description. Remember when you suggested the legs of Sharovipteryx might be its arms? So what if the pteroid is a neomorph? The wing finger wasn't "rotated" 180 degrees. Its a description to explain how your hand would have to be changed to make it look like a pterosaur one. I'm double-jointed. I don't have to spin my ring finger around. I can move it back so it faces in the opposite direction from my three inner fingers. Most people aren't double-jointed, so their fingers don't allow them to do this. And you still don't understand what sesamoids are and why they're important. Of course, we're not suggesting that the pteroid is a finger, so the idea of their being a sesamoid appearing at a carpal/metacarpal joint doesn't arise.

    ReplyDelete
  142. People will notice that what I have been proposing is parsimonious. I do not require bones to magically appear out of the blue.
    I do not require bones to magically rotate 180 degrees from their normal position.
    I do not require bone structures that are not found in any other creature that ever existed.

    My approach is to not require magic.

    People could approach this topic differently. Take a look at what I am proposing and see how the evidence supports it.
    Spend your time productively considering the alternative I am suggesting. Rather than doing your utmost to rationalize magic.

    ReplyDelete
  143. A Nonny Mouse posted:
    "Look for them yourself. There's enough specimens out there that you should have seen by now. You shouldn't need spoonfeeding."

    This is the kind of run-around I am very familiar with. It is obvious that you have no evidence to present.
    Tell you what. When you have some evidence come back and present it.

    ReplyDelete
  144. I posted:
    "All that Hone is doing is presenting the consensus opinion. He presents no evidence."

    A Nonny Mouse posted:
    "Actually he does. Read it again."

    There is the run-around again.
    A Nonny Mouse does not simply copy and paste the material from Hone that he thinks supports his case. (Which should be easy, if he is looking right at it). Instead, he tells me to read the article again.
    And A Nonny Mouse does that in spite of the fact that I have asked people again and again to copy and paste what they think is the relevant material.

    If anyone can actually present some evidence then I am very interested.

    ReplyDelete
  145. Perhaps A Nonny Mouse means that I should read again the passages that he posted from Hone.
    If that is what he means, then my point is still that those quoted passages do not present evidence. They simply present the consensus opinion.

    ReplyDelete
  146. To this point I have been presenting the phalange count as:
    2-2-3-4-4 Pterosaur
    This is based on the current thinking that the wing finger is the last finger and has 4 phalanges.
    If the index finger is the wing finger then the pattern would be:
    2-4-3-4-4 Pterosaur

    I am not sure about the exact numbers but it would be something like that.

    The progression would be:
    2-4-3-4-4 Pterosaur
    2-3-4-x-x Primitive bird (maniraptors that are not modern birds)
    2-2-1-x-x Modern bird


    I remind folks again that the pterosaur to bird theory does not count on the index finger being the wing finger.

    ReplyDelete
  147. I should remind people that I will not post comments that contain insults.

    ReplyDelete
  148. I must say it is funny to have people here who believe in magic, yet are critical of the idea that the index finger could be the wing finger.
    If someone believes in bones appearing magically out of the blue; bones rotating 180 degrees; and pterosaurs flying with their hands upside down, it really is funny to expect me to take your criticisms seriously.

    ReplyDelete
  149. As I said, I am not sure of the exact numbers.
    The pterosaur pattern could be:
    2-4-4-3-2
    (This depends on the phalanges in digits 3, 4 and 5.)

    The progression would then be:

    2-4-4-3-2 Pterosaur
    2-3-4-x-x Primitive bird (maniraptors that are not modern birds)
    2-2-1-x-x Modern bird

    "x" means that the finger is not expressed.

    ReplyDelete
  150. It would be good to nail this down.
    Do people actually believe that the pterosaur flew with its hands upside down? In other words with its palms up?

    ReplyDelete
  151. Yes. The pterosaur flew palms up. Everyone in the scientific community believes this to be the case

    ReplyDelete
  152. So everyone in the scientific community believes
    that pterosaurs flew palms up.
    Does that mean that they also believe that the forearm was also facing upwards? I assume you must mean that, but this is such an odd idea, I want to make sure I understand it correctly.

    ReplyDelete
  153. Here is how one blogger put it:

    "Put your arms out to your sides, slightly bent at the elbows, palms facing up. Now chop off your pinkie finger--you won't need that. Also, reorient your thumb so that it's no longer offset. Curl your now injured thumb, index finger, and middle finger. Notice how they all curl toward the palm. Great. Now here's the painful part: Dislocate your ring finger, spin it 180 degrees, and pop it back in place. Your ring finger will now curl toward the back of your hand. Ouch, right? Keep your palms up! When you curl that ring finger, notice that it starts pointing toward your elbow.That's basically the situation in pterosaurs."

    But I have not seen any published article on this. Can anyone present a reference link to a published article (preferably peer-reviewed) supporting the idea of pterosaur palms-up flight?

    I have a feeling that people here are just joking.

    ReplyDelete
  154. Let's look at what I am suggesting.
    Extend you arms to your sides, palms down.
    Now lower your index finger slightly.

    That's it. No contortions. No anomalies.
    Just a parsimonious explanation.

    Given that fossils are not found with little labels on the bones or little schematics included with the bones, it is impossible to tell for sure exactly how the bones were arranged.
    Given that it is not possible to know for sure, we should prefer a parsimonious explanation.

    ReplyDelete
  155. Here is an article that seems to present a more bird-like flight motion:

    http://www.jstor.org/pss/2400656
    "An analysis of the structure and kinematics of the forelimbs and hindlimbs of pterosaurs, and functional analogy with recent and fossil vertebrates, supports a reappraisal of the locomotory abilities of pterosaurs. A hypothesis of structural, aerodynamic, and evolutionary differences distinguishing vertebrate gliders from fliers is proposed; pterosaurs fit all the criteria of fliers but none pertaining to gliders. The kinematics of the reconstructed pterosaur flight stroke reveal a down-and-forward component found also in birds and bats; structural features of the shoulder girdle and sternum unique to pterosaurs may be explained in light of this motion. The recovery stroke of flight was accomplished, in birdlike fashion, by a functional reversal of the action of the M. supracoracoideus by the pronounced enlargement of the acrocoracoid process, which acted as a pulley."

    ReplyDelete
  156. Perhaps you should do some research yourself. Sadly you may well find that the work has been done long ago and is not available on the internet. The forearm would have faced forwards, in the direction of flight. The palms would be pointing slightly upwards. The twist in the ring finger knuckle joint is based on how pterosaurs would have folded their wing finger.

    http://books.google.co.uk/books?id=idta6AVV-tIC&pg=PA26&lpg=PA26&dq=pterosaur+palm&source=bl&ots=2FVT5U7cKs&sig=UypWm265M2Eta4iCsTiwLD8pJJc&hl=en&ei=kZiyTrXJAZSU8gO-sJjsBA&sa=X&oi=book_result&ct=result&resnum=2&ved=0CCUQ6AEwAQ#v=onepage&q=pterosaur%20palm&f=false

    People are not joking. They are serious about this.

    ReplyDelete
  157. I have done research on this.
    It is "sad" and convenient that published support for this palms-up idea is not available.
    But there is an article presenting an alternative, which I posted above, which happily is available.

    It looks like people do not really have a consistent story for how ptetosaurs flew, based on the idea of the wing finger being the finger furthest from the thumb.

    The idea that the index finger is the wing finger is the most parsimonious explanation.
    In fact it seems to be the only explanation given the confusion and inconsistencies about any alternative.

    We are getting to a point where there is actually no point in even continuing to argue about this.
    There is no support for the palm-up idea.
    And the index finger as the wing finger is the most parsimonious explanation - in fact the only consistent explanation available.

    But I know full well that people will argue to till the cows come home. That means nothing.

    ReplyDelete
  158. In case it is not clear, I am not proposing that the hand fingers were magically switched in the pterosaur. I am saying that the fossil reconstructions are incorrectly labelled. And that may well be because the 3rd, 4th and 5th fingers would appear to be above the index finger when the index finger is slightly lowered.
    But there is no point in arguing this because we all agree that it is impossible to know for sure what the actual construction was.

    Our best strategy is to prefer the most parsimonious explanation as we always prefer in science.

    ReplyDelete
  159. People keep thinking I will post comments that include insults.
    If you want your comment published, act professionally.
    Your choice.

    ReplyDelete
  160. The reason I stress that the index finger is slightly lowered is because that is how it would have to be, given the length and weight of it when the membrane was extended.

    And all pictures show the wing finger being slightly bent downward. Which stands to reason.
    But the 3rd, 4th and 5th fingers would not be bent downwards.

    ReplyDelete
  161. "But the 3rd, 4th and 5th fingers would not be bent downwards".

    They would FLEX downwards though. Which means that, since they would lie dorsally to the wing membrane, their flexion would be pretty much useless.

    Another thing for you to ignore.

    ReplyDelete
  162. A Nonny Mouse gave us this reference:
    http://books.google.co.uk/books?id=idta6AVV-tIC&pg=PA26&lpg=PA26&dq=pterosaur+palm&source=bl&ots=2FVT5U7cKs&sig=UypWm265M2Eta4iCsTiwLD8pJJc&hl=en&ei=kZiyTrXJAZSU8gO-sJjsBA&sa=X&oi=book_result&ct=result&resnum=2&ved=0CCUQ6AEwAQ#v=onepage&q=pterosaur%20palm&f=false

    On page 26, it seems to support what I am saying.

    For example it says:
    "The first metacarpal forms the leading edge".

    It is a pdf - is there some way to copy and paste from it?

    ReplyDelete
  163. Hold your arms out to your sides palms down. Visualize your index finger being quite long. Visualize a membrane being attached to this extended index finger and attaching to the body, for example at the hip.

    Where would the other fingers be? In what direction would they flex? In that position and function, would they be of ANY use?

    Think about it, doc.

    ReplyDelete
  164. "The first metacarpal forms the leading edge".

    Exactly.

    Which places it ANTERIORLY to the wing metacarpal.

    Like all the pictures I posted (and you deleted) show.

    ReplyDelete
  165. There does not seem to be any consistency in people's thinking about the orientation of the pterosaur wing.

    It seems that people are really stuck, trying to figure out how the wing worked when they assume that the wing finger is the finger furthest from the thumb.

    On the other hand it seems to be completely simple, if the index finger is the wing finger. Everything works in the normal way, as in all other creatures.

    ReplyDelete
  166. "Where would the other fingers be? In what direction would they flex? In that position and function, would they be of ANY use?"

    I don't see the problem.
    As long as they are out of the way and do not tear the membrane, then they do not interfere with flying.

    And pterosaurs were specialized for flying.
    The fact that they do not interfere with the membrane is another piece of evidence in support of what I am proposing.

    I am happy to work with anyone on visualizing what I am proposing.

    ReplyDelete
  167. "They would FLEX downwards though. Which means that, since they would lie dorsally to the wing membrane, their flexion would be pretty much useless."

    I don't understand the problem here. This is a FLYING CREATURE.

    What role do you want for those tiny little fingers?

    ReplyDelete
  168. What always captivates me is how Nature makes use of the basic tetrapod structure.
    It is so flexible that with no significant change it can be adapted even for flying.
    With the pterosaur, I am proposing that the index finger supports the wing. And the 3rd, 4th and 5th fingrs are not needed so they are tiny - and most important - do not interfere with flying.

    And concerning the thumb, Nature does not need to create new bones out of thin air. It just uses what is already available.

    There are certain themes in what I propose.
    Making use of existing structures is one theme and parsimony is another theme.

    ReplyDelete
  169. To elaborate a bit.
    I said:
    And the 3rd, 4th and 5th fingrs are not needed so they are tiny

    And in birds, fingers are fused because they are not needed. And a VERY strong structure is needed.

    Nature makes use of what it has.

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  170. The way I approach this is, that if an explanation is offered that is not parsimonious and/or requires some absolutely UNIQUE structure then I am inclined to think that that explanation is based on some incorrect interpretation of the evidence.
    I look for the researcher to have made a misjudgment, rather than think that Nature has done something completely peculiar.

    ReplyDelete
  171. "They would FLEX downwards though. Which means that, since they would lie dorsally to the wing membrane, their flexion would be pretty much useless."

    I don't understand the problem here. This is a FLYING CREATURE.

    What role do you want for those tiny little fingers"?

    First of all, it directly contradicts the walking method seen in fossil tracks:

    http://www.pterosaur.net/terrestrial_locomotion.php

    Where you can see the traces of the fingers, as well as a print of the folded wing finger on the posterior.

    Secondly, the placement of the fingers dorsally to the wing, at a plane with the second one, produces nothing but needless drag, and also makes the arms completely useless for not only grasping and clinging (which invalidates a gliding arboreal origin), but also of walking. Unless the pterosaur walked on the back of its palm, which is not only inconsistent with the evidence, but also mechanically inefficient.
    Also, if the other metacarpals were not anteriorly, they would not be supported posteriorly by the thick wing metacarpal, and be subject to the power of the wind. Both inefficient AND potentially harmful.

    But all that does not matter since, in the pictures I showed you (as you demanded), you can see that the first three metacarpals lie anteriorly to the wing metacarpal (as A Nonny Mouse's source also describes). On the same pictures (and even the ones you yourself have posted, as I told you) you can see that the wing metacarpal articulates with the ulnar side of the carpus. And the other metacarpals lie anteriorly to that. In the african pterosaur picture, you can see them correspond to the radial side. You can also see that they flex anteriorly, as would be expected in the gliding ancestors of pterosaurs (which you also postulate).

    You wanted to see fossils, and the fossils prove you wrong.

    ReplyDelete
  172. Concerning the idea that researchers may have made a misjudgement - we notice that ideas change all the time. One theory is replaced by another.

    I don't think we need to hallow any current theory. Chances are it will be superseded by a different theory.

    But Nature just keeps on tickin.

    ReplyDelete
  173. "First of all, it directly contradicts the walking method seen in fossil tracks:
    http://www.pterosaur.net/terrestrial_locomotion.php
    Where you can see the traces of the fingers, as well as a print of the folded wing finger on the posterior."


    If you want to claim that, you will have to give details. This looks like pretty ambiguous evidence. Evidence cited on behalf of 4 different theories.
    But please go ahead - show us exactly what you mean. I am interested in all evidence.

    ReplyDelete
  174. "Also, if the other metacarpals were not anteriorly, they would not be supported posteriorly by the thick wing metacarpal, and be subject to the power of the wind. Both inefficient AND potentially harmful."


    If the other metacarpals were anterior they would be on the leading edge and take the full brunt of the wind would they not?

    Are you still working with the idea that the palms were UP?

    ReplyDelete
  175. "..and also makes the arms completely useless for not only grasping and clinging (which invalidates a gliding arboreal origin), but also of walking.

    I am not even sure that that is correct. If the index finger is lifted and folded back would it interfere? Would it interfere more than if it were the finger furthest from the thumb?
    I am not so sure about that.
    We would need to study that. And it would relate to the way that the wing finger joints operate.

    ReplyDelete
  176. "If you want to claim that, you will have to give details. This looks like pretty ambiguous evidence. Evidence cited on behalf of 4 different theories.
    But please go ahead - show us exactly what you mean. I am interested in all evidence".

    The source provided was pretty detailed:

    "First and foremost, Pteraichnus and its ichno-kin demonstrate to us that pterosaurs walked quadrupedally on digitigrade forelimbs and plantigrade hindlimbs. Only the first three fingers regularly touch the floor as the flight finger was apparently folded and stowed alongside the body when grounded, occasionally leaving a fourth digit trace in the manus print. Folding the wing in this way requires the metacarpals to be medially rotated at the wrist, thereby forcing the manual digits to produce laterally- and posterolaterally directed digit impressions. The comparatively shallow pes prints have a narrow ankle that, in Haenamichnus at least, appears to have borne a large, fleshy pad with toes that often curve medially due to the presence of long toe claws".

    Observe the accompanying picture:

    http://www.pterosaur.net/terrestrial_locomotion/image002.jpg

    Such prints would be unobtainable in your position, unless the pterosaur walked with the back of its hands.

    "If the other metacarpals were anterior they would be on the leading edge and take the full brunt of the wind would they not"?

    They would form "the leading edge", as the paper says, but they would also be supported posteriorly by the thick wing metacarpal. In your position, the metacarpals lie on a plane against the wind, and have no support.

    And why are you not addressing the most crucial piece of evidence- THE FOSSILS THEMSELVES, that show the wing metacarpal on the ulnar side and the others anteriorly?

    ReplyDelete
  177. Remember that the fourth finger is BIG, that the membrane extends to the body, and the fingers would flex posteriorly. Visualize it on your body.

    ReplyDelete
  178. "The first metacarpal forms the leading edge".

    "Exactly.
    Which places it ANTERIORLY to the wing metacarpal."

    If the palms are facing UP would the first metacarpal form the leading edge?
    How do you visualize that?

    The way I see it, the first metacarpal would form the leading edge only if the palms were facing down.
    I see that if I stretch my hands out to my sides.

    ReplyDelete
  179. "If the other metacarpals were anterior they would be on the leading edge and take the full brunt of the wind would they not"?

    They would form "the leading edge", as the paper says, but they would also be supported posteriorly by the thick wing metacarpal. In your position, the metacarpals lie on a plane against the wind, and have no support."


    The obvious answer is that they would be tucked behind the large index finger and not take any brunt of the wind.
    Just stretch your arms out to your side to see how to line up your fingers in a plane so the 3rd, 4th and 5th are behind the index finger.

    This is not rocket science. You are pretending to see problems where there are no problems.

    I do not mind discussing this with you but you do need to use some common sense.

    ReplyDelete
  180. "Only the first three fingers regularly touch the floor as the flight finger was apparently folded and stowed alongside the body when grounded, occasionally leaving a fourth digit trace in the manus print."

    This does not seem to be inconsistent with what I am proposing.
    The fourth digit trace would be left occasionally when the index finger touches the ground.

    I think you are looking for problems when there are no problems.

    ReplyDelete
  181. "the palms are facing UP would the first metacarpal form the leading edge?
    How do you visualize that?

    The way I see it, the first metacarpal would form the leading edge only if the palms were facing down.
    I see that if I stretch my hands out to my sides".

    Oh dear. Pterosaurs were not flying standing up, doc. Think about it.

    In pterosaur flight, the leading edge is not the frontal side as in humans walking or running. The leading edge is the head and the extended wings to the sides.

    ReplyDelete
  182. "Remember that the fourth finger is BIG, that the membrane extends to the body, and the fingers would flex posteriorly. Visualize it on your body."

    Are you working with the idea that the palms are up? or that they are down?

    ReplyDelete
  183. "In pterosaur flight, the leading edge is not the frontal side as in humans walking or running. The leading edge is the head and the extended wings to the sides."

    I agree. I always visualized it that way. Imagine lying on the floor with arms outstretched.
    My point still stands.

    Are you working with the idea that the palms were up? or that they were down?

    ReplyDelete
  184. "Are you working with the idea that the palms are up? or that they are down"?

    I am showing you the implications of your "palm down" theory. Try to visualize it, as you have before. Drop on all fours, to imitate the stance of a walking pterosaur (you can crouch if you like, to accomodate for the shorter hindlimbs).
    Now pronate your forearm to bring the hand in a position that the "palm down" stance would have during quadrupedal locomotion. try to have the second digit flex posterolaterally, to imitate the wing finger during locomotion.
    Now try to support your weight on the other three digits.

    As you see, you can only stand on the tips of the digits if you hyperextend them, and even so the digits face anteromedially, and not posterolaterally as in the tracks. The only way to have them face posterolaterally would be to direct the flexed "wing finger" anteromedially, towards the body, which means it would not fold.

    So the tracks disprove you.

    As for the palms:

    "Are you working with the idea that the palms were up? or that they were down"? Neither. They are directed anteriorly. Which would relate to "up" only if the pterosaur had a completely erect stance like a human. In the flight stance of a pterosaur, that faces forward. Do not confuse the analogy for reality.

    Imagine you're a gliding pterosaur ancestor, and you want to land and cling onto a branch. How yould you hold it in order to not let go? How would your 'palms' face?

    And you keep forgetting the elephant in the living room: We HAVE detailed fossils, which show the wing metacarpal articulating to the ULNAR side of the carpus, and the other metacarpals anteriorly to that. See the picture I posted. See the drawings you yourself have posted.

    What more evidence do you need? You said you wanted to see pictures of fossils. Well there they are, and they show you are wrong.

    ReplyDelete
  185. Oudenoida, you are saying it was palms up.
    If it is palms up, then the leading edge would not be the first metacarpal.

    But the article that I quoted from AND THAT YOU AGREED WITH said that "The first metacarpal forms the leading edge".

    ReplyDelete
  186. Would anyone else like to contribute on this? It looks like Oudenoida is just going to give us the run-around.

    How about you A Nonny Mouse? After all, you were the one that gave us the reference that I am quoting from*. And you also believe in the palms up model.
    Do you accept now that the article contradicts that?


    * Page 26
    http://books.google.co.uk/books?id=idta6AVV-tIC&pg=PA26&lpg=PA26&dq=pterosaur+palm&source=bl&ots=2FVT5U7cKs&sig=UypWm265M2Eta4iCsTiwLD8pJJc&hl=en&ei=kZiyTrXJAZSU8gO-sJjsBA&sa=X&oi=book_result&ct=result&resnum=2&ved=0CCUQ6AEwAQ#v=onepage&q=pterosaur%20palm&f=false

    ReplyDelete
  187. Yes I accept the "palms up model". It is an analogy. Perhaps it should better be renamed the "palms forward model" given that that's what it would look like in pterosaurs. And no, I do not accept that the article contradicts it. The article discusses what happens in pterosaurs. The blog post tries to explain how you'd turn a human into a pterosaur to better visualise what the arms and hands are doing.

    The fossils still contradict you, and as Oudenoida points out (and I did in a comment that you have still not published despite containing no insults whatsoever) that you are confusing the analogy for reality (as it appears I may have done), and furthermore that both the fossils and the trackways demonstrate that the wing finger is not the index finger.

    We seem to have missed something...

    "What role do you want for those tiny little fingers?"

    They used them for climbing and walking. As demonstrated by the trackways.

    ReplyDelete
  188. "Oudenoida, you are saying it was palms up.
    If it is palms up, then the leading edge would not be the first metacarpal.

    But the article that I quoted from AND THAT YOU AGREED WITH said that "The first metacarpal forms the leading edge".

    Of course I agree with it,because it represents the ACTUAL STATE of fossils as we see them. This is the point you keep avoiding: that FOSSILS show the wing metacarpal on the ULNAR side of the carpus, and the other metacarpals anteriorly to it.
    The reason that all other metacarpals lie anteriorly to it is because they are much smaller, and supported by the bulk of the fourth metacarpal posteriorly. The original stage in the formation of the wing had an elongated 4th finger with the forearm in pronation: as the wing became larger, the distal part of the forearm supinated and helped in flexing of the fingers on the plane of the wing, facilitating grasping.

    Bennet has made an extensive study of the myology of pterosaurs, a study that I'm sure you were pointed to.

    https://docs.google.com/viewer?a=v&q=cache:fR6WhxtE5r4J:bigcat.fhsu.edu/biology/cbennett/flotsam/Bennett-2008-forelimb-myology.pdf+&hl=en&pid=bl&srcid=ADGEESic8vISDFjEDswx-YNqt31Dzp_8SsEY5zteeUzy3dIHQbnkb0iblpfv-HeSOrG9RyIsI_dng8U92OXSx0kZtjcHwF9VgJY7RaHY3KiNn82kHnTK0fgSDi9hMSqaWjQjg0tTXlPq&sig=AHIEtbSwrUsrRo4QjxxKuTrXGsEyKimYDg

    Notice how the first metacarpals lie anteriorly to the much thicker fourth one, even though the forearm is supinated.

    As for your opinion, it requires the second "wing" metacarpal to form the leading edge (remember that you consider the preaxial carpal the first metacarpal- another impossibility), and the other metacarpals lying dorsally or posterodorsally to it (fully pronate your forearm and see where the other fingers point to). Which is completely at odds with the fossils, unless you propose a major (dare I say "magical"? ;))reconficuration of carpals, metacarpals and fingers on the wing.

    And of course, you would still have all the problems with using the fingers, either for grasping and clinging to branches, or walking according to the way seen on trackways.

    Any way you look at it you lose.

    ReplyDelete
  189. "As for your opinion, it requires the second "wing" metacarpal [index finger] to form the leading edge"

    Just as the article says:
    "The first metacarpal [index finger] forms the leading edge".

    I do not know why we are discussing this. The article is crystal clear.

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  190. "Yes I accept the "palms up model". It is an analogy."

    Our arm bones are the same as the pterosaur. We can visualize the pterosaur wing formation by seeing how our bones work.

    And the most parsimonious formation is palms down with the membrane extending from the index finger.

    And that is consistent with the article you referenced:
    "The first metacarpal [index finger] forms the leading edge".


    There is NO published article supporting the palms up idea. If there is such a reference please present it.
    And please - no more excuses like:
    "Sadly you may well find that the work has been done long ago and is not available on the internet."

    That ranks up there with "My dog ate my homework".

    ReplyDelete
  191. Let me try again:

    THE WING METACARPAL IS NOT THE LEADING EDGE.

    The paper says that the leading edge is formed by the FIRST metacarpal, which is NOT the wing metacarpal in the description.

    Your opinion needs the index finger to be the WING finger.

    The paper says nothing of the sort. editing [index finger] doesn't help.

    ReplyDelete
  192. All people have to do is lay down on the floor and stretch out your arms. There is the model for the pterosaur wings.

    It is strange that people prefer some convoluted abnormal UNIQUE configuration of the arms when the answer is so straightforward.

    UNIQUE meaning that this is not seen elsewhere in Nature.

    All your complications are based on misinterpreting and mislabeling disarticulated bones.

    But as usual you folks will argue this till the cows come home.

    ReplyDelete
  193. Oudenoida said...
    Let me try again:
    THE WING METACARPAL IS NOT THE LEADING EDGE.
    The paper says that the leading edge is formed by the FIRST metacarpal, which is NOT the wing metacarpal in the description.
    Your opinion needs the index finger to be the WING finger.
    The paper says nothing of the sort. editing [index finger] doesn't help.

    We are really having trouble on this.
    I suspect it is because we are not visualizing the same thing.

    But you are so obnoxious that I am not interested in trying to come to an understanding.
    I will not be responding to you from this point.

    ReplyDelete
  194. "The first metacarpal [thumb] forms the leading edge".

    I realized that the consensus thinking is that the 3 little fingers are the thumb, index and middle fingers.

    So when the article* says that
    "The first metacarpal forms the leading edge"
    they mean that the thumb forms the leading edge.

    The thumb can form the leading edge only if the palms are down.



    * Page 26
    http://books.google.co.uk/books?id=idta6AVV-tIC&pg=PA26&lpg=PA26&dq=pterosaur+palm&source=bl&ots=2FVT5U7cKs&sig=UypWm265M2Eta4iCsTiwLD8pJJc&hl=en&ei=kZiyTrXJAZSU8gO-sJjsBA&sa=X&oi=book_result&ct=result&resnum=2&ved=0CCUQ6AEwAQ#v=onepage&q=pterosaur%20palm&f=false

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  195. I have said that:
    There is NO published article supporting the palms up idea. If there is such a reference please present it.

    I see some informal speculations including the blogger but no published peer-reviewed article.
    And in the article I referenced above we see the palms down idea.

    With palms down, people can still claim that the wing finger is the finger furthest from the thumb. It would be the trailing finger.

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  196. No, we don't see the "palms down" idea in that reference. It describes the blogger's "palms up" analogy. The blogger is explaining what it looks like when you are a human and your arms are raised forwards in the direction that your spine points in. In pterosaurs the palms face in the direction of flight, as I have already tried to explain this is better described as being a "palms forward" model, where the first metacarpal is at the front.

    The article describes what is actually going on in pterosaurs. That is your peer-reviewed reference. Furthermore the articulated specimens bear this out. Specimens you should be examining if you want to be taken seriously.

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  197. Posters here think that this is a discussion group for them to express whatever unpleasantness they wish. I assure you it is not.
    It is a serious analysis of a novel idea - that pterosaurs are the ancestors of modern birds.
    If people just want to argue, there are other forums for that. Feel free to vent your spleen there.

    Since nobody has any reference for the thumbs up idea we can leave it till someone supplies a published peer-reviewed reference.

    Now I will go back to the mainline discussion of pterosaurs to modern birds.

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  198. A Nonny Mouse, describing these things in words gets confusing.
    Let's start with a person lying on the floor with their arms stretched out, with palms down.
    I am proposing that is the flight arrangement for pterosaurs.
    It is also the form of airplane wings in relation to the body of the plane.

    In this arrangement the hand slices through the air with the thumb on the leading edge.

    Is this the arrangement you see for the pterosaur?
    If not, how would you describe it using our person lying on the floor.

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  199. I am starting to wonder if part of the problem here is that the wing is positioned differently at different points in time in the flapping motion.
    At one point the palm could be facing forward and at other times facing downward.

    I cannot see how at any time it would be facing upward.

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  200. I cannot see how at any time it would be facing upward.

    That would be like an airplane with its wings upside down.

    ReplyDelete