Tuesday, September 6, 2011

Pterosaur Bird Correspondences (1)

http://www.pnas.org/content/98/10/5393.full.pdf

"Over the course of Cenozoic diversification,
other birds did assume modes of life similar to those
vacated by pterosaurs: skimmers may roughly correspond to
Tropeognathus with its keeled jaws, swallows and swifts to
Pterodactylus with its similar size and wing proportions, flamingos
to Pterodaustro with its bristling array of fringe-like teeth, and
perhaps even condors to the enormous Quetzlcoatlus".

123 comments:

  1. Isn't your hypothesis that pterosaurs first became dromaeosaurs that became birds? If so, it's the corresponding dromaeosaurs to the giant Quetzlcoatlus, Tropeognathus with its keeled jaws, etc. you should be looking at.

    Otherwise, you are claiming that these pterosaurs lost these similarities as dromaeosaurs only to regain them again as birds. That isn't parsimonious at all.

    TBH, your hypothesis doesn't seem well thought through at all.

    ReplyDelete
  2. Actually it is well thought through.
    What specific criticism do you have?
    Please support your assertion with details that:
    "these pterosaurs lost these similarities as dromaeosaurs only to regain them again as birds."

    ReplyDelete
  3. Apologies, I hadn't read the link itself. Jablonski was talking about niches being exploited after mass extinctions, not birds being descended from pterosaurs.

    So, there's no need to explain how a Quetzlcoatus would become a Velociraptor on the way to becoming a condor.

    ReplyDelete
  4. You are right in noting that the Jablonski article is itself not on the topic of birds being descended from pterosaurs.
    But he has supported that idea, by what he said. That was my point.
    I thought everyone realized that.
    But if you missed that, then perhaps others did as well, so it is good to clarify.

    But your question is still an interesting one and if you would like to support your point, please feel free to do so.

    ReplyDelete
  5. Quetzlcoatus (Pterosaur)
    http://upload.wikimedia.org/wikipedia/commons/thumb/4/42/Quetzalcoatlus07.jpg/220px-Quetzalcoatlus07.jpg

    Dromaeosaur (Primitive Bird)
    http://upload.wikimedia.org/wikipedia/commons/thumb/c/cd/Velociraptor_dinoguy2.jpg/220px-Velociraptor_dinoguy2.jpg

    Condor (Modern Bird)
    http://upload.wikimedia.org/wikipedia/commons/thumb/3/33/Colca-condor-c03.jpg/250px-Colca-condor-c03.jpg

    ReplyDelete
  6. Pterosaurs and dromaeosaurs don't look anything like each other. So you have to lose all the features of Quetzalcoatlus that are supposedly shared between them and condors in the dromaeosaurs, and then regain them. Furthermore there are very few features that Azdarchids and condors share- Azdarchids are much more like ground living storks. Nor have any pterosaurs converged on a skimming lifestyle- their beaks are utterly unsuited for this (Darren Naish and Mark Witton have written extensively on this).

    ReplyDelete
  7. "So you have to lose all the features of Quetzalcoatlus that are supposedly shared between them and condors in the dromaeosaurs, and then regain them."

    Could you give some examples of those features please.
    Also could you give the Naish and Witton links you are referring to please?

    ReplyDelete
  8. While we are at it, could you please tell us which dinosaur type (non-maniraptor coelurosaur) you are proposing that birds evolved from.
    That way we will be able to make a comparison with what I am proposing.

    ReplyDelete
  9. I am afraid that we may never get answers from Anonymous to these questions.
    Which is a shame.

    ReplyDelete
  10. A reference to start with is the first hit from googling "Naish Witton":

    Witton MP, Naish D (2008) A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology. PLoS ONE 3(5).

    If you look at Witton's Flickr stream, or search Tetrapod Zoology for "pterosaurs" you should find much more information about this. Information you have been pointed at before.

    And I don't actually know what features Quetzalcoatlus and Condors share. The ones Jablonski lists I expect. They are presumably to do with supposed adaptations to soaring. They have no other adaptations to obligate scavenging- the neck is long, but inflexible, the long, and relatively weak jaws don't have hooked tips. Dromaeosaurs don't have any of these characteristics either- they're clearly not soarers of any kind. And if you're going from Azdarchids to Dromaeosaurs to Condors there's the re-aquisition of wrist bones, the loss of fingers, and indeed the whole flight apparatus, the convergent evolution of feathers between them and "true" dinosaurs, and all the other skeletal features that are lost or modified in pterosaurs, but would appear to be identical between dromaeosaurs and "real" dinosaurs.

    ReplyDelete
  11. Anonymous posted:
    "And I don't actually know what features Quetzalcoatlus and Condors share. The ones Jablonski lists I expect."

    If you don't know what you are talking about then why would I take you seriously?
    I am coming to the conclusion that you know nothing about this topic that I have researched and posted about.
    When you have something to contribute please come back.

    And if you do come back please provide links to support what you are saying.

    If anyone else would like to tell us which dinosaur type (non-maniraptor coelurosaur) you are proposing that birds evolved from, then please tell us.

    ReplyDelete
  12. You're the one claiming- via approvingly citing Jablonski- that there are features that link condors and Quetzalcoatlus. As I stated, the only ones I am aware of are associated with soaring behaviour. Not having read Jablonski's article I do not know which features he regards as being important. Perhaps you would care to enlighten us as to what they are?

    ReplyDelete
  13. I referenced Jablonski's article because he refers to the similarities between pterosaurs and birds. I also noticed those similarities.

    But it is obvious that birds are like pterosaurs.
    This whole site has been on that topic.

    If you want to make a point then make your point, support it with a link and quote the part of the reference you think is relevant. That is how I have built my argument post by post for over a year.

    I am not wasting my time in games with people who do not know this topic and are not able to support their opinions with links.

    ReplyDelete
  14. "I am not wasting my time in games with people who do not know this topic and are not able to support their opinions with links."

    That statement is uncalled for. It is clear from the above discussion that the guy did support his argument with links and that he is more well read on the subject than you are. You seem to have a habit of attempting to belittle anyone that questions you when you have no arguments.

    ReplyDelete
  15. He did not give links.
    And he is not better read on this subject than I am.
    Do you have something to contribute?
    How about this:
    While we are at it, could you please tell us which dinosaur type (non-maniraptor coelurosaur) you are proposing that birds evolved from.
    That way we will be able to make a comparison with what I am proposing.

    ReplyDelete
  16. "He did not give links"

    What then is this?

    Witton MP, Naish D (2008) A Reappraisal of Azhdarchid Pterosaur Functional Morphology and Paleoecology. PLoS ONE 3(5).

    His first post cited it

    "And he is not better read on this subject than I am."

    So you seem to flatter yourself but the evidence suggest you are not well read at all

    ReplyDelete
  17. Links is plural.
    And links have the form
    www.xxxxx.com.

    Also I have asked that when people provide a link they copy and paste the part they feel is relevant.

    Can you contribute anything constructive yourself on this subject or will you just carp from the sidelines.
    I have posted over 200 posts stemming back over a year.
    When you contribute I will be interested.

    ReplyDelete
  18. The entire paper is relevant Mr Pterosaur. Read the whole thing.

    ReplyDelete
  19. That is a copout. I used to waste time on wild goose chases where people gave me a link to an article and did not indicate what was relevant.
    If you feel something is relevant then it should be easy for you to copy and paste it.

    You are still carping from the sidelines.
    What constructive thing do you have to contribute?

    ReplyDelete
  20. For those following this, I have requested LINKS not just references.
    And I have asked for you to copy what you feel is the relevant part.

    That is the format of most of my posts.
    I back up what I say.
    I expect the same from those who wish to object.

    ReplyDelete
  21. I have had real difficulty commenting on this blog. having had no indication that my submitted comments have been successfully sent, and when they have I find that two thirds of the comment is missing. I do not know if this is associated with directly embedding link or not, so I'm avoiding doing so, and writing the full title of the paper. Its not my fault that Wordpress is acting up, or that you're unwilling to C&P the title into google.

    "You're the one claiming- via approvingly citing Jablonski- that there are features that link condors and Quetzalcoatlus. As I stated, the only ones I am aware of are associated with soaring behaviour. Not having read Jablonski's article I do not know which features he regards as being important. Perhaps you would care to enlighten us as to what they are?

    Witton and Naish's article certainly shows no similarities other than adaptations to soaring flight. So there is little reason to think that the two shared similar ecologies. Perhaps you have important evidence to the contrary?

    I am proposing- as does everyone else- that maniraptorans shared a common ancestor with the non-maniraptoran coelurosaurs. So far there are no candidates for a last common ancestor for this because most of the species we have good specimens of lived too late to be that ancestor, or are too derived. This is a common problem in palaeontology, as you would know if you had researched this topic. However Ornitholestes is a pretty good candidate for what such an animal would have been like. As you should know from the various times it has been mentioned at Talk Rational. Coelurus is often mentioned as being the same as Ornitholestes- but this seems to be closer to the tyrannosauroids. Which is exactly what one would expect when looking at the early diversification of coelurosaurians into the tyrannosauroids and the maniraptorans.

    Your references are Senter's other papers on coelurosaurian phylogenetics. The ones that don't use baraminology, but actually look at the distribution of shared derived characters. The ones that you've been told about, and had cited to you many times before.

    You can start here:

    A new look at the phylogeny of coelurosauria (Dinosauria: Theropoda), Phil Senter, Journal of Systematic Palaeontology; Vol. 5, Iss. 4, 2010

    For some reason it won't allow the link. The DOI is: 10.1017/S1477201907002143"

    Its not hard to enter a DOI or a paper title into google. This will take you to exactly the paper I'm talking about. More importantly it can lead you to other work that cites this, and gives you more information. Nor is it difficult to search for the two authors and bring up the numerous blog posts and further discussions of the paper that were centred around it. More importantly the entire paper is freely available, and the whole thing is relevant to the comparison between Azdarchids and vultures. The same thing goes for Senter's analysis of Coelurosauria. That huge data matrix. The description of every character state, it is all relevant and important. Surprisingly enough I'm not going to reprint it in a comment to a blog. If only because of copyright violations and space.

    Additionally, why should I provide a link to the paper you specifically discuss in the blog? Especially when I'm asking you a question about what he says?

    As for your level of understanding, well, I guarantee I own and have read more books and papers on palaeontology, cladistics, stratigraphy, anatomy, evolution, basic alpha taxonomy and species descriptions. I've seen and prepared more fossils than you ever have (I'm not convinced you've even seen a real pterosaur bone in the flesh as it were), and attended conferences and met more palaeontologists than you ever will.

    ReplyDelete
  22. Anonymous I appreciate your persistence in posting this after the original difficulties. It looked to me like the blogspot system itself was having problems that day and I myself was not able to post.

    I will respond to your comment shortly.

    ReplyDelete
  23. Let me begin with this point. You have said:

    "I am proposing- as does everyone else- that maniraptorans shared a common ancestor with the non-maniraptoran coelurosaurs."

    What is that common ancestor? What species is it? What genus?

    We can move ahead on solid ground once you provide that information.

    ReplyDelete
  24. The reason I ask for the common ancestor - species and/or genus - is that then we can compare that lineage with the pterosaur/lineage I have proposed.
    Otherwise we have no common ground for a discussion.

    ReplyDelete
  25. Just as a sidenote, I need to remind people that I have presented two significant ideas. One is that pterosaurs developed into primitive birds (eg. into maniraptors).
    And the other is that specific primitive bird categories developed, in a series of parallel lines, into the specific categories of birds we see today.

    I also believe that specific the advanced pterosaur categories developed into specific dromaeosaurid etc categories again through parallel lines.

    But I have not spelled that part out yet.
    That is more slugging kind of work to do.

    ReplyDelete
  26. Anonymous said...
    You already know what the answer to that is.I wrote it in the very next sentence.

    "So far there are no candidates for a last common ancestor for this because most of the species we have good specimens of lived too late to be that ancestor, or are too derived."

    No single species can be identified as such. we can say (roughly- depending on what some enigmatic early Jurassic fossils turn out to be) when it lived. We can hazard a guess as to what it probably looked like (Ornitholestes, or at least something like it), but as you well know you cannot make definitive statements about ancestor/descendant relationships based on very small sample numbers known from localities widely separated in both time and space. If you have some way of doing so why aren't you writing this up for publication as we speak. I guarantee you'll be hailed as a genius by the paleontological community.

    Now, how about engaging with the rest of what I wrote. Most of which has nothing to do about our inability to identify isolated bits of bone as being directly ancestral to any other isolated bit of bone.

    ReplyDelete
  27. Anonymous you posted:
    "No single species can be identified as such".

    Okay what was the genus?

    ReplyDelete
  28. You don't need to compare direct ancestor-descendant relationships. You don't need us to say X evolved into Y. We are saying that X is the closest relative to Y. That's enough. In fact we can take what you say about pterosaurs evolving into dromaeosaurs and rephrase it to talk about sister groups (to reflect the uncertainty that we must have about such relationships- as we have not yet seen your groundbreaking paper that I await with bated breath). You are saying that specific pterosaurs are closer relatives to specific dromaeosaurs than other dromaeosaurs are, and that these then gave rise to specific bird groups. Which means that some pterosaurs are closer to some birds than birds are to each other.

    You don't need to say that Quetzalcoatlus is ancestral to a condor. Merely that it is the sister taxon to it (and presumably other vultures).

    We had the discussion about sister taxa with zero branch lengths on TalkRational a year or so ago. You would do well to revisit the thread and re-read some of the responses you got then.

    ReplyDelete
  29. Which part of "there are no candidates for a last common ancestor" are you having trouble with?

    ReplyDelete
  30. For those following this please note:
    "No single species can be identified as such. we can say (roughly- depending on what some enigmatic early Jurassic fossils turn out to be) when it lived. We can hazard a guess as to what it probably looked like..."

    This what the dino to bird folks have - they "hazard a guess".

    Here is also the unmentioned part:
    The so-called "sister taxa" are determined on the basis of the hazarded guess. Not on the basis of evidence.
    In other words the whole thing is a house of cards.

    This gets us into the whole problem with cladistics.

    ReplyDelete
  31. No the "sister taxa" are not determined on the basis of the "hazarded guess". They are determined through scoring large numbers of species for huge numbers of characters and creating a data matrix. A computer program reconstructs the tree and tells you what the sister taxa are. You don't know beforehand what they are.

    The "hazarded guess" comes in when you want to reconstruct what the last common ancestor of two taxa would have looked like, i.e. what characters it may have posessed, when it may have lived, etc. Identification of sister taxa comes first. Not the characters expected of an ancestor we do not have, and are incapable of identifying as such (or at least will be until your amazing paper that tells us how to do this appears).

    What this in fact gets us into is your complete misunderstanding of how cladistics operates.

    ReplyDelete
  32. Evolutionary systematics is more scientific and credible than cladistics.

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

    ReplyDelete
  33. Anonymous posted...
    "Which part of "there are no candidates for a last common ancestor" are you having trouble with?"


    This phrase "What part of X are you having trouble with" is just an insult and does not move the discussion forward.

    ReplyDelete
  34. Anonymous:
    "You don't need to compare direct ancestor-descendant relationships. You don't need us to say X evolved into Y. We are saying that X is the closest relative to Y. That's enough."

    In fact that is not enough.
    Tell you what.
    Since cladistics is not helpful in the fundamental area of ancestor/descendant relationships and there are alternatives such as evolutionary systematics, then let's just look at this not from the point of view of cladistics.

    I do not need to agree to a method such as cladistics. Let's analyze it in a more fundamental way.

    ReplyDelete
  35. Not when the following is true:

    "Cladistics collects character data only from the taxa being classified. It does not consider the inferred characters of ancestors."

    So Evolutionary Taxonomy makes claims about what the characters present in ancestors (that are unknown) are like. Cladistics does not. If anything Evolutionary Systematics is the one "hazarding a guess", not Cladistics.

    "Cladistics involves collecting data and feeding it into a computer program. Evolutionary systematics involves a researcher following flexible guidelines which consider various kinds of evidence (which need not be represented as discrete alternatives)."

    So there is far more room for personal interpretation and bias. This does not make it more scientific at all. It allows you to say that character X is far more important than any other character- whereas cladistics weights each character equally, and removes this bias. There is a reason that cladistics is the dominant methodology these days.

    ReplyDelete
  36. For those following this, what Anonymous and I are discussing is very important.
    If a proposed lineage is valid it should show itself as valid, without having to use one particular method such as cladistics.

    ReplyDelete
  37. "This phrase "What part of "there are no candidates for a last common ancestor" are you having trouble with" is just an insult and does not move the discussion forward."

    You seemed to think that because I couldn't name a species I should name a genus. When in fact that sentence indicates I can't name either.

    And evolutionary systematics doesn't identify ancestor-descendant relationships either (at least not until your eagerly awaited revolutionary paper outlining your methodology). It just allows you to have paraphyletic groups. That's it. It becomes a naming convention and nothing more. I just told you that you can apply cladistic terminology to your ideas. Change the word "ancestor" to "sister taxa" and it doesn't change the fact that you're claiming that vultures are closer to Querzalcoatlus than they are to any other bird (for example).

    Does this make sense?

    ReplyDelete
  38. "If a proposed lineage is valid it should show itself as valid, without having to use one particular method such as cladistics."

    Nobody using evolutionary systematics ever claimed birds were closer to pterosaurs than they were to dinosaurs.

    ReplyDelete
  39. Anonymous is not familiar with Evolutionary Systematics and has copy and pasted a tiny part from the wiki reference. There is much more to it than that.

    This is a fascinating discussion for me (it really is) but at this point I would like to make progress.
    My basic point is that we can and should analyze the lineage proposals not based on one particular method such as cladistics.

    Notice that those who promote the dino to bird theory expect those who disagree with that theory to agree to using cladistics.

    ReplyDelete
  40. Anonymous:
    "Does this make sense"?

    My point is that I do not have to evaluate the method that you prefer.
    We can just agree to use some method that we both agree on.
    Are you in the position of saying that the dino to bird theory only stands up if we all agree to use cladistics?
    That means that in order to evaluate different bird evolution alternatives, we have to agree to use a particular method that you demand we use?

    Does that make sense? It does not make sense to me.

    ReplyDelete
  41. Anonymous said...
    "If a proposed lineage is valid it should show itself as valid, without having to use one particular method such as cladistics."
    Nobody using evolutionary systematics ever claimed birds were closer to pterosaurs than they were to dinosaurs."

    That very confident assertion is actually false.
    See:
    http://pterosaurnet.blogspot.com/2010/05/harry-govier-seeley.html
    People can learn a lot if they read the posts in this blog.


    I expect this will de-rail the discussion, but I could hardly allow a false statement to go unchallenged.

    ReplyDelete
  42. Anonymous will try to justify himself by pointing out that after Seeley claimed that pterosaurs were the ancestors of birds, that "under intense criticism from his peers", he recanted.
    My point is that somebody (Seeley) "using evolutionary systematics claimed birds were closer to pterosaurs than they were to dinosaurs."

    That he was forced "under intense criticism from his peers" to toe the party line, only shows that nothing has changed.

    The idea that birds evolved from pterosaurs is a very threatening idea and anyone proposing that heresy can expect a great deal of personal attack. Including attacks on their family.

    I will not let this de-rail the more interesting and constructive discussion we have been having.

    ReplyDelete
  43. I am no longer going to reply to this blog as I cannot get it to accept comments. I will say this. Read a book on cladistics. Perhaps this one:

    http://books.google.com/books?id=F4JvBaeAj_oC&pg=PR9&source=gbs_selected_pages&cad=3#v=onepage&q&f=false

    ReplyDelete
  44. It is a shame that Anonymous will not be continuing.

    ReplyDelete
  45. You can find me on TalkRational. You already have.

    ReplyDelete
  46. It seems like Anonymous' comments are getting through.
    And I am not having problems.

    ReplyDelete
  47. OK, one last try. Long comments don't seem to get through, and anything with HTML has problems. (So no links I'm afraid).

    You claim that Seeley changed his mind after "intense criticism from his peers". What was the nature of this criticism? Was it perhaps pointing out the significant anatomical differences between the two groups. And its worth mentioning that Seeley had abandoned his ideas by 1901- they have not been seriously revised, and we know vastly more about dinosaurs and pterosaurs nowadays (for instance dromaeosaurs were completely unknown at the time he was writing).

    I quoted the small part of the wiki article because its the bit dealing with the differences between evolutionary systematics and cladistics. The historical background is irrelevant. I don't need to mention Willi Hennig each time I talk about cladistics for much the same reason.

    Plenty of people before cladistics came into common use used evolutionary systematics and found that birds grouped with dinosaurs- in fact many found birds grouped within dinosaurs- and many of these people were intensely opposed to cladistics. (Alan Charig is a good example).

    You are claiming that your ideas are more parsimonious. However cladistics runs on parsimony. Part and parcel of cladistics is to look for the tree with the fewest changes in character state. If your ideas are so parsimonious then why do cladistic analyses never find that birds group within pterosaurs, that individual families of birds are closer to one group of "primitive birds" than another, and that Coelurosauria is polyphyletic? If your idea is correct, surely multiple methodologies should support it? Why don't they?

    The use of computers allows you to evaluate thousands of characters without claiming one as being more important than any other. Modern cladistic papers use thousands of characters and hundreds of taxa. This is why I expect you to agree to using computer programs to evaluate huge data sets. We can argue about whether to name paraphyletic groups to exist or not. But that isn't important. If your theory is correct then cladistics would require you to include birds and maniraptorans within pterosaurs in order for pterosaurs to be monophyletic. If you want to use evolutionary systematics terminology pterosaurs can be paraphyletic with respect to that group.

    But you still need to show that it is more parsimonious for maniraptorans to be closer to pterosaurs than to any other dinosaurs. And you have continually failed to do so. You're looking at single characters, you're making no attempt to test for convergence. You're assuming all the detailed anatomical characters that link maniraptorans to coelurosaurs (and all other dinosaurs) are convergent- and yet there are far more of these (as all the various phylogenies have shown- Sterling Nesbitt's massive archosaur phylogeny, Senter's Coelurosauria paper, and so on) than link pterosaurs and maniraptorans.

    Why is this if maniraptorans are so closely related to pterosaurs? It just doesn't make sense.

    ReplyDelete
  48. You said that nobody NOBODY ever claimed that pterosaurs were the ancestors of birds.
    That is False.
    Seeley did. I already spelled out the justification you would make for your incorrect statement.
    Why not just say - okay one guy did.
    If you cannot be honest about a small thing like that then you will be dishonest in larger things.
    And I am not interested in wasting my time on someone who is dishonest and will post dishonest tricks that I will waste my time catching.

    I am very familiar with this pattern.

    You can leave if you wish. Or you can man up to it and settle in for an honest discussion.
    Your call.

    ReplyDelete
  49. For those following this (if anyone is) please notice that Anonymous is still trying to persuade me to accept cladistics.
    That I will not be doing.
    If the dino to bird theory requires one particular method (cladistics) to justify it then just say so.

    ReplyDelete
  50. I don't expect to see Anonymous here again so I will make a few points.
    Let's take a look at this issue:
    "So there is far more room for personal interpretation and bias [in evolutionary systematics]. This does not make it more scientific at all. It allows you to say that character X is far more important than any other character- whereas cladistics weights each character equally, and removes this bias".
    and
    "The use of computers allows you to evaluate thousands of characters without claiming one as being more important than any other."

    When cladistics "weights each character equally," that is a subjective approach. The subjective approach is that each character is considered equal when obviously they are not.
    So the first point I am making is that cladistics is not objective and unbiased.
    The second point is that it is absurd to weight them equally.
    Nobody can actually justify that idea, except by saying that it is a simple rule that a computer can implement. In the real world of actual creatures it is an absurd idea.

    ReplyDelete
  51. For those who have followed the entries on this blog you will see that I have in fact used evolutionary systematics type thinking in the transition from primitive birds to modern birds*. (See Dec 17, 2010 entry).
    It would not even be possible for me to express the primitive bird to modern bird relationships that I have proposed if I was limited by the contrivances of cladistics.

    ReplyDelete
  52. Anonymous posted:
    "Plenty of people before cladistics came into common use used evolutionary systematics and found that birds grouped with dinosaurs- in fact many found birds grouped within dinosaurs- and many of these people were intensely opposed to cladistics. (Alan Charig is a good example)."

    If that is the case, then we can use a method other than cladistics to evaluate the alternatives.
    That is what I am suggesting.
    In fact we can use evolutionary systematics.

    ReplyDelete
  53. Here is perhaps the biggest question of all.
    Has any researcher ever done an evolutionary systematic analysis or a cladistic analysis including pterosaurs and maniraptors?

    I think not. If anyone has a link to one, I would be very interested.

    So we see the problem - the idea I have been proposing has never actually been analyzed.
    It is absurd for people to rule it out when it has never actually been analyzed.
    That is why I get such a laugh out of people who are so adamant that the dino to bird theory is better.

    ReplyDelete
  54. As I have already mentioned the Dino-Bird theory does not require cladistics. But if it is wrong why do both cladistics and phenetics (evolutionary taxonomy) find the link to be very strong?

    Yes one guy did. And he changed his mind because he was shown to be wrong. This happens all the time.

    It is even more subjective to weight characters unequally. How do you know that a character is more important in terms of relationship than another before you do the analysis? Everyone thinks that milk evolved in mammals and unifies them all to the exclusion of all other groups. You could weight this very heavily. But if mammals are not a natural group you'll find that you'll be masking the real pattern. How do you account for one researcher using one character and another researcher using another? Weight the two characters equally in the analysis and it will give you an indication of which characters are more significant. As another example, you have claimed that "crests" are a significant character uniting birds and pterosaurs. But the crests in the two groups are not the same structure. In most birds they're made of feathers. In pterosaurs they're made of bone. They are not the same character. Therefore that character cannot be used to examine relationships. Some birds do have bony crests. Perhaps these particular crests are evidence of a relationship. But plenty of dinosaurs also have bony crests. So even without plugging it into a cladistic analysis this character is too widely distributed to be helpful.

    Character choice is also extremely important. The best characters are ones that are not strongly correlated with ecology. Whales, mosasaurs, seals, plesiosaurs and ichthyosaurs all have hands modified into flippers. But they're also all dedicated aquatic organisms, so we should expect this to happen if they aren't closely related because they're all adapted to the same environment. So ideally you should look for characters that don't depend on ecology- features of the skull for instance. And in that case we find that whales and seals have more in common with each other than either do with the other taxa, and when we add in non-aquatic organisms we see that mosasaurs group with lizards, plesiosaurs and ichthyosaurs are quite closely related, and mammals and seals end up in quite different parts of the mammalian tree. All because of characters that aren't dependant on ecology. You can continue to claim that the groups are all related to the exclusion of others, but you'll be arguing from a completely unparsimonious position.

    ReplyDelete
  55. You are wrong that you could not phrase your hypothesis using cladistics. I've already told you how. Until you publish your paper telling us how to recognise ancestor-descendant relationships on the basis of partial remains separated by millions of years, all scientists would be willing to say is that Quetz is the sister taxon to an un-named dromaeosaur, which is the sister-taxon to a condor. Because of how cladograms are drawn they will appear on separate branches even if they're ancestral to each other. But if that's what the cladogram shows, then it is perfectly compatible with your idea. Of course this would mean that Dromaeosauridae are polyphyletic- some dromaeosaurs are closer to some pterosaurs than they are to other dromaeosaurs. Similarly Aves is also polyphyletic. Some birds are closer to some pterosaurs than they are to other birds. Neither evolutionary systematics nor cladistics has any truck with polyphyletic groups. So under your scheme neither birds nor dromaeosaurs are a natural group, both having evolved from ancestors which are not themselves birds or dromaeosaurs, but pterosaurs.

    If you want to use evolutionary systematics terminology then that is your perogative. But you'll find it very hard to find anyone using as few characters as the evolutionary systematists did these days.

    Pterosaurs and maniraptorans have been used in the same cladistic analyses. Sterling Nesbitt used Velociraptor and a couple of pterosaurs in his analysis of early archosaurs. Velociraptor goes with all the other dinosaurs. Pterosaurs don't. Its here and freely available. 80 taxa, 412 characters, in an astonishing level of detail:

    http://digitallibrary.amnh.org/dspace/handle/2246/6112

    Wilson and Sereno did something similar with fewer taxa and characters in 1998. They didn't group pterosaurs and maniraptorans together either.

    And even with just coelurosaurs, if maniraptorans do not belong in that group then they should not turn up nested deeply within them. They should end up outside the group. And yet they don't. So that's another point you're wrong on.

    ReplyDelete
  56. "Yes one guy did. And he changed his mind because he was shown to be wrong."

    I see you are still trying to spin the Seeley case. You have no idea why he publicly recanted.
    I said I would not be sidetracked by this and yet that is what you are doing.
    Even though there is much of interest in your posts I am not interested in discussion with someone who spins whatever we are talking about. That is the exact pattern I was talking about and I am not wasting time on someone like that.
    I have begun researching another interesting area and have no time for you and your spin.

    ReplyDelete
  57. For those others here (if there are any) please note this:
    "Because of how cladograms are drawn they [ancestors] will appear on separate branches even if they're ancestral to each other."

    This is exactly one of the problems with cladistics that I have been talking about.

    ReplyDelete
  58. Cladistics is so misconceived that you cannot even conceive or present the ideas I show in the Dec 17, 2010 post.
    There is no way that what I am proposing there could even be drawn in a cladogram. If someone thinks it could be, then please show us.

    ReplyDelete
  59. There's no "spin" involved in the Seeley case. He published an idea. Then he found more data, and he changed his mind. You have no idea either why he did so- or you would be able to point to more information about why he changed his mind- quoting the exact "criticism" for example, pointing to what Seeley himself wrote when he changed his mind, rather than repeating the same quote. Anyway, it is indeed a side issue. I see no need to pursue this any further.

    Its not a problem with cladistics. Its the recognition of the fact that we cannot identify an ancestor based on a couple of specimens widely separated in time and space. As you have been told time and time again you don't put taxa at the nodes on a cladogram. Ever. Its a property of the diagram. Please re-read those threads on Talk Rational and attempt to understand them. Cladistics doesn't even have to make claims about whether evolution occurred- you can do it for pottery, pasta and biscuits. These things don't evolve and don't descend from one another but can still be grouped in nested hierarchies according to similarity. That, if anything is a strength of cladistics.

    You've also never suggested what your magic formula for identifying ancestors and descendants in the fossil record is. I'm starting to think you have no such method.

    Now, what about the other criticisms that you haven't yet addressed. Why doesn't Senter find Coelurosauria to be polyphyletic. Why does Nesbitt find Dinosauria to be monophyletic. Why is your idea so much less parsimonious? Why does it fall apart when you look at features that are not intimately associated with an animal's ecology?

    ReplyDelete
  60. Someone already tried.

    http://i936.photobucket.com/albums/ad202/Scrotacus/6a047c97.gif

    Note that the fact that they put names on some of the lines is not important in this case- its supposed to indicate that the taxon on the leaf of that node is a member of a larger. more inclusive group that contains lots of species not listed

    Basically each time you derive a modern bird from a "primitive bird" and then from a dromaeosaur, and then from a pterosaur your cladogram would look like this (fingers crossed the formatting works):

    -+--Pterosaur species
    `-+--Dromaeosaur species
    `-+--Primitive Bird species
    `--Modern Bird species

    Eventually everything links up at the base of the tree, so the last common ancestor of all living "birds" was not a bird, but a pterosaur.

    As a result Droameosauridae is polyphyletic. Its various members are descended from a common ancestor that was not a member of the dromaeosauridae- something expressly forbidden by Evolutionary Systematics and cladistics.

    ReplyDelete
  61. Note in the gif that whoever created it, put the names of taxa ON THE LINES.
    That is not a cladogram.
    Also the

    -+--Pterosaur species
    `-+--Dromaeosaur species
    `-+--Primitive Bird species
    `--Modern Bird species

    does not represent what I am saying.

    ReplyDelete
  62. I explained why the names are on the lines. Its for convenience of illustrating the point that the species at the leaf is a member of a larger and more inclusive group, the other members of which have been removed for convenience's sake (note that none of the names of the individual taxa are on the nodes at any point.)

    The formatting has failed. The cross is supposed to represent the node on a cladogram. The lines are then supposed to branch off at each point. You are stating that a modern bird species is the sister taxon to (and according to you descended from) a "primitive bird" species, which is in turn descended from a dromaeosaur species- this dromaeosaur is the sister to the primitive bird + modern bird clade. That is what I attempted to draw. That you don't realise this, is yet more evidence of your inability to understand cladistics. Something I have witnessed countless times.

    Taking your example from foot propelled birds:
    (the dots are included in order to make the formatting work, as white space is automatically removed, pay no attention to them. The cross represents the node which links the two sister groups.) According to you Baptornis is the sister taxon to the clade that includes Cormorants and Loons. Hesperornis the sister group to Grebes (regardless of whether those particular genera, or a close relative from the same family is the actual ancestor according to you).

    ---+--- Dromaeosaur Species (unnamed by you)
    ....`-+-+----- Baptornis
    ......| `-+-- Cormorants
    ......| `- Loon
    ......`-+----- Hesperornis
    .........`---- Grebe

    ReplyDelete
  63. Anonymous you still cannot break free from the cladistic programming in your mind.
    "Sister taxon" is a cladistic idea.
    I am definitely NOT saying that
    "Baptornis is the sister taxon to the clade that includes Cormorants and Loons."

    There are no clades in what I have presented.
    Think beyond clades and cladistics.
    You cannot understand what I am proposing if your mind is molded and limited by cladistic thinking.
    You are a smart fellow. Give it a try. Think beyond your cladistic programming.


    (I myself had to break down the cladistic programming in my own mind in order to arrive at the pterosaur to bird conception. I know how hard it is to break down that programming.)

    ReplyDelete
  64. Note also that you overlooked the Enantiornithes connection.

    ReplyDelete
  65. You asked me to place them in a cladistic framework, claiming that this wasn't possible. I did what you asked. In a cladogram they are always represented as sister taxa, and would be even if one species is *known* to be ancestral to another, that's how it will appear on the cladogram, and that's how they'll be described. It cannot be any other way as taxa are not placed at the nodes on such a diagram.

    And there are clades in what you are claiming, even if you wish it were otherwise. If you say that loons and cormorants evolved from a species in the Baptornithidae then by the definition of what a monophyletic clade is they must be members of that family, as in order to be monophyletic a clade contains the last common ancestor of two species and *all* its descendants. so a family will contain two distinct orders. Either you allow paraphyletic groups, or you abolish the notion of ranks. Taxonomists have taken the latter position, deciding that having families that will include whole orders is silly.

    Its long been quite clear to me that you don't understand cladistics and are not competent to criticise it. This interaction has been another shining example of this. For instance your whole "pterosaurs to birds" nonsense is completely consistent with cladistic nomenclature if you include birds within pterosaurs. Pterosauria is still monophyletic if it includes birds, maniraptorans and all the other things you think "developed" into the various modern birds (including perhaps bats?). As I said, it becomes a semantic argument.

    Note also that you're the one who left out the enantiornithines as they are not mentioned in the section of your post about the ancestry of loons, grebes and cormorants. You go from dromaeosaurs to hesperornithiforms to grebes, loons and cormorants. You have no mention of any enantiornithines. Presumably the ones that you think are relevant them will slot in as branches between the dromaeosaur and the two families of hesperornithiforms.

    ReplyDelete
  66. This is from the Dec 17, 2010 post:

    "AQUATIC BIRDS (Hesperornithes line)
    A Dromaeosaurid* subgroup -->
    An Enantiornithes aquatic subgroup --> Baptornithidae (Hesperornithes) --> (primarily foot-propelled) WEB FOOT diving bird orders, eg. Cormorants (Phalacrocoracidae), Loons (Gaviidae)).
    AND
    An Enantiornithes aquatic subgroup --> Hesperornithidae (Hesperornithes) --> (primarily foot-propelled) LOBE FOOT diving bird orders eg. Grebes (Podicipedidae)."

    Is this not what you were referring to?

    ReplyDelete
  67. "In a cladogram they are always represented as sister taxa, and would be even if one species is *known* to be ancestral to another, that's how it will appear on the cladogram, and that's how they'll be described."

    This is exactly the problem with cladistics. On the important subject of ancestor/descendant relationships it is always and completely unclear.

    ReplyDelete
  68. "Either you allow paraphyletic groups, .."

    Of course I allow paraphyletic groups. That is part of evolutionary systematics.
    The problem is you do not understand what a paraphyletic group is.

    You have just been programmed with the wrong idea about it, and then programmed to have a negative attitude about it.

    ReplyDelete
  69. Why are you suggesting that Hesperonithiformes is polyphyletic? What evidence do you have that it is? Which "subgroup" of the Enantiornithines are you talking about? Until you name them there is no real point in including them. In fact there are one or two primitive Hesperornithiformes that don't appear to belong to either the Baptornithidae or the Hesperornithidae. So rather than looking like this:

    ---+--- Dromaeosaur Species (unnamed by you)
    ...`+-+-Enantiornithine A
    ....| `-+----- Baptornis
    ....| `-+-- Cormorant
    ....| `- Loon
    ....`-+-Enantiornithine B
    .......`-+----- Hesperornis
    .........`---- Grebe

    But this:

    ---+--- Dromaeosaur Species (unnamed by you)
    ...`-+--Enantiornithine Species (unnamed)
    ......`-+--Enaliornis
    .........`-+-+----- Baptornis
    ...........| `-+-- Cormorants
    ...........| `- Loon
    ...........`-+----- Hesperornis
    ..............`---- Grebe

    And as I have stated time and time again it does not matter that cladistics doesn't identify ancestor descendant relationships. It makes statements about similarity and that leads us to make conclusions about relatedness Evolutionary Taxonomists don't make these kinds of claims either. You have given no indication that you can do any better. What is your methodology? I keep asking, and you keep ignoring me.

    If species A evolves into species B you would expect the two to be more similar to each other than species C. That should be picked up by a cladistic analysis. And yet it never finds the results you want.

    ReplyDelete
  70. I know damn well what a paraphyletic group is you fool. Its a group that contains the last common ancestor of two species but does not include all of its descendants. That's it. That's all it is. I have a negative attitude because its completely arbitrary about what you do and don't put in it. It becomes completely meaningless. Monophyletic groups are far better.

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  71. In fact you do not know what a paraphyletic group actually is. That is the point.
    Calling me a fool does not change that.

    Your cladistic programming limits you and makes you angry at the thought that there is something you do not understand.

    That is why you cannot learn new things - you already think you know.
    And you think that nobody can teach you - especially someone like me who you have such disdain for.

    All this is not a problem for me - it is human nature. You are not unique.

    ReplyDelete
  72. Anonymous posted:
    "Which "subgroup" of the Enantiornithines are you talking about? Until you name them there is no real point in including them"

    Here again we have the pattern - you did not notice that Enantiornithes is in fact in the material I posted.
    You could simply say that you missed it and that would be the end of it. Instead you make up some justification.

    This makes the whole discussion not an attempt to learn anything but an exercise in you tap dancing to show that you are never wrong.

    This is tedious.

    Shortly you will begin swearing.

    ReplyDelete
  73. The only reason I would begin swearing is because of your infuriating attitude. I shall however attempt to restrain myself.

    There is no such thing as "cladistic programming".

    Why am I wrong about what a paraphyletic group is? I have given you the definition as is accepted by every source I have read. What is yours?

    As I said. Enantiornithines is not actually relevant. So I missed that particular group out? So what? You seem to have forgotten that Hesperornithiformes doesn't just contain the two families, but also Enaliornis. Which is not as similar to the Baptornithidae and Hesperornithidae as either are to each other. Until you can be specific as to which enantiornithine you claim is closer to which family in the Hesperornithiformes I see no reason to include them. You're being even less specific about the species that are supposedly ancestors and descendants in your ideas than you claim cladistics is.

    Are all enantiornithines in this "subgroup" or only some of them? If only some of them then "Enantiornithines" is not a natural group, as it contains thing that are not descended from something that was itself an enantiornithine, but in your scheme a dromaeosaur. You therefore cannot use the name "Enantiornithine" whether you are using evolutionary systematic or cladistic terminology. Neither accepts polyphyletic groups. I can ask the same question about the dromaeosaurs too.

    Why are you so reluctant to be specific about these "aquatic enantiornithine subgroups"? Do they even exist outside of your imagination?

    ReplyDelete
  74. Here is a quote from Anonymous (who calls himself Dave Godfrey) about this discussion:

    "In case you were wondering Scrotacles still doesn't understand cladistics, let alone accept it as a valid technique. He's still blathering on about evolutionary systematics as being superior. And is still an arrogant supercilious arsehole with a wordpress site with a seriously shaky commenting system."


    So the swearing has begun as I predicted.
    It is all so dreary

    ReplyDelete
  75. Dave Godfrey it is too late.
    Goodbye.

    ReplyDelete
  76. Dr Pterosaur -

    As a third party following this discussion, I have to say it appears as if you are doing everything in your power to avoid answering difficult questions about your theory.

    ReplyDelete
  77. I disagree.
    What question do you have?

    I have spent a great deal of time on this subject. I am very interested in any serious contribution.

    ReplyDelete
  78. A primer on "paraphyletic".
    Let's look at a completely different lineage for perspective.

    http://en.wikipedia.org/wiki/Pelycosaur
    "Because more advanced groups of synapsids evolved directly from 'pelycosaurs', the term had fallen out of favor among scientists by the 21st century, and is only used informally if at all in the modern scientific literature.[1]"

    "Pelycosauria is a paraphyletic taxon because it excludes the therapsids."

    It "excludes" the therapsids because they evolved directly from Pelycosauria.
    AND THAT IS HOW NATURE WORKS SOMETIMES.

    There is absolutely nothing wrong with being paraphyletic. Cladistics ignores the way Nature actually works.

    ReplyDelete
  79. You just don't get it do you? Pelycosauria is paraphyletic because it arbitrarily excludes some of its descendants. If it included all the descendants then Therapsida would be members of the Pelycosauria too, and Pelycosauria would now become monophyletic. Based on their ancestry there is no reason to exclude Therapsida from Pelycosauria. In the same way as there is no reason to exclude Aves from Pterosauria under your scheme.

    Its a naming convention you're objecting to and nothing more.

    ReplyDelete
  80. "The world is not inhabited exclusively by fools, and when a subject arouses intense interest, as this one has, something other than semantics is usually at stake."

    Stephen Jay Gould (1982)

    ReplyDelete
  81. www.mobot.org/plantscience/resbot/EvSy/Intro.htm
    "Paraphyly is a phylogenetic somewhat disparaging word for what is generally known as ancestors involved in macroevolution, that is, a label for a group from which one or more other groups at the same (or higher) taxonomic rank have apparently evolved. “Para” implies faulty, wrong, amiss, recrementitious, or merely similar to the true form. Evolutionary systematists, however, celebrate that which is presently known as paraphyly.

    ReplyDelete
  82. As I said earlier, since cladistics is just one method we need not base everything on that one method.
    People here will not do the analysis that you need to do to dig deeply into cladistics to see its misconceptions. That is okay - we can simply not use it.

    We do not need cladistics to evaluate the pterosur to bird idea.
    We need not use up our time debating cladistics.

    ReplyDelete
  83. For those who may wish to post more comments about cladistics, here is how to reconcile this issue:

    We do not need cladistics to evaluate the pterosur to bird idea.

    People can see from the Dec 17, 2010 post what I have proposed concerning the primitive bird to modern bird part of the lineage.
    We do not need cladistics to evaluate it.

    ReplyDelete
  84. Well that is part of my issue with your evasiveness. if you're not going to use cladistics and you are going to use systematics then you are going to need thousands of fossils showing a gradual change from the latest pterosaur to the earliest dromosaurid. You seem to want to avoid answering questions about this problem as these fossils of these creatures do not exist. As it stands now, whichever methodology you use, cladistics or systematics, you are going to have deal with the massive leap between a pterosaur and a dromosaurid.

    ReplyDelete
  85. Please support your claim of the "massive leap between a pterosaur and a dromosaurid."

    Have you read the posts on this site? Dozens and dozens of them are on that exact point.

    ReplyDelete
  86. compare the wings of pterosaur to the arm/hand of an early dromosaurid. What were the transitional organisms between the two and where are the fossils?

    ReplyDelete
  87. My point to you was that you claimed a massive leap between a pterosaur and a dromaeosurid.
    Are you claiming there is a massive leap between the arm/hand of a pterosaur and the arm/hand of a early dromaeosaurid?
    If that is your claim, have you read the posts I have written on those differences?
    May I suggest you use the search feature and then we can talk specifics.
    There is a search function on the right side of the page.

    ReplyDelete
  88. I have read your posts about the differences. But what I haven't read in your posts is anything about the fossils in between the two. You say yourself the fossil record is well supported. If so, where are the transitional fossils you claim exist?

    ReplyDelete
  89. If you have read my posts on this, are you now seeing that there is only a small difference between pterosaur arm/hands and primitive bird arm/hands?
    We must start with that first.

    ReplyDelete
  90. And to expand the discussion, do you see that there is very little difference (if any) between the unique breathing system of pterosaurs and primitive birds?

    ReplyDelete
  91. Pterosaurs have four fingers on the hand. Maniraptorans have five. Why do the fingers look so different? Why are pterosaurs clearly adapted to quadrupedality and bird are bipedal? Where's the link between the two?

    ReplyDelete
  92. I explained the fingers of pterosaurs. What did I say about them?

    Please support your claim that
    "pterosaurs clearly adapted to quadrupedality and bird are bipedal". Please provide link(s) to support your claim and copy and paste what you think is relevant.

    The link between pterosaurs and modern birds are the primitive birds.

    ReplyDelete
  93. I don't know why I wrote "Pterosaurs have four fingers on the hand. Maniraptorans have five." Maniraptorans only have three. Oops. No matter. The following is what you claim about pterosaur fingers:

    "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)
    0-2-1-x-x Modern birds"

    Accepting for the sake of argument your erroneous ideas about the pteroid, where are the fossils that show the enlargement and re-acquisition of a claw on the first finger? Where are the fossils showing the loss of the fingers you identify as being the fourth and fifth- that fifth finger is especially important, as its the one that supports the wing membrane in pterosaurs, but is completely absent in maniraptorans, where the most robust finger is the second one.

    These fossils are missing. That is the gap.

    Everything you can see about bird anatomy indicates their bipedality. Just looking at every reconstruction of a maniraptoran or avian skeleton shows that. "Primitive birds" could not have waked on their hands, as they are adapted into wings. Do modern birds walk on their wings? No, they do not. Nor could maniraptorans (or indeed any theropod) as their wrists don't allow their hands to lay flat on the ground- its a common mistake made in many restorations. The limb proportions are all wrong. Restore the animal to an erect stance that the limb articulations indicate it must have had and the hands don't reach the ground.

    Pterosaur quadrupedality is supported by their limb proportions (much longer front legs than hind legs in the majority of species (taken to an extreme in the Ornithocheirids) and by trackways.

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

    "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."

    ReplyDelete
  94. Before I use up a lot more time on this, please indicate what you think is the alternative ancestor.
    And please do so at the same level of detail that we are dealing with in regards to my proposal.


    Also you have posted:
    "Accepting for the sake of argument your erroneous ideas about the pteroid,.."

    It would be better for you to say
    that in your opinion it is erroneous.

    ReplyDelete
  95. I am not proposing any alternative yet. I am asking you questions about your theory. Don't evade the questions. What transitional fossils do you have which document the change from the pterosaur hand to the maniraptoran hand?

    ReplyDelete
  96. Since we are analyzing fingers here, it would be good to bring toether a few ideas.
    Concerning the pterosaur 5th finger - it did not gradually get shorter necessarily. With "facilitated variation" it could have been shortened in one step and the rest of the muscles, nerves etc would modify automatically to accommodate the change.
    Facilitated variation makes the idea of saltation-type changes feasible.

    ReplyDelete
  97. But your "facilitated variation" would completely remove the majority of the wing, supporting as it does (in your numbering scheme) the majority of the wing membrane.

    ReplyDelete
  98. Anonymous, you are making this much more complicated than it would actually be.
    Here is an interesting idea.
    Let us say you agreed with the idea that birds developed from pterosiars.
    How would you see the changes take place?

    I bet that with 5 minutes of thought you would have visualized a series of VERY small credible changes faciltated by faciltated variation.
    Having you approach it that way we can avoid the mindless objections which you have made to this point.
    And it would be a heck of a lot more fun.

    You may call this evasion. But in fact all the info is already in the posts of this blog. You have simply not read the material and put your thinking cap on. And you expect something from me while you simply carp from the sidelines.
    The reason I know this is because you are pretending that the loss of 1 claw and regaining it, is a BIG deal.
    If that is a big deal then show me your alternative that requires less than that.
    Tell us the species/genus that you think was the dino alternative and what changes occurred between it and maniraptors.

    And if you cannot tell us what the specific species/genus was then describe what it was like and roughly when it lived.

    ReplyDelete
  99. For those who may be as bewildered as Anonymous you must realize that when the membrane SKIN disappears the internal fiber structures* of the membrane (that are already there) function as feathers.
    Think about that picture.
    It is MUCH MUCH simpler than anyone here has ever conceived it to be.

    And if you think this is too big a leap then please show us your alternative for the development of feathers.


    *actinofibrils - see relevant posts on this blog

    ReplyDelete
  100. So you are suggesting that the internal support structure (which do not have the hook-and-barb structure of flight feathers) immediately became external structures? But actinofibrils are flexible, elastic bundles that are internal to the skin. Feathers are external to the skin, and distinctly not elastic. Is this happening at the same time as the wing finger and the majority of the wing membrane almost instantly disappears?

    If this does not happen, then where are the transitional forms that show actinofibrils becoming more and more feather-like, becoming external structures rather than internal ones, acquiring the hook-and-barb structure and then taking over the function of the wing membrane?

    The transition from downy fuzz to vaned, barbed feathers is pretty clear from the excellent maniraptoran specimens, as well as several non-maniraptoran ones. In fact pterosaurs already have structures that can be interpreted as very basic protofeathers, ones that you are completely ignoring.

    These are not mindless objections. If you cannot document the transition that you claim must have happened, then why should we believe your theory? Just because something can be imagined does not make it true. You need to provide evidence to support this. The evidence for the bird/dinosaur link is pretty strong, and can be easily found through even the most basic of web searches. I see no need to spoon-feed you information that you should already be very familiar with if you wish to overturn an established idea.

    I expect you to have worked through the flaws in your idea. I expect to be able to ask reasonable questions, and you to be able to show me fossils that you think document these changes. So far you have provided nothing of the sort. I am not carping, I genuinely want to know how your alternative ideas work.

    I do not need to present an alternative. The information is readily out there for those who care to look.

    If we assume for the sake of argument that maniraptorans are theropods we see the following:

    Herrerasaurus has a count of 2-3-4-1-0 and claws on the first three digits. Digits I-V possess metacarpals, but digit V has lost the phalanges.
    Coelophysis has a count of 2-3-4-1-x and claws on the first three fingers. It has a lost the metacarpal from digit V, and still has a small phalange on digit IV.
    Allosaurus has a count of 2-3-4-x-x and has no metacarpals or phalanges for digits IV and V
    Coelurus (a tyrannosauroid often confused with Ornitholestes, a mnairaptoran), Ornitholestes, Deinonychus, and Archaeopteryx all have a phalange count of 2-3-4-x-x. There is a gradual loss of fingers, phalanges and metacarpals in the very early Theropods, during the Triassic and early Jurassic.

    ReplyDelete
  101. Anonymous posted:
    "So you are suggesting that the internal support structure (which do not have the hook-and-barb structure of flight feathers)"

    Is that correct? Please support that with a link and copy and paste the material you think is relevant.

    ReplyDelete
  102. Anonymous said
    "I do not need to present an alternative. The information is readily out there for those who care to look."

    Is this a joke? You go to great lengths to stretch to find some small criticism with what I have proposed and you cannot give ANY alternative?
    No alternative? NOTHING?
    Not even a description of what the species/genus was like and roughly the time it existed?

    ReplyDelete
  103. Your sources describing actinofibrils make no mention of any hook-and-barb structure. If they had found evidence of such a thing do you not think they would mention it?

    What is your evidence that they do possess a hook-and-barb structure? Please support that with a link and copy and paste the material you think is relevant.

    It is not "some small criticism" it is the complete absence of any transitional form between pterosaurs and maniraptorans. You are expecting us to believe that the one is descended from the other, and yet even at the level of gross morphology they appear very distinctive. And yet Coelurus and Ornitholestes are much less different, but in your scheme they are completely unrelated. You need to account for this discrepancy with fossils. So far you haven't. If you cannot then your idea falls at the first fence.

    As I said, I am not presenting an alternative. I am asking questions about your ideas that have not been sufficiently explained, or skim over huge gaps in our knowledge. Your unwillingness to answer them has been noted.

    ReplyDelete
  104. Well, Anonymous has declined to offer any alternative. Not even a description of what the species/genus was like and roughly the time it existed.

    Anyone else?

    ReplyDelete
  105. For those following this, (if anyone is) please note that in the analysis of my proposal we are down to the level of the hook-and-barb structure - in order to see how close pterosaurs are to birds.
    And at the same time the dino to bird folks have offered literally nothing.

    ReplyDelete
  106. Well, Anonymous has declined to offer any alternative. Not even a description of what the species/genus was like and roughly the time it existed.

    Anyone else?

    ReplyDelete
  107. Anonymous posted:
    "And yet Coelurus and Ornitholestes are much less different, but in your scheme they are completely unrelated."

    He does not explain why he says this, but presumably it is because he considers Coelurus to be a dinosaur and Ornitholestes to be a maniraptor. And perhaps he thinks that I think that also. But I do not.
    Ornitholestes is in the Tyrannosaur cluster according to Senter.

    But as a sidenote, there is an implication that Anonymous might consider Coelurus as the ancestor of maniraptors.

    It would be interesting to see if anyone considers Coelurus as the ancestor of maniraptors.

    ReplyDelete
  108. Let's do an interesting exercise and analyze what it would look like if coelurus was the ancestor of maniraptors.
    First of all what does that mean?
    Does it mean that there was a lineage of creatures stemming from a few members of the coelurus genus?
    What then? Did they evolve into some other creatures? Where are they? What did they look like. Have any of their fossils been found?
    And then what - did they evolve into some other creatures? Where are they? What did they look like. Have any of their fossils been found?
    And then what?
    Have any of the fossils of any of the supposed creatures of that linage been found?
    Did they gradually begin to accumulate charteristics that eventually would give rise to the maniraptors? Is there any evidence for that at all?

    This is just the top of the iceberg of questions about the supposed lineage.

    Perhaps someone would like to respond to this and advise us on what the lineage would have looked like.

    ReplyDelete
  109. I say it because of the data Senter used to construct his "baraminological analysis". Read his 2007 work on Coelurosauria.

    Your use of Senter does not help you. Oviraptorans and Therizinosaurs (excluding Falcarius) are not contained in the "Birdlike Cluster" either, but independent of it and they "Tyrannosaur cluster". By the same logic they are not considered to be maniraptorans either. Nor would the Ornithomimosauria- and yet you have claimed that they are ancestors of the ratites.

    As Senter's 2010 paper states

    "Between the least-separated members of the two clusters (Guanlong in the Tyrannosaur Cluster and Falcarius in the Birdlike Cluster) is a gap of only 0.135, which is smaller than the span of either cluster (0.143 for the Tyrannosaur Cluster, and 0.263 for the Birdlike Cluster). Distances of ‡ 0.200, indicating gaps, continue to isolate Oviraptoridae, Caudipteryx, Shuvuuia, Ornithomimidae and Therizinosauridae from all other taxa."

    "The distance between the two groups is also small enough that within the baraminological paradigm both groups are arguably genetically related to each other."

    If you wish to use this to support your contention that maniraptorans are pterosaurs then add some pterosaur species to Senter's dataset and re-run the analysis.

    ReplyDelete
  110. "The distance between the two groups is also small enough that within the baraminological paradigm both groups are arguably genetically related to each other."

    Notice the word "arguably". That is not a scientific word.
    Rather than arguing about how it MIGHT be interpreted if you are a biased* dino to bird enthusiast, let's just work from the EVIDENCE.


    *Biased due to the pre-conceived notion that birds evolved from dinos.

    ReplyDelete
  111. "If you wish to use this to support your contention that maniraptorans are pterosaurs.."

    I did not say that maniraptors are pterosaurs. Maniraptors developed FROM pterosaurs.

    Do you see how your cladistic thinking has programmed your mind. You cannot understand what I am saying if your mind is molded and limited by cladistic thinking.

    If you learn nothing else from this discussion you have the chance to see how your mind operates in a programmed and limited way.

    ReplyDelete
  112. Why are you evading the questions?

    And the evidence is that the two clusters are separated by a smaller distance than the total spread that the clusters cover. Furthermore the therizinosaurs and ornithomimids which you include in various parts of your ideas as maniraptorans and ratite ancestors are not included in either of these clusters.

    Your incessant whinging about cladistics making me "operate in a limited and programmed way" are both insulting and irrelevant. You can rephrase what I wrote to say that "maniraptorans evolved from pterosaurs". The question remains the same.

    Would you please answer this one, the one regarding the figures Senter provides, and the one requesting more evidence that actinofibrils are homologous with feathers.

    ReplyDelete
  113. Perhaps we are making progress.
    You have said that I can say that maniraptors evolved from pterosaurs.
    Are you willing to say, concerning your theory, that maniraptors evolved from dinosaurs?

    If so, we have a firm basis for further discussion. If not, then your other questions have no meaning since we are not talking the same language.

    ReplyDelete
  114. Let's do an interesting exercise and analyze what it would look like if coelurus was the ancestor of maniraptors.
    First of all what does that mean?
    Does it mean that there was a lineage of creatures stemming from a few members of the coelurus genus?
    What then? Did they evolve into some other creatures? Where are they? What did they look like. Have any of their fossils been found?
    And then what - did they evolve into some other creatures? Where are they? What did they look like. Have any of their fossils been found?
    And then what?
    Have any of the fossils of any of the supposed creatures of that linage been found?
    Did they gradually begin to accumulate charteristics that eventually would give rise to the maniraptors? Is there any evidence for that at all?

    This is just the top of the iceberg of questions about the supposed lineage.

    Perhaps someone would like to respond to this and advise us on what the lineage would have looked like.

    ReplyDelete
  115. No lets not. Lets see you have the decency to answer the questions I have asked you. What about the actinofibrils and feathers? What about the numbers Senter discusses? What about the fact that Therizinosaurs and Ornithomimids are not members of the "bird-like cluster" and yet according to you are maniraptorans?

    ReplyDelete
  116. I would think that with the vast amount of research you have done into pterosaurs, bird evolution, dinosaurs, anatomy, genetics and paleontology, that you would already know the answer to that. I mean what institution gave you you're doctorate in the subject if you don't??

    ReplyDelete
  117. Well it looks like we may have hit the end of the road with Anonymous.
    I am VERY familiar with this tactic. The person I am talking to finds some particular (usually not all that significant) question and will not answer any reasonable important question of mine.
    As I have said, I have seen this before. In fact if I answer the question, then there is another insignificant question and then another. Of course to the person who is asking these questions their pretense is that they are really important.
    This is from people who are not serious about the topic.

    And by the way, this "have the decency" rings hollow from someone who has yet to give ANY actual alternative.

    ReplyDelete
  118. Anonymous said:

    "I would think that with the vast amount of research you have done into pterosaurs, bird evolution, dinosaurs, anatomy, genetics and paleontology, that you would already know the answer to that. I mean what institution gave you you're doctorate in the subject if you don't??"

    ReplyDelete
  119. I do know the answer to that.

    Note, I am very familiar with every tactic that people use.
    We are at a point where I have laid out a model at a certain level of detail.
    The person I am discussing this with has laid out NOTHING.
    Yet incredibly the person wants more detail from me while offering NOTHING as an alternative.

    The dino to bird theory has been around a while. Just tell us about some of the taxa that you think are on the lineage.
    And if you cannot identify any, then DESCRIBE what the species/genus were like and when they existed.

    ReplyDelete
  120. Let me clear about this. I have definite ideas about all the questions I have been asked. But people will just mindlessly attack them as they have mindlessly attacked all the ideas I have put forward to this point.
    That is the game the dino to bird folks play.
    They propose NOTHNG themselves and wait for more and more detail from me to attack.

    You propose something yourself. Then we can talk.
    Otherwise stop wasting your time and mine.

    ReplyDelete
  121. It is unfortunate that we have gotten hung up at this point.
    I am interested in any serious constructive contribution on the pterosaur to bird idea.

    But I am not interested in mindless nit-picking from someone like Anonymous (who is probably a blogger who goes by the name Dave Godfrey).

    I have put too much time into this to waste my time now on mindless arguments from people who are not serious. The fact that all the posts are in this one thread indicates that he is not interested in posting his objections in the particular posts concerning specific points I have researched and posted about.

    ReplyDelete
  122. The dino to bird theory has been around a while. Just tell us about some of the taxa that you think are on the lineage.
    And if you cannot identify any, then DESCRIBE what the species/genus were like and when they existed.

    ReplyDelete
  123. Let's do an interesting exercise and analyze what it would look like if coelurus was the ancestor of maniraptors.
    First of all what does that mean?
    Does it mean that there was a line of creatures stemming from a few members of the coelurus genus?
    Did those creatures evolve into some other creatures? Where are they? What did they look like. Have any of their fossils been found?
    And then what - did they evolve into some other creatures? Where are they? What did they look like. Have any of their fossils been found?
    And then what?

    Have any of the fossils of any of the supposed creatures of that linage been found?
    Did they gradually begin to accumulate characteristics that eventually would give rise to the maniraptors? Is there any evidence for that at all?

    This is just the tip of the iceberg of questions about the supposed lineage.

    Perhaps someone would like to respond to this and advise us on what the lineage would have looked like.

    ReplyDelete