This site presents the idea that birds developed from flying pterosaurs.
This is a credible alternative to the current, mainstream idea that birds developed from land-based dinosaurs.
Thursday, September 15, 2011
Which one of these is not like the others?
Which one of these is not like the others? Actually there are two, if you look carefully.
Notice also the size depicted for the bird in the top right. It is as big as a tyrannosaurus. This chart is wrong in so many ways.
Birds are dinosaurs according to cladists. So not all dinosaurs are extinct. Right? And yet it was said earlier that: "The aligator and bird are still alive whereas the rest are extinct".
"Birds" are a set of animals that belong to a larger set we call "Dinosaurs". All "birds" can be placed into the set called "Dinosaurs". The reverse is not the case. Many "dinosaurs" are not birds. All the dinosaurs that are alive today are members of the set called "birds". There are no living dinosaurs that are not members of this set. There is no ambiguity involved. Either an organism is alive today or it is not.
"Birds" are a set of animals that belong to a larger set we call "Dinosaurs".
That is the point right there. YOU CALL THEM DINOSAURS. You embed your assumption of phylogeny into your vocabulary and then expect others to use your vocabulary.
That is why it is best not to use cladistics. We can simply use a natural system of calling taxa by their proper names. For example "dinosaurs" are actual dinosaurs and not an artificial category (a clade) that includes dinosaurs and other creatures that the dino to bird enthusiasts think evolved from them.
If you believe that birds evolved from dinosaurs then simply say that.
Your arguments against cladistics are a red herring. We can say exactly the same thing with respect to your classification scheme. "Birds" are a set of animals that belong to a larger set we call "Pterosaurs". All "birds" can be placed into the set called "Pterosaurs". The reverse is not the case. Many "Pterosaurs" are not birds. All the pterosaurs that are alive today are members of the set called "birds". There are no living pterosaurs that are not members of this set. There is no ambiguity involved. Either an organism is alive today or it is not.
Anonymous posted: "Birds" are a set of animals that belong to a larger set we* call "Pterosaurs".
That is what YOU would call them. Cladists can misleadingly call them pterosaurs. But I am not saying that. I am making the simple statement that birds developed from pterosaurs.
Is it possible for you to think outside the conventions of cladistics? It appears not. That is what I mean by your mind being programmed. Your mind runs the "cladistics program" and you cannot think beyond that.
If anyone else is following this, I wonder if anyone can think beyond the limitations of cladistics. Anyone?
Let's save time, by simply not using the particular method called "cladistics".
*Note that the "we" is a reference to cladists. It really means "we cladists". So the sentence is actually: Birds" are a set of animals that belong to a larger set we cladists call "Pterosaurs. And that is because cladists embed in their vocabulary the assumptions of their theory.
If you don't want to use cladistics, then show us the damn fossils already! Fossils the document every little step from pterosaur to bird. Why are you being so coy about this?
Would you please document every little step from DINOSAUR to bird. OR just give ANYTHING about that presumed lineage. At the moment you have proposed NOTHING. And yet you have the gall to ask me for all the detail steps.
I have already given the pterosaur to primitive bird to modern bird model. What is yours - even at that level of detail.
"They evolved from the advanced pterosaurs - the pterodactlys."
Which group? Pterodactyloidea is a very large sub-order with some very specialised forms. Also it appeared in the mid Jurassic, which is either contemporary with, or possibly even after, the appearance of the first maniraptors (particularly if Eshanosaurus is confirmed as a Therizonosaur). Your scenario seems to suffer from the same time problem Archaeopteryx used to suffer from (until the discovery of forms such as Scansoriopterygidae)
Hello Anonymous. As I have mentioned elsewhere I have not worked out the details of the specific pterodactyl subgroups and their relationship with their corresponding primitive bird counterparts. Would you like to work with me on this? That would be great. My first inclination is that each of the 4 superfamilies developed into a corresponding form of primitive bird line. So on the one hand we have the 4 pterodactyl superfamilies:
and on the other we have the primitive bird groups I laid out in the Dec 17, 2010 post. Each of those primitive bird groupings begins with a Dromaeosaurid subgroup.
Care to join in the analysis? If not, could you give us the dino to bird lineage as you see it, if you think that is more to your liking.
We begin looking for similarities. For example consider this: http://en.wikipedia.org/wiki/Pteranodon "The wing shape of Pteranodon suggests that it would have flown rather like a modern-day albatross. This is based on the fact that Pteranodon had a high aspect ratio (wingspan to chord length) similar to that of the albatross — 9:1 for Pteranodon, compared to 8:1 for an albatross. Albatrosses spend long stretches of time at sea fishing, and use a flight pattern called "dynamic soaring" which exploits the vertical gradient of wind speed near the ocean surface to travel long distances without flapping, and without the aid of thermals (which do not occur over the open ocean the same way they do over land).[11] While most of a Pteranodon flight would have depended on soaring, like long-winged seabirds, it probably required an occasional active, rapid burst of flapping, and studies of Pteranodon wing loading (the strength of the wings vs. the weight of the body) indicate that they were capable of substantial flapping flight, contrary to some earlier suggestions that they were so big they could only glide.[3]"
Here we see a possible connection to seabirds and albatross-type creatures. This means there is a possible connection to the seabird line which is presented in the Dec 17, 2010 post.
http://en.wikipedia.org/wiki/Pterodactylus "In 1998, the discovery of one specimen assigned to P. kochi shed light on the life appearance of Pterodactylus, as it preserved unique soft-tissue traits not present in previous fossil skeletons, including long, bristly pycnofibres (a fur-like body covering known only in pterosaurs) on the neck, details of a urpatagium (hind wing membrane between the legs and tail) that also stretched between the toes as webbing, and a pelican-like throat pouch."
So there is a possible connection to the bird line that includes foot webbing and pelican-like throat pouches. For example the line that includes pelicans.
Here is some more relevant material that may help: 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".
Oh I thought you meant like go on expeditions and dig up fossils that show a gradual progression from pterosaur to primitive bird. I mean wikipedia saying something is blank-like isn't really science. A raccoon's paw is chimp-like but that doesn't mean it evolved from a primate.
Anyway, when you're ready to go dig up some fossils, let me know!
Nope, not expeditions. Lots of evidence already. It just needs to be analyzed properly.
But if you do not want to participate on the pterosaurs, perhaps you could present the dino to bird lineage. Or are you content with that being a mystery?
I was hoping to go on expeditions, but lab analysis sounds interesting too. Does your lab have teleconferencing? Because unless we're in the same region, I probably won't be able to afford to go to your lab and analyze the fossils. Maybe I could take the bus on weekends if you're close enough.
As to dinosaurs to birds, well I'm not really sure what you mean by lineage. I'm also just starting my studies so I'm not super knowledgeable yet on the whole subject. But I do not intend to waste my academic career being a follower. I want to break new ground!
You can break new ground with the material and ideas I have outlined on this site. You really don't need anything further from me. Good luck with your studies.
I thought your thesis was that maniraptors came after pterosaurs, then from them came the modern bird groups. Now you seem to be arguing for a direct lineage from various pterosaur groups to modern bird groups so where do maniraptors fit into this new analysis?
So the descendants of pteranodon lost their similarities with the albatross, even lost the ability of flight, to regain it along with all the albatross features again later? Then what is the point in comparing pteranodon to the albatross?
I'm sorry, I don't understand how that works. Perhaps you could explain.
Have you been following what I have said at all? Flying pteranadons developed into flying primitive birds that developed into flying modern birds such as albatross. This is really not all that difficult.
There are no non-avian maniraptors (flying on not) that have albatross-like features. So you are saying they lost those features and then regained them? In which case why would a comparison between an albatross and a pteranodon be relevant?
I have been following that. That is exactly why I am confused by your pteranodon to albatross comparison. It is meaningless, since all those similarities (including the basic ability of flight) would have to be lost in the non-avian "primitive bird" descendant of pteranodon, and reappear in the "modern flying" albatross.
OK, I see, you clarified that you meant FLYING "non-avian maniraptors". So basic flight was retained, which, apparently, means that there was a flying non-avian maniraptor that retained all those albatross-like features of pteranodon, that later appeared in its descendant the albatross.
Do you have evidence of such a flying non-avian maniraptor, one 'transitional' between pteranodon and albatross?
Anonymous, this conversation is somewhat interesting, but it is clear you have not read the posts I have accumulated over the last year. I am not interested in repeating it all for you here point by point. Let's save time and have you post your questions with the post that it relates to. You can find the related posts to any question you have by using the search function.
As to which primitive birds have characteristics like the albatross - I have not analyzed every detail. Would you like to join me in taking the analysis to that level of detail? If not, that is okay. But if not, then please give us the dino to bird alternative, What is the dino to bird lineage leading to albatross? Please indicate which taxa are on that line. And if you cannot give the taxa names, then give us a description of the characteristics of the type of taxa purported to be on the line and the rough time of their existence.
Here is a very preliminary draft lineage leading to albatross:
Pteranodon* (Ornithocheiroidea**) --> a Dromaeosaurid subgroup --> an Enantiornithes seabird subgroup --> Ichthyornithes*** subgroup --> Albatross
* http://en.wikipedia.org/wiki/Pteranodon "The wing shape of Pteranodon suggests that it would have flown rather like a modern-day albatross. This is based on the fact that Pteranodon had a high aspect ratio (wingspan to chord length) similar to that of the albatross — 9:1 for Pteranodon, compared to 8:1 for an albatross. Albatrosses spend long stretches of time at sea fishing, and use a flight pattern called "dynamic soaring" which exploits the vertical gradient of wind speed near the ocean surface to travel long distances without flapping, and without the aid of thermals (which do not occur over the open ocean the same way they do over land).
** http://s1.zetaboards.com/Conceptual_Evolution/topic/1162271/1/ "Based on Mark Witton's research (he's the most decent pterosaur paleobiologist I've seen so far), here's a brief comparation between pterosaur and bird niches (note: niches occupied as adults; since pterosaurs were precocial, they occupied several niches throw their lifestyle, and I have no idea what can be said about them): -Ornitocheiroids: albatrosses, frigate birds, pseudodontorns, vultures"
*** http://en.wikipedia.org/wiki/Ichthyornis "The beak of Ichthyornis, like the hesperornithids and other primitive birds, was compound and made up of several distinct plates, similar to the beak of an albatross, rather than a single sheet of keratin as in most modern birds."
"Here is a very preliminary draft lineage leading to albatross:
Pteranodon* (Ornithocheiroidea**) --> a Dromaeosaurid subgroup --> an Enantiornithes seabird subgroup --> Ichthyornithes*** subgroup --> Albatross"
Hmm. Since, out of all this lineage, we only have fossils of pteranodon and samples of albatross, it seems that you suffer from the same lack-of-fossils problem that the traditional theory has. Ichthyornis could not be a link from pteranodon to albatross because it completely lacks wings, could not fly, and therefore did not have the similarities pteranodon had to the albatross. Those features would have to have been lost and regained. We also have no fossils of anything like a flying dromaeosaurid that looked like an albatross. Or a flying dromeosaurid that looked like a pteranodon.
So, all you have is that pteranodon had the same wing ratio (but entirely different wings) with the albatross, and ichthyornis had (unlike pteranodon) a similar beak to the albatross (but no wings at all). How can you get that into a plausible lineage?
It seems that your theory suffers from a much greater "lack of fossils" than the dino-to-bird one.
Anonymous posted: "Ichthyornis could not be a link from pteranodon to albatross because it completely lacks wings, could not fly, and therefore did not have the similarities pteranodon had to the albatross."
Take a look at Ichthyornis: http://en.wikipedia.org/wiki/Ichthyornis
I think you're confusing Icthyornis with Hesperornis there. Icthyornis certainly could fly. However it was more gull like than albatross like and of course a dromaeosaurid is nothing like an albatross or a pteranodon (and also had teeth and proper jaws, not a horny beak) - so the same problems in essence are still there. Also it is clear Dr. Pterosaur is not interested in doing real research - digging round for quotes from Wikipedia is far from anything like a scientific approach
Anoymous posted: "It seems that your theory suffers from a much greater "lack of fossils" than the dino-to-bird one.
No model could have a greater "lack of fossils" than the dino-to-bird one, since the dino to bird model has none. If you think it it has some, please let us know what they are.
Anonymous posted: "Ichthyornis could not be a link from pteranodon to albatross because it completely lacks wings, could not fly, and therefore did not have the similarities pteranodon had to the albatross."
Do you now see that Ichthyornis indeed has wings and could fly?
Pteranodon was from the Late Cretaceous, 86–84.5 Ma, far too recent and far too derived for it to have been an ancestor of "a dromaeosaurid group", let alone an Enantiornithe group. In fact it was probably a contemporary of Icthyornis.
Anonymous posted: "Pteranodon was from the Late Cretaceous, 86–84.5 Ma, far too recent and far too derived for it to have been an ancestor of "a dromaeosaurid group", let alone an Enantiornithe group. In fact it was probably a contemporary of Icthyornis."
Anonymous, you said that Ichthyornis "completely lacks wings, could not fly". Do you still think that? Let's see if we can get that straight.
Perhaps the ability for people to post anonymously is confusing you. You seem to think they are all the same person sometimes. Maybe better to get people to post with names only
It gets a bit confusing with multiple anonymous posters. I respect completely your wish to be anonymous. But if it is acceptable, you might choose to give a made-up name to help sort things out. You can put the made-up name in your anonymous post.
"Pteranodon was from the Late Cretaceous, 86–84.5 Ma, far too recent and far too derived for it to have been an ancestor of "a dromaeosaurid group", let alone an Enantiornithe group. In fact it was probably a contemporary of Icthyornis."
Simon a comment like that would make more sense if it were made after some time had passed for it to be answered. Right? Especially after the confusion about which anonymous was posting.
Indeed, I confused Ichthyornis with Hesperornis. My bad, I was confused by the name and because they have similar beaks (which is the similarity you propose).
But somehow, that seems an even further stretch. Hesperornis was a small animal, no larger than a pigeon. Pteranodon was huge. You now need transitionals to bridge the size gap as well, confirm that Ichthyornis maintained the wing-to-body ratio that pteranodon had (which seems unlikely, according to its size), find enantiornithines and dromaeosaurids that maintained pteranodon and albatross characteristics, and finally, explain why the toothless beak of the pteranodon developed teeth, to lose them again. And that does not even count all the radical changes needed in the skeletal morphology of the limbs and wings.
As you can see, you seem to suffer from the same lack of fossils the dino-to-bird theory does. Even more, in fact, if you stop looking for similarities and ignoring the differences. You have to take into account the differences as well.
"Simon a comment like that would make more sense if it were made after some time had passed for it to be answered."
Some more time has passed now. I see you have modified your proposal, does that also include taking pteranodon out of the line to albatrosses (and presumably other Procellariiformes) given that it is too recent and too derived?
Why can't Dromaeosaurs simply be dinosaurs? And be unrelated to your pterosaur to bird lineage? There is certainly enough evidence to place them within dinosaurs.
Anonymous could you please include a made-up name in your Anonymous post please. Also please give us what you think the dino to bird lineage was. That would be great. I will take your concerns seriously when you present an alternative.
How do people respond to this*: http://www.ucmp.berkeley.edu/diapsids/saurischia/troodontidae.html "It has been suggested that they [troodontidae] were the ancestors of birds, but this is not accepted; a dromaeosaur is currently thought to be the ancestor of all birds."
* This quote is part of my post: http://pterosaurnet.blogspot.com/2010/06/pterosaur-dromaeosaurids-birds-1.html
Any theory about the lineage leading to modern birds will face the same two challenges. One is - where did the primitive birds come from? And second is - how did the primitive birds (basically maniraptors) develop into the vast array of modern birds.
The dino to bird theory does not answer either challenge.
The theory I am proposing answers both as follows: Primitive birds developed from pterosaurs. And primitive birds developed into modern birds in a set of parallel lineages.
Concerning the dino to bird model, to this point, NOBODY has offered an answer for either challenge.
http://en.wikipedia.org/wiki/Pteranodon "It is likely that, as in other polygynous animals (in which males compete for association with harems of females), Pteranodon lived primarily on offshore rookeries, where they could nest away from land-based predators and feed far from shore; most Pteranodon fossils are found in locations which at the time, were hundreds of kilometres from the coastline.[6]
This leads to the conclusion that pteranodon relates to seabirds.
We still have the timing issue (that has been raised) to work through.
Sotos, I have a question for you and it relates to your use of the word "dinosaur".
You posted: "Why can't Dromaeosaurs simply be dinosaurs? And be unrelated to your pterosaur to bird lineage? There is certainly enough evidence to place them within dinosaurs."
Remember the ambiguity around the word "dinosaur" that I have been mentioning again and again and again?
Is your question: Why can't Dromaeosaurs simply be non-maniraptor coelurosuars (dinosaurs)? And be unrelated to your pterosaur to bird lineage? There is certainly enough evidence to place them within non-maniraptor coelurosaurs (dinosaurs)."
"Hello Sotos. Dromaeosaurs are a part of the total picture. See: http://pterosaurnet.blogspot.com/2010/06/pterosaur-dromaeosaurids-birds-1.html"
I know you have them as part of the picture, I just don't see why. The differences between pterosaurs and dromeosaurs are too big to overlook. And there are no transitionals between pterosaurs and dromeosaurs. On the other hand, dromeosaurs fit in morphologically in a continuum from basal coelurosaurs to primitive birds. Even that study you quoted spoke of significant correlation between paraves (which includes dromeosaurs) and coelurosaurs (dinosaurs).
In that regard, the traditional theory has more going for it. They do not propose direct ancestry for any fossil, but have a great number of fossils that indicate features diplaying a transitional lineage were present in all the related dinosaur groups. You, on the other hand, propose a dircet ancestry from pterosaurs to modern birds, but have no fossils whatsoever to substantiate it (since no ptero-dromeosaur transitionals have been found, whether sister groups or in direct ancestral line).
With that in mind, it would be better if you left dromeosaurids out of the picture, and focused on a direct immediate descent from pterosaurs to birds. If you need a major form of saltation for your lineage, then why not a saltation from, say, pteranodon directly to the albatross, and the same for every other pterosaur-bird transition? Let dinosaurs be dinosaurs.
"Why can't Dromaeosaurs simply be dinosaurs? And be unrelated to your pterosaur to bird lineage? There is certainly enough evidence to place them within dinosaurs."
Remember the ambiguity around the word "dinosaur" that I have been mentioning again and again and again?
Is your question: Why can't Dromaeosaurs simply be non-maniraptor coelurosuars (dinosaurs)? And be unrelated to your pterosaur to bird lineage? There is certainly enough evidence to place them within non-maniraptor coelurosaurs (dinosaurs)."
I don't think so, since dromeosaurs are also firmly included within maniraptora. If you were to exclude something from the group, it would be more parsimonious to exclude Avialae, which is the most derived bird-like form. Perhaps that is the direct developement from pterosaurs. I'm not saying that's the right choice, I'm just saying it's less wrong.
"If you need a major form of saltation for your lineage, then why not a saltation from, say, pteranodon directly to the albatross, and the same for every other pterosaur-bird transition?"
It would probably have to be like this anyway as Enantionithes precede pteranodon and icthyornis are its contemporaries. So a direct transition to a modern bird group would make more sense; the only problem then is which group corresponds to which modern bird group as pretty much all pterosaurs seem to have been in coastal/seafaring niches. They can't all correspond to gulls and tubenoses.
Sotos you posted: "On the other hand, dromeosaurs fit in morphologically in a continuum from basal coelurosaurs to primitive birds."
That is not correct. If you want to claim that, then please present the taxa in the dino to bird lineage. Nobody has ever presented the lineage.
What they have done is said that IF there is a lineage, then these other taxa (which are not on the line) would be sister taxa. But there is NO evidence of any actual ancestors. NONE. Take a look at my most recent post: http://pterosaurnet.blogspot.com/2011/09/dino-to-bird-problem.html
Sotos you are using confusing cladistic terminology which assumes the dino to bird model. I have pointed out the problem with that throughout this blog.
Just use the names of the actual groups. Use the labels: Non-maniraptor coelurosaurs (dinosaurs) Non-avian* maniraptors (maniraptors) Modern birds
Please reword your question/point for us, using those labels.
"Sotos you are using confusing cladistic terminology which assumes the dino to bird model. I have pointed out the problem with that throughout this blog.
Just use the names of the actual groups. Use the labels: Non-maniraptor coelurosaurs (dinosaurs) Non-avian maniraptors (maniraptors) Modern birds
Please reword your question/point for us, using those labels".
Since I am proposing that maniraptors are dinosaurs, there is no need to use the second label. I am saying it would be less wrong to consider Avialae as distinct from dinosaurs (including maniraptors and of course dromaeosaurs), and related to pterosaurs.
"Sotos you posted: "On the other hand, dromeosaurs fit in morphologically in a continuum from basal coelurosaurs to primitive birds."
That is not correct".
But even the source you yourself quoted says so. Senter says he finds a positive taxon correlation between paraves and coelurosaurs, which means that they share a morphological continuum. That is the case whether there are proposed taxa in a direct ancestry line or not.
"If you want to claim that, then please present the taxa in the dino to bird lineage. Nobody has ever presented the lineage".
I don't see why one needs to propose a direct lineage to detect this morphological connection, but either way I don't think no one has ever done so. Here is a proposed line: From a Theropod group to a Maniraptor group, to a Paraves group, to Avialae. Now, I still think it would be less wrong to hypothesize that such a line led to dromeosaurids and troodontids (all dinosaurs), but NOT to Avialae. Why do you find that less possible than your assumption?
"What they have done is said that IF there is a lineage, then these other taxa (which are not on the line) would be sister taxa. But there is NO evidence of any actual ancestors. NONE".
What would you consider as "evidence of an actual ancestor"? I cannot think of any possible evidence, either for the traditional theory or yours. Can you?
Sotos, you are proposing that maniraptors are dinosaurs. That is a confusing cladistic way of putting it. Are you proposing that maniraptors evolved from non-maniraptor coelurosaurs?
No, I am proposing that maniraptors are dinosaurs in the same way coelurosaurs are dinosaurs. They are a dinosaurian group that evolved (or 'developed' if you like) from basal coelurosaurs.
Like you say "coelurosaurs (dinosaurs)" I also say "maniraptors (dinosaurs)".
I think that your theory would be more coherent if you only excluded Avialae from maniraptors (and dinosaurs). What do you think?
Simon posted: "If you need a major form of saltation for your lineage, then why not a saltation from, say, pteranodon directly to the albatross, and the same for every other pterosaur-bird transition?" It would probably have to be like this anyway as Enantionithes precede pteranodon and icthyornis are its contemporaries. So a direct transition to a modern bird group would make more sense; the only problem then is which group corresponds to which modern bird group as pretty much all pterosaurs seem to have been in coastal/seafaring niches. They can't all correspond to gulls and tubenoses."
Pterosaurs developed into primitive birds (non-aves maniraptors) which then developed into modern birds. Pterosaurs did not develop directly into modern birds. You are rightly interested in the timing but it is not a showstopper. I must say again because it is important. What is the dino to bird lineage alternative? What are we comparing my proposal to? For example, did a tyrannosaur type creature leap to being modern birds? What is the dino to bird lineage? Lay it out.
Sotos posted: Like you say "coelurosaurs (dinosaurs)" I also say "maniraptors (dinosaurs)".
I do not say "coelurosaurs (dinosaurs)". I say non-maniraptor coelurosaurs (dinosaurs).
Just use the names of the actual groups. As I suggested. Then there will be no confusion and no embedding your dino to bird assumption in the vocabulary.
"I do not say "coelurosaurs (dinosaurs)". I say non-maniraptor coelurosaurs (dinosaurs)".
So you also agree that maniraptors are coelurosaurs? If you don't, and you think that maniraptors and coelurosaurs are distinct, then the term "non-maniraptor coelurosaurs" is redundant: Either it's a maniraptor, or it's a coelurosaur.
Like you say, let's keep it simple. So, what do you think about my alternative?
Anyway, to avoid bringing the dfiscussion to a halt, I will use your term, although I think it's redundant if one considers coelurosaurs and maniraptors distinct.
So, I say "maniraptors (dinosaurs)" in the same way you say "non-maniraptor coelurosaurs (dinosaurs)".
For those interested, Senter uses the terms "Tyrannosaur cluster" and "Bird-like cluster". He does not include modern birds in his study, so by "bird-like cluster" he means primitive birds (basically non-aves maniraptors)
And by "Tyrannosaur cluster" he means basically non-maniraptor coelurosaurs (actual dinosaurs).
His baraminological analysis clarifies the groups of creatures we are dealing with.
Sotos posted: "So, I say "maniraptors (dinosaurs)" in the same way you say "non-maniraptor coelurosaurs (dinosaurs)". Is that accepteble?"
Obviously it is not acceptable. What is your aversion to simply using the names of the actual groups? There were dinosaurs (non-maniraptor coelurosaurs). There were primitive birds (non-aves maniraptors). And there are modern birds.
Just express your questions and points in terms of those actual groups.
Sotos posted: "I do not say "coelurosaurs (dinosaurs)". I say non-maniraptor coelurosaurs (dinosaurs)". So you also agree that maniraptors are coelurosaurs? If you don't, and you think that maniraptors and coelurosaurs are distinct, then the term "non-maniraptor coelurosaurs" is redundant: Either it's a maniraptor, or it's a coelurosaur. Like you say, let's keep it simple. So, what do you think about my alternative?"
Why are we using up time on this? Just use the names of the actual groups.
The problem you are having Sotos is that you choose to only think in clades. When I say "non-maniraptor coleurosaurs" I am trying to convey the idea that Senter conveys with "Tyrannosaur cluster".
I realize that when I use the phrase "non-maniraptor coelurosaurs" it can be confusing to people because "coelurosaur" is defined as a clade that is defined to include maniraptors*. That is a perfect example of embedding your dino to bird assumption in the vocabulary. That is a bad idea.
When I say "non-maniraptor coelurosaurs" I am trying to convey the idea that Senter conveys with "Tyrannosaur cluster".
*But I have to say something to try to get across the idea.
I must say again because it is important. What is the dino to bird lineage alternative? What are we comparing my proposal to? For example, did a tyrannosaur type creature leap to being modern birds? What is the dino to bird lineage? Lay it out.
Dr. Pterosaur, Perhaps you missed my post where I AGREED to use the actual terms. I am using the terms "maniraptors" and "non-maniraptor coelurosaurs".
These are the 'actual terms', are they not?
Now, just as you clarify "coelurosaurs" with "(dinosaurs)", I also clarify "maniraptors" in the same bway.
How is that unacceptable? It is my position. Are you asking me to accept your position brforehand, without discussing it?
Sotos posted: "Now, just as you clarify 'coelurosaurs' with "(dinosaurs)",
I do not "clarify coelurosaurs with dinosaurs" (whatever that means). I have never said that.
I have been patient with you, but this is all I intend to say on this. You are wasting your time and mine (perhaps on purpose*). Use the terms "Tyrannosaur cluster" and "Bird-like cluster" if you wish to discuss this topic with me. (And use the term "modern birds" if you wish to refer to existing modern birds.)
* I have had discussions in the past with people where they actually admitted afterward that their goal was to waste my time.
"If you need a major form of saltation for your lineage, then why not a saltation from, say, pteranodon directly to the albatross, and the same for every other pterosaur-bird transition?" It would probably have to be like this anyway as Enantionithes precede pteranodon and icthyornis are its contemporaries. So a direct transition to a modern bird group would make more sense; the only problem then is which group corresponds to which modern bird group as pretty much all pterosaurs seem to have been in coastal/seafaring niches. They can't all correspond to gulls and tubenoses."
Pterosaurs developed into primitive birds (non-aves maniraptors) which then developed into modern birds. Pterosaurs did not develop directly into modern birds. You are rightly interested in the timing but it is not a showstopper. I must say again because it is important. What is the dino to bird lineage alternative? What are we comparing my proposal to? For example, did a tyrannosaur type creature leap to being modern birds? What is the dino to bird lineage? Lay it out.
-------------------------
Let's analyze this from the most parsimonious point of view. We have flying pterosaurs similar to flying ichthyornithes. And we have flying ichthyornithes similar to flying modern seabirds. Does the timing work out for a development from pteranodon subgroup to ichthyornis subgroup to modern seabirds?
I am proposing that specific pterosaur groups developed into specific primitive bird groups. In this case, some pteranodon subgroups would develop into some ichthyornithes subgroups. I will analyze that idea in the next post.
Note: Other specific bird lineages would develop through dromaeosaurids and some through enantiornithes.
http://en.wikipedia.org/wiki/Pteranodon Late Cretaceous, 86–84.5 Ma
http://en.wikipedia.org/wiki/Ichthyornis Late Cretaceous, 95–85 Ma
At this point, I will consider that the dino to bird theory is based on a saltation from a tyrannosaur-type creature to the diversity of modern birds. That really is all the evidence that has ever been provided. So we can compare that to what I am proposing.
Does the timing work out for a development from pteranodon subgroup to ichthyornis subgroup to modern seabirds?
According to the wiki articles pteranodon fossils have been found back as far as 86 mya and ichthyornithes as far back as 95 mya.
Let me make an interesting point. When this sort of timing information is found related to an accepted lineage we all know the answer that is given. As a test for fun, what is the answer that is given?
I will answer in a bit but I wanted to see if anyone could for fun answer this.
"I must say again because it is important. What is the dino to bird lineage alternative? What are we comparing my proposal to? For example, did a tyrannosaur type creature leap to being modern birds? What is the dino to bird lineage? Lay it out".
I gave you a proposed lineage a few posts ago.
Now, why do you oppose to me using the terms "manitaptor" and "non-maniraptor coelurosaur"? You have used them repeatedly.
I simply consider both dinosaurs, and not just the second.
I see that you are now proposing a direct lineage from pteranodon to sea birds- essentially, you are doing for pteranodon what I proposed you should do for all pterosaur-bird lineages. You leave dromeosaurids and other Paraves aside and propose a direct transition from Pterosaurs to Avialae.
Perhaps you should consider expanding on the details of that. I am glad to have offered some food for thought.
"At this point, I will consider that the dino to bird theory is based on a saltation from a tyrannosaur-type creature to the diversity of modern birds".
I do not think anyone proposes that. Where do you get that idea?
Let me be more precise, since the word "seabird" is not precise enough for my purposes. I am linking some specific pterosaurs to some specific primitive seabirds (Ichthyornithes) to some specific modern seabirds.
Anonymous: "At this point, I will consider that the dino to bird theory is based on a saltation from a tyrannosaur-type creature to the diversity of modern birds". I do not think anyone proposes that. Where do you get that idea?"
In fact, that is all that has ever been proposed. No evidence beyond that idea has ever been given.
If you can contribute anything beyond that, please do. I am very interested.
"Let me be more precise, since the word "seabird" is not precise enough for my purposes. I am linking some specific pterosaurs to some specific primitive seabirds (Ichthyornithes) to some specific modern seabirds".
Exactly, which means that you leave dromaeosaurids aside in some cases, and propose a direct transition from pterosaurs to Avialae (avialae includes extinct birds like Ichthyornis). This is what I suggested you do for all proposed pterosaur-bird transitions.
Well, I previously offered a proposed lineage which is inferred by reading cladograms (I know you do not think cladistics are valid, but you asked for the opposite, 'dino-to-bird' position and I'm presenting it).
Indeed, I do not think there is a proposed lineage that postulates a direct transition from a tyrranosaurid to all modern birds.
"I am definitely not leaving Paraves (which includes dromaeosaurids) aside".
Why not? You do so for the pteranodon-albatross transition. I believe a similar position for all pterosaur-bird transitions will solve problems and not cause any. Why do you disagree?
Everything we say is corrupted by the cladistic terms that are used. That may well be why there is misunderstanding. I am not talking in terms of clades.
I know this is difficult for the people here who have been programmed with cladistic thinking. It is almost impossible for you to think beyond the distortions of cladistics and actually understand the straightforward things I am saying.
I must say again, that Senter did you all a service by showing how to think beyond cladistics and just work with the actual groups of creatures that exist and existed.
"I am definitely not leaving Paraves (which includes dromaeosaurids) aside".
Why not? You do so for the pteranodon-albatross transition. I believe a similar position for all pterosaur-bird transitions will solve problems and not cause any. Why do you disagree?"
Each lineage needs to be analyzed on its own. By the way it is misleading for you to say "pteranodon-albatross" transition. It would be better to say pteranodon-ichthyonithes-albatross transition.
All lineages take the form of pterosaur group to primitive bird group to modern bird group.
Sotos said... "Well, I previously offered a proposed lineage which is inferred by reading cladograms (I know you do not think cladistics are valid, but you asked for the opposite, 'dino-to-bird' position and I'm presenting it). Indeed, I do not think there is a proposed lineage that postulates a direct transition from a tyrranosaurid to all modern birds. Do you have any in mind?"
I think I will shortly stop discussion with you Sotos (even though I have enjoyed it) because you have no conception as to what it means to think beyond the limitations of cladistics thinking. And you have no interest in trying to think beyond those limitations.
Post from June 29, 2010 http://pterosaurnet.blogspot.com/2010/06/pterosaur-dromaeosaurids-birds-1.html
Dromaeosaurs and Birds Let's look in detail at the acknowledged closeness between Dromaeosaurs and birds. Keep in mind that Dromaeosaur fossils date back 167 million years ago!
Dromaeosaurs were very, very bird-like. (In fact they were birds. The earliest ones flew and some of those, but not all of them, later became flightless).
http://en.wikipedia.org/wiki/Origin_of_birds "Early analyses suggested that dromaeosaurid theropods like Deinonychus were particularly closely related to birds, a result which has been corroborated many times since.[32][33]" AND http://www.geol.umd.edu/~tholtz/G104/10424arch.htm "Also hard to recognize good shared derived characters for Avialae at present, because basal deinonychosaurs are very, very avialian-like." AND http://en.wikipedia.org/wiki/Cryptovolans "Czerkas also believed that Cryptovolans [a dromaeosaurid] may have been able to fly better than Archaeopteryx, the animal usually referred to as the earliest known bird. He cited the fused sternum and asymmetrical feathers, and argued that Cryptovolans has modern bird features that make it more derived than Archaeopteryx. Czerkas cited the fact that this possibly volant animal is also very clearly a dromaeosaurid to suggest that the Dromaeosauridae might actually be a basal bird group, and that later, larger, species such as Deinonychus were secondarily flightless (Czerkas, 2002)." AND http://www.ucmp.berkeley.edu/diapsids/saurischia/dromaeosauridae.html "Dromaeosauridae is thus termed the sister group of the clade Aves (which includes all birds). It may even be that the ancestry of birds lies within this group, which would make them dromaeosaurs too, but this is not at all established [accepted]." "He [J. Ostrom] also saw similarities between it [Deinonychus] and modern birds, and has today continued to be a leading proponent for the dromaeosaurian kinship with birds." AND http://www.ucmp.berkeley.edu/diapsids/saurischia/troodontidae.html "It has been suggested that they [troodontidae] were the ancestors of birds, but this is not accepted; a dromaeosaur is currently thought to be the ancestor of all birds. " AND http://en.wikipedia.org/wiki/Dromaeosauridae "Dromaeosaurids are so birdlike that they have led some researchers to argue that they would be better classified as birds." "As late as 2001, Mark Norell and colleagues analyzed a large survey of coelurosaur fossils and produced the tentative result that dromaeosaurids were most closely related to birds, with troodontids as a more distant outgroup. They even suggested that Dromaeosauridae could be paraphyletic relative to Avialae.[37]" "Their phylogenetic analysis [Mayr and Peters in 2005] produced the controversial result that Confuciusornis [an avialae] was closer to Microraptor [a dromaeosaur] than to Archaeopteryx, making the Avialae a paraphyletic taxon. " AND http://dml.cmnh.org/2002Sep/msg00255.html "Steve's [Steve Czerkas'] analysis that Cryptovolans [a Dromaeosaur] was a fully developed flier is entirely correct." "Dromaeosaurs were sophisticated fliers (some or all basal examples) or secondarily flightless (derived examples). They are very probably closer to modern birds than Archaeopteryx (see DA for the analysis). Since troodonts are probably relatives of dromaeosaurs, and basal troodonts are more bird-like than derived examples, they too should be neoflightless
http://www.ucmp.berkeley.edu/diapsids/saurischia/troodontidae.html "It has been suggested that they [troodontidae] were the ancestors of birds, but this is not accepted; a dromaeosaur is currently thought to be the ancestor of all birds."
Here is something noteworthy concerning the dino (tyrannosaur cluster) to bird idea: There are fossils for a NUMBER of taxa in the fossil record. But none of those work out as ancestors. Thus it strains credulity that the dino to bird enthusiasts push the story that there is a lack of fossils to establish the identity of ancestors.
http://www.kheper.net/evolution/systematics/evolutionary.htm "Also, unlike Cladistics, with it's reliance on a hypothetical Most Recent Common Ancestor that is never actually described or discovered (a missing link that is always missing), Evolutionary systematics gives illustrations of the actual evolution of one species or higher taxon into another."
I am certainly not the only one who has seen through cladistics and its excuses.
"Does the timing work out for a development from pteranodon subgroup to ichthyornis subgroup to modern seabirds? According to the wiki articles pteranodon fossils have been found back as far as 86 mya and ichthyornithes as far back as 95 mya. Let me make an interesting point. When this sort of timing information is found related to an accepted lineage we all know the answer that is given. As a test for fun, what is the answer that is given? I will answer in a bit but I wanted to see if anyone could for fun answer this."
Well I guess nobody wanted to answer this. The answer is "ghost lineage".
http://en.wikipedia.org/wiki/Pteranodon "Pteranodon fossils are known primarily from the Niobrara Formation of the central United States. Broadly defined, Pteranodon existed for more than four million years, during the late Coniacian - early Campanian stages of the Cretaceous period.[5] The genus is present in most layers of the Niobrarra Formation except for the upper two; in 2003, Kenneth Carpenter surveyed the distribution and dating of fossils in this formation, demonstrating that Pteranodon sternbergi existed there from 88-85 million years ago, while P. longiceps existed between 86-84.5 million years ago. A possible third species, which Kellner named Geosternbergia maysei in 2010, is known from the Sharon Springs member of the Pierre Shale Formation in Kansas, Wyoming, and South Dakota, dating to between 81.5 and 80.5 million years ago.[8]"
If fossils are found in most layers "except the upper two" then how can they tell how far back it actually goes?
"I think I will shortly stop discussion with you Sotos (even though I have enjoyed it) because you have no conception as to what it means to think beyond the limitations of cladistics thinking. And you have no interest in trying to think beyond those limitations".
I think that is an unfair assumption. I have suggested that you apply the kind of modified lineage you already now use for pteranodon to albatross, to all your pterosaur-bird transitions. In what way does that reveal "cladistic thinking"?
Also, I explained that I consider maniraptors to be dinosaurs, in the same way you consider 'non-maniraptor coelurosaurs' to be dinosaurs. If that somehow reveals cladistic thinking, then aren't we both guilty of it?
Either way, if you decide to end our discussion, although I also enjoy it, that is fine.
Sotos, your cladistic thinking is that when you present the dino to bird idea you only can present it in cladistic terms. You cannot evaluate the dino to bird idea (or any lineage idea) without using the cladistic method. And cladistics is just one way (and a poor way) of evaluating phylogenies.
I have received a couple of Anonymous comments but neither has a made-up name included. If the individual or individuals would like to contribute please re-submit with a made-up name included. Thanks.
Let's accumulate some reference material for the pelican lineage:
PELICAN* http://www.dinosaursfaq.com/Dinosaur/Rhamphorhynchus-Dinosaur.html "According to scientists and paleontologists, the Rhamphorhynchus hunted in a manner similar to the modern-day pelican wherein it would dive into water and use its long beak to scoop out fish, insects and frogs from water and then toss them down its throat pouch. The fossils of Rhamphorhynchus that have been found have been well-preserved. One can see not just the skeleton but also the outline of the internal organs. Some fossils have been found with the throat pouch intact. Many Rhamphorhynchus fossils have been found in southern England and in Bavaria in southern part of Germany." http://archosaurmusings.wordpress.com/2008/07/25/pterosaur-soft-tissues "Throat pouches (like those of a pelican) can be seen in Pterodactylus and can be inferred in Ludodactylus." http://www.statemaster.com/encyclopedia/Rhamphorhynchus-%28animal%29 "Rhamphorhynchus probably ate fish and it is believed that one of the ways it hunted was by dragging its beak in the water, catching fish and tossing them into its throat pouch, a structure similar to that of pelicans, which has been preserved in some fossils. This method of catching fish is found today in skimmers."
http://en.wikipedia.org/wiki/Pterodactylus "In 1998, the discovery of one specimen assigned to P. kochi shed light on the life appearance of Pterodactylus, as it preserved unique soft-tissue traits not present in previous fossil skeletons, including long, bristly pycnofibres (a fur-like body covering known only in pterosaurs) on the neck, details of a urpatagium (hind wing membrane between the legs and tail) that also stretched between the toes as webbing, and a pelican-like throat pouch."
* From http://pterosaurnet.blogspot.com/2010/04/pterosaur-and-modern-bird.html
"If fossils are found in most layers "except the upper two" then how can they tell how far back it actually goes?"
By looking at the bottom layers, and where you have the first occurance of the fossil. You can use various statistical methods to evaluate how good your fossil record is for that species, and see if you should see more fossils a little earlier.
However I see a major problem with your Pteranodon evolved into Ichthyornis idea. It requires the simultaneous evolution of all the traits Ichthyornis shares with all other birds, the traits it shares with maniraptorans, and the traits it shares with dinosaurs, but does not share with pterosaurs. You have multiple origins of feathers, and all the other uniquely avian characters, etc.
This makes "birds" polyphyletic, something that Evolutionary Systematics has as little truck with as cladistcs does.
To be honest, I don't understand your aversion to cladistics. All it states is that if an organism is descended from a particular group then it is a member of that group, and that groups should defined to contain everything that is descended from a member of that group. As has been explained before, you could present your ideas in a cladistic framework- stating for instance that because Albatrosses are descended from pteranodontians that they *are* pteranodontians. It changes nothing about the evidence you have so far presented.
In fact given the large number of characters used to evaluate relatedness even people who use evolutionary systematics and are perfectly happy to give names to paraphyletic groups use the same tools that cladists use to generate phylogenies. Your alternative method appears to use single (or very few) characters many of which are not homologous (and when you suggest they are, have not backed up your assertation with evidence- why for instance should we believe that the pteroid is a finger, when you have presented no anatomical reason for us to think that it is. You have not compared it and the sesamoid with other phalanges to make your case, something you need to do in order for anyone to take your idea seriously for example.) In other cases you're taking descriptions of species from Wikipedia, and similar sources as evidence for relatedness, when they are usually describing a species' ecology or general shape to a lay audience. What morphological evidence not related to ecology do you have for linking Pteranodon, ichthyornis and the albatrosses to each other that is not based on their ecology?
And to forstall your usual objection I am not presenting any alternative idea. I want to see you support your ideas with a higher standard of evidence.
Rhamphorhynchus and Pterodactylus are contemporary. The first is not going to be ancestral to the other for that reason alone.
There is no evidence for skimming behaviour in any pterosaur- none possess the jaw structure required for skimming behaviour. Their jaws are either the wrong shape, or simply not robust enough for skimming.
http://en.wikipedia.org/wiki/Seabird "Seabirds (also known as marine birds) are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution*, as the same environmental problems and feeding niches have resulted in similar adaptations. The first seabirds evolved in the Cretaceous period, and modern seabird families emerged in the Paleogene." "Gannets, boobies, tropicbirds, some terns and Brown Pelicans all engage in plunge diving, taking fast moving prey by diving into the water from flight. Plunge diving allows birds to use the energy from the momentum of the dive to combat natural buoyancy (caused by air trapped in plumage),[19] and thus uses less energy than the dedicated pursuit divers, allowing them to utilise more widely distributed food resources, for example, in impoverished tropical seas."
Ann O'Nymous posted: "And to forstall your usual objection I am not presenting any alternative idea. I want to see you support your ideas with a higher standard of evidence."
Please come back when you are prepared to talk about an alternative. If you cannot make ANY effort to describe an alternative, then why should I make more effort to help you understand better what I have proposed.
"Please come back when you are prepared to talk about an alternative."
There are numerous holes in your "theory". Even without your insistence on any and all visitors to your site proposing alternatives, that is enough for us to doubt your claims.
"If you cannot make ANY effort to describe an alternative, then why should I make more effort to help you understand better what I have proposed."
Because what you have proposed lack sufficient support. You have not demonstrated that the pteroid is a finger for instance. You have provided no evidence for this claim- no comparison with other phalanges, etc. If I were to suggest that dinosaurs were ancestral to birds you would demand a series of ancestral species- which I am not willing to provide as I have no method of identifying one fossil as being ancestral to another. I can provide names of taxa that are progressively more similar, and lists of characters- but other people have done that and you have not been satisfied.
"While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution*
* Actually homology explains it "
Why? What about the characters that they do not share in common, but share with other birds that don't have these diving adaptations, and aren't related to diving? Why should we believe that just because organisms are adapted to similar environments that they are closely related? What happens when you ignore these adaptations and look at characters that aren't affected by this- such as genetics? Why does the DNA evidence- evidence that you have cited elsewhere on this blog give a different result?
"Sotos, your cladistic thinking is that when you present the dino to bird idea you only can present it in cladistic terms".
I don't understand how, since I used the same terms you did (maniraptors and non-maniraptor coelurosaurs). Perhaps I am doing so without realizing it. Can you point out where and how I am using cladistic thinking in my terms? Then I will try to modify them accordingly.
Sotos - two things: 1. Use the terms that Senter uses - Tyrannosaur cluster and Bird-like cluster. Re-word any point you want to make using thhose terms. 2. Read up on Evolutionary Systematics. Start here: http://en.wikipedia.org/wiki/Evolutionary_taxonomy and http://www.kheper.net/evolution/systematics/evolutionary.htm
Ann O'Nymous posted "Because what you have proposed lack sufficient support."
You are unwilling (unable) to even present an alternative lineage! If you cannot even give an alternative you are hardly in a position to say that I have proposed insufficient support. You have presented NONE.
How do people respond to this*: http://www.ucmp.berkeley.edu/diapsids/saurischia/troodontidae.html "It has been suggested that they [troodontidae] were the ancestors of birds, but this is not accepted; a dromaeosaur is currently thought to be the ancestor of all birds."
Is it correct that a dromaeosaur is currently thought to be the ancestor of all birds?
Plenty of other people have done so. Why should I repeat their work? You don't seem to understand that I don't have to present an alternative. I am not asking you to critique an alternative theory. I am asking you to explain your theory better. I am asking you to give me a reason to believe the statements you make in support of your claims. Why should I believe what you say about the pteroid for example?
Your ideas should stand on their own merits. So far they don't appear to be doing terribly well. Besides, given that you have been promoting your ideas for quite some time you should have amassed a great deal of literature about what the currently accepted alternative is. I shouldn't need to present an alternative to you, you should already be very familiar with it.
I have no problem with a "dromaeosaur" being the ancestor of all birds. It certainly fits the morphological evidence better than your alternative- that different birds are descended from different pterosaurs and must have acquired all their birdlike features independently.
Dr. pterosaur, I don't understand how I can use the two 'clusters' to present my proposed modification to your lineage, when you do not directly use those terms yourself, when presenting your lineage! You speak of specific groups and subgroups.why can't I do the same? I am on my smartphone right now, but I'll read the links you posted and try to figure out what you believe I'm doing wrong.
Ann O'Nymous "Plenty of other people have done so."
Nobody has done so. But I am getting tired of your excuses and run-arounds. Believe me I have seen them all before. Including the one that claims somebody else has already done it. If somebody else has identified the ancestors on the lineage of dinos to birds, please point us to it. Or just give it yourself.
We both know that nobody has done it. Why not be honest and say that.
My Dec 17, 2010 post outlined a set of lineages leading from pterosaurs to specifc sets of modern birds. The lines are based on the pattern: Pterosaur --> Dromaeosaur subgroup--> Enantiornithes subgroup --> specific primitive bird group (eg. Ichtyorniithes etc) --> modern birds.
In the recent posts I delved more deeply into the line that leads to seabirds such as albatross. Because I believed that the line stems from Pteranodontidae I considered that the line might be simplified to Pteranodontidae --> Icthyornithes --> Albatross. However I had research and reasons back in Dec 2010 to include Dromaeosaurs and Enantiornithes in the line and I want to continue to hold to that idea and work through any issues in that idea.
So basically the Dec 17, 2010 proposal stands. If anyone wishes to work with me on enhancing that, please let me know.
* http://jpaleontol.geoscienceworld.org/cgi/content/abstract/84/6/1071 "However, the lack of Early Cretaceous Lagerstätten in North America may produce underestimates of true pterosaur richness during this interval, thereby obscuring a subsequent drop in diversity."
** http://en.wikipedia.org/wiki/Dromaeosauridae "The presence of dromaeosaurs as early as the Middle Jurassic has been confirmed [surmised] by the discovery of isolated fossil teeth, though no dromaeosaurid body fossils have been found from this epoch.[3]
For reference: http://en.wikipedia.org/wiki/Azhdarchidae "Azhdarchids were originally classified as close relatives of Pteranodon due to their long, toothless beaks. Others have suggested they were more closely related to the toothy Ctenochasmatids (which include filter-feeders like Ctenochasma and Pterodaustro). Currently it is widely agreed that azhdarchids were closely related to pterosaurs such as Tupuxuara and Tapejara."
How will you be establishing ancestry between these groups?
And does it make sense to you that Pteranodon (Ornithocheiroidea) loses its albatross-like flight only to gain it back as an albatross? Or do you have a dromaeosaurid subgroup with albatross-like flight in mind?
http://www.pnas.org/content/early/2011/08/29/1112694108.abstract The crop is characteristic of seed-eating birds today, yet little is known about its early history despite remarkable discoveries of many Mesozoic seed-eating birds in the past decade. Here we report the discovery of some early fossil evidence for the presence of a crop in birds. Two Early Cretaceous birds, the basal ornithurine Hongshanornis and a basal avian Sapeornis, demonstrate that an essentially modern avian digestive system formed early in avian evolution. The discovery of a crop in two phylogenetically remote lineages of Early Cretaceous birds and its absence in most intervening forms indicates that it was independently acquired as a specialized seed-eating adaptation. Finally, the reduction or loss of teeth in the forms showing seed-filled crops suggests that granivory was possibly one of the factors that resulted in the reduction of teeth in early birds.
Friend-O said... "How will you be establishing ancestry between these groups? And does it make sense to you that Pteranodon (Ornithocheiroidea) loses its albatross-like flight only to gain it back as an albatross? Or do you have a dromaeosaurid subgroup with albatross-like flight in mind?"
Flying pteranodons developed into flying dromaeosaurs which then in a few additional steps developed into modern birds. It comes as a surprise to people to learn that dromaeosaurs could fly. They were primitive birds.
In the earlier posts I have proposed lineages that stem from Ornithocheiroidea and Ctenochasmatoidea. I have said that it may well be that root lineages stemmed from the four Pterodactyloidea taxa: Azhdarchoidea Ctenochasmatoidea Dsungaripteroidea Ornithocheiroidea
If anyone would like to contribute, perhaps you could suggest the lineages that could have stemmed from the two that I have not touched on - Azhdarchoidea and Dsungaripteroidea.
http://en.wikipedia.org/wiki/Azhdarchidae Azhdarchids are characterized by their long legs and extremely long necks, made up of elongated neck vertebrae which are round in cross section. Most species of azhdarchids are still known mainly from their distinctive neck bones and not much else. The few azhdarchids that are known from reasonably good skeletons include Zhejiangopterus and Quetzalcoatlus. Azhdarchids are also distinguished by their relatively large heads and long, spear-like jaws. It had been suggested azhdarchids were skimmers,[2][3] but further research has cast doubt on this idea, demonstrating that azhdarchids lacked the necessary adaptations for a skim-feeding lifestyle, and that they may have led a more terrestrial existence similar to modern storks.[4][5][6][7]
For reference: http://www.nature.com/news/2011/110414/full/news.2011.236.html The nocturnal hunters ranged from Microraptor gui, a winged dinosaur no more than 90 centimetres long, to Megapnosaurus kayentakatae, a pack-hunting species that could grow up to 3 metres, and Velociraptor mongoliensis, the viciously clawed predator made famous in the novel Jurassic Park.
Several pterosaurs, flying reptiles that were closely related to the dinosaurs, also had eye shapes that indicated they were active at night. What these pterosaurs were doing in the dark is unclear, but Schmitz and Motani suggest that they could have been behaving like petrels and albatrosses (Procellariiformes) or waterfowl (Anseriformes), which often forage at night.
http://en.wikipedia.org/wiki/Charadriiformes That the Charadriiformes are an ancient group is also borne out by the fossil record. Much of the Neornithes' fossil record around the Cretaceous–Tertiary extinction event is made up of bits and pieces of birds which resemble this order. In many, this is probably due to convergent evolution brought about by semi-aquatic habits.
"Sotos - two things: 1. Use the terms that Senter uses - Tyrannosaur cluster and Bird-like cluster. Re-word any point you want to make using thhose terms. 2. Read up on Evolutionary Systematics".
In what way should I use those "clusters" to express my modification to your lineage? And after all, you do not solely and generally rely on those two 'clusters' either, when presenting your methodologies. You specifically refer to particular subgroups. Like, for example, above:
"Pteranodon (Ornithocheiroidea) --> A Dromaeosaurid subgroup --> An Enantiornithes seabird subgroup --> An Ichthyornithes subgroup --> Gulls, Skimmers (Charadriiformes/Lari)".
You are quite specific in the subgroups you use, and you don't just say 'a series of subgroups from the bird-like cluster', for example. Surely that does not entail cladistic thinking! Why can't I do the same?
I read your links on evolutionary systematics and they are interesting, but again I see no problem towards what I am proposing. Like you, I am looking at morphologies, and propose lineages.
If you think some ascpects of my proposed modifications are permeated by 'cladistic thinking', please highlight them and explain how I'm doing that, with examples. Maybe that will help me understand your objections better.
But if there are no issues with that, why not consider my proposal? I think it solves several problems, and better fits those similarities you have indicated and collected between pterosaurs and modern birds. I hope we can work together on that option, and evaluate its plausibility.
Sotos: "But if there are no issues with that, why not consider my proposal? I think it solves several problems, and better fits those similarities you have indicated and collected between pterosaurs and modern birds. I hope we can work together on that option, and evaluate its plausibility."
If you would like to participate, then please look for similarities of morphology, environment and behavior between pterosaurs (eg pteranodon) and dromaeosaur taxa. That is the idea I am working with. On the other hand, if you wish to work with the idea you are proposing, then please proceed and tell me your results.
For example, there may well be a lineage stemming from Azhdarchidae to some specific modern bird groups such as storks. Analyze that possible lineage if you like.
"Dr. Pterosaur said... Friend-O, we would look for similarities of morphology, environment and behavior. Care to participate?"
How will those elements establish lineage? For instance, we as humans share similarities of morphology, environment and behavior with chimps, but it doesn't necessarily mean that we descended from a chimp. How will your methodology resolve this issue?
It is starting to look like Friend-O may be setting this up simply to waste my time. Let's see if I am right about that. I hope not. This sounds like a way to sneak back to the stale cladistics argument.
Well... it's not really resolved now in a sense as the data is too inconclusive to make a determination that y evolved from x.
Most will say with conclusivity that x and y share a last common ancestor with each other, but it not know exactly what that ancestor is. It very well could be x but that would just be speculation. More likely, because of the vagaries and rareness of fossilization, the shared LCA of X and Y is very X-like. That is all that can be said with certainty.
How does your methodology resolve this? I am very interested in this as it could be a major scientific breakthrough
Friend-O, read up about evolutionary systematics. I am not proposing a radical unknown methodology breakthrough. If anything, I am making a breakthrough to propose an alternative to the dino to bird idea.
But I am not interested in arguing more on this. If you would like to actually roll up your sleeves and analyze the details of the taxa then please join in. I will warn you it is a lot of hard work. Much harder than proposing cladistic excuses for why you cannot determine ancestors.
I am afraid then that I must add to the growing list of commenters who note your evasion on this topic and most other questions that are asked of you.
As a final suggestion, have you perhaps considered adjusting your bedside manner? You may find you catch more flies with honey than vinegar. Just a thought.
Friend-O I will point out that I earlier predicted where this was going - that you were simply out to waste my time. The issue is not my "bedside" manner. You were going down this path right from the start. I have seen this pattern MANY times. MANY TIMES. You were never going to actually roll up your sleeves and participate. You are just one more individual that is programmed to think a certain way and cannot think beyond it. The way I act is not the issue.
http://www.kheper.net/evolution/systematics/evolutionary.htm "Also, unlike Cladistics, with it's reliance on a hypothetical Most Recent Common Ancestor that is never actually described or discovered (a missing link that is always missing), Evolutionary systematics gives illustrations of the actual evolution of one species or higher taxon into another."
I am certainly not the only one who has seen the problems with cladistics .
"Admitedly, Evolutionary Systematics suffers from a number of shortcomings. For example the use of several very different criteria (phylogeny, divergence, adaptational level) to define particular taxa, as well as inconsistencies inherent in the paraphyletic approach (e.g. separating Class Aves (Birds) from the Archosauria). This, together with the greater rigour and precion of the and practical and heuristic superiority of the Cladistic (Phylogenetic) approach has meant that over the past decades.Evolutionary Systematics has greatly declined; the result being the rise of cladistics.as the dominant paradigm."
Greater rigor and precision is of no value if you are doing the wrong thing.
It reminds me of the joke. I have good news and bad news. The bad news is that we are going in the wrong direction. The good news is that we are making good time.
Cladistics is an example of going in the wrong direction. It is no compensation that the computer can efficiently do the calculations. What has happened is that the computer's lack of thinking has replaced actual thinking.
Note how he ends the article: "Why I prefer Evolutionary Systemmatics Granted Evolutionary Systematics has problems, as does any conceptual system. But the thing I myself like about it - and here I am talking intuitively rather than scientistically - is that it is based on two very important intuitive ideas: deep time and metamorphosis. Deep time means time extending over millions of years. This is part of the vastness of the universe - the temporal vastness that goes alongside the spatial vastness. Deep Time provides the theatre for metamorphosis, for the change and transformation of organsims - and indeed of Gaia and the universe as a whole - over time. I think of organisms changing through time - one evolving into the next - like one of those time-lapse films of plants growing. We can't see plants growing - it is too slow. But if things were speeded up the astonishing metamorphosis would be visible. It's the same with evolution. Evolutionary systemmatics is a means of describing this process. "
Worth repeating till it sinks in: http://www.kheper.net/evolution/systematics/evolutionary.htm "Also, unlike Cladistics, with it's reliance on a hypothetical Most Recent Common Ancestor that is never actually described or discovered (a missing link that is always missing), Evolutionary systematics gives illustrations of the actual evolution of one species or higher taxon into another."
I am certainly not the only one who has seen the problems with cladistics .
By the way, it is not just ONE hypothetical most recent common ancestor that is missing - it is a whole series of them along the purported lineage line. Cladistics has not discovered or described ANY of them!
"If you would like to participate, then please look for similarities of morphology, environment and behavior between pterosaurs (eg pteranodon) and dromaeosaur taxa. That is the idea I am working with. On the other hand, if you wish to work with the idea you are proposing, then please proceed and tell me your results".
Well, I believe the idea you're working with doesn't have that much evidence. You detected and presented many interesting similarities between pterosaurs and modern birds, in morphology as well as habitat and indicated behavior. But these similarities become irrelevant if you include dromeosaurids in the lineage, since the similarities would have to be lost in them and regained in their early bird descendants. For example, what is the point in making much of the similarity in wing-to-body ratio between pteranodon and the albatross, when that would be lost in the transitional dromeosaurid form? And if you assume that some kind of flying dromeosaurid with similar wing-to-body ratio existed, then you have the same problem with the dino to bird theory, if not a larger one; because no fossils of such an animal have been found and also no fossils of animals vaguely similar to it (that famous 'sister taxa' that proponents of the conventional theory say they have) have been found either. You don't just need a common ancestor, but you need even the slightest sign that something like it existed. On the other hand, since you already agree to a form of saltational transition, a lineage from pterosaurs directly to avialae (via saltation) might create less of a problem, and explain the similarities much better.
Anyway, that is my analysis. In your latest post, I had a feeling of a dismissive attitude on your part, like you were telling me to either agree and work on the theory you support or make my own. I understand that, in order to fence all the attacks you must get for presenting such an unconventional view, you must always keep your guard up. But I assure you I am not being competitive, and I am not interested in tooting my horn, but simply in presenting an alternative which I think is worthy of consideration (and, in fact, you yourself briefly considered, for pteranodon at least, a few days ago). But you are the owner of this blog, and if you do not wish me to present my alternative here, I will gladly refrain.
Sotos, I have specifically invited you to present your alternative* if you wish. It is kind of odd of you now to say the opposite - that if I do not wish you to present your alternative here, you will gladly refrain. It is when you say such completely opposite things that I get suspicious. Just present the details of your alternative if you wish, for goodness sake.
*Here is what I specifically said: "If you would like to participate, then please look for similarities of morphology, environment and behavior between pterosaurs (eg pteranodon) and dromaeosaur taxa. That is the idea I am working with. On the other hand, if you wish to work with the idea you are proposing, then please proceed and tell me your results".
There is very little info on the different taxa within dromaeosauridae. Here is some info on Microraptor (Dromaeosauridae). http://en.wikipedia.org/wiki/Microraptor "It has been proposed that the animal glided and probably lived mainly in trees, because the hind wings anchored to the feet of Microraptor would have hindered their ability to run on the ground."
Earlier I presented the idea that we can trace lineages by habitat - roughly Seabird, Shorebird, and Landbird.
It may well be that microraptor is part of the LANDBIRD lineage which developed from the corresponding pterosaur taxon and leads on to the landbird taxa within Enantiornithes leading eventually to modern landbirds.
Sotos posted: "For example, what is the point in making much of the similarity in wing-to-body ratio between pteranodon and the albatross, when that would be lost in the transitional dromeosaurid form? And if you assume that some kind of flying dromeosaurid with similar wing-to-body ratio existed, then you have the same problem with the dino to bird theory, if not a larger one; because no fossils of such an animal have been found and also no fossils of animals vaguely similar to it (that famous 'sister taxa' that proponents of the conventional theory say they have) have been found either."
I am surprised at this comment. Can you support it with reference(s)?
One might as well ask if you can provide evidence of a fossil dromaeosaur with a wing to body ratio similar to that of either an albatross or a Pteranodon? I am not aware of any such fossil that has been found.
Ann O'Nymous you are missing the point. Sotos has made an assertion. It does not do to just make up things and state them as if they were true. And then expect others to have to disprove you. If Sotos makes that assertion then he/she is the one to back it up.
There is a general principle here. People make statements with great assurance as if they knew them to be true. Then when questioned they try to wiggle out.
Since you have taken the time to comment on this Ann O'Nymous, then perhaps you will support what Sotos has asserted. Please provide reference(s).
"Within Ornithocheiroidea are Pteranodontids which are similar to the modern day albatross. http://en.wikipedia.org/wiki/Pteranodon "The wing shape of Pteranodon suggests that it would have flown rather like a modern-day albatross. This is a suggestion based on the fact that the Pteranodon had a high aspect ratio (wingspan to chord length) similar to that of the albatross — 9:1 for Pteranodon, compared to 8:1 for an albatross."
http://en.wikipedia.org/wiki/Aspect_ratio_(wing) In aerodynamics, the aspect ratio of a wing is essentially the ratio of its length to its breadth (chord). A high aspect ratio indicates long, narrow wings, whereas a low aspect ratio indicates short, stubby wings.[1]
Dsungaripterids may be the pterosaur ancestors of LANDBIRDS.
http://scienceblogs.com/tetrapodzoology/2007/09/_in_celebration_of_the.php The hindlimb and pelvic morphology of dsungaripterids indicates that they were well suited for terrestrial locomotion - perhaps more so than most other pterosaurs - with relatively robust limb bones well able to resist compression and buckling (Fastnacht 2005). This is in agreement with the fact that their fossils come from terrestrial environments; in fact we have increasingly good evidence that dsungaripterids and members of a related pterodactyloid pterosaur clade were not seabird analogues (as has so often been said of all pterosaurs [e.g., Naish & Martill 2003]), but radiated widely inland.
I have presented the idea on this blog that it may be the case that even as early as the pterosaurs there were already taxa that inhabited particular habitats and then their primitive bird and modern bird descendants specialized in those habitats. For example it may be that Ornithocheiroidea developed in a series of steps into modern seabirds and Ctenochasmatoidea developed in a series of steps into modern aquatic birds and Dsungaripteroidea developed in a series of steps into modern land birds
More analysis is required to see where Azhdarchoidea fits in.
The Azhdarchoidea may have developed in a series of steps into modern shorebirds.
Support for that idea: http://en.wikipedia.org/wiki/Azhdarchidae Azhdarchids are characterized by their long legs and extremely long necks, made up of elongated neck vertebrae which are round in cross section. Most species of azhdarchids are still known mainly from their distinctive neck bones and not much else. The few azhdarchids that are known from reasonably good skeletons include Zhejiangopterus and Quetzalcoatlus. Azhdarchids are also distinguished by their relatively large heads and long, spear-like jaws. It had been suggested azhdarchids were skimmers,[2][3] but further research has cast doubt on this idea, demonstrating that azhdarchids lacked the necessary adaptations for a skim-feeding lifestyle, and that they may have led a more terrestrial existence similar to modern storks.[4][5][6][7]
It also makes sense to relate the different taxa, their environment and kind of wing.
http://en.wikipedia.org/wiki/Bird_flight Most kinds of bird wing can be grouped into four types, with some falling between two of these types. These types of wings are elliptical wings, high speed wings, high aspect ratio wings and soaring wings with slots.
http://en.wikipedia.org/wiki/Enantiornithes They have been found in both inland and marine sediments, suggesting that they were an ecologically diverse group. Enantiornithine fossils appear to include waders, swimmers, fish-catchers, and raptors. The smallest are described as sparrow-sized, but some were much larger, such as Avisaurus which had an estimated wingspan of 1.2 meters (4 ft). And http://en.wikipedia.org/wiki/Bird Enantiornithes occupied a wide array of ecological niches, from sand-probing shorebirds and fish-eaters to tree-dwelling forms and seed-eaters.
The reference you require is the complete absence of fossil dromaeosaurs capable of powered flight. None are known. Therefore no such reference to these organisms exists. You are the one proposing this idea, it is up to you to find more evidence to support it. Currently the dromaeosaurs are a problem for you- you don't have any that link specific pterosaurs to specific birds, and until you can identify some your ideas have a serious flaw.
You are the one making claims about multiple ancestors of dromaeosaurs as individual pterosaur groups give rise to individual bird groups. You are making birds, dromaeosaurs, and maniraptorans polyphyletic. Evolutionary systematics does not recognise polyphyletic groups. And yet your idea requires them.
I posted a comment with a list of animals forming a general lineage, but it does not appear to have shown up. I do hope it got through to you.
Dr.pterosaur, I have replied to your request to support my statement.I did not see my comment appear. And now yout talk to others about me as if I did not provide a reply. Perhaps the comment was lost by the software. If that's the case, then inform me and I'll repeat it,a well a my reply to your request to present the details of my proposal (which also seems to be missing).
I do not control the blogspot.com software.At times it does not post comments but when that is the case you can tell because the comment still appears where you have entered it. It is frustrating but if you do not see a post of yours, then all I can say is to try entering it later.
Given the lack of any winged dromaeosaurs this clarification is not particularly relevant. We can substitute "aspect ratio" (ie. the wingspan to chord depth) for "wing to body ratio" and the argument is the same. Additionally there are no Pteranodon specimens preserving wing membranes, hence the large number of different reconstructions usedwhen modelling pterosaur flight.
Ann O'Nymous posted: "You are the one making claims about multiple ancestors of dromaeosaurs as individual pterosaur groups give rise to individual bird groups. You are making birds, dromaeosaurs, and maniraptorans polyphyletic. Evolutionary systematics does not recognise polyphyletic groups. And yet your idea requires them."
Read up about "convergent evolution" and then let's discuss. Please state your concern in a more concrete way.
Ann O'Nymous and Sotos present themselves as if they were experts in the subject we are discussing. And yet both were confused about the wing aspect ratio issue.
Normally I would not mention people's confusion, but it is relevant here because they both make comments as if they knew what they were talking about when they do not.
This is why I keep asking people for references and for folks to copy and paste what they think the relevant material is.
I have a number of posts on flying dromaeosaurs. People should read them and if you have questions please post your comments on those thread(s). I am definitely not repeating all that material again.
Now I am matching up the pterosaur, dromaeosaur, enantiornithes, modern bird relationships by habitat (seabird, shorebird, aquatic bird, landbird). If anyone would care to contribute please do so. I am quite amazed at how they line up according to what is known about the various taxa.
Concerning dromaeosaurs - the fundamental idea is that the FLYING dromaeosaurs CAME FIRST. Later some (not all) of them became flightless. People really need to take that fact in, because that fact contradicts the dino-to-bird idea and is completely consistent with the pterosaur to bird model.
It stands to reason that the shape of the head, the shape of the wings, length of the legs, length of the neck etc are related to the habitat. And each habitat supports a separate lineage. Within each line we see a great similarity in morphology and behavior. For example: The pterosaurs that lived on the shore gave rise to the primitive birds that lived on the shore which in turn gave rise to the modern birds that live on the shore (ie. shorebirds).
For example, it may be that: Ornithocheiroidea developed in a series of steps into modern seabirds and Ctenochasmatoidea developed in a series of steps into modern aquatic birds and Dsungaripteroidea developed in a series of steps into modern land birds and Azhdarchoidea developed in a series of steps into modern shorebirds.
I was not "confused". I merely repeated the phrasing used by someone else.
Could you kindly tell us which posts discuss these "flying dromaeosaurs" and which specific dromaeosaurs you believe to be "flying"? There is evidence of gliding in Anchiornis and Microraptor but neither of them had true powered flight which is what is generally meant by "flying".
I am familar with convergent evolution. Your scenario requires the origin of the characteristics common to all birds to be convergent. It requires that the last common ancestor of all birds was not itself a bird, and that all the modern birds acquired their uniquely birdy characteristics independently of each other. If Azdarchids gave rise to storks and Pteranodontians to albatrosses, then the characters they share in common- feathers, the avian wing, the various details of the skull and skeletal morphology not found in pterosaurs, but present in all modern birds have to be evolved multiple times. You claim your ideas are more parsimonious that the generally accepted ideas. That your idea requires the convergent evolution of all these characters makes it orders of magnitude less parsimonious.
Why do you think it is not more reasonable to think that pterosaurs and birds have independently evolved wings (of remarkably different designs), but that complex feathers are convergent?
Ann O'Nymous posted: "I was not "confused". I merely repeated the phrasing used by someone else."
I guess if you need to make an excuse, any excuse will do. But why should I take you seriously?
I see you are still talking in cladistic terms. You seem not to have taken in all that I have said about cladistics - you still phrase your objections in cladistic terms as if that means something. It does not.
Also if you are going to object to what I am saying, you really need to present an alternative so we can see if it is more parsimonius. You have a completely imaginary alternative.
This bears repeating: People will say something like: "You claim your ideas are more parsimonious that the generally accepted ideas. That your idea requires the convergent evolution of all these characters makes it orders of magnitude less parsimonious."
But NOBODY has EVER presented the ancestor/descendant relationships in the dino to bird model. How in the world can anyone make the absurd comment that what I am proposing is "orders of magnitude less parsimonious" when there has never been anything presented to compare it to?
Folks, let that sink in. Could someone actually acknowledge this point?
No "excuses" are being presented. Why should I take you seriously when all you do is sneer at your commentors instead of actively engaging with their disagreements.
Perhaps you should acknowledge the point that your ideas require birds to acquire all their uniquely birdy characters independently. Whereas the conventional alternative states that birds evolved their characteristics once and inherited them from a common ancestor. It doesn't actually matter whether they are descended from pterosaurs or not. You are proposing that birds are polyphyletic- a grouping rejected by both evolutionary systematics and cladistics, and a term used by both.
You do not need to present ancestor-descendant relationships in order to do this examination.
Ann O'Nymous said... "Whereas the conventional alternative states that birds evolved their characteristics once and inherited them from a common ancestor."
Remember that at each step in the purported dino to bird lineage there is another "common ancestor". There would be hundreds (thousands? millions?) of them Right?
What are the taxa on the purported dino to bird lineage? Please present that and we can evaluate its credibility.
How many times do we have to go over this? You need to present an alternative.
Let's do a rough analysis. Pterosaurs did not have feathers. Dromaeosaurs had feathers. In the development from pterosaurs to dromaeosaurs we see the development of feathers. I have been showing how it is possible to categorize the taxa by habitat - shorebirds, seabirds, aquatic birds, landbirds. And I have proposed pterosaur lineages in each habitat. So we would see parallel evolution occurring in each of the habitats. That is a very common and accepted idea since all the pterosaurs flew and the development of feathers developed in all the streams of FLYING creatures. This is normal accepted "evolution" thinking.
If anyone objects to the specific parallel development of feathers please provide references to support your objection.
I think I figured it out. The aligator and bird are still alive whereas the rest are extinct.
ReplyDeleteOthers may come to a simpler answer.
ReplyDeleteBut the dino to bird people can be humorous.
I have never denied that.
"The aligator and bird are still alive whereas the rest are extinct."
ReplyDeleteThis humorous statement does raise an interesting point.
According to the dino to bird folks would you say that the rest are "extinct"?
It always seems to me that the term "extinct" is used in an ambiguous way by cladists.
Are dinosaurs "extinct"?
Non-avian dinosaurs are.
ReplyDeleteBirds are dinosaurs according to cladists.
ReplyDeleteSo not all dinosaurs are extinct. Right?
And yet it was said earlier that:
"The aligator and bird are still alive whereas the rest are extinct".
That is the ambiguity I am talking about.
There's no ambiguity. There are 17 organisms pictured on that chart. 2 of them exist today. The rest don't. How is that ambiguou?
ReplyDeleteAnonymous is pretending to not get it.
ReplyDeleteCan anyone else contribute on this?
All birds are dinosaurs. Not all dinosaurs are birds. The dinosaurs that aren't also birds are extinct. Does this help?
ReplyDeleteWhat you mean is that birds evolved from dinosaurs. Right?
ReplyDeleteOr are you saying that birds did not evolve from dinosaurs?
No. I meant exactly what I said.
ReplyDelete"Birds" are a set of animals that belong to a larger set we call "Dinosaurs". All "birds" can be placed into the set called "Dinosaurs". The reverse is not the case. Many "dinosaurs" are not birds. All the dinosaurs that are alive today are members of the set called "birds". There are no living dinosaurs that are not members of this set. There is no ambiguity involved. Either an organism is alive today or it is not.
Can anyone else contribute to this?
"Birds" are a set of animals that belong to a larger set we call "Dinosaurs".
ReplyDeleteThat is the point right there. YOU CALL THEM DINOSAURS. You embed your assumption of phylogeny into your vocabulary and then expect others to use your vocabulary.
That is why it is best not to use cladistics.
We can simply use a natural system of calling taxa by their proper names.
For example "dinosaurs" are actual dinosaurs and not an artificial category (a clade) that includes dinosaurs and other creatures that the dino to bird enthusiasts think evolved from them.
If you believe that birds evolved from dinosaurs then simply say that.
Your arguments against cladistics are a red herring. We can say exactly the same thing with respect to your classification scheme. "Birds" are a set of animals that belong to a larger set we call "Pterosaurs". All "birds" can be placed into the set called "Pterosaurs". The reverse is not the case. Many "Pterosaurs" are not birds. All the pterosaurs that are alive today are members of the set called "birds". There are no living pterosaurs that are not members of this set. There is no ambiguity involved. Either an organism is alive today or it is not.
ReplyDeleteAnonymous posted:
ReplyDelete"Birds" are a set of animals that belong to a larger set we* call "Pterosaurs".
That is what YOU would call them. Cladists can misleadingly call them pterosaurs. But I am not saying that.
I am making the simple statement that birds developed from pterosaurs.
Is it possible for you to think outside the conventions of cladistics? It appears not. That is what I mean by your mind being programmed. Your mind runs the "cladistics program" and you cannot think beyond that.
If anyone else is following this, I wonder if anyone can think beyond the limitations of cladistics. Anyone?
Let's save time, by simply not using the particular method called "cladistics".
*Note that the "we" is a reference to cladists. It really means "we cladists".
So the sentence is actually:
Birds" are a set of animals that belong to a larger set we cladists call "Pterosaurs.
And that is because cladists embed in their vocabulary the assumptions of their theory.
If you don't want to use cladistics, then show us the damn fossils already! Fossils the document every little step from pterosaur to bird. Why are you being so coy about this?
ReplyDeleteWould you please document every little step from DINOSAUR to bird.
ReplyDeleteOR just give ANYTHING about that presumed lineage. At the moment you have proposed NOTHING. And yet you have the gall to ask me for all the detail steps.
I have already given the pterosaur to primitive bird to modern bird model. What is yours - even at that level of detail.
You catch up with what I have already laid out.
you can't document every little step from birds to dinosaurs because there aren't the fossils for it. That's exactly the point.
ReplyDeleteOkay tell us a few then.
ReplyDeleteWhat pterosaurs did birds evolve from then?
ReplyDeleteThey evolved from the advanced pterosaurs - the pterodactlys.
ReplyDeleteWhat dinos did birds evolve from in your thinking?
"They evolved from the advanced pterosaurs - the pterodactlys."
ReplyDeleteWhich group? Pterodactyloidea is a very large sub-order with some very specialised forms. Also it appeared in the mid Jurassic, which is either contemporary with, or possibly even after, the appearance of the first maniraptors (particularly if Eshanosaurus is confirmed as a Therizonosaur). Your scenario seems to suffer from the same time problem Archaeopteryx used to suffer from (until the discovery of forms such as Scansoriopterygidae)
Hello Anonymous.
ReplyDeleteAs I have mentioned elsewhere I have not worked out the details of the specific pterodactyl subgroups and their relationship with their corresponding primitive bird counterparts.
Would you like to work with me on this? That would be great.
My first inclination is that each of the 4 superfamilies developed into a corresponding form of primitive bird line.
So on the one hand we have the 4 pterodactyl superfamilies:
Azhdarchoidea
Ctenochasmatoidea
Dsungaripteroidea
Ornithocheiroidea (eg. pteranodon)
and on the other we have the primitive bird groups I laid out in the Dec 17, 2010 post. Each of those primitive bird groupings begins with a Dromaeosaurid subgroup.
Care to join in the analysis?
If not, could you give us the dino to bird lineage as you see it, if you think that is more to your liking.
Concerning Dromaeosauridae subgroups there are plenty
ReplyDeletehttp://en.wikipedia.org/wiki/Dromaeosauridae
Dromaeosauroides
Eudromaeosauria
Luanchuanraptor
Mahakala
Microraptoria
Ornithodesmus
Pamparaptor
Pyroraptor
Tianyuraptor
Unenlagiinae
Variraptor
I would love to join in the analysis! How can I help? What's your methodology?
ReplyDeleteFor reference:
ReplyDeleteAzhdarchoidea (eg. quetzalcoatlus)
Ctenochasmatoidea (eg. pterodactylus)
Dsungaripteroidea (eg. Dsungaripterus)
Ornithocheiroidea (eg. pteranodon)
http://en.wikipedia.org/wiki/Azhdarchoidea
http://en.wikipedia.org/wiki/Quetzalcoatlus
http://en.wikipedia.org/wiki/Ctenochasmatoidea
http://en.wikipedia.org/wiki/Pterodactylus
http://en.wikipedia.org/wiki/Dsungaripteroidea
http://en.wikipedia.org/wiki/Dsungaripterus
http://en.wikipedia.org/wiki/Ornithocheiroidea
http://en.wikipedia.org/wiki/Pteranodon
We begin looking for similarities.
ReplyDeleteFor example consider this:
http://en.wikipedia.org/wiki/Pteranodon
"The wing shape of Pteranodon suggests that it would have flown rather like a modern-day albatross. This is based on the fact that Pteranodon had a high aspect ratio (wingspan to chord length) similar to that of the albatross — 9:1 for Pteranodon, compared to 8:1 for an albatross. Albatrosses spend long stretches of time at sea fishing, and use a flight pattern called "dynamic soaring" which exploits the vertical gradient of wind speed near the ocean surface to travel long distances without flapping, and without the aid of thermals (which do not occur over the open ocean the same way they do over land).[11] While most of a Pteranodon flight would have depended on soaring, like long-winged seabirds, it probably required an occasional active, rapid burst of flapping, and studies of Pteranodon wing loading (the strength of the wings vs. the weight of the body) indicate that they were capable of substantial flapping flight, contrary to some earlier suggestions that they were so big they could only glide.[3]"
Here we see a possible connection to seabirds and albatross-type creatures.
This means there is a possible connection to the seabird line which is presented in the Dec 17, 2010 post.
THIS IS A LOT OF SLUGGING WORK.
I will give another example in the next post.
here is another possible example:
ReplyDeletehttp://en.wikipedia.org/wiki/Pterodactylus
"In 1998, the discovery of one specimen assigned to P. kochi shed light on the life appearance of Pterodactylus, as it preserved unique soft-tissue traits not present in previous fossil skeletons, including long, bristly pycnofibres (a fur-like body covering known only in pterosaurs) on the neck, details of a urpatagium (hind wing membrane between the legs and tail) that also stretched between the toes as webbing, and a pelican-like throat pouch."
So there is a possible connection to the bird line that includes foot webbing and pelican-like throat pouches. For example the line that includes pelicans.
This thread is a very preliminary beginning:
ReplyDeletehttp://pterosaurnet.blogspot.com/2010/04/pterosaur-and-modern-bird.html
Here is some more relevant material that may help:
ReplyDeletehttp://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".
Oh I thought you meant like go on expeditions and dig up fossils that show a gradual progression from pterosaur to primitive bird. I mean wikipedia saying something is blank-like isn't really science. A raccoon's paw is chimp-like but that doesn't mean it evolved from a primate.
ReplyDeleteAnyway, when you're ready to go dig up some fossils, let me know!
Nope, not expeditions.
ReplyDeleteLots of evidence already. It just needs to be analyzed properly.
But if you do not want to participate on the pterosaurs, perhaps you could present the dino to bird lineage.
Or are you content with that being a mystery?
I was hoping to go on expeditions, but lab analysis sounds interesting too. Does your lab have teleconferencing? Because unless we're in the same region, I probably won't be able to afford to go to your lab and analyze the fossils. Maybe I could take the bus on weekends if you're close enough.
ReplyDeleteAs to dinosaurs to birds, well I'm not really sure what you mean by lineage. I'm also just starting my studies so I'm not super knowledgeable yet on the whole subject. But I do not intend to waste my academic career being a follower. I want to break new ground!
You can break new ground with the material and ideas I have outlined on this site.
ReplyDeleteYou really don't need anything further from me.
Good luck with your studies.
I thought your thesis was that maniraptors came after pterosaurs, then from them came the modern bird groups. Now you seem to be arguing for a direct lineage from various pterosaur groups to modern bird groups so where do maniraptors fit into this new analysis?
ReplyDeleteI have not changed my thinking.
ReplyDeleteSo what came between, say, pteranodon and the albatross?
ReplyDeletePrimitive birds (non-avian maniraptors).
ReplyDeleteCare to work with me analyzing the details?
We can begin with the Dec 17, 2010 post and take it from there.
So the descendants of pteranodon lost their similarities with the albatross, even lost the ability of flight, to regain it along with all the albatross features again later? Then what is the point in comparing pteranodon to the albatross?
ReplyDeleteI'm sorry, I don't understand how that works. Perhaps you could explain.
Have you been following what I have said at all?
ReplyDeleteFlying pteranadons developed into flying primitive birds that developed into flying modern birds such as albatross.
This is really not all that difficult.
There are no non-avian maniraptors (flying on not) that have albatross-like features. So you are saying they lost those features and then regained them? In which case why would a comparison between an albatross and a pteranodon be relevant?
ReplyDeleteI have been following that. That is exactly why I am confused by your pteranodon to albatross comparison. It is meaningless, since all those similarities (including the basic ability of flight) would have to be lost in the non-avian "primitive bird" descendant of pteranodon, and reappear in the "modern flying" albatross.
ReplyDeleteOK, I see, you clarified that you meant FLYING "non-avian maniraptors". So basic flight was retained, which, apparently, means that there was a flying non-avian maniraptor that retained all those albatross-like features of pteranodon, that later appeared in its descendant the albatross.
ReplyDeleteDo you have evidence of such a flying non-avian maniraptor, one 'transitional' between pteranodon and albatross?
Anonymous, this conversation is somewhat interesting, but it is clear you have not read the posts I have accumulated over the last year.
ReplyDeleteI am not interested in repeating it all for you here point by point.
Let's save time and have you post your questions with the post that it relates to.
You can find the related posts to any question you have by using the search function.
As to which primitive birds have characteristics like the albatross - I have not analyzed every detail.
Would you like to join me in taking the analysis to that level of detail?
If not, that is okay.
But if not, then please give us the dino to bird alternative,
What is the dino to bird lineage leading to albatross? Please indicate which taxa are on that line. And if you cannot give the taxa names, then give us a description of the characteristics of the type of taxa purported to be on the line and the rough time of their existence.
That would be great.
Here is a very preliminary draft lineage leading to albatross:
ReplyDeletePteranodon* (Ornithocheiroidea**) -->
a Dromaeosaurid subgroup -->
an Enantiornithes seabird subgroup -->
Ichthyornithes*** subgroup -->
Albatross
*
http://en.wikipedia.org/wiki/Pteranodon
"The wing shape of Pteranodon suggests that it would have flown rather like a modern-day albatross. This is based on the fact that Pteranodon had a high aspect ratio (wingspan to chord length) similar to that of the albatross — 9:1 for Pteranodon, compared to 8:1 for an albatross. Albatrosses spend long stretches of time at sea fishing, and use a flight pattern called "dynamic soaring" which exploits the vertical gradient of wind speed near the ocean surface to travel long distances without flapping, and without the aid of thermals (which do not occur over the open ocean the same way they do over land).
** http://s1.zetaboards.com/Conceptual_Evolution/topic/1162271/1/
"Based on Mark Witton's research (he's the most decent pterosaur paleobiologist I've seen so far), here's a brief comparation between pterosaur and bird niches (note: niches occupied as adults; since pterosaurs were precocial, they occupied several niches throw their lifestyle, and I have no idea what can be said about them):
-Ornitocheiroids: albatrosses, frigate birds, pseudodontorns, vultures"
***
http://en.wikipedia.org/wiki/Ichthyornis
"The beak of Ichthyornis, like the hesperornithids and other primitive birds, was compound and made up of several distinct plates, similar to the beak of an albatross, rather than a single sheet of keratin as in most modern birds."
"Here is a very preliminary draft lineage leading to albatross:
ReplyDeletePteranodon* (Ornithocheiroidea**) -->
a Dromaeosaurid subgroup -->
an Enantiornithes seabird subgroup -->
Ichthyornithes*** subgroup -->
Albatross"
Hmm. Since, out of all this lineage, we only have fossils of pteranodon and samples of albatross, it seems that you suffer from the same lack-of-fossils problem that the traditional theory has. Ichthyornis could not be a link from pteranodon to albatross because it completely lacks wings, could not fly, and therefore did not have the similarities pteranodon had to the albatross. Those features would have to have been lost and regained.
We also have no fossils of anything like a flying dromaeosaurid that looked like an albatross. Or a flying dromeosaurid that looked like a pteranodon.
So, all you have is that pteranodon had the same wing ratio (but entirely different wings) with the albatross, and ichthyornis had (unlike pteranodon) a similar beak to the albatross (but no wings at all). How can you get that into a plausible lineage?
It seems that your theory suffers from a much greater "lack of fossils" than the dino-to-bird one.
Anonymous posted:
ReplyDelete"Ichthyornis could not be a link from pteranodon to albatross because it completely lacks wings, could not fly, and therefore did not have the similarities pteranodon had to the albatross."
Take a look at Ichthyornis:
http://en.wikipedia.org/wiki/Ichthyornis
Anon
ReplyDeleteI think you're confusing Icthyornis with Hesperornis there. Icthyornis certainly could fly. However it was more gull like than albatross like and of course a dromaeosaurid is nothing like an albatross or a pteranodon (and also had teeth and proper jaws, not a horny beak) - so the same problems in essence are still there. Also it is clear Dr. Pterosaur is not interested in doing real research - digging round for quotes from Wikipedia is far from anything like a scientific approach
Anoymous posted:
ReplyDelete"It seems that your theory suffers from a much greater "lack of fossils" than the dino-to-bird one.
No model could have a greater "lack of fossils" than the dino-to-bird one, since the dino to bird model has none. If you think it it has some, please let us know what they are.
Anonymous posted:
ReplyDelete"Ichthyornis could not be a link from pteranodon to albatross because it completely lacks wings, could not fly, and therefore did not have the similarities pteranodon had to the albatross."
Do you now see that Ichthyornis indeed has wings and could fly?
http://en.wikipedia.org/wiki/Ichthyornis
Pteranodon was from the Late Cretaceous, 86–84.5 Ma, far too recent and far too derived for it to have been an ancestor of "a dromaeosaurid group", let alone an Enantiornithe group. In fact it was probably a contemporary of Icthyornis.
ReplyDeleteAnonymous posted:
ReplyDelete"Pteranodon was from the Late Cretaceous, 86–84.5 Ma, far too recent and far too derived for it to have been an ancestor of "a dromaeosaurid group", let alone an Enantiornithe group. In fact it was probably a contemporary of Icthyornis."
Anonymous, you said that Ichthyornis "completely lacks wings, could not fly".
Do you still think that? Let's see if we can get that straight.
No I didn't - that was someone else. I corrected him in fact.
ReplyDeleteI think it was just a mix up and he had Hesperornis in mind
ReplyDeleteLet's let him/her speak for himself/herself.
ReplyDeletePerhaps the ability for people to post anonymously is confusing you. You seem to think they are all the same person sometimes. Maybe better to get people to post with names only
ReplyDeleteIt gets a bit confusing with multiple anonymous posters.
ReplyDeleteI respect completely your wish to be anonymous.
But if it is acceptable, you might choose to give a made-up name to help sort things out.
You can put the made-up name in your anonymous post.
"Pteranodon was from the Late Cretaceous, 86–84.5 Ma, far too recent and far too derived for it to have been an ancestor of "a dromaeosaurid group", let alone an Enantiornithe group. In fact it was probably a contemporary of Icthyornis."
ReplyDeleteThis seems to have gotten lost
Simon a comment like that would make more sense if it were made after some time had passed for it to be answered.
ReplyDeleteRight?
Especially after the confusion about which anonymous was posting.
The pattern I have proposed to this point is basically
ReplyDeletePterosaur --> Dromaeosaur --> Enantiornithes ---> particular primitive bird --> modern bird
I am beginning to consider that the development step to Dromaeosaur is unnecessary.
Taking an example from the Dec 17, 2010 post this is a simpler model for seabirds:
SEABIRDS (Ichthyornithes line)
Pterosaur subgroup -->
An Enantiornithes seabird subgroup -->
An Ichthyornithes subgroup --> Gulls, Skimmers (Charadriiformes/Lari)
AND
A separate Ichthyornithes subgroup --> Petrels (Procellariiformes*), Sphenisciformes, Pelecaniformes
I will continue to consider this.
The Dromaeosaurs may be their own distinct line (from pterosaurs) leading to a specific set of modern birds.
* Procellariiformes includes albatrosses
Indeed, I confused Ichthyornis with Hesperornis. My bad, I was confused by the name and because they have similar beaks (which is the similarity you propose).
ReplyDeleteBut somehow, that seems an even further stretch. Hesperornis was a small animal, no larger than a pigeon. Pteranodon was huge. You now need transitionals to bridge the size gap as well, confirm that Ichthyornis maintained the wing-to-body ratio that pteranodon had (which seems unlikely, according to its size), find enantiornithines and dromaeosaurids that maintained pteranodon and albatross characteristics, and finally, explain why the toothless beak of the pteranodon developed teeth, to lose them again.
And that does not even count all the radical changes needed in the skeletal morphology of the limbs and wings.
As you can see, you seem to suffer from the same lack of fossils the dino-to-bird theory does. Even more, in fact, if you stop looking for similarities and ignoring the differences. You have to take into account the differences as well.
"Simon a comment like that would make more sense if it were made after some time had passed for it to be answered."
ReplyDeleteSome more time has passed now. I see you have modified your proposal, does that also include taking pteranodon out of the line to albatrosses (and presumably other Procellariiformes) given that it is too recent and too derived?
Why can't Dromaeosaurs simply be dinosaurs? And be unrelated to your pterosaur to bird lineage? There is certainly enough evidence to place them within dinosaurs.
ReplyDeleteAnonymous could you please include a made-up name in your Anonymous post please.
ReplyDeleteAlso please give us what you think the dino to bird lineage was.
That would be great.
I will take your concerns seriously when you present an alternative.
Simon, Pteranodon forms a part of the pterosaur to bird lineage. Care to work with me on the details?
ReplyDeleteHello Sotos.
ReplyDeleteDromaeosaurs are a part of the total picture. See:
http://pterosaurnet.blogspot.com/2010/06/pterosaur-dromaeosaurids-birds-1.html
How do people respond to this*:
ReplyDeletehttp://www.ucmp.berkeley.edu/diapsids/saurischia/troodontidae.html
"It has been suggested that they [troodontidae] were the ancestors of birds, but this is not accepted; a dromaeosaur is currently thought to be the ancestor of all birds."
* This quote is part of my post:
http://pterosaurnet.blogspot.com/2010/06/pterosaur-dromaeosaurids-birds-1.html
Any theory about the lineage leading to modern birds will face the same two challenges.
ReplyDeleteOne is - where did the primitive birds come from?
And second is - how did the primitive birds (basically maniraptors) develop into the vast array of modern birds.
The dino to bird theory does not answer either challenge.
The theory I am proposing answers both as follows:
Primitive birds developed from pterosaurs.
And primitive birds developed into modern birds in a set of parallel lineages.
Concerning the dino to bird model, to this point, NOBODY has offered an answer for either challenge.
Some info on the location of Pteranodon:
ReplyDeletehttp://en.wikipedia.org/wiki/Pteranodon
"It is likely that, as in other polygynous animals (in which males compete for association with harems of females), Pteranodon lived primarily on offshore rookeries, where they could nest away from land-based predators and feed far from shore; most Pteranodon fossils are found in locations which at the time, were hundreds of kilometres from the coastline.[6]
This leads to the conclusion that pteranodon relates to seabirds.
We still have the timing issue (that has been raised) to work through.
Sotos, I have a question for you and it relates to your use of the word "dinosaur".
ReplyDeleteYou posted:
"Why can't Dromaeosaurs simply be dinosaurs? And be unrelated to your pterosaur to bird lineage? There is certainly enough evidence to place them within dinosaurs."
Remember the ambiguity around the word "dinosaur" that I have been mentioning again and again and again?
Is your question:
Why can't Dromaeosaurs simply be non-maniraptor coelurosuars (dinosaurs)? And be unrelated to your pterosaur to bird lineage? There is certainly enough evidence to place them within non-maniraptor coelurosaurs (dinosaurs)."
"Hello Sotos.
ReplyDeleteDromaeosaurs are a part of the total picture. See:
http://pterosaurnet.blogspot.com/2010/06/pterosaur-dromaeosaurids-birds-1.html"
I know you have them as part of the picture, I just don't see why. The differences between pterosaurs and dromeosaurs are too big to overlook. And there are no transitionals between pterosaurs and dromeosaurs. On the other hand, dromeosaurs fit in morphologically in a continuum from basal coelurosaurs to primitive birds. Even that study you quoted spoke of significant correlation between paraves (which includes dromeosaurs) and coelurosaurs (dinosaurs).
In that regard, the traditional theory has more going for it. They do not propose direct ancestry for any fossil, but have a great number of fossils that indicate features diplaying a transitional lineage were present in all the related dinosaur groups. You, on the other hand, propose a dircet ancestry from pterosaurs to modern birds, but have no fossils whatsoever to substantiate it (since no ptero-dromeosaur transitionals have been found, whether sister groups or in direct ancestral line).
With that in mind, it would be better if you left dromeosaurids out of the picture, and focused on a direct immediate descent from pterosaurs to birds. If you need a major form of saltation for your lineage, then why not a saltation from, say, pteranodon directly to the albatross, and the same for every other pterosaur-bird transition? Let dinosaurs be dinosaurs.
"Why can't Dromaeosaurs simply be dinosaurs? And be unrelated to your pterosaur to bird lineage? There is certainly enough evidence to place them within dinosaurs."
ReplyDeleteRemember the ambiguity around the word "dinosaur" that I have been mentioning again and again and again?
Is your question:
Why can't Dromaeosaurs simply be non-maniraptor coelurosuars (dinosaurs)? And be unrelated to your pterosaur to bird lineage? There is certainly enough evidence to place them within non-maniraptor coelurosaurs (dinosaurs)."
I don't think so, since dromeosaurs are also firmly included within maniraptora. If you were to exclude something from the group, it would be more parsimonious to exclude Avialae, which is the most derived bird-like form. Perhaps that is the direct developement from pterosaurs. I'm not saying that's the right choice, I'm just saying it's less wrong.
"If you need a major form of saltation for your lineage, then why not a saltation from, say, pteranodon directly to the albatross, and the same for every other pterosaur-bird transition?"
ReplyDeleteIt would probably have to be like this anyway as Enantionithes precede pteranodon and icthyornis are its contemporaries. So a direct transition to a modern bird group would make more sense; the only problem then is which group corresponds to which modern bird group as pretty much all pterosaurs seem to have been in coastal/seafaring niches. They can't all correspond to gulls and tubenoses.
Sotos you posted:
ReplyDelete"On the other hand, dromeosaurs fit in morphologically in a continuum from basal coelurosaurs to primitive birds."
That is not correct.
If you want to claim that, then please present the taxa in the dino to bird lineage.
Nobody has ever presented the lineage.
What they have done is said that IF there is a lineage, then these other taxa (which are not on the line) would be sister taxa.
But there is NO evidence of any actual ancestors. NONE.
Take a look at my most recent post:
http://pterosaurnet.blogspot.com/2011/09/dino-to-bird-problem.html
Sotos you are using confusing cladistic terminology which assumes the dino to bird model.
ReplyDeleteI have pointed out the problem with that throughout this blog.
Just use the names of the actual groups.
Use the labels:
Non-maniraptor coelurosaurs (dinosaurs)
Non-avian* maniraptors (maniraptors)
Modern birds
Please reword your question/point for us, using those labels.
* Non-aves
"Sotos you are using confusing cladistic terminology which assumes the dino to bird model.
ReplyDeleteI have pointed out the problem with that throughout this blog.
Just use the names of the actual groups.
Use the labels:
Non-maniraptor coelurosaurs (dinosaurs)
Non-avian maniraptors (maniraptors)
Modern birds
Please reword your question/point for us, using those labels".
Since I am proposing that maniraptors are dinosaurs, there is no need to use the second label. I am saying it would be less wrong to consider Avialae as distinct from dinosaurs (including maniraptors and of course dromaeosaurs), and related to pterosaurs.
Why do you think that is not possible?
"Sotos you posted:
ReplyDelete"On the other hand, dromeosaurs fit in morphologically in a continuum from basal coelurosaurs to primitive birds."
That is not correct".
But even the source you yourself quoted says so. Senter says he finds a positive taxon correlation between paraves and coelurosaurs, which means that they share a morphological continuum. That is the case whether there are proposed taxa in a direct ancestry line or not.
"If you want to claim that, then please present the taxa in the dino to bird lineage.
Nobody has ever presented the lineage".
I don't see why one needs to propose a direct lineage to detect this morphological connection, but either way I don't think no one has ever done so. Here is a proposed line:
From a Theropod group to a Maniraptor group, to a Paraves group, to Avialae.
Now, I still think it would be less wrong to hypothesize that such a line led to dromeosaurids and troodontids (all dinosaurs), but NOT to Avialae. Why do you find that less possible than your assumption?
"What they have done is said that IF there is a lineage, then these other taxa (which are not on the line) would be sister taxa.
But there is NO evidence of any actual ancestors. NONE".
What would you consider as "evidence of an actual ancestor"? I cannot think of any possible evidence, either for the traditional theory or yours. Can you?
Time machines don't count ;)
Sotos, you are proposing that maniraptors are dinosaurs. That is a confusing cladistic way of putting it.
ReplyDeleteAre you proposing that maniraptors evolved from non-maniraptor coelurosaurs?
No, I am proposing that maniraptors are dinosaurs in the same way coelurosaurs are dinosaurs. They are a dinosaurian group that evolved (or 'developed' if you like) from basal coelurosaurs.
ReplyDeleteLike you say "coelurosaurs (dinosaurs)" I also say "maniraptors (dinosaurs)".
I think that your theory would be more coherent if you only excluded Avialae from maniraptors (and dinosaurs). What do you think?
Simon posted:
ReplyDelete"If you need a major form of saltation for your lineage, then why not a saltation from, say, pteranodon directly to the albatross, and the same for every other pterosaur-bird transition?"
It would probably have to be like this anyway as Enantionithes precede pteranodon and icthyornis are its contemporaries. So a direct transition to a modern bird group would make more sense; the only problem then is which group corresponds to which modern bird group as pretty much all pterosaurs seem to have been in coastal/seafaring niches. They can't all correspond to gulls and tubenoses."
Pterosaurs developed into primitive birds (non-aves maniraptors) which then developed into modern birds.
Pterosaurs did not develop directly into modern birds.
You are rightly interested in the timing but it is not a showstopper.
I must say again because it is important. What is the dino to bird lineage alternative? What are we comparing my proposal to?
For example, did a tyrannosaur type creature leap to being modern birds? What is the dino to bird lineage?
Lay it out.
Sotos posted:
ReplyDeleteLike you say "coelurosaurs (dinosaurs)" I also say "maniraptors (dinosaurs)".
I do not say "coelurosaurs (dinosaurs)".
I say non-maniraptor coelurosaurs (dinosaurs).
Just use the names of the actual groups. As I suggested. Then there will be no confusion and no embedding your dino to bird assumption in the vocabulary.
"I do not say "coelurosaurs (dinosaurs)".
ReplyDeleteI say non-maniraptor coelurosaurs (dinosaurs)".
So you also agree that maniraptors are coelurosaurs? If you don't, and you think that maniraptors and coelurosaurs are distinct, then the term "non-maniraptor coelurosaurs" is redundant: Either it's a maniraptor, or it's a coelurosaur.
Like you say, let's keep it simple. So, what do you think about my alternative?
Anyway, to avoid bringing the dfiscussion to a halt, I will use your term, although I think it's redundant if one considers coelurosaurs and maniraptors distinct.
ReplyDeleteSo, I say "maniraptors (dinosaurs)" in the same way you say "non-maniraptor coelurosaurs (dinosaurs)".
Is that accepteble?
For those interested, Senter uses the terms
ReplyDelete"Tyrannosaur cluster" and "Bird-like cluster".
He does not include modern birds in his study, so by "bird-like cluster" he means primitive birds (basically non-aves maniraptors)
And by "Tyrannosaur cluster" he means basically non-maniraptor coelurosaurs (actual dinosaurs).
His baraminological analysis clarifies the groups of creatures we are dealing with.
Sotos posted:
ReplyDelete"So, I say "maniraptors (dinosaurs)" in the same way you say "non-maniraptor coelurosaurs (dinosaurs)".
Is that accepteble?"
Obviously it is not acceptable. What is your aversion to simply using the names of the actual groups?
There were dinosaurs (non-maniraptor coelurosaurs).
There were primitive birds (non-aves maniraptors).
And there are modern birds.
Just express your questions and points in terms of those actual groups.
Sotos posted:
ReplyDelete"I do not say "coelurosaurs (dinosaurs)".
I say non-maniraptor coelurosaurs (dinosaurs)".
So you also agree that maniraptors are coelurosaurs? If you don't, and you think that maniraptors and coelurosaurs are distinct, then the term "non-maniraptor coelurosaurs" is redundant: Either it's a maniraptor, or it's a coelurosaur.
Like you say, let's keep it simple. So, what do you think about my alternative?"
Why are we using up time on this?
Just use the names of the actual groups.
The problem you are having Sotos is that you choose to only think in clades.
ReplyDeleteWhen I say "non-maniraptor coleurosaurs" I am trying to convey the idea that Senter conveys with "Tyrannosaur cluster".
I realize that when I use the phrase "non-maniraptor coelurosaurs" it can be confusing to people because "coelurosaur" is defined as a clade that is defined to include maniraptors*. That is a perfect example of embedding your dino to bird assumption in the vocabulary. That is a bad idea.
When I say "non-maniraptor coelurosaurs" I am trying to convey the idea that Senter conveys with "Tyrannosaur cluster".
*But I have to say something to try to get across the idea.
I must say again because it is important. What is the dino to bird lineage alternative? What are we comparing my proposal to?
ReplyDeleteFor example, did a tyrannosaur type creature leap to being modern birds? What is the dino to bird lineage?
Lay it out.
Dr. Pterosaur, Perhaps you missed my post where I AGREED to use the actual terms. I am using the terms "maniraptors" and "non-maniraptor coelurosaurs".
ReplyDeleteThese are the 'actual terms', are they not?
Now, just as you clarify "coelurosaurs" with "(dinosaurs)", I also clarify "maniraptors" in the same bway.
How is that unacceptable? It is my position. Are you asking me to accept your position brforehand, without discussing it?
Sotos posted:
ReplyDelete"Now, just as you clarify 'coelurosaurs' with "(dinosaurs)",
I do not "clarify coelurosaurs with dinosaurs" (whatever that means). I have never said that.
I have been patient with you, but this is all I intend to say on this. You are wasting your time and mine (perhaps on purpose*).
Use the terms "Tyrannosaur cluster" and "Bird-like cluster" if you wish to discuss this topic with me. (And use the term "modern birds" if you wish to refer to existing modern birds.)
* I have had discussions in the past with people where they actually admitted afterward that their goal was to waste my time.
"If you need a major form of saltation for your lineage, then why not a saltation from, say, pteranodon directly to the albatross, and the same for every other pterosaur-bird transition?"
ReplyDeleteIt would probably have to be like this anyway as Enantionithes precede pteranodon and icthyornis are its contemporaries. So a direct transition to a modern bird group would make more sense; the only problem then is which group corresponds to which modern bird group as pretty much all pterosaurs seem to have been in coastal/seafaring niches. They can't all correspond to gulls and tubenoses."
Pterosaurs developed into primitive birds (non-aves maniraptors) which then developed into modern birds.
Pterosaurs did not develop directly into modern birds.
You are rightly interested in the timing but it is not a showstopper.
I must say again because it is important. What is the dino to bird lineage alternative? What are we comparing my proposal to?
For example, did a tyrannosaur type creature leap to being modern birds? What is the dino to bird lineage?
Lay it out.
-------------------------
Let's analyze this from the most parsimonious point of view.
We have flying pterosaurs similar to flying ichthyornithes. And we have flying ichthyornithes similar to flying modern seabirds.
Does the timing work out for a development from pteranodon subgroup to ichthyornis subgroup to modern seabirds?
I am proposing that specific pterosaur groups developed into specific primitive bird groups. In this case, some pteranodon subgroups would develop into some ichthyornithes subgroups. I will analyze that idea in the next post.
Note: Other specific bird lineages would develop through dromaeosaurids and some through enantiornithes.
http://en.wikipedia.org/wiki/Pteranodon
Late Cretaceous, 86–84.5 Ma
http://en.wikipedia.org/wiki/Ichthyornis
Late Cretaceous, 95–85 Ma
At this point, I will consider that the dino to bird theory is based on a saltation from a tyrannosaur-type creature to the diversity of modern birds.
ReplyDeleteThat really is all the evidence that has ever been provided.
So we can compare that to what I am proposing.
Does the timing work out for a development from pteranodon subgroup to ichthyornis subgroup to modern seabirds?
ReplyDeleteAccording to the wiki articles pteranodon fossils have been found back as far as 86 mya and ichthyornithes as far back as 95 mya.
Let me make an interesting point. When this sort of timing information is found related to an accepted lineage we all know the answer that is given.
As a test for fun, what is the answer that is given?
I will answer in a bit but I wanted to see if anyone could for fun answer this.
"I must say again because it is important. What is the dino to bird lineage alternative? What are we comparing my proposal to?
ReplyDeleteFor example, did a tyrannosaur type creature leap to being modern birds? What is the dino to bird lineage?
Lay it out".
I gave you a proposed lineage a few posts ago.
Now, why do you oppose to me using the terms "manitaptor" and "non-maniraptor coelurosaur"? You have used them repeatedly.
I simply consider both dinosaurs, and not just the second.
I see that you are now proposing a direct lineage from pteranodon to sea birds- essentially, you are doing for pteranodon what I proposed you should do for all pterosaur-bird lineages. You leave dromeosaurids and other Paraves aside and propose a direct transition from Pterosaurs to Avialae.
Perhaps you should consider expanding on the details of that. I am glad to have offered some food for thought.
"At this point, I will consider that the dino to bird theory is based on a saltation from a tyrannosaur-type creature to the diversity of modern birds".
ReplyDeleteI do not think anyone proposes that. Where do you get that idea?
Sotos, I am not proposing a direct lineage from pteranodon to sea birds.
ReplyDeleteLet me be more precise, since the word "seabird" is not precise enough for my purposes.
ReplyDeleteI am linking some specific pterosaurs to some specific primitive seabirds (Ichthyornithes) to some specific modern seabirds.
Anonymous:
ReplyDelete"At this point, I will consider that the dino to bird theory is based on a saltation from a tyrannosaur-type creature to the diversity of modern birds".
I do not think anyone proposes that. Where do you get that idea?"
In fact, that is all that has ever been proposed. No evidence beyond that idea has ever been given.
If you can contribute anything beyond that, please do. I am very interested.
Anonymous, please add some made up name to your Anonymous post.
ReplyDeleteShortly I will stop posting Anonymous posts that do not have a made-up name included.
"Let me be more precise, since the word "seabird" is not precise enough for my purposes.
ReplyDeleteI am linking some specific pterosaurs to some specific primitive seabirds (Ichthyornithes) to some specific modern seabirds".
Exactly, which means that you leave dromaeosaurids aside in some cases, and propose a direct transition from pterosaurs to Avialae (avialae includes extinct birds like Ichthyornis).
This is what I suggested you do for all proposed pterosaur-bird transitions.
Sotos suggested:
ReplyDelete"You leave dromeosaurids and other Paraves aside and propose a direct transition from Pterosaurs to Avialae."
I am definitely not leaving Paraves (which includes dromaeosaurids) aside.
Well, I previously offered a proposed lineage which is inferred by reading cladograms (I know you do not think cladistics are valid, but you asked for the opposite, 'dino-to-bird' position and I'm presenting it).
ReplyDeleteIndeed, I do not think there is a proposed lineage that postulates a direct transition from a tyrranosaurid to all modern birds.
Do you have any in mind?
"I am definitely not leaving Paraves (which includes dromaeosaurids) aside".
ReplyDeleteWhy not? You do so for the pteranodon-albatross transition. I believe a similar position for all pterosaur-bird transitions will solve problems and not cause any. Why do you disagree?
Everything we say is corrupted by the cladistic terms that are used. That may well be why there is misunderstanding.
ReplyDeleteI am not talking in terms of clades.
I know this is difficult for the people here who have been programmed with cladistic thinking. It is almost impossible for you to think beyond the distortions of cladistics and actually understand the straightforward things I am saying.
I must say again, that Senter did you all a service by showing how to think beyond cladistics and just work with the actual groups of creatures that exist and existed.
"I am definitely not leaving Paraves (which includes dromaeosaurids) aside".
ReplyDeleteWhy not? You do so for the pteranodon-albatross transition. I believe a similar position for all pterosaur-bird transitions will solve problems and not cause any. Why do you disagree?"
Each lineage needs to be analyzed on its own.
By the way it is misleading for you to say "pteranodon-albatross" transition.
It would be better to say pteranodon-ichthyonithes-albatross transition.
All lineages take the form of pterosaur group to primitive bird group to modern bird group.
Sotos said...
ReplyDelete"Well, I previously offered a proposed lineage which is inferred by reading cladograms (I know you do not think cladistics are valid, but you asked for the opposite, 'dino-to-bird' position and I'm presenting it).
Indeed, I do not think there is a proposed lineage that postulates a direct transition from a tyrranosaurid to all modern birds.
Do you have any in mind?"
I think I will shortly stop discussion with you Sotos (even though I have enjoyed it) because you have no conception as to what it means to think beyond the limitations of cladistics thinking. And you have no interest in trying to think beyond those limitations.
Post from June 29, 2010
ReplyDeletehttp://pterosaurnet.blogspot.com/2010/06/pterosaur-dromaeosaurids-birds-1.html
Dromaeosaurs and Birds
Let's look in detail at the acknowledged closeness between Dromaeosaurs and birds. Keep in mind that Dromaeosaur fossils date back 167 million years ago!
Dromaeosaurs were very, very bird-like. (In fact they were birds. The earliest ones flew and some of those, but not all of them, later became flightless).
http://en.wikipedia.org/wiki/Origin_of_birds
"Early analyses suggested that dromaeosaurid theropods like Deinonychus were particularly closely related to birds, a result which has been corroborated many times since.[32][33]"
AND
http://www.geol.umd.edu/~tholtz/G104/10424arch.htm
"Also hard to recognize good shared derived characters for Avialae at present, because basal deinonychosaurs are very, very avialian-like."
AND
http://en.wikipedia.org/wiki/Cryptovolans
"Czerkas also believed that Cryptovolans [a dromaeosaurid] may have been able to fly better than Archaeopteryx, the animal usually referred to as the earliest known bird. He cited the fused sternum and asymmetrical feathers, and argued that Cryptovolans has modern bird features that make it more derived than Archaeopteryx. Czerkas cited the fact that this possibly volant animal is also very clearly a dromaeosaurid to suggest that the Dromaeosauridae might actually be a basal bird group, and that later, larger, species such as Deinonychus were secondarily flightless (Czerkas, 2002)."
AND
http://www.ucmp.berkeley.edu/diapsids/saurischia/dromaeosauridae.html
"Dromaeosauridae is thus termed the sister group of the clade Aves (which includes all birds). It may even be that the ancestry of birds lies within this group, which would make them dromaeosaurs too, but this is not at all established [accepted]."
"He [J. Ostrom] also saw similarities between it [Deinonychus] and modern birds, and has today continued to be a leading proponent for the dromaeosaurian kinship with birds."
AND
http://www.ucmp.berkeley.edu/diapsids/saurischia/troodontidae.html
"It has been suggested that they [troodontidae] were the ancestors of birds, but this is not accepted; a dromaeosaur is currently thought to be the ancestor of all birds. "
AND
http://en.wikipedia.org/wiki/Dromaeosauridae
"Dromaeosaurids are so birdlike that they have led some researchers to argue that they would be better classified as birds."
"As late as 2001, Mark Norell and colleagues analyzed a large survey of coelurosaur fossils and produced the tentative result that dromaeosaurids were most closely related to birds, with troodontids as a more distant outgroup. They even suggested that Dromaeosauridae could be paraphyletic relative to Avialae.[37]"
"Their phylogenetic analysis [Mayr and Peters in 2005] produced the controversial result that Confuciusornis [an avialae] was closer to Microraptor [a dromaeosaur] than to Archaeopteryx, making the Avialae a paraphyletic taxon. "
AND
http://dml.cmnh.org/2002Sep/msg00255.html
"Steve's [Steve Czerkas'] analysis that Cryptovolans [a Dromaeosaur] was a fully developed flier is entirely correct."
"Dromaeosaurs were sophisticated fliers (some or all basal examples) or secondarily flightless (derived examples). They are very probably closer to modern birds than Archaeopteryx (see DA for the analysis). Since troodonts are probably relatives of dromaeosaurs, and basal troodonts are more bird-like than derived examples, they too should be neoflightless
Earlier I asked about this but nobody answered.
ReplyDeletehttp://www.ucmp.berkeley.edu/diapsids/saurischia/troodontidae.html
"It has been suggested that they [troodontidae] were the ancestors of birds, but this is not accepted; a dromaeosaur is currently thought to be the ancestor of all birds."
Here is something noteworthy concerning the dino (tyrannosaur cluster) to bird idea:
ReplyDeleteThere are fossils for a NUMBER of taxa in the fossil record. But none of those work out as ancestors.
Thus it strains credulity that the dino to bird enthusiasts push the story that there is a lack of fossils to establish the identity of ancestors.
That excuse just does not stand up.
http://www.kheper.net/evolution/systematics/evolutionary.htm
ReplyDelete"Also, unlike Cladistics, with it's reliance on a hypothetical Most Recent Common Ancestor that is never actually described or discovered (a missing link that is always missing), Evolutionary systematics gives illustrations of the actual evolution of one species or higher taxon into another."
I am certainly not the only one who has seen through cladistics and its excuses.
"Does the timing work out for a development from pteranodon subgroup to ichthyornis subgroup to modern seabirds?
ReplyDeleteAccording to the wiki articles pteranodon fossils have been found back as far as 86 mya and ichthyornithes as far back as 95 mya.
Let me make an interesting point. When this sort of timing information is found related to an accepted lineage we all know the answer that is given.
As a test for fun, what is the answer that is given?
I will answer in a bit but I wanted to see if anyone could for fun answer this."
Well I guess nobody wanted to answer this.
The answer is "ghost lineage".
http://en.wikipedia.org/wiki/Pteranodon
ReplyDelete"Pteranodon fossils are known primarily from the Niobrara Formation of the central United States. Broadly defined, Pteranodon existed for more than four million years, during the late Coniacian - early Campanian stages of the Cretaceous period.[5] The genus is present in most layers of the Niobrarra Formation except for the upper two; in 2003, Kenneth Carpenter surveyed the distribution and dating of fossils in this formation, demonstrating that Pteranodon sternbergi existed there from 88-85 million years ago, while P. longiceps existed between 86-84.5 million years ago. A possible third species, which Kellner named Geosternbergia maysei in 2010, is known from the Sharon Springs member of the Pierre Shale Formation in Kansas, Wyoming, and South Dakota, dating to between 81.5 and 80.5 million years ago.[8]"
If fossils are found in most layers "except the upper two" then how can they tell how far back it actually goes?
http://en.wikipedia.org/wiki/Pteranodontidae
ReplyDeleteTemporal range: Late Cretaceous, 98–80.5 Ma
http://en.wikipedia.org/wiki/Pteranodontidae
ReplyDeleteTemporal range: Late Cretaceous, 98–80.5 Ma
Ichthyornis
Temporal range: Late Cretaceous, 95–85 Ma
Time-wise it does not seem to be a problem for pteranodons to be the ancestors of ichthyornithes.
"I think I will shortly stop discussion with you Sotos (even though I have enjoyed it) because you have no conception as to what it means to think beyond the limitations of cladistics thinking. And you have no interest in trying to think beyond those limitations".
ReplyDeleteI think that is an unfair assumption. I have suggested that you apply the kind of modified lineage you already now use for pteranodon to albatross, to all your pterosaur-bird transitions. In what way does that reveal "cladistic thinking"?
Also, I explained that I consider maniraptors to be dinosaurs, in the same way you consider 'non-maniraptor coelurosaurs' to be dinosaurs. If that somehow reveals cladistic thinking, then aren't we both guilty of it?
Either way, if you decide to end our discussion, although I also enjoy it, that is fine.
Sotos, your cladistic thinking is that when you present the dino to bird idea you only can present it in cladistic terms.
ReplyDeleteYou cannot evaluate the dino to bird idea (or any lineage idea) without using the cladistic method.
And cladistics is just one way (and a poor way) of evaluating phylogenies.
I have received a couple of Anonymous comments but neither has a made-up name included.
ReplyDeleteIf the individual or individuals would like to contribute please re-submit with a made-up name included.
Thanks.
Let's accumulate some reference material for the pelican lineage:
ReplyDeletePELICAN*
http://www.dinosaursfaq.com/Dinosaur/Rhamphorhynchus-Dinosaur.html
"According to scientists and paleontologists, the Rhamphorhynchus hunted in a manner similar to the modern-day pelican wherein it would dive into water and use its long beak to scoop out fish, insects and frogs from water and then toss them down its throat pouch.
The fossils of Rhamphorhynchus that have been found have been well-preserved. One can see not just the skeleton but also the outline of the internal organs. Some fossils have been found with the throat pouch intact. Many Rhamphorhynchus fossils have been found in southern England and in Bavaria in southern part of Germany."
http://archosaurmusings.wordpress.com/2008/07/25/pterosaur-soft-tissues
"Throat pouches (like those of a pelican) can be seen in Pterodactylus and can be inferred in Ludodactylus."
http://www.statemaster.com/encyclopedia/Rhamphorhynchus-%28animal%29
"Rhamphorhynchus probably ate fish and it is believed that one of the ways it hunted was by dragging its beak in the water, catching fish and tossing them into its throat pouch, a structure similar to that of pelicans, which has been preserved in some fossils. This method of catching fish is found today in skimmers."
http://en.wikipedia.org/wiki/Pterodactylus
"In 1998, the discovery of one specimen assigned to P. kochi shed light on the life appearance of Pterodactylus, as it preserved unique soft-tissue traits not present in previous fossil skeletons, including long, bristly pycnofibres (a fur-like body covering known only in pterosaurs) on the neck, details of a urpatagium (hind wing membrane between the legs and tail) that also stretched between the toes as webbing, and a pelican-like throat pouch."
* From http://pterosaurnet.blogspot.com/2010/04/pterosaur-and-modern-bird.html
"If fossils are found in most layers "except the upper two" then how can they tell how far back it actually goes?"
ReplyDeleteBy looking at the bottom layers, and where you have the first occurance of the fossil. You can use various statistical methods to evaluate how good your fossil record is for that species, and see if you should see more fossils a little earlier.
However I see a major problem with your Pteranodon evolved into Ichthyornis idea. It requires the simultaneous evolution of all the traits Ichthyornis shares with all other birds, the traits it shares with maniraptorans, and the traits it shares with dinosaurs, but does not share with pterosaurs. You have multiple origins of feathers, and all the other uniquely avian characters, etc.
This makes "birds" polyphyletic, something that Evolutionary Systematics has as little truck with as cladistcs does.
To be honest, I don't understand your aversion to cladistics. All it states is that if an organism is descended from a particular group then it is a member of that group, and that groups should defined to contain everything that is descended from a member of that group. As has been explained before, you could present your ideas in a cladistic framework- stating for instance that because Albatrosses are descended from pteranodontians that they *are* pteranodontians. It changes nothing about the evidence you have so far presented.
In fact given the large number of characters used to evaluate relatedness even people who use evolutionary systematics and are perfectly happy to give names to paraphyletic groups use the same tools that cladists use to generate phylogenies. Your alternative method appears to use single (or very few) characters many of which are not homologous (and when you suggest they are, have not backed up your assertation with evidence- why for instance should we believe that the pteroid is a finger, when you have presented no anatomical reason for us to think that it is. You have not compared it and the sesamoid with other phalanges to make your case, something you need to do in order for anyone to take your idea seriously for example.) In other cases you're taking descriptions of species from Wikipedia, and similar sources as evidence for relatedness, when they are usually describing a species' ecology or general shape to a lay audience. What morphological evidence not related to ecology do you have for linking Pteranodon, ichthyornis and the albatrosses to each other that is not based on their ecology?
And to forstall your usual objection I am not presenting any alternative idea. I want to see you support your ideas with a higher standard of evidence.
Rhamphorhynchus and Pterodactylus are contemporary. The first is not going to be ancestral to the other for that reason alone.
ReplyDeleteThere is no evidence for skimming behaviour in any pterosaur- none possess the jaw structure required for skimming behaviour. Their jaws are either the wrong shape, or simply not robust enough for skimming.
http://en.wikipedia.org/wiki/Seabird
ReplyDelete"Seabirds (also known as marine birds) are birds that have adapted to life within the marine environment. While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution*, as the same environmental problems and feeding niches have resulted in similar adaptations. The first seabirds evolved in the Cretaceous period, and modern seabird families emerged in the Paleogene."
"Gannets, boobies, tropicbirds, some terns and Brown Pelicans all engage in plunge diving, taking fast moving prey by diving into the water from flight. Plunge diving allows birds to use the energy from the momentum of the dive to combat natural buoyancy (caused by air trapped in plumage),[19] and thus uses less energy than the dedicated pursuit divers, allowing them to utilise more widely distributed food resources, for example, in impoverished tropical seas."
* Actually homology explains it
Ann O'Nymous posted:
ReplyDelete"And to forstall your usual objection I am not presenting any alternative idea. I want to see you support your ideas with a higher standard of evidence."
Please come back when you are prepared to talk about an alternative. If you cannot make ANY effort to describe an alternative, then why should I make more effort to help you understand better what I have proposed.
Beginning analysis:
ReplyDeleteAQUATIC BIRDS (Hesperornithes line)
Pterosaur (Pterodactylus?)--> An Enantiornithes aquatic subgroup --> Baptornithidae (Hesperornithes) --> (primarily foot-propelled) WEB FOOT diving bird orders, eg. Cormorants (Phalacrocoracidae), Loons (Gaviidae)).
We will need to see if Enantiornithes is involved in this lineage.
Pelican is web footed.
"Please come back when you are prepared to talk about an alternative."
ReplyDeleteThere are numerous holes in your "theory". Even without your insistence on any and all visitors to your site proposing alternatives, that is enough for us to doubt your claims.
"If you cannot make ANY effort to describe an alternative, then why should I make more effort to help you understand better what I have proposed."
Because what you have proposed lack sufficient support. You have not demonstrated that the pteroid is a finger for instance. You have provided no evidence for this claim- no comparison with other phalanges, etc. If I were to suggest that dinosaurs were ancestral to birds you would demand a series of ancestral species- which I am not willing to provide as I have no method of identifying one fossil as being ancestral to another. I can provide names of taxa that are progressively more similar, and lists of characters- but other people have done that and you have not been satisfied.
"While seabirds vary greatly in lifestyle, behaviour and physiology, they often exhibit striking convergent evolution*
* Actually homology explains it "
Why? What about the characters that they do not share in common, but share with other birds that don't have these diving adaptations, and aren't related to diving? Why should we believe that just because organisms are adapted to similar environments that they are closely related? What happens when you ignore these adaptations and look at characters that aren't affected by this- such as genetics? Why does the DNA evidence- evidence that you have cited elsewhere on this blog give a different result?
"Sotos, your cladistic thinking is that when you present the dino to bird idea you only can present it in cladistic terms".
ReplyDeleteI don't understand how, since I used the same terms you did (maniraptors and non-maniraptor coelurosaurs).
Perhaps I am doing so without realizing it. Can you point out where and how I am using cladistic thinking in my terms? Then I will try to modify them accordingly.
Sotos - two things:
ReplyDelete1. Use the terms that Senter uses - Tyrannosaur cluster and Bird-like cluster. Re-word any point you want to make using thhose terms.
2. Read up on Evolutionary Systematics.
Start here:
http://en.wikipedia.org/wiki/Evolutionary_taxonomy
and
http://www.kheper.net/evolution/systematics/evolutionary.htm
Ann O'Nymous posted
ReplyDelete"Because what you have proposed lack sufficient support."
You are unwilling (unable) to even present an alternative lineage!
If you cannot even give an alternative you are hardly in a position to say that I have proposed insufficient support. You have presented NONE.
How do people respond to this*:
ReplyDeletehttp://www.ucmp.berkeley.edu/diapsids/saurischia/troodontidae.html
"It has been suggested that they [troodontidae] were the ancestors of birds, but this is not accepted; a dromaeosaur is currently thought to be the ancestor of all birds."
Is it correct that
a dromaeosaur is currently thought to be the ancestor of all birds?
Plenty of other people have done so. Why should I repeat their work? You don't seem to understand that I don't have to present an alternative. I am not asking you to critique an alternative theory. I am asking you to explain your theory better. I am asking you to give me a reason to believe the statements you make in support of your claims. Why should I believe what you say about the pteroid for example?
ReplyDeleteYour ideas should stand on their own merits. So far they don't appear to be doing terribly well. Besides, given that you have been promoting your ideas for quite some time you should have amassed a great deal of literature about what the currently accepted alternative is. I shouldn't need to present an alternative to you, you should already be very familiar with it.
I have no problem with a "dromaeosaur" being the ancestor of all birds. It certainly fits the morphological evidence better than your alternative- that different birds are descended from different pterosaurs and must have acquired all their birdlike features independently.
Dr. pterosaur, I don't understand how I can use the two 'clusters' to present my proposed modification to your lineage, when you do not directly use those terms yourself, when presenting your lineage! You speak of specific groups and subgroups.why can't I do the same?
ReplyDeleteI am on my smartphone right now, but I'll read the links you posted and try to figure out what you believe I'm doing wrong.
Sotos (on thephone).
Sotos the primitive birds I have been speaking of are the "bird-like cluster".
ReplyDeleteHope you read the evolutionary systematics references.
Ann O'Nymous
ReplyDelete"Plenty of other people have done so."
Nobody has done so. But I am getting tired of your excuses and run-arounds. Believe me I have seen them all before. Including the one that claims somebody else has already done it.
If somebody else has identified the ancestors on the lineage of dinos to birds, please point us to it.
Or just give it yourself.
We both know that nobody has done it. Why not be honest and say that.
My Dec 17, 2010 post outlined a set of lineages leading from pterosaurs to specifc sets of modern birds.
ReplyDeleteThe lines are based on the pattern:
Pterosaur --> Dromaeosaur subgroup--> Enantiornithes subgroup --> specific primitive bird group (eg. Ichtyorniithes etc) --> modern birds.
In the recent posts I delved more deeply into the line that leads to seabirds such as albatross. Because I believed that the line stems from Pteranodontidae I considered that the line might be simplified to
Pteranodontidae --> Icthyornithes --> Albatross.
However I had research and reasons back in Dec 2010 to include Dromaeosaurs and Enantiornithes in the line and I want to continue to hold to that idea and work through any issues in that idea.
So basically the Dec 17, 2010 proposal stands.
If anyone wishes to work with me on enhancing that, please let me know.
In line with this, the idea is that primitive birds developed from pterodactyloids.
ReplyDeletehttp://en.wikipedia.org/wiki/Pterodactyloidea
Pterodactyloids
Temporal range: Middle Jurassic-Late Cretaceous, 160–65.5 Ma
Roughly the times are:
ReplyDeletePterodactyloidea 160 mya
http://en.wikipedia.org/wiki/Pterodactyloidea
Pterodactylidae 150.8
http://en.wikipedia.org/wiki/Pterodactylidae
Pteranodontidae 98*??
http://en.wikipedia.org/wiki/Pteranodontidae
Dromaeosauridae 164**??
http://en.wikipedia.org/wiki/Dromaeosauridae
Enantiornithes 140
http://en.wikipedia.org/wiki/Enantiornithes
Ichthyornithes 95
http://en.wikipedia.org/wiki/Ichthyornithes
Hesperornithes 100
http://en.wikipedia.org/wiki/Hesperornithes
Presbyornithidae "Late Cretaceous?"
http://en.wikipedia.org/wiki/Presbyornithidae
*
http://jpaleontol.geoscienceworld.org/cgi/content/abstract/84/6/1071
"However, the lack of Early Cretaceous Lagerstätten in North America may produce underestimates of true pterosaur richness during this interval, thereby obscuring a subsequent drop in diversity."
**
http://en.wikipedia.org/wiki/Dromaeosauridae
"The presence of dromaeosaurs as early as the Middle Jurassic has been confirmed [surmised] by the discovery of isolated fossil teeth, though no dromaeosaurid body fossils have been found from this epoch.[3]
SEABIRDS (Ichthyornithes line)
ReplyDeletePteranodon (Ornithocheiroidea) -->
A Dromaeosaurid subgroup -->
An Enantiornithes seabird subgroup -->
An Ichthyornithes subgroup --> Gulls, Skimmers (Charadriiformes/Lari)
AND
Pteranodon (Ornithocheiroidea) -->
A Dromaeosaurid subgroup -->
An Enantiornithes seabird subgroup -->
An Ichthyornithes subgroup --> Petrels, Albatross (Procellariiformes), Sphenisciformes, Pelecaniformes
AQUATIC BIRDS (Hesperornithes line)
ReplyDeletePterodactylus (Ctenochasmatoidea)-->
A Dromaeosaurid subgroup -->
An Enantiornithes aquatic subgroup --> Baptornithidae (Hesperornithes) --> (primarily foot-propelled) WEB FOOT diving bird orders, eg. Cormorants (Phalacrocoracidae), Loons (Gaviidae)).
AND
Pterodactylus (Ctenochasmatoidea)-->
A Dromaeosaurid subgroup -->
An Enantiornithes aquatic subgroup --> Hesperornithidae (Hesperornithes) --> (primarily foot-propelled) LOBE FOOT diving bird orders eg. Grebes (Podicipedidae).
For reference:
ReplyDeletehttp://en.wikipedia.org/wiki/Azhdarchidae
"Azhdarchids were originally classified as close relatives of Pteranodon due to their long, toothless beaks. Others have suggested they were more closely related to the toothy Ctenochasmatids (which include filter-feeders like Ctenochasma and Pterodaustro). Currently it is widely agreed that azhdarchids were closely related to pterosaurs such as Tupuxuara and Tapejara."
How will you be establishing ancestry between these groups?
ReplyDeleteAnd does it make sense to you that Pteranodon (Ornithocheiroidea) loses its albatross-like flight only to gain it back as an albatross? Or do you have a dromaeosaurid subgroup with albatross-like flight in mind?
For reference:
ReplyDeletehttp://www.pnas.org/content/early/2011/08/29/1112694108.abstract
The crop is characteristic of seed-eating birds today, yet little is known about its early history despite remarkable discoveries of many Mesozoic seed-eating birds in the past decade. Here we report the discovery of some early fossil evidence for the presence of a crop in birds. Two Early Cretaceous birds, the basal ornithurine Hongshanornis and a basal avian Sapeornis, demonstrate that an essentially modern avian digestive system formed early in avian evolution. The discovery of a crop in two phylogenetically remote lineages of Early Cretaceous birds and its absence in most intervening forms indicates that it was independently acquired as a specialized seed-eating adaptation. Finally, the reduction or loss of teeth in the forms showing seed-filled crops suggests that granivory was possibly one of the factors that resulted in the reduction of teeth in early birds.
Friend-O said...
ReplyDelete"How will you be establishing ancestry between these groups?
And does it make sense to you that Pteranodon (Ornithocheiroidea) loses its albatross-like flight only to gain it back as an albatross? Or do you have a dromaeosaurid subgroup with albatross-like flight in mind?"
Flying pteranodons developed into flying dromaeosaurs which then in a few additional steps developed into modern birds.
It comes as a surprise to people to learn that dromaeosaurs could fly. They were primitive birds.
how will you be establishing that relationship?
ReplyDeleteFriend-O please elaborate.
ReplyDeleteFriend-O did you catch my point about the fact that dromaeosaurs were flying primitive birds?
ReplyDeleteIn the earlier posts I have proposed lineages that stem from Ornithocheiroidea and Ctenochasmatoidea.
ReplyDeleteI have said that it may well be that root lineages stemmed from the four Pterodactyloidea taxa:
Azhdarchoidea
Ctenochasmatoidea
Dsungaripteroidea
Ornithocheiroidea
If anyone would like to contribute, perhaps you could suggest the lineages that could have stemmed from the two that I have not touched on - Azhdarchoidea and Dsungaripteroidea.
http://en.wikipedia.org/wiki/Azhdarchidae
ReplyDeleteAzhdarchids are characterized by their long legs and extremely long necks, made up of elongated neck vertebrae which are round in cross section. Most species of azhdarchids are still known mainly from their distinctive neck bones and not much else. The few azhdarchids that are known from reasonably good skeletons include Zhejiangopterus and Quetzalcoatlus. Azhdarchids are also distinguished by their relatively large heads and long, spear-like jaws. It had been suggested azhdarchids were skimmers,[2][3] but further research has cast doubt on this idea, demonstrating that azhdarchids lacked the necessary adaptations for a skim-feeding lifestyle, and that they may have led a more terrestrial existence similar to modern storks.[4][5][6][7]
For reference (very rough)
ReplyDeleteWADERS/SHOREBIRDS
Pterosaur --->
A Dromaeosaurid subgroup -->
An Enantiornithes shorebird subgroup --> Primitive shorebird (eg. Graculavus) --> Modern shorebirds - eg. plovers, oystercatchers, sandpipers (Charadriiformes/Charadrii)
For reference:
ReplyDeletehttp://www.nature.com/news/2011/110414/full/news.2011.236.html
The nocturnal hunters ranged from Microraptor gui, a winged dinosaur no more than 90 centimetres long, to Megapnosaurus kayentakatae, a pack-hunting species that could grow up to 3 metres, and Velociraptor mongoliensis, the viciously clawed predator made famous in the novel Jurassic Park.
Several pterosaurs, flying reptiles that were closely related to the dinosaurs, also had eye shapes that indicated they were active at night. What these pterosaurs were doing in the dark is unclear, but Schmitz and Motani suggest that they could have been behaving like petrels and albatrosses (Procellariiformes) or waterfowl (Anseriformes), which often forage at night.
http://en.wikipedia.org/wiki/Charadriiformes
ReplyDeleteThat the Charadriiformes are an ancient group is also borne out by the fossil record. Much of the Neornithes' fossil record around the Cretaceous–Tertiary extinction event is made up of bits and pieces of birds which resemble this order. In many, this is probably due to convergent evolution brought about by semi-aquatic habits.
"Sotos - two things:
ReplyDelete1. Use the terms that Senter uses - Tyrannosaur cluster and Bird-like cluster. Re-word any point you want to make using thhose terms.
2. Read up on Evolutionary Systematics".
In what way should I use those "clusters" to express my modification to your lineage? And after all, you do not solely and generally rely on those two 'clusters' either, when presenting your methodologies. You specifically refer to particular subgroups. Like, for example, above:
"Pteranodon (Ornithocheiroidea) -->
A Dromaeosaurid subgroup -->
An Enantiornithes seabird subgroup -->
An Ichthyornithes subgroup --> Gulls, Skimmers (Charadriiformes/Lari)".
You are quite specific in the subgroups you use, and you don't just say 'a series of subgroups from the bird-like cluster', for example. Surely that does not entail cladistic thinking! Why can't I do the same?
I read your links on evolutionary systematics and they are interesting, but again I see no problem towards what I am proposing. Like you, I am looking at morphologies, and propose lineages.
If you think some ascpects of my proposed modifications are permeated by 'cladistic thinking', please highlight them and explain how I'm doing that, with examples. Maybe that will help me understand your objections better.
But if there are no issues with that, why not consider my proposal? I think it solves several problems, and better fits those similarities you have indicated and collected between pterosaurs and modern birds. I hope we can work together on that option, and evaluate its plausibility.
"Dr. Pterosaur said...
ReplyDeleteFriend-O please elaborate."
what I mean is...
say you have a Pteranodon (Ornithocheiroidea) and a Dromaeosaurid subgroup you think is its descendant.
How will you evidence the ancestor-descendant relationship between the two?
Friend-O, we would look for similarities of morphology, environment and behavior.
ReplyDeleteCare to participate?
Sotos:
ReplyDelete"But if there are no issues with that, why not consider my proposal? I think it solves several problems, and better fits those similarities you have indicated and collected between pterosaurs and modern birds. I hope we can work together on that option, and evaluate its plausibility."
If you would like to participate, then please look for similarities of morphology, environment and behavior between pterosaurs (eg pteranodon) and dromaeosaur taxa. That is the idea I am working with.
On the other hand, if you wish to work with the idea you are proposing, then please proceed and tell me your results.
For example, there may well be a lineage stemming from Azhdarchidae to some specific modern bird groups such as storks. Analyze that possible lineage if you like.
ReplyDeleteAnother clue is that when you read that a similarity is "analogous", check to see if it could be homologous in a pterosaur to bird lineage.
ReplyDelete"Dr. Pterosaur said...
ReplyDeleteFriend-O, we would look for similarities of morphology, environment and behavior.
Care to participate?"
How will those elements establish lineage? For instance, we as humans share similarities of morphology, environment and behavior with chimps, but it doesn't necessarily mean that we descended from a chimp. How will your methodology resolve this issue?
How is it resolved now?
ReplyDeleteIt is starting to look like Friend-O may be setting this up simply to waste my time. Let's see if I am right about that. I hope not. This sounds like a way to sneak back to the stale cladistics argument.
ReplyDelete"Dr. Pterosaur said...
ReplyDeleteHow is it resolved now?"
Well... it's not really resolved now in a sense as the data is too inconclusive to make a determination that y evolved from x.
Most will say with conclusivity that x and y share a last common ancestor with each other, but it not know exactly what that ancestor is. It very well could be x but that would just be speculation. More likely, because of the vagaries and rareness of fossilization, the shared LCA of X and Y is very X-like. That is all that can be said with certainty.
How does your methodology resolve this? I am very interested in this as it could be a major scientific breakthrough
Friend-O, read up about evolutionary systematics.
ReplyDeleteI am not proposing a radical unknown methodology breakthrough.
If anything, I am making a breakthrough to propose an alternative to the dino to bird idea.
But I am not interested in arguing more on this. If you would like to actually roll up your sleeves and analyze the details of the taxa then please join in.
I will warn you it is a lot of hard work.
Much harder than proposing cladistic excuses for why you cannot determine ancestors.
I have read a lot about Evolutionary Systematics and do not see how it resolves this problem of ancestry other than just pure assertion.
ReplyDeleteWould you care to post links and copy and paste the relevant parts that show how systematics determines ancestry?
I would like to contribute to your analysis, as I find it very interesting, but I must first understand your methodology.
Friend-O, I have told you the methodology.
ReplyDeleteI am not going to try to persuade you or teach you. I have better things to do.
I am afraid then that I must add to the growing list of commenters who note your evasion on this topic and most other questions that are asked of you.
ReplyDeleteAs a final suggestion, have you perhaps considered adjusting your bedside manner? You may find you catch more flies with honey than vinegar. Just a thought.
Friend-O I will point out that I earlier predicted where this was going - that you were simply out to waste my time.
ReplyDeleteThe issue is not my "bedside" manner. You were going down this path right from the start. I have seen this pattern MANY times. MANY TIMES.
You were never going to actually roll up your sleeves and participate.
You are just one more individual that is programmed to think a certain way and cannot think beyond it. The way I act is not the issue.
Worth repeating;
ReplyDeletehttp://www.kheper.net/evolution/systematics/evolutionary.htm
"Also, unlike Cladistics, with it's reliance on a hypothetical Most Recent Common Ancestor that is never actually described or discovered (a missing link that is always missing), Evolutionary systematics gives illustrations of the actual evolution of one species or higher taxon into another."
I am certainly not the only one who has seen the problems with cladistics .
It is also worth noting that you left this part out:
ReplyDeletehttp://www.kheper.net/evolution/systematics/evolutionary.htm
"Admitedly, Evolutionary Systematics suffers from a number of shortcomings. For example the use of several very different criteria (phylogeny, divergence, adaptational level) to define particular taxa, as well as inconsistencies inherent in the paraphyletic approach (e.g. separating Class Aves (Birds) from the Archosauria). This, together with the greater rigour and precion of the and practical and heuristic superiority of the Cladistic (Phylogenetic) approach has meant that over the past decades.Evolutionary Systematics has greatly declined; the result being the rise of cladistics.as the dominant paradigm."
Greater rigor and precision is of no value if you are doing the wrong thing.
ReplyDeleteIt reminds me of the joke. I have good news and bad news. The bad news is that we are going in the wrong direction. The good news is that we are making good time.
Cladistics is an example of going in the wrong direction.
It is no compensation that the computer can efficiently do the calculations.
What has happened is that the computer's lack of thinking has replaced actual thinking.
Note how he ends the article:
ReplyDelete"Why I prefer Evolutionary Systemmatics
Granted Evolutionary Systematics has problems, as does any conceptual system. But the thing I myself like about it - and here I am talking intuitively rather than scientistically - is that it is based on two very important intuitive ideas: deep time and metamorphosis. Deep time means time extending over millions of years. This is part of the vastness of the universe - the temporal vastness that goes alongside the spatial vastness. Deep Time provides the theatre for metamorphosis, for the change and transformation of organsims - and indeed of Gaia and the universe as a whole - over time. I think of organisms changing through time - one evolving into the next - like one of those time-lapse films of plants growing. We can't see plants growing - it is too slow. But if things were speeded up the astonishing metamorphosis would be visible. It's the same with evolution. Evolutionary systemmatics is a means of describing this process. "
Worth repeating till it sinks in:
ReplyDeletehttp://www.kheper.net/evolution/systematics/evolutionary.htm
"Also, unlike Cladistics, with it's reliance on a hypothetical Most Recent Common Ancestor that is never actually described or discovered (a missing link that is always missing), Evolutionary systematics gives illustrations of the actual evolution of one species or higher taxon into another."
I am certainly not the only one who has seen the problems with cladistics .
By the way, it is not just ONE hypothetical most recent common ancestor that is missing - it is a whole series of them along the purported lineage line. Cladistics has not discovered or described ANY of them!
ReplyDelete"If you would like to participate, then please look for similarities of morphology, environment and behavior between pterosaurs (eg pteranodon) and dromaeosaur taxa. That is the idea I am working with.
ReplyDeleteOn the other hand, if you wish to work with the idea you are proposing, then please proceed and tell me your results".
Well, I believe the idea you're working with doesn't have that much evidence. You detected and presented many interesting similarities between pterosaurs and modern birds, in morphology as well as habitat and indicated behavior. But these similarities become irrelevant if you include dromeosaurids in the lineage, since the similarities would have to be lost in them and regained in their early bird descendants. For example, what is the point in making much of the similarity in wing-to-body ratio between pteranodon and the albatross, when that would be lost in the transitional dromeosaurid form? And if you assume that some kind of flying dromeosaurid with similar wing-to-body ratio existed, then you have the same problem with the dino to bird theory, if not a larger one; because no fossils of such an animal have been found and also no fossils of animals vaguely similar to it (that famous 'sister taxa' that proponents of the conventional theory say they have) have been found either. You don't just need a common ancestor, but you need even the slightest sign that something like it existed.
On the other hand, since you already agree to a form of saltational transition, a lineage from pterosaurs directly to avialae (via saltation) might create less of a problem, and explain the similarities much better.
Anyway, that is my analysis. In your latest post, I had a feeling of a dismissive attitude on your part, like you were telling me to either agree and work on the theory you support or make my own. I understand that, in order to fence all the attacks you must get for presenting such an unconventional view, you must always keep your guard up. But I assure you I am not being competitive, and I am not interested in tooting my horn, but simply in presenting an alternative which I think is worthy of consideration (and, in fact, you yourself briefly considered, for pteranodon at least, a few days ago). But you are the owner of this blog, and if you do not wish me to present my alternative here, I will gladly refrain.
Sotos, I have specifically invited you to present your alternative* if you wish.
ReplyDeleteIt is kind of odd of you now to say the opposite - that if I do not wish you to present your alternative here, you will gladly refrain.
It is when you say such completely opposite things that I get suspicious.
Just present the details of your alternative if you wish, for goodness sake.
*Here is what I specifically said:
"If you would like to participate, then please look for similarities of morphology, environment and behavior between pterosaurs (eg pteranodon) and dromaeosaur taxa. That is the idea I am working with.
On the other hand, if you wish to work with the idea you are proposing, then please proceed and tell me your results".
There is very little info on the different taxa within dromaeosauridae.
ReplyDeleteHere is some info on Microraptor (Dromaeosauridae).
http://en.wikipedia.org/wiki/Microraptor
"It has been proposed that the animal glided and probably lived mainly in trees, because the hind wings anchored to the feet of Microraptor would have hindered their ability to run on the ground."
Earlier I presented the idea that we can trace lineages by habitat - roughly Seabird, Shorebird, and Landbird.
ReplyDeleteIt may well be that microraptor is part of the LANDBIRD lineage which developed from the corresponding pterosaur taxon and leads on to the landbird taxa within Enantiornithes leading eventually to modern landbirds.
This is a possible line for further analysis.
Sotos posted:
ReplyDelete"For example, what is the point in making much of the similarity in wing-to-body ratio between pteranodon and the albatross, when that would be lost in the transitional dromeosaurid form? And if you assume that some kind of flying dromeosaurid with similar wing-to-body ratio existed, then you have the same problem with the dino to bird theory, if not a larger one; because no fossils of such an animal have been found and also no fossils of animals vaguely similar to it (that famous 'sister taxa' that proponents of the conventional theory say they have) have been found either."
I am surprised at this comment. Can you support it with reference(s)?
One might as well ask if you can provide evidence of a fossil dromaeosaur with a wing to body ratio similar to that of either an albatross or a Pteranodon? I am not aware of any such fossil that has been found.
ReplyDeleteAre you aware of one that has?
Can you support it with references?
Ann O'Nymous you are missing the point.
ReplyDeleteSotos has made an assertion. It does not do to just make up things and state them as if they were true. And then expect others to have to disprove you. If Sotos makes that assertion then he/she is the one to back it up.
There is a general principle here. People make statements with great assurance as if they knew them to be true. Then when questioned they try to wiggle out.
Since you have taken the time to comment on this
Ann O'Nymous, then perhaps you will support what Sotos has asserted. Please provide reference(s).
For reference:
ReplyDelete"Within Ornithocheiroidea are Pteranodontids which are similar to the modern day albatross.
http://en.wikipedia.org/wiki/Pteranodon
"The wing shape of Pteranodon suggests that it would have flown rather like a modern-day albatross. This is a suggestion based on the fact that the Pteranodon had a high aspect ratio (wingspan to chord length) similar to that of the albatross — 9:1 for Pteranodon, compared to 8:1 for an albatross."
http://en.wikipedia.org/wiki/Aspect_ratio_(wing)
In aerodynamics, the aspect ratio of a wing is essentially the ratio of its length to its breadth (chord). A high aspect ratio indicates long, narrow wings, whereas a low aspect ratio indicates short, stubby wings.[1]
Dsungaripterids may be the pterosaur ancestors of LANDBIRDS.
ReplyDeletehttp://scienceblogs.com/tetrapodzoology/2007/09/_in_celebration_of_the.php
The hindlimb and pelvic morphology of dsungaripterids indicates that they were well suited for terrestrial locomotion - perhaps more so than most other pterosaurs - with relatively robust limb bones well able to resist compression and buckling (Fastnacht 2005). This is in agreement with the fact that their fossils come from terrestrial environments; in fact we have increasingly good evidence that dsungaripterids and members of a related pterodactyloid pterosaur clade were not seabird analogues (as has so often been said of all pterosaurs [e.g., Naish & Martill 2003]), but radiated widely inland.
Notice that the wing issue is not wing-to-body as Sotos and Ann O'Nymous were talking about, but wingspan-to-chord length.
ReplyDeleteI have presented the idea on this blog that it may be the case that even as early as the pterosaurs there were already taxa that inhabited particular habitats and then their primitive bird and modern bird descendants specialized in those habitats.
ReplyDeleteFor example it may be that
Ornithocheiroidea developed in a series of steps into modern seabirds
and
Ctenochasmatoidea developed in a series of steps into modern aquatic birds
and
Dsungaripteroidea developed in a series of steps into modern land birds
More analysis is required to see where Azhdarchoidea fits in.
The Azhdarchoidea may have developed in a series of steps into modern shorebirds.
ReplyDeleteSupport for that idea:
http://en.wikipedia.org/wiki/Azhdarchidae
Azhdarchids are characterized by their long legs and extremely long necks, made up of elongated neck vertebrae which are round in cross section. Most species of azhdarchids are still known mainly from their distinctive neck bones and not much else. The few azhdarchids that are known from reasonably good skeletons include Zhejiangopterus and Quetzalcoatlus. Azhdarchids are also distinguished by their relatively large heads and long, spear-like jaws. It had been suggested azhdarchids were skimmers,[2][3] but further research has cast doubt on this idea, demonstrating that azhdarchids lacked the necessary adaptations for a skim-feeding lifestyle, and that they may have led a more terrestrial existence similar to modern storks.[4][5][6][7]
It also makes sense to relate the different taxa, their environment and kind of wing.
ReplyDeletehttp://en.wikipedia.org/wiki/Bird_flight
Most kinds of bird wing can be grouped into four types, with some falling between two of these types. These types of wings are elliptical wings, high speed wings, high aspect ratio wings and soaring wings with slots.
For future reference concerning Enantiornithes:
ReplyDeletehttp://en.wikipedia.org/wiki/Enantiornithes
They have been found in both inland and marine sediments, suggesting that they were an ecologically diverse group. Enantiornithine fossils appear to include waders, swimmers, fish-catchers, and raptors. The smallest are described as sparrow-sized, but some were much larger, such as Avisaurus which had an estimated wingspan of 1.2 meters (4 ft).
And
http://en.wikipedia.org/wiki/Bird
Enantiornithes occupied a wide array of ecological niches, from sand-probing shorebirds and fish-eaters to tree-dwelling forms and seed-eaters.
The reference you require is the complete absence of fossil dromaeosaurs capable of powered flight. None are known. Therefore no such reference to these organisms exists. You are the one proposing this idea, it is up to you to find more evidence to support it. Currently the dromaeosaurs are a problem for you- you don't have any that link specific pterosaurs to specific birds, and until you can identify some your ideas have a serious flaw.
ReplyDeleteYou are the one making claims about multiple ancestors of dromaeosaurs as individual pterosaur groups give rise to individual bird groups. You are making birds, dromaeosaurs, and maniraptorans polyphyletic. Evolutionary systematics does not recognise polyphyletic groups. And yet your idea requires them.
I posted a comment with a list of animals forming a general lineage, but it does not appear to have shown up. I do hope it got through to you.
Dr.pterosaur, I have replied to your request to support my statement.I did not see my comment appear. And now yout talk to others about me as if I did not provide a reply.
ReplyDeletePerhaps the comment was lost by the software. If that's the case, then inform me and I'll repeat it,a well a my reply to your request to present the details of my proposal (which also seems to be missing).
I do not control the blogspot.com software.At times it does not post comments but when that is the case you can tell because the comment still appears where you have entered it. It is frustrating but if you do not see a post of yours, then all I can say is to try entering it later.
ReplyDeleteAnn O'Nymous and Sotos, do you realize that the wing issue is not wing-to-body but wingspan-to-chord length?
ReplyDeleteGiven the lack of any winged dromaeosaurs this clarification is not particularly relevant. We can substitute "aspect ratio" (ie. the wingspan to chord depth) for "wing to body ratio" and the argument is the same. Additionally there are no Pteranodon specimens preserving wing membranes, hence the large number of different reconstructions usedwhen modelling pterosaur flight.
ReplyDeleteAnn O'Nymous posted:
ReplyDelete"You are the one making claims about multiple ancestors of dromaeosaurs as individual pterosaur groups give rise to individual bird groups. You are making birds, dromaeosaurs, and maniraptorans polyphyletic. Evolutionary systematics does not recognise polyphyletic groups. And yet your idea requires them."
Read up about "convergent evolution" and then let's discuss.
Please state your concern in a more concrete way.
Ann O'Nymous and Sotos present themselves as if they were experts in the subject we are discussing. And yet both were confused about the wing aspect ratio issue.
ReplyDeleteNormally I would not mention people's confusion, but it is relevant here because they both make comments as if they knew what they were talking about when they do not.
This is why I keep asking people for references and for folks to copy and paste what they think the relevant material is.
I have a number of posts on flying dromaeosaurs. People should read them and if you have questions please post your comments on those thread(s).
ReplyDeleteI am definitely not repeating all that material again.
Now I am matching up the pterosaur, dromaeosaur, enantiornithes, modern bird relationships by habitat (seabird, shorebird, aquatic bird, landbird).
If anyone would care to contribute please do so.
I am quite amazed at how they line up according to what is known about the various taxa.
Interesting pictures of pterosaur heads:
ReplyDeletehttp://www.ucmp.berkeley.edu/diapsids/images/pteroheads.jpg
Would anyone care to relate these different head shapes to habitat?
Concerning dromaeosaurs - the fundamental idea is that the FLYING dromaeosaurs CAME FIRST.
ReplyDeleteLater some (not all) of them became flightless.
People really need to take that fact in, because that fact contradicts the dino-to-bird idea and is completely consistent with the pterosaur to bird model.
It stands to reason that the shape of the head, the shape of the wings, length of the legs, length of the neck etc are related to the habitat.
ReplyDeleteAnd each habitat supports a separate lineage. Within each line we see a great similarity in morphology and behavior.
For example:
The pterosaurs that lived on the shore gave rise to the primitive birds that lived on the shore which in turn gave rise to the modern birds that live on the shore (ie. shorebirds).
http://en.wikipedia.org/wiki/Wader
For example, it may be that:
ReplyDeleteOrnithocheiroidea developed in a series of steps into modern seabirds
and
Ctenochasmatoidea developed in a series of steps into modern aquatic birds
and
Dsungaripteroidea developed in a series of steps into modern land birds
and
Azhdarchoidea developed in a series of steps into modern shorebirds.
I was not "confused". I merely repeated the phrasing used by someone else.
ReplyDeleteCould you kindly tell us which posts discuss these "flying dromaeosaurs" and which specific dromaeosaurs you believe to be "flying"? There is evidence of gliding in Anchiornis and Microraptor but neither of them had true powered flight which is what is generally meant by "flying".
I am familar with convergent evolution. Your scenario requires the origin of the characteristics common to all birds to be convergent. It requires that the last common ancestor of all birds was not itself a bird, and that all the modern birds acquired their uniquely birdy characteristics independently of each other. If Azdarchids gave rise to storks and Pteranodontians to albatrosses, then the characters they share in common- feathers, the avian wing, the various details of the skull and skeletal morphology not found in pterosaurs, but present in all modern birds have to be evolved multiple times. You claim your ideas are more parsimonious that the generally accepted ideas. That your idea requires the convergent evolution of all these characters makes it orders of magnitude less parsimonious.
Why do you think it is not more reasonable to think that pterosaurs and birds have independently evolved wings (of remarkably different designs), but that complex feathers are convergent?
Ann O'Nymous posted:
ReplyDelete"I was not "confused". I merely repeated the phrasing used by someone else."
I guess if you need to make an excuse, any excuse will do. But why should I take you seriously?
I see you are still talking in cladistic terms. You seem not to have taken in all that I have said about cladistics - you still phrase your objections in cladistic terms as if that means something. It does not.
Also if you are going to object to what I am saying, you really need to present an alternative so we can see if it is more parsimonius.
You have a completely imaginary alternative.
This bears repeating:
ReplyDeletePeople will say something like:
"You claim your ideas are more parsimonious that the generally accepted ideas. That your idea requires the convergent evolution of all these characters makes it orders of magnitude less parsimonious."
But NOBODY has EVER presented the ancestor/descendant relationships in the dino to bird model.
How in the world can anyone make the absurd comment that what I am proposing is "orders of magnitude less parsimonious" when there has never been anything presented to compare it to?
Folks, let that sink in.
Could someone actually acknowledge this point?
Go ahead. Acknowledge it.
No "excuses" are being presented. Why should I take you seriously when all you do is sneer at your commentors instead of actively engaging with their disagreements.
ReplyDeletePerhaps you should acknowledge the point that your ideas require birds to acquire all their uniquely birdy characters independently. Whereas the conventional alternative states that birds evolved their characteristics once and inherited them from a common ancestor. It doesn't actually matter whether they are descended from pterosaurs or not. You are proposing that birds are polyphyletic- a grouping rejected by both evolutionary systematics and cladistics, and a term used by both.
You do not need to present ancestor-descendant relationships in order to do this examination.
Ann O'Nymous said...
ReplyDelete"Whereas the conventional alternative states that birds evolved their characteristics once and inherited them from a common ancestor."
Remember that at each step in the purported dino to bird lineage there is another "common ancestor". There would be hundreds (thousands? millions?) of them Right?
What are the taxa on the purported dino to bird lineage? Please present that and we can evaluate its credibility.
How many times do we have to go over this? You need to present an alternative.
Let's do a rough analysis.
ReplyDeletePterosaurs did not have feathers. Dromaeosaurs had feathers.
In the development from pterosaurs to dromaeosaurs we see the development of feathers.
I have been showing how it is possible to categorize the taxa by habitat - shorebirds, seabirds, aquatic birds, landbirds.
And I have proposed pterosaur lineages in each habitat.
So we would see parallel evolution occurring in each of the habitats.
That is a very common and accepted idea since all the pterosaurs flew and the development of feathers developed in all the streams of FLYING creatures.
This is normal accepted "evolution" thinking.
If anyone objects to the specific parallel development of feathers please provide references to support your objection.