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Thread: Birds arose from therapods?! Where are the featherless fossil intermediates?

  1. #1 Birds arose from therapods?! Where are the featherless fossil intermediates? 
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    It is a common belief that the avian line arose from therapod dinosaurs, apparently over tens of millions of years of evolution, following the P-T mass extinction (ca. 252 mya).

    There is a problem with this relationship however. Therapod fossils date back to ca. 230 mya. However, the first real (though not modern) feathered flying bird fossils do not appear until ca. 150 mya. This is an 80 million year gap in the fossil record which prevents a true understanding of how avian evolution actually occurred.

    All unquestionably "non-avian" therapod fossils have a body plan totally unsuited to evolve flight. The massive lower body, legs and tail, combined with the light upper body, with short arms, is not a format that readily lends itself to evolution of the avian line. Moreover, they were apex terrestrial predators (well grounded!), and the only thing they had to worry about was a bigger therapod.

    Evolution requires a driving force, typically one or more aspects of the environment by which selective pressures dictate changes. To be sure, apex predators have little reason to significantly diversify. Alligators and crocodiles evolved 40-50 million years ago and modern animals are nearly identical to the originals (although, like therapods, there was/is large variations in size). They are simply too successful to change. There are many examples of this. The horseshoe crab looks almost identical to fossils that were formed shortly after the P-T event. They too were simply not subjected to evolutionary changes - there was no "need". This should be rather apparent after 230 million years of the horseshoe crabs to the present day. No selective pressure, no changes.

    Looking at all the (presumed) therapods which have been discovered, most charts show relationships between similar lines, all the way to T. rex, a period of ca. 160 million years. Of all these animals, the only one with a dramatically altered body plan are birds. They appear very much "out of place".

    Since major changes in therapod morphology (and the complex neurology required for controlled flight) would have had to occur for this apex terrestrial predator to evolve feathers and flight, the fossil record should reveal them. However, it appears to be silent on this issue, perhaps because of their habitat. If they evolved in forests, the ideal place for such a line to appear, those fossils may be hard to find since such places are conducive to the rapid degradation of remains (over mineralization to fossils).

    It seems that any obvious "links" between the two is a reptilian origin and, in the first birds, a therapod-like head - one full of teeth. Most of the "telling" morphological aspects are specifically different - birds simply would never fly if they were similar to all other therapods! The closest thing to flight a therapod could manage was falling off a cliff.

    So, if birds evolved from therapods, where are the fossil intermediates demonstrating such a dramatic evolutionary change? Therapods are not going to evolve flight from the "ground-down". It would seem that birds must have arose like all other flying vertebrates, first as gliders from elevated "platforms", and on to fully powered flight.

    To close, there are no fossils yet discovered that link therapods to such dramatic changes in body plan. It seems they either have not been found, or never existed. The more rational evolution of birds is from a distinct non-therapod archosaurian line, breaking off the main reptilian trunk some millions of years after the P-T event, and are not directly related to the therapods.

    Any comments relating to such "missing" fossils would be of great interest.

    Posts about "feathered dinosaurs" or fake fossils out of China would not. Such fossils and their "labeling" only prove that avian evolution in the earliest phases remains poorly understood. It is the transitional fossils which are of interest, and likely the most instructive, at least from the perspective of paleontology.


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    Quote Originally Posted by Double Helix View Post
    It is a common belief that the avian line arose from therapod dinosaurs, apparently over tens of millions of years of evolution, following the P-T mass extinction (ca. 252 mya).

    There is a problem with this relationship however. Therapod fossils date back to ca. 230 mya. However, the first real (though not modern) feathered flying bird fossils do not appear until ca. 150 mya. This is an 80 million year gap in the fossil record which prevents a true understanding of how avian evolution actually occurred.

    All unquestionably "non-avian" therapod fossils have a body plan totally unsuited to evolve flight. The massive lower body, legs and tail, combined with the light upper body, with short arms, is not a format that readily lends itself to evolution of the avian line. Moreover, they were apex terrestrial predators (well grounded!), and the only thing they had to worry about was a bigger therapod.

    Evolution requires a driving force, typically one or more aspects of the environment by which selective pressures dictate changes. To be sure, apex predators have little reason to significantly diversify. Alligators and crocodiles evolved 40-50 million years ago and modern animals are nearly identical to the originals (although, like therapods, there was/is large variations in size). They are simply too successful to change. There are many examples of this. The horseshoe crab looks almost identical to fossils that were formed shortly after the P-T event. They too were simply not subjected to evolutionary changes - there was no "need". This should be rather apparent after 230 million years of the horseshoe crabs to the present day. No selective pressure, no changes.

    Looking at all the (presumed) therapods which have been discovered, most charts show relationships between similar lines, all the way to T. rex, a period of ca. 160 million years. Of all these animals, the only one with a dramatically altered body plan are birds. They appear very much "out of place".

    Since major changes in therapod morphology (and the complex neurology required for controlled flight) would have had to occur for this apex terrestrial predator to evolve feathers and flight, the fossil record should reveal them. However, it appears to be silent on this issue, perhaps because of their habitat. If they evolved in forests, the ideal place for such a line to appear, those fossils may be hard to find since such places are conducive to the rapid degradation of remains (over mineralization to fossils).

    It seems that any obvious "links" between the two is a reptilian origin and, in the first birds, a therapod-like head - one full of teeth. Most of the "telling" morphological aspects are specifically different - birds simply would never fly if they were similar to all other therapods! The closest thing to flight a therapod could manage was falling off a cliff.

    So, if birds evolved from therapods, where are the fossil intermediates demonstrating such a dramatic evolutionary change? Therapods are not going to evolve flight from the "ground-down". It would seem that birds must have arose like all other flying vertebrates, first as gliders from elevated "platforms", and on to fully powered flight.

    To close, there are no fossils yet discovered that link therapods to such dramatic changes in body plan. It seems they either have not been found, or never existed. The more rational evolution of birds is from a distinct non-therapod archosaurian line, breaking off the main reptilian trunk some millions of years after the P-T event, and are not directly related to the therapods.

    Any comments relating to such "missing" fossils would be of great interest.

    Posts about "feathered dinosaurs" or fake fossils out of China would not. Such fossils and their "labeling" only prove that avian evolution in the earliest phases remains poorly understood. It is the transitional fossils which are of interest, and likely the most instructive, at least from the perspective of paleontology.
    I'm not sure you are right about the "massive" lower body of therapods. Did they all have such a body plan?

    Perhaps you could indicate where the "gap" you are talking about is, by reference to this article: https://evolution.berkeley.edu/evoli...le/evograms_06

    The diagram, in particular, lays out the successive appearance various features we now associate with birds, developing over a period of some 80m years, from 240m yrs ago to 160m yrs ago, i.e. almost the exact span of the "gap" you refer to. It does not look at all like a gap to me. Or am I misunderstanding you?


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    Quote Originally Posted by exchemist View Post
    Perhaps you could indicate where the "gap" you are talking about is, by reference to this article: https://evolution.berkeley.edu/evoli...le/evograms_06

    The diagram, in particular, lays out the successive appearance various features we now associate with birds, developing over a period of some 80m years, from 240m yrs ago to 160m yrs ago, i.e. almost the exact span of the "gap" you refer to. It does not look at all like a gap to me. Or am I misunderstanding you?
    This graphic displays many of the body forms related to therapods, and thus presumably to birds since the P-T extinction. It confirms that the therapod line starts at ca. 230 mya with euraptor and goes all the way to tyrannosauroids, beginning ca. 165 mya. None of these animals are suited for evolving flight with the observed body format. That is the start of the issue of the evolution of flight, and the problem with the therapod origin of birds.

    The chart is confusing in that it lists the appearance of various traits with a vertical red line, yet not a single species from which these traits began. It is not clear to me how they insert various features of bones and feathers (vertical red lines) without a specific animal to demonstrate their appearance. For this aspect we start with hollow feathers.

    The graphic indicates that "hollow cylindrical feathers" appeared ca. 200 mya, but there is no direct therapod line (or any animal line) where this is established - only a vertical red mark in the time line. The earliest feathered animals that were capable of flight are found around 150 mya (and with it the earliest flight feathers). What animal appeared with "hollow cylindrical feathers" at 200 mya? The graphic provides no clue - apparently we are only meant to agree that this is correct. The same is true of "tufted" feathers. There is a red line where they apparently appeared ca. 190 mya, but where is the fossil evidence for that?

    And then I read the part about Sinosauropteryx, and the hair-like "feathers" associated with these fossils. It was established quite some time ago that such features are collagen remnants that puff out from the surface of decaying animals. They have been seen in many other fossils totally unrelated to the animals in this graphic. It suggests whoever put this together does not have all the facts. And besides, how does the appearance of "hairy feathers" in Sinosauropteryx, which lived ca. 120 mya, showcase them as the origin of real feathers?! How is that possible when Archaeopteryx was flying around with real feather at least 30 million years prior to this? It makes no sense at all.

    Such issues with the chart render it suspect to interpretation, much less accuracy. At any rate, the final four at the bottom are now beginning to show, for the first time, animals likely related to modern birds for at least one reason - they all have real feathers. While the chart is very interesting regarding the time line of the animals involved, it does not provide a direct link to birds from the first therapods, or any of them. At best the chart shows animals in the same time frame with similar characteristics, which are used to draw conclusions on relationships which may not be accurate. There is nothing in this graphic, or the related commentary, which changes this story.

    Perhaps you can give me a step-by-step description using real fossils going from one stage to the next (from 230 mya to 150 mya), instead of grand associations which can be highly misleading about relationships. I fail to see that this chart reveals how birds arose from animals which are totally unsuited as precursors. The evolution of flight relies on direct morphological and neurological changes leading to birds. The graphic gives no details regarding these steps. Indeed, it fails to provide these critical steps at any point, except with the appearance of those animals having real feathers. The graphic proves nothing but the temporal relationship all of these creatures share. A genetic relationship between therapods and real birds is clearly not established.
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    Quote Originally Posted by Double Helix View Post
    Quote Originally Posted by exchemist View Post
    Perhaps you could indicate where the "gap" you are talking about is, by reference to this article: https://evolution.berkeley.edu/evoli...le/evograms_06

    The diagram, in particular, lays out the successive appearance various features we now associate with birds, developing over a period of some 80m years, from 240m yrs ago to 160m yrs ago, i.e. almost the exact span of the "gap" you refer to. It does not look at all like a gap to me. Or am I misunderstanding you?
    This graphic displays many of the body forms related to therapods, and thus presumably to birds since the P-T extinction. It confirms that the therapod line starts at ca. 230 mya with euraptor and goes all the way to tyrannosauroids, beginning ca. 165 mya. None of these animals are suited for evolving flight with the observed body format. That is the start of the issue of the evolution of flight, and the problem with the therapod origin of birds.

    The chart is confusing in that it lists the appearance of various traits with a vertical red line, yet not a single species from which these traits began. It is not clear to me how they insert various features of bones and feathers (vertical red lines) without a specific animal to demonstrate their appearance. For this aspect we start with hollow feathers.

    The graphic indicates that "hollow cylindrical feathers" appeared ca. 200 mya, but there is no direct therapod line (or any animal line) where this is established - only a vertical red mark in the time line. The earliest feathered animals that were capable of flight are found around 150 mya (and with it the earliest flight feathers). What animal appeared with "hollow cylindrical feathers" at 200 mya? The graphic provides no clue - apparently we are only meant to agree that this is correct. The same is true of "tufted" feathers. There is a red line where they apparently appeared ca. 190 mya, but where is the fossil evidence for that?

    And then I read the part about Sinosauropteryx, and the hair-like "feathers" associated with these fossils. It was established quite some time ago that such features are collagen remnants that puff out from the surface of decaying animals. They have been seen in many other fossils totally unrelated to the animals in this graphic. It suggests whoever put this together does not have all the facts. And besides, how does the appearance of "hairy feathers" in Sinosauropteryx, which lived ca. 120 mya, showcase them as the origin of real feathers?! How is that possible when Archaeopteryx was flying around with real feather at least 30 million years prior to this? It makes no sense at all.

    Such issues with the chart render it suspect to interpretation, much less accuracy. At any rate, the final four at the bottom are now beginning to show, for the first time, animals likely related to modern birds for at least one reason - they all have real feathers. While the chart is very interesting regarding the time line of the animals involved, it does not provide a direct link to birds from the first therapods, or any of them. At best the chart shows animals in the same time frame with similar characteristics, which are used to draw conclusions on relationships which may not be accurate. There is nothing in this graphic, or the related commentary, which changes this story.

    Perhaps you can give me a step-by-step description using real fossils going from one stage to the next (from 230 mya to 150 mya), instead of grand associations which can be highly misleading about relationships. I fail to see that this chart reveals how birds arose from animals which are totally unsuited as precursors. The evolution of flight relies on direct morphological and neurological changes leading to birds. The graphic gives no details regarding these steps. Indeed, it fails to provide these critical steps at any point, except with the appearance of those animals having real feathers. The graphic proves nothing but the temporal relationship all of these creatures share. A genetic relationship between therapods and real birds is clearly not established.
    Well obviously there must be fossils displaying the traits they identify at each stage, or there would be no scientific basis for the chart.

    The way I read the chart is that the examples to the right of each feature display the feature in question. For example, allosaurids had hollow bones. And some tyrannosaurids, e.g. yutyrannus , had feathers. So the examples you ask for seem to be shown on the chart.

    You suddenly seem strangely aggressive in your repeated assertion that these animals are unsuitable as precursors to birds. As for the suggestion that the chart was put together by someone without access to the facts, this material is from the University of California at Berkeley. I feel confident they have access to most of the relevant facts, and very likely more than you do.

    My crank detector has gone off, now, and my creationist detector is flashing amber.
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    Quote Originally Posted by exchemist View Post
    Well obviously there must be fossils displaying the traits they identify at each stage, or there would be no scientific basis for the chart.
    There appears to be no actual scientific basis for some claims made in the chart : Especially the early appearance of real feathers at 200 mya. From all that is published, there are simply no true feathers in the fossil record that predate ca. 150 mya (1), at least none known from numerous searches of published research. Claims to the contrary must be speculation, and are likely educated guesses based on real feathers at 150 mya. After all, Archaeopteryx might have flown into the blue, but it and its feathers did not fly out of the blue. Those animals arose from others over many millions of years. This means those feathers appeared much earlier, they just haven't been found yet, nor has the actual precursor of birds.

    Some of the "evolutionary introductions" of various body parts etc. presented in that graph must be speculative, based on what is known from fossils (again, the hard evidence, no pun intended!).

    So the first true feathers found in the fossil record dates to Archaeopteryx, 150 mya (still true as of last year at least). Again, I submit that there remains no fossil evidence supporting the evolution of birds from therapods within the 80 million gap previously noted, the only time-frame such evolution could have occurred. And the University of California at Berkeley is an excellent school. That does not make them error-free.

    1. https://www.nytimes.com/2020/09/30/s...aeopteryx.html


    Quote Originally Posted by exchemist View Post
    You suddenly seem strangely aggressive in your repeated assertion that these animals are unsuitable as precursors to birds.
    Not at all, really. Actually that was the over-riding theme of my first post (please re-read it to be sure!), and remains the over-riding problem of this evolutionary scheme.

    Need I remind you of the therapod flight plan for falling off a cliff? ETA is PDQ!


    Quote Originally Posted by exchemist View Post
    My crank detector has gone off, now, and my creationist detector is flashing amber.

    You need to get your creationist detector checked out. "Intensely devoted atheist" only begins to describe me!

    I appreciate your input - except that part about the detector!
    Last edited by Double Helix; January 25th, 2021 at 09:21 PM.
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    It seems that your understanding of feather evolution is notably out of date. Cite your sourcing for the suggestions you have made regarding body heat and feathered dinosaurians (theropods are far from the only dinosaurs which showed feathers and protofeathers)
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    Quote Originally Posted by Paleoichneum View Post
    It seems that your understanding of feather evolution is notably out of date. Cite your sourcing for the suggestions you have made regarding body heat and feathered dinosaurians (theropods are far from the only dinosaurs which showed feathers and protofeathers)
    Sadly your post provides no clues (at least to me) what you are meaning to present, at least relative to the nature of this thread. So I am going to have to wing it, so to say!

    If you have evidence contradicting my claims for what is known about the appearance of flight feathers in the fossil record predating 150 mya, please present some references. Unattributed commentary does not aid in a true understanding.

    Do not recall discussing anything about thermal regulation (any quoted references stating this are ancillary to my posts). Please point that out specifically. For me, flight feathers are the only ones that matter since their unequivocal function eliminates all notions contrary to their true origin - the avian line.

    However, I did catch the comment about "theropods are far from the only dinosaurs which showed feathers", and am really glad you brought that up. In the scheme shown from the Berkeley post made previously (see below), all of the feathered "dinosaurs" are at the bottom of the groupings.

    The biggest take-home message from this graphic is that all of these lines of so-called "feathered dinosaurs" must necessarily have their origin in an animal that also gave rise most importantly to Archaeopteryx (a true bird!), which itself predates all of the other feathered animal lines by ca. 20 million years. Doubtless the appearance of real feathers with any fossil indicates an avian descent. If you wish to refer to them as dinosaurs, that is your call. I am only saying they did not descend from therapods - none of them (assuming no fossils are ever found for the transition to the avian body plan, which has already been covered) . And so-called "protofeathers" are highly contentious, with some of these appearing 10s of millions of years after true flight feather are seen in Archaeopteryx at 150 mya. It is highly unlikely that avian feathers evolved more than once in the history of life on earth.

    And I really hope you can provide me with fossil evidence for a 200 mya flight feather to bring me "up to date". Indeed, I would settle for one that is only 180 mya, or even 160 mya - anything older than what we currently have. If I am missing something, I want to be the first to know. But something tells me if such fossils existed, we would not be debating the issue.

    Be kind enough to assist me on this one, as you surely present yourself so well versed in the appearance and evolution of feathers.


    https://evolution.berkeley.edu/evoli...le/evograms_06
    Last edited by Double Helix; January 28th, 2021 at 05:59 PM. Reason: clarification
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    A good starting overview is found here https://en.m.wikipedia.org/wiki/Feathered_dinosaur and the myriad peer reviewed articles used as the foundational sourcing for the page.
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    Quote Originally Posted by Paleoichneum View Post
    A good starting overview is found here https://en.m.wikipedia.org/wiki/Feathered_dinosaur and the myriad peer reviewed articles used as the foundational sourcing for the page.
    One or two sentence responses indicate a strict reliance on the interpretations of others. Things can go very wrong when people do that. This is clearly such a case. Yet another infamous echo chamber, hard at work.

    Nothing in that link indicates the origin of feathers from any known "protofeather" structures, nor does it demonstrate any real feathers older than 150 mya, an obvious requirement for a relationship, and certainly for your erroneous notion of my being "out of date".

    Cutting to the chase, the "feather-like integument", better known as protofeathers, apparently begins and ends with protofeathers. Evolution requires change. No series of fossils exist showing the evolution of true feathers from such "protofeathers". They would be better defined as pseudoprotofeathers, or at best maybe-sorta-protofeathers. All fossil remains with real feathers cannot be linked to such structures without hard evidence. This is the requirement which is clearly lacking, or you would have provided reliable evidence for it. This also demonstrates that any fossil remains which have flight feathers must be of avian descent, whether they could fly or not. Modern birds which are flightless might feel quite ill at ease if they knew they were so unique in the history of avian flight!

    Perhaps another clipped response will keep things going?

    Get back to me when you have evidence of such "feather-like integument" evolving into real feathers. Otherwise, it is the purest form of speculation.

    BTW, evolution does not do retrograde. It starts and continues in one direction - forward in time. Any "feather-like integument" developing into real feathers must predate 150 mya by tens of millions of years, and proof of their evolution into real feathers requires much more than the speculation provided. It requires hard data, the hardest kind - i.e. real fossils demonstrating the required evolutionary changes. Real feathers, especially flight feathers, are vastly more advanced structures than any "feather-like integument".

    This is not even a close call, sadly. Was really hoping for something new. Clearly will have to wait for that from future fossil finds.
    Last edited by Double Helix; January 28th, 2021 at 08:49 PM.
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    [QUOTE=Double Helix;631309]
    Quote Originally Posted by Paleoichneum View Post
    A good starting overview is found here https://en.m.wikipedia.org/wiki/Feathered_dinosaur and the myriad peer reviewed articles used as the foundational sourcing for the page.
    Quote Originally Posted by Double Helix View Post
    One or two sentence responses indicate a strict reliance on the interpretations of others. Things can go very wrong when people do that. This is clearly such a case. Yet another infamous echo chamber, hard at work.
    So you ask for evidence, but reject the starting points as not original research/fossil description...

    Quote Originally Posted by Double Helix View Post
    Nothing in that link indicates the origin of feathers from any known "protofeather" structures, nor does it demonstrate any real feathers older than 150 mya, an obvious requirement for a relationship, and certainly for your erroneous notion of my being "out of date".

    Cutting to the chase, the "feather-like integument", better known as protofeathers, apparently begins and ends with protofeathers. Evolution requires change. No series of fossils exist showing the evolution of true feathers from such "protofeathers". They would be better defined as pseudoprotofeathers, or at best maybe-sorta-protofeathers. All fossil remains with real feathers cannot be linked to such structures without hard evidence. This is the requirement which is clearly lacking, or you would have provided reliable evidence for it. This also demonstrates that any fossil remains which have flight feathers must be of avian descent, whether they could fly or not. Modern birds which are flightless might feel quite ill at ease if they knew they were so unique in the history of avian flight!
    So we combine a god of the gaps argument with a no true Scotsman fallacy. Protofeathers (in all three developments stages) lead up to modern down and quill feathers.

    Please supply the data that indicates that protofeathers are not precursors to feathers.

    Quote Originally Posted by Double Helix View Post
    Perhaps another clipped response will keep things going?
    snark noted

    Quote Originally Posted by Double Helix View Post
    Get back to me when you have evidence of such "feather-like integument" evolving into real feathers. Otherwise, it is the purest form of speculation.
    But you have already indicated that no evidence presented will be good enough, with no indication of any alternative that fits ALL the phylogenetic evidence

    Quote Originally Posted by Double Helix View Post
    BTW, evolution does not do retrograde. It starts and continues in one direction - forward in time. Any "feather-like integument" developing into real feathers must predate 150 mya by tens of millions of years, and proof of their evolution into real feathers requires much more than the speculation provided. It requires hard data, the hardest kind - i.e. real fossils demonstrating the required evolutionary changes. Real feathers, especially flight feathers, are vastly more advanced structures than any "feather-like integument".

    This is not even a close call, sadly. Was really hoping for something new. Clearly will have to wait for that from future fossil finds.
    Evolution is a complex bush like process that involves much mosaic trait expression, trait development-trait loss-trait redevelopment, complex convergent trait development in related and unrelated groups.

    Or are you suggesting that kiwis, emus, and ostriches are not true birds, since they do not have complex feathers, but evolved from a non-Neoavian precursor?
    If evolution is only linear, are you suggesting that
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    Quote Originally Posted by Paleoichneum View Post
    Please supply the data that indicates that protofeathers are not precursors to feathers.
    Of all your posts, this one is the most telling. It exposes the lack of real data. A clear indication of the "non-scientific" approach.

    "Please provide the evidence that they are precursors" is the the real issue, and the fundamental approach to real science.

    One can speculate on anything regardless of how impossible it is, and simply reply to the naysayers: "please supply the data that this not accurate".

    Not how real science works. One has to prove their premise. The inability to disprove an unsupported premise means nothing.

    A clear example : "We all live in a black hole. Prove that we don't." It doesn't take a lot of smarts to know experts work the other way - they will tell you to prove your premise, which you have not. Instead you fall back on that tired old dodge of proving that you are wrong.

    Bottom line: You present insufficient "evidence" to indicate you are right, or even close. That is all that need be said about the issue.

    At least this is amusing!

    The most valid question remains unanswered: Where are the real fossil feathers that must predate (by many millions of years) those real feathers at 150 mya?

    It is clear that some of us need to brush up on evolution. Would suggest :

    https://en.wikipedia.org/wiki/Evolution


    Last edited by Double Helix; January 29th, 2021 at 04:15 PM.
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    For those following this thread, and perhaps finding it a bit confusing, there is very good reason for that. In many such cases, the fossil record is rather spotty. It is very difficult for the individual remains of a plant or creature to result in a fossil, much less survive for millions to hundreds of millions of years through various churning plate tectonics, volcanic eruptions, weathering, etc. This problem of the fossil record often has many scratching their heads about the origin of numerous species because of "missing link type" fossils in the evolutionary chain of whatever plant or animal is under study.

    This problem is most pronounced in the origin and early evolution of birds - the avian line - from the first climbing-glider to the first real bird - having a full suite of feathers and full powered flight.

    When indulging in such a search through the fossil record, the single most import feature one needs to address is the flight feather, the reason I have brought this up repeatedly. My mantra in this regard is "follow the flight feather". That is because there is no more definitive feature which identifies the avian line than the flight feather. There simply couldn't be. It evolved for one purpose only - flight. Any fossils which have such feathers must be intimately related to the avian line, unless one proposes that such a complex structure as the flight feather arose more than once (in a unrelated line), a highly unlikely event.

    Since the oldest known flight feathers belong to the oldest known flying bird - Archaeopteryx from 150 mya - one is forced to conclude that such feathers must have arisen long before this time frame. These feathers are remarkably complex - and should be. Having evolved to assist climbing gliders finally obtain powered flight due to their aerodynamic characteristics, real flight feathers likely date back tens of millions of years before Archaeopteryx. Yet no such fossils have yet been found.

    To link such feathers to epidermal projections requires that they be very ancient, and demonstrate structural changes which might reasonably lead to the appearance of real feathers. Again, such evidence does not yet exist in the fossil record in the required time frame (or any time frame for that matter).

    So the search for the origin of real flight feathers, and the origin of birds, persists. It is hoped that the fossil record will finally provide the evolutionary sequences which gave rise to the avian line, the appearance of flight feathers being foremost in that analysis.

    Most importantly, relevant featherless fossils with characteristics leading to a "flying format" body plan must also be found and scrutinized, and all these would of course have to pre-date 150 mya. These are in fact the most important fossils of all. If they can be found with feathers, and even realistic precursors to feathers, in a climbing-glider type format, so much the better. The earliest evolving avian animals clearly are most critical, since their evolving behavior is the only basis for the development of flight feathers. There is much to be learned if such fossils can be discovered.
    Last edited by Double Helix; January 30th, 2021 at 04:30 PM.
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    Archaeopteryx is ALSO constantly returned by phylogenetic analysis as a maniraptoran dinosaur.

    Feathers did arise before 150 MYA, as the protofeathers that you have consistently ignored show.

    Climbing-glider is one suggested flight evolution track, but not the only one, yet you have ignored the others, and as your mantra indicates you are myopicly ignoring the experts in the paleontology since they are providing data that contradicts what you want to see.

    Yet no such fossils have yet been found.


    For those following (I recongnize that phrase from before the site crash, I suspect double helix has been on site before under a different pseudonym)
    Here are the dinosaurian genera that show various fossilized feathers (as defined by paleontologists, not by DH):
    Sciurumimus - filamentous feathers
    Dilong – plumulaceous feathers
    Yutyrannus – plumulaceous feathers
    Sinocalliopteryx – plumulaceous feathers
    Sinosauropteryx – plumulaceous feathers
    Juravenator – filamentous feathers
    Ornithomimus – plumulaceous feathers
    Deinocheirus – plumulaceous feathers
    Shuvuuia – plumulaceous feathers
    Beipiaosaurus – plumulaceous feathers
    Jianchangosaurus
    – plumulaceous feathers
    Avimimus– pennaceous feathers
    Nomingia – pennaceous feathers
    Caudipteryx – pennaceous feathers
    Similicaudipteryx – pennaceous feathers
    Protarchaeopteryx – pennaceous feathers
    Ningyuansaurus – pennaceous feathers
    Citipati – pennaceous feathers
    Conchoraptor – pennaceous feathers
    Scansoriopteryx – pennaceous feathers
    Epidexipteryx – pennaceous feathers
    Eosinopteryx – pennaceous feathers
    Sinornithosaurus – pennaceous feathers
    Microraptor – pennaceous feathers
    Velociraptor – pennaceous feathers
    Changyuraptor – pennaceous feathers
    Jinfengopteryx – pennaceous feathers
    Plus the fossil members of Clade Avalae

    As a note the Bathonian (168-161mya) genus Kulindadromeus also posessed basally branching filament like protofeathers

    Here is the source peer reviewed paper for this list :Xu, Xing (2020), Foth, Christian; Rauhut, Oliver W. M. (eds.), "Filamentous Integuments in Nonavialan Theropods and Their Kin: Advances and Future Perspectives for Understanding the Evolution of Feathers"The Evolution of Feathers: From Their Origin to the Present, Fascinating Life Sciences, Cham: Springer International Publishing, pp. 67–78, doi:10.1007/978-3-030-27223-4_5, ISBN 978-3-030-27223-4

    Plus see this graphic https://en.wikipedia.org/wiki/File:D...integument.png
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    Quote Originally Posted by Paleoichneum View Post
    Feathers did arise before 150 MYA, as the protofeathers that you have consistently ignored show.
    On the contrary. My continuous hammering at the avian flight feather and my persistent but required demands about a rational evolutionary path to the appearance of such a complex structure has been an over-riding feature of my most recent posts. Perhaps you should re-read some of them, but no need as your last post is proof enough.

    As suspected, most of these listings post-date 150 mya, so could not possibly have evolved into real feathers. Even Sciurumimus at 150 mya are hair like, while Archaeopteryx is flying about on real feathers around the same time. And Kulindadromeus evolving into a bird is like suggesting that a hippo evolve into a bat. Look at the ultra-heavy body format of Kulindadromeus and tell me how this ungainly, land-bound creature is going to evolve flight? If it has your "protofeathers", there is a very good reason to start calling them something else entirely. At 168 mya, we need something small and agile, climbing into trees or onto rocky areas to gain altitude to evolve from gliders. Ground-down flight evolution is not going to make it.

    Putting an end to my interest in debating your origin of feathers, I will insist that the (mostly) later appearance of so called "protofeathers" leading to real feathers have the impossible time barrier (i.e. 150 mya). As a result, some are compelled to believe that other epidermal "appendages" developed over time, and some may or may not go beyond the single hair-like structure, however it has been found - in a splayed manner or as a single element. It could however be distantly related to some reptilian epidermal feature evolved well before the P-T event, as could feathers.

    It would seem that this is what those "protofeathers" you have referred to actually represent. A unique form of a "hairy" epidermal structure, but a dead-end to real feathers. They apparently persisted for ca. 100 million years (according to the data) and then are gone. Good riddance, at least for the evolution of real feathers. No role seen here. They lack the time and animal body plan to play a role. Without a reasonable doubt. Period.

    None of your links changes the story that we are without fossils which describe the origin of the avian line from when it arose over 200 mya.

    It is doubtless that true feathers are the most advanced epidermal extension which ever evolved in any animal. Feathers have remarkable features that mere curly hairs cannot support as their basil structures, especially those which do not seem to change much over 100 million years. Intermediates from some future fossils will be definitive if indeed they are ever found. True flight feathers must have arose at least 20 million years before powered flight (which itself may have been going on for millions of year before 150 mya!), and those from an already advanced feature of similar construction and purpose.
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    20 million years before {{cn}}

    "Intermediates from some future fossils"
    -Already provided-

    "It would seem that this is what those "protofeathers" you have referred to actually represent. A unique form of a "hairy" epidermal structure, but a dead-end to real feathers."
    Per WHICH paleontologist"

    Your entire post is basically summed up as
    "Lalala i cant hear you, I don't like it so I'm ignoring it"

    It very clear that you did not actually intend to discuss this topic at all, but wanted to create a soapbox from which to say "I know better then "so called" experts on the subject! Here me roar"

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    Quote Originally Posted by Paleoichneum View Post
    20 million years before {{cn}}

    "Intermediates from some future fossils"
    -Already provided-

    "It would seem that this is what those "protofeathers" you have referred to actually represent. A unique form of a "hairy" epidermal structure, but a dead-end to real feathers."
    Per WHICH paleontologist"

    Your entire post is basically summed up as
    "Lalala i cant hear you, I don't like it so I'm ignoring it"

    It very clear that you did not actually intend to discuss this topic at all, but wanted to create a soapbox from which to say "I know better then "so called" experts on the subject! Here me roar"


    None of your posts provide a path forward to the avian line from the "data" or fossils you have provided.

    I leave the roaring to the ill-informed, and take on more confidence from the ever more irrational notions on this subject from the echo chamber.

    Clearly the origin, and true path forward for avian evolution has not yet be discovered. And my position that birds evolved from a distinct archosaurian line is more firmly established as a result of your references.

    What those references lack in accuracy (or perhaps reality) is easily made up for by their irrelevance to avian evolution. I appreciate that contribution at least.
    Last edited by Double Helix; January 31st, 2021 at 03:38 PM.
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    Quote Originally Posted by Double Helix View Post
    Quote Originally Posted by Paleoichneum View Post
    20 million years before {{cn}}

    "Intermediates from some future fossils"
    -Already provided-

    "It would seem that this is what those "protofeathers" you have referred to actually represent. A unique form of a "hairy" epidermal structure, but a dead-end to real feathers."
    Per WHICH paleontologist"

    Your entire post is basically summed up as
    "Lalala i cant hear you, I don't like it so I'm ignoring it"

    It very clear that you did not actually intend to discuss this topic at all, but wanted to create a soapbox from which to say "I know better then "so called" experts on the subject! Here me roar"


    None of your posts provide a path forward to the avian line from the "data" or fossils you have provided.

    I leave the roaring to the ill-informed, and take on more confidence from the ever more irrational notions on this subject from the echo chamber.

    Clearly the origin, and true path forward for avian evolution has not yet be discovered. And my position that birds evolved from a distinct archosaurian line is more firmly established as a result of your references.

    What those references lack in accuracy (or perhaps reality) is easily made up for by their irrelevance to avian evolution. I appreciate that contribution at least.
    Thanks! I haven't looked at bird evolution in quite a while, but your posts piqued my interest. Quite a bit of new data has been found since I last researched this. Unfortunately the data and research does not agree with your hypothesis, but thanks for the 'nudge' to do the research. Very interesting stuff.

    By the way the "Great Backyard Bird Count" is this weekend. I encourage everyone to participate!
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    Quote Originally Posted by Origin View Post
    Unfortunately the data and research does not agree with your hypothesis......
    Be kind enough to provide some specifics as to the lack of agreement with the hypothesis. Quoting the above contrary sources would of course be redundant, and hope that is not your source for such a comment.

    However, do feel free to quote from those posts if you feel they indeed present solid evidence. All aspects of this debate can be re-hashed, and that would be fine. Really looking for new data. Particularly fossils which demonstrate the appearance of reptilian creatures which might have started the avian line, well over 200 mya.

    And as noted from the title of this thread, where are the featherless fossil intermediates? But would equally appreciate fossils earlier than 150 mya showing the evolution of feathers, as no evidence even remotely exists prior to this "time problem". Please recall my mantra : Follow the flight feather in the fossil record. Its path to demonstrate the real course of avian evolution must be definitive since they evolved for only one reason. There is nothing like the flight feather in any other life form. Nothing of its early evolution has been found, although they must have existed for tens of millions of years before Archaeopteryx (i.e 150 mya). ("Split hairs" on dinosaurs went extinct with them, 66 mya)

    Learning new things is essential to our understanding of all of the sciences. But only open minds are capable of learning new things.

    And it is not my hypothesis, but those of top-flight (so to say) real scientists who are world experts in the evolution of birds.

    Of course the dinophiles insist on their poorly defined evolutionary path, the vast majority having no expertise in birds or their origin.

    Good luck in your "Great Backyard Bird Count"! Sadly you will need more and more luck as their numbers are crashing. Is it correct that some billions have perished for various reasons in the last decade or so?
    Last edited by Double Helix; February 2nd, 2021 at 07:36 PM.
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    Quote Originally Posted by Double Helix View Post
    Quote Originally Posted by Origin View Post
    Unfortunately the data and research does not agree with your hypothesis......
    Be kind enough to provide some specifics as to the lack of agreement with the hypothesis. Quoting the above contrary sources would of course be redundant, and hope that is not your source for such a comment.

    However, do feel free to quote from those posts if you feel they indeed present solid evidence. All aspects of this debate can be re-hashed, and that would be fine. Really looking for new data. Particularly fossils which demonstrate the appearance of reptilian creatures which might have started the avian line, well over 200 mya.

    And as noted from the title of this thread, where are the featherless fossil intermediates? But would equally appreciate fossils earlier than 150 mya showing the evolution of feathers, as no evidence even remotely exists prior to this "time problem". Please recall my mantra : Follow the flight feather in the fossil record. Its path to demonstrate the real course of avian evolution must be definitive since they evolved for only one reason. There is nothing like the flight feather in any other life form. Nothing of its early evolution has been found, although they must have existed for tens of millions of years before Archaeopteryx (i.e 150 mya). ("Split hairs" on dinosaurs went extinct with them, 66 mya)

    Learning new things is essential to our understanding of all of the sciences. But only open minds are capable of learning new things.

    And it is not my hypothesis, but those of top-flight (so to say) real scientists who are world experts in the evolution of birds.

    Of course the dinophiles insist on their poorly defined evolutionary path, the vast majority having no expertise in birds or their origin.

    Good luck in your "Great Backyard Bird Count"! Sadly you will need more and more luck as their numbers are crashing. Is it correct that some billions have perished for various reasons in the last decade or so?
    Which top flight scientists and can you provide any references? I Would be interested to read something about this.
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    And it is not my hypothesis, but those of top-flight (so to say) real scientists who are world experts in the evolution of birds.
    Whom exactly.

    Citations to the relevant peer reviewed papers needed
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    Quote Originally Posted by Double Helix View Post
    Learning new things is essential to our understanding of all of the sciences. But only open minds are capable of learning new things.
    The evolution of birds from therapod dinosaurs is brought into extreme doubt based on the evolution of the avian flight digits derived from embryological studies of modern birds (there could be no greater proof). Alan Feduccia (see 1) et al. have demonstrated that the three flight digits ("fingers") develop from digits II, III and IV, with complete reduction in digits I and V (see 2, 3, 4).

    And they have the photographs to prove it.

    This is in stark contradiction to what is expected from birds being derived from therapods, the latter with forearm digits well established as arising from digits I, II and III following reduction of digits IV and V during development. The earliest therapod fossils support this assignment, since they possess all five digits, with IV and V already diminished.

    Anyone with significant knowledge of embryology will agree these observations represent an insurmountable problem for the descent of birds from therapods. Once such a major change like this occurs, it is not reversible, and is one of the most definitive lines of evidence to establish evolutionary relationships. In this case, it is very bad news for the notion of "living dinosaurs". To be sure, all of them went out with the impactor 66 mya. There were NO survivors.

    The advocates of "birds from therapods" were then faced with a rather shocking development. In order to preserve the concept that birds evolved from therapods, they devised a mutation known as "frame shift". In order to "work", this mutation requires that at some point therapods shifted their digit formation during development, providing a means for therapods to also form their "hands" from digits II, III, and IV. Before the data from modern birds, all therapods were unquestionably deemed to derive these digits from I, II and III. Many still insist this is the case. Apparently they are unaware of the claim for the frame shift concept, or even a need for it.

    Of course there is no evidence to support such a claim, and it clearly requires special pleading.

    To reiterate. observations from modern birds demonstrate therapods are not a possible line for their evolution, since the development of avian hands clearly reveal the classic pentadactyl development in their very early stages, and then reducing digits I and V to generate the II, III and IV flight digits which form the avian wing - for all avian species.

    The work with modern birds has largely been buried by those who do not wish to face up to the facts. Instead they invent highly questionable frame shift mutations that directly contradict even the fossil record regarding the origin of therapod forearm digits. Careers are at stake, many erroneous papers published, multi-million dollar exhibits "demonstrating" the appearance of birds from therapods, etc. (Such exhibits sometimes have a small sign which reads 'Some scientists do not agree with this relationship'). These people continue to insist that birds evolved from therapods, regardless of the absolute empirical evidence to the contrary.

    Certainly there can be no greater source for evidence of what really happened - the clear development of the avian flight digits obtained from embryological studies of modern birds. Indeed, they are the focus of interest, and their developmental stages dictate their origins. There are a number of other aspects of morphology which demonstrate that birds arose from an alternate ancient archosaur, but none could be more convincing based on the origin if these digits.

    Birds simply did not evolve from therapods. It is impossible.


    1. https://en.wikipedia.org/wiki/Alan_Feduccia

    2. Feduccia, A.; Nowicki, J. (2002). "The hand of birds revealed by early ostrich embryos". Naturwissenschaften. 89 (9): 391–393.

    3. Kundrαt, Martin; Seichert, Vαclav; Russell, Anthony P.; Smetana, Karel (August 2002). "Pentadactyl pattern of the avian wing autopodium and pyramid reduction hypothesis". Journal of Experimental Zoology. 294 (2): 152–159.

    4. Galis, F.; Kundrat, M.; Sinervo, B. (2003). "An old controversy solved: bird embryos have five fingers". Trends in Ecology and Evolution. 18: 7–9.
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    Quote Originally Posted by Double Helix View Post
    Birds simply did not evolve from therapods. It is impossible.
    Wow, it's impossible!? And yet ever major university teaches this 'impossibility' as the most likely path of evolution. Hmmm, it seems like someone is wrong, wonder who it is? All the major universities in the world of some guy on the internet?
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    Quote Originally Posted by Origin View Post
    Quote Originally Posted by Double Helix View Post
    Birds simply did not evolve from therapods. It is impossible.
    Wow, it's impossible!? And yet ever major university teaches this 'impossibility' as the most likely path of evolution. Hmmm, it seems like someone is wrong, wonder who it is? All the major universities in the world of some guy on the internet?
    Shooting the messenger, which is exactly what you are doing, does not change the facts. But it does have a very long history for those who don't like hearing facts which contradict their long-held beliefs. It is not my fault that modern birds put a dagger into the heart of the therapod origin of birds. You really have to blame it on those blasted birds!

    Claiming that some poster on the internet is the only one suggesting that the development of the bird hand is in conflict with the widely accepted view taught in all the schools etc. indicates you did not bother to read the articles referencing the contrary data. I do not expect any real challenges because the data is beyond doubt.

    I asked you to come back and give me reasons for why the hypothesis of an alternate theory of avian evolution was wrong, and this is your response? For any credibility, you should provide another reason for why you don't believe this. Attacking the poster does not prove anything. Try attacking the facts, if you can.

    They used to teach in all universities etc. that fission of heavy nuclei was impossible because they were certain the atomic nucleus was immutable. It was absolute heresy to suggest otherwise. And this from the top brains in physics, of all people.

    This was before the lowly radio-chemist Otto Hahn proved they were all wrong with his test tubes and centrifuge. Niels Bohr was quoted as having said "How could we have been so wrong?" This from one of the world's greatest minds, and the father of atomic structure and dynamics. He and all of physicists were certainly wrong - big time. And the Japanese learned the hard way about the implications of fission.

    Everyone used to say that infectious pathogenic proteins without DNA or RNA were impossible, until mad cows finally proved they were wrong. ALL of them.

    Prions are now well established in the scientific community, as is fission.

    There are many examples of this, but the two above are some that stick out at you. Grand accepted theories sometimes do not pan out. Even Einstein of all people did not believe black holes were possible.

    Still waiting for your data to support or oppose any of these posts. You said it was wrong, where is the data? Statements from "some guy on the internet" is not exactly hard evidence. I provided evidence from peer-reviewed journals. What exactly is it you provided?

    I must give Paleoichneum a lot of credit for a very spirited debate. At least he had a lot of ideas and reasons to doubt alternate concepts. He also provided me with a lot of work chasing down many species. One can only wonder if he replies to this latest post. I held back the Feduccia et al. data in reserve so as not to bias the thread from the start. Why don't you attack Feduccia et al. (along with the birds), instead of the messenger? Again, none of this was my idea.

    Read the articles and tell me this is wrong. Simplistic "rebuttals" such as yours are very common for those who cannot challenge real data. It is a common issue on all internet forums of this nature. Fortunately this is not about politics or religion. Real science demands real data for proofs. Read the real data.
    Last edited by Double Helix; February 4th, 2021 at 07:33 PM.
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    Double Helix I know you are dedicated to your belief that birds evolving from therapod dinosaurs is impossible, but are you familiar with the work of Jack Horner? He is working on a project to reverse engineer a dinosaur from a modern bird, specifically a chicken. https://dinosaurculture.com/my-dinoc...h-jack-horner/ That's just a quick link to a discussion about his work.
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    Quote Originally Posted by Falconer360 View Post
    Double Helix I know you are dedicated to your belief that birds evolving from therapod dinosaurs is impossible, but are you familiar with the work of Jack Horner? He is working on a project to reverse engineer a dinosaur from a modern bird, specifically a chicken. https://dinosaurculture.com/my-dinoc...h-jack-horner/ That's just a quick link to a discussion about his work.
    I appreciate the link and will certainly investigate it, Falconer360. Your handle suggests a major league flyer is also appreciated, and a predator at that! Most appropriate for this thread. I suppose the 360 is the range covered in degrees.

    But if there is anything to comment on it with regards to the actual evolution of birds, perhaps you should address that here.

    Otherwise, if you do not hear back about this reference, it is because I found nothing in the link to alter the empirical evidence that birds did not evolve from therapods. I note this here again since the earliest known flying bird, Archaeopteryx, is not believed to be on the main avian line to modern birds, but an off-branch, as are most of those fossils found with real feathers. After all, a clearly flightless creature with loads of flight feathers must also be avian, yet they abound in the "therapod only" designation. Very difficult to accept when all the data is comprehensively evaluated - especially that from modern birds.

    This is why I am requesting that you provide any data which you believe supports the opposing position. In that way, the thread will be presented with a unique aspect (i.e not my interpretation) that contradicts the empirical evidence I have recently posted. That is the data which compelled me to start this thread to begin with. Some of those truly expert paleornithologists have clearly gotten their hooks into me with the contrarian data. It is very difficult to reject, after a life-time researching the complexity of life sciences. More to follow.

    Thanks again. One never knows when or where a piece to the puzzle might appear, sometimes right out of the blue!
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    Quote Originally Posted by Double Helix View Post
    More to follow.
    Working our way back from modern birds to how they might have evolved, there are unique aspects of their anatomy strikingly different from most animals that arose after the P-T extinction. Comparison of modern bird anatomy to ancient fossils might also be definitive in this regard.

    One of the most significant differences immediately obvious are the legs of modern birds. Their "knees" point and hinge in the opposite direction of nearly all other vertebrates. That is, they appear to be backwards. There is a very good reason for this and it all boils down to aerodynamics.

    The less drag that flying animals present, the less energy needs to be spent on flight. Evolution of the modern bird leg is very revealing about their origin when looking at various fossils of ancient animals purported to be birds, or therapods.

    The "backward legs" of birds resulted from a prolonged evolution of the entire leg structure, greatly enhancing aerodynamic efficiency. The femur in modern birds is internalized, i.e. inside the body cavity, but still rotates to some degree on the ball and socket.

    The remaining leg parts evolved from the lower leg bones, providing a "new" femur, and as a result, a reverse-hinged joint. Again, this change resulted in a major decrease in aerodynamic drag, increasing a birds ability to sustain flight and duration. The arctic tern is a prime example of this evolutionary advantage!

    Comparing these traits to ancient fossils, one can see that many of the definite therapods do not have this dramatic change in leg structure, but retain the forward "knee", like that of almost all other walking vertebrates. But looking closely at other specimens, particularly those with real feathers, one can see these uniquely avian features in the legs of many ancient fossils currently defined as therapods. It seem quite likely they are not properly classified. They would appear to be an independent line of descent as these changes are very profound, and happened for a very good reason, and a very long time ago.

    Understanding how these characteristics evolved provides yet another reason for questioning the therapod-to-bird relationship. So the next time you see a bird, look closely at its legs, and wonder how such a remarkable feature could develop from the "standard" therapod body format, which has the standard, hinged knee joint. The change in the legs, and long arms, are a very discriminating feature of the primary avian line leading to modern birds, the final discriminator as to its origin.
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    Quote Originally Posted by Falconer360 View Post
    Double Helix I know you are dedicated to your belief that birds evolving from therapod dinosaurs is impossible, but are you familiar with the work of Jack Horner? He is working on a project to reverse engineer a dinosaur from a modern bird, specifically a chicken. https://dinosaurculture.com/my-dinoc...h-jack-horner/ That's just a quick link to a discussion about his work.

    Do you have an introductory link to this Horner project?

    The link above reads like I just opened a detective novel in the middle of the book, without a background on what they are actually trying to accomplish, and how.

    TIA.
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    Quote Originally Posted by Double Helix View Post
    Quote Originally Posted by Falconer360 View Post
    Double Helix I know you are dedicated to your belief that birds evolving from therapod dinosaurs is impossible, but are you familiar with the work of Jack Horner? He is working on a project to reverse engineer a dinosaur from a modern bird, specifically a chicken. https://dinosaurculture.com/my-dinoc...h-jack-horner/ That's just a quick link to a discussion about his work.

    Do you have an introductory link to this Horner project?

    The link above reads like I just opened a detective novel in the middle of the book, without a background on what they are actually trying to accomplish, and how.

    TIA.
    Here's a link to his attempt to crowdsource fund the project, he has quite a bit of information there: https://www.gofundme.com/f/making-a-live-dinosaur Also here is a TED Talk on the subject: https://www.ted.com/talks/jack_horne...en?language=en

    Jack Horner is probably the most famous living paleontologist in the world, having served as the technical advisor for all of the Jurassic Park films.
    "For every moment of triumph, for every instance of beauty, many souls must be trampled." Hunter S Thompson

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  30. #29  
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    Firstly it must be stated that the entire concept of bringing back dinosaurs from ancient DNA is really science fantasy. There are no means by which such reconstructions could be made.

    The same can be said for dinochickens. It is beyond very unlikely that the DNA of a chicken will hold all of its ancestral DNA sequences, which would be essential for the recovery of any ancient ancestral form. Such a concept would suggest that, with enough effort, one could also reduce a chicken to the first cell that gave rise to all life forms on earth, billions of years ago. There is simply insufficient related DNA to "reactivate" to permit any such transformations.

    Surely some features can be brought out that resemble ancient relatives, but the entire animal recovered, after millions of years of evolution is not going to happen. And DNA from fossils, even if it could be found, would be highly damaged by background radiation (over many millions of years!), and therefore worthless. And to any naysayers out there, yes, you are hearing this from an expert (like it or not).

    To obtain, by "reverse engineering", a complete ancient creature from its living descendant is simply not possible. Horner has spent too much time in Jurassic Park movies and needs to spend more time in the real world of today, and with what is available for such a project. Dinochicken is never going to happen, and anyone donating to this cause is wasting their money. Or hoping to see how far along they go to create a Frakenchicken!


    To reiterate - While the concept of bringing back a chicken's ancient relative's by manipulating its current DNA might seems like a fabulous idea, it is simply not possible to achieve. Over such extended periods of time, too many genes have been altered, and by too much, or have simply been deleted altogether. Jack would have better luck working on a time machine. Sorry if this is blunt, but sometimes such evaluations are unavoidable.
    Last edited by Double Helix; February 7th, 2021 at 06:00 PM.
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    Reviewing the Wiki references in the Feduccia link (1) given earlier, I am reminded of a fossil which does represent a possible relationship to a precursor for Archaeopteryx (and the avian line), and which appeared at least 165 mya.

    This creature, Scansoriopteryx ("climbing wing") was first reported by Czerkas and Yuan (2). While it does not have flight feathers (at least not preserved in this fossil), it does have a long tail with feathers, likely used as a prop when climbing, as seen with woodpeckers. It also possessed a body full of plumage, and real feathers on the forelimbs - 165 million years ago!

    Most noteworthy is that Scansoriopteryx has forelimbs much longer than a therapod, which is expected from a morphology which evolved for flight. Indeed, its forearms are longer than its legs, something clearly not related to any therapod fossils I have ever seen, and likely anyone else. Also notable is the apparent reduction in the femur, a characteristic previously noted as an evolutionary advantage to evolving flight, and seen in all modern birds. And it displays the reverse-hinged "knees", also suggestive of modern birds. No "typical" therapod ever demonstrates such characteristics to commit to any direct relationship between them, especially at this very important time in their co-evolution. Indeed, is seems ludicrous to even remotely suggest it!

    Moreover, the forelimb claws are those of the type used in climbing trees, and Scansoriopteryx possessed the feet of an creature which perched in trees. So the evidence indicates this was a climbing glider - previously proposed (in previous posts) as one of the initial stages in the appearance of birds. This aspect of the avian line distinguishes it yet again from any real therapod fossils that are known, and represents another challenge (aside from the origin of modern bird flight digits) to the therapod origin of birds.

    Clearly some of us wonder why the text for Scansoriopteryx continues to refer to such creatures as "dinosaurs" when no evidence exists for such a designation, except for several comparative features expected for relatives of the immense radiation of reptiles following the P-T extinction. The only thing truly evident in such a relationship is that they are all of reptilian descent.

    However, Scansoriopteryx likely is not on the main avian line as it does not have flight feathers, at least not with this fossil. And appearing at ca. 165 mya, it does not seem a likely precursor for fully feathered birds. They probably arose from a common ancestor, since Archeopteryx, or something very much like it, was likely flying around at the same time Scansoriopteryx was only gliding.

    Still, it provides more evidence that the fossil record is far from complete regarding such creatures. The true story on avian evolution will be better defined when additional fossils are found in the 50-80 million year gap, from the origin of the avian line to powered flight.

    Finally, Czerkas and Feduccia (3, 4) argue that the traits of Scansoriopteryx remove it from the line of therapods, and even all of dinosaurs. They suggest that Scansoriopteryx evolved from an ancient archosarian line, as previously noted in numerous posts.

    Incidentally, it should also be pointed out that it was Feduccia who convinced the world that Archaeopteryx was capable of powered flight based on its upper skeletal structure. Exactly what one expects from an expert on the evolution of birds.


    1. https://en.wikipedia.org/wiki/Alan_Feduccia


    2. https://en.wikipedia.org/wiki/Scansoriopteryx


    3. Czerkas, S. A., & Feduccia, A. (2014). Jurassic archosaur is a non-dinosaurian bird. Journal of Ornithology, 155, pages 841–851. (abstract - https://link.springer.com/article/10...336-014-1098-9 )


    "Birdlike fossil challenges notion that birds evolved from ground-dwelling dinosaurs"

    4. https://www.sciencedaily.com/release...0709140203.htm - For a concise overvew of (3).
    Last edited by Double Helix; February 23rd, 2021 at 05:47 PM.
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