So perhaps 240-250 mya there were birdish creatures.
These 'birdish creatures' couldn't fly; and lived on land. And they would not have been birdish.
All that is being discussed here is the idea that feathers, all of the various quills and things discovered on fossil dinosaurs, and the fuzzy stuff that covered some pterosaurs, are all evolved from the same thing. That's something palaeontologists argue about. Some think pterosaur fuzz evolved separately. Some think ornithischian quills evolved separately as well.
But, if Xu Xing is right, all that means is that the common ancestor of dinosaurs and pterosaurs already possessed some kind of integument that later evolved into pterosaur fuzz and proto-feathers. It didn't have feathers, though, and wasn't a bird.
I wonder if birds before land creatures is so much of an absurd anachronism now?
There was also a mention of these types of things evolving more than once throughout history. (which seems a lot more possible than lignin evolving separately).
We know that Pterosaurs had a lot in common with birds, and appeared suddenly. And before 200 million years ago..
Pterosaurs did stuff in common with birds; in the sense that they were also flying animals; and in that they appear to be the closest known relatives of dinosaurs (which birds, of course, are).
Pterosaurs and dinosaurs both appear before 200 million years ago, but I'm not sure why you consider this significant. Both groups first appear during the Triassic (which lasted from about 250-200 million years). You seem to be assuming that 'amphibian' means an animal which lives in water; but even today we have amphibians that live in deserts. At a time when the only terrestrial vertebrates were 'amphibians' (which in this sense just means non-amniote - ie; not part of the group including reptiles, birds and mammals), there would be less competition in fully terrestrial ecosystems. Whether or not something is a 'reptile' does not tell us whether it lived in dry conditions.
But in the Permian, there were lots of uncontroversial amniotes, and some of them lived in deserts.
There was a monkey type fossil found that dated to 47 million years ago, and before that discovery (roughly) a decade ago, nobody would have placed anything so old.
There are several problems with this:
First, it's not true to claim that "nobody would have placed anything so old". Algeripithecus was published in Nature as the oldest known monkey back in 1992; with a reported age between 46 and 50 million years. Now, that was controversial then and still is now, but the idea that a 47-million year old monkey was something no one had expected is simply media hype (more on that in a minute). In the 1992 paper, the authors wrote that their find "confirms predictions about the great antiquity of Simiiformes" - ie. people were expecting to find a monkey that old. Some models of primate evolution should have much older monkeys than this.
Second, the find you're describing is not a monkey. The discoverers received a lot of criticism in the scientific community for the way they released their find via marketing to the media; creating a load of hyperbole and hype about a conclusion which, when it was eventually published, didn't stand up to criticism.
Neither of those points were particularly important to this argument, but I had to make them because I'm a pedant. The key point is that, although fossils sometimes are indeed found which mean groups of animals must have been around longer than we thought, this is not relevant to your point. Birds evolved from terrestrial animals; so they could not have predated them.
They had more in common with birds than you make it sound, and especially a lot more in common with archaeopteryx.
That's a lot of copy and paste to say the same as I did. The features you mention like hollow bones are common to dinosaurs - it's not something birds specifically share with pterosaurs.
I'm unsure of the point of the rest of what you write. Birds do share features with crocodiles through common ancestry, but I don't really get why that is significant. It's not like they share things with crocodiles that they don't share with other dinosaurs; in case you were trying to use this to suggest that they weren't dinosaurs. We don't have any extinct dinosaur hearts, of course, but there's no reason to assume they wouldn't be four-chambered.
Look at the Carboniferous period, which had lots of acidic forests, in which bird-like bones would dissolve.
So what you're getting at is that birds may have been around for more than 300 million years; and simply left no fossil evidence for most of that time.
Thing is, this doesn't only require birds to have been around for such a long time without leaving any evidence. Birds are not a sister group to dinosaurs, or anything - though even that would pose problems. Birds are deeply nested within dinosaurs; and your scenario requires all sorts of dinosaur lineages to also have been around since the Carboniferous without leaving a hint of a trace anywhere; along, of course, with the ancestors of crocodiles and mammal.
Basically, you need most terrestrial vertebrates to be living in secret for tens of millions of years, before suddenly all deciding to start being fossilised in the Late Permian. This is unlikely.
Now, you posted some comments from Alan Feduccia suggesting that birds may not be dinosaurs. Feduccia is wrong - his claim that "the issue will never be laid to rest" is laughable and a bit sad; since it was already laid to rest long ago. He, for some reason, refused to accept the fact that he was wrong and has sadly gone totally off the rails in trying to defend an indefensible position.
Birds [i]are[i/] theropod dinosaurs - the similarities are not few or suggestive; they are conclusive.; and cladistic analyses always find birds to be nestled deeply within theropods. Feduccia's sad derailment from reality when it comes to his blind spot can be seen in his changing view of paravians - dinosaurs most closely related to modern birds. He has at different times insisted that Microraptor was clearly a dinosaur and disputed the obvious similarities to birds; and then later that it's clearly a bird and not a theropod dinosaur. You'd think the fact that even he finds it hard to tell the difference would be a clue, but no.
Thing is, though, even if Feduccia was not obviously wrong; or even if these long ghost lineages of every group of amniotes existed, this would not really help you. If Feduccia's interpretation of bird origins is correct - they still evolved from terrestrial animals. If we simply move evolution back a hundred million years or so, hiding somewhere, birds still evolved from terrestrial animals. I am at a loss to understand how you think birds evolved from swimming animals.
and don't get the relevance of the fact that we no longer consider pterodactyls to be seabird analogues.
The jury is still out.
No, it's not. I'm not sure what your point is about the pterodactyls; unless you're just trying to make the general point that we don't know everything and interpretations change. That is, of course, true, but that doesn't mean every absurdist scenario someone can dream up is plausible. You're not defending a controversial interpretation of the evidence. You're defending a wild, half-baked idea which you haven't clearly articulated, that is not supported by anyone anywhere; on account of the fact that there is no hint of any evidence suggesting it may be true.
With regards to this:
I would ask about the heart issue.
Can crocodiles hearts (which are like birds) be said to resemble the dinosaurs PaulK mentioned as ancestors?
Can Crocodiles (I'm thinking of their ancestors) be said to be in a vertical line that dates AFTER the dinosaurs PaulK mentioned?
Can Crocodiles (ancestors) be said to be in a horizontal line with the dinosaurs PaulK mentioned?
(They seem to be in a vertical line that pre-dates PaulK's theropod dinosaurs.)
We don't have any dinosaur hearts (excluding those of birds, of course), and I don't understand what the rest of this means.
I think there is a major issue with the Crocodile heart (which is like birds), and there was, I suspect, common ancestor to both (300 million years ago?) which had hearts like birds/crocodiles on the one hand while it would later split off into other lines (with typical reptile hearts) like the LATER (in my opinion and speculation) "240 million year old common ancestor", which is only a "so-called common ancestor" birds.
Why on earth are you so interested in the heart? Everyone (except creationists) is in entire agreement that crocodiles are the nearest living relatives of birds. The hearts don't matter to their relations to extinct animals.
I'm a little bit confused by the rest of your sentence, but I am wondering if you're trying to suggest that dinosaur hearts were more like lizard hearts than bird and crocodile hearts. Why would anyone think that?
Just in case this is the source of confusion; lizards and snakes are not descended from dinosaurs. To be clear, here's a phylogeny of the main groups of living verterbrates (chosen because it simplifies things by not including anything with controversial or uncertain placements):
ABE: And to be clear about the above picture; dinosaurs would all be on the 'birds/crocodiles' branch; closer to birds than crocodiles.
But the 4 chambered heart belonging to dinosaurs actually backs up my point ( I did not notice it earlier).
No it doesn't.
Your point seems to be that dinosaurs are descended from birds; so in your view, dinosaurs, pterosaurs, birds and crocodilomorphs form a clade, and thus share certain features.
According to everyone else, birds are nested within dinosaurs; but this means that birds, dinosaurs, pterosaurs and crocodilomorphs still form a clade, so they still share certain features.
We're all agreed on what an archosaur is, as far as I can interpret your argument, so shared features of archosaurs are not a point in anyone's favour.
But they do. (hearts matter to the relationships of birds and dinosaurs)
Here is a scientist that proposes a pre-dinosaur "crocodilomorph" creature that evolved into birds.
That article's behind a paywall, and the introduction doesn't mention hearts. The only scientist quoted in the introduction was one of the main popularisers of the idea that birds are dinosaurs. Given that you mention you don't have a subscription either, why do you think this has anything to do with hearts?
Flying birds are unlikely to be buried, and they must be considered a candidate for much earlier dates, considering all the evidence.
And yet the fossil record of birds has grown exponentially in recent years; with no hint of anything pre-Jurassic.
Now, of course that doesn't prove that birds were not around earlier - such a thing is always possible. But it's possible for every lineage of organisms - what you have failed to provide is any reason to expect such a thing.
Note the key difference with the butterfly situation. As your article itself points out; there was a phylogenetic reason to expect early butterflies; because the sister group to Lepidoptera is known from much earlier. The sister group to birds is not - maniraptorans are known only from the Jurassic.
The main hypotheses for the origins or bird flight are that they evolve from arboreal dinosaurs like Scansoriopteryx, as you quote in a later post; or (the more popular view) from cursorial (running) dinosaurs. No-one has ever proposed birds evolving from an aquatic ancestor; and it's difficult to imagine a model of how that would work.
Of course, that I can't come up with a plausible scenario doesn't say much, but the key point here is that you still haven't given us any reason why we should try to?
All you have done so far is point out that our knowledge is not absolute; and tried to therefore argue that we could try to twist the evidence in such a way that it doesn't 100% rule out your strange scenario. But why should be entertain your scenario in the first place? What evidence is there for it?
I found this following the relevant part of Caffeine's Wikipedia paste.(...)
quote:(...)What makes the discovery especially surprising and puzzling is that the heart resembles a mammal's or bird's but it belonged to an ornithischian, or bird-hipped, dinosaur, one of the two main lineages of these great reptiles. Despite the name, these dinosaurs were far removed from those that were presumed by many paleontologists to have been ancestors of birds; these ancestors were presumed to be theropods, members of the other main lineage known as the saurischian, or lizard-hipped, dinosaurs.(...)
I didn't paste anything from Wikipedia; but with regards to the quote - why do you think this helps your case? Birds are dinosaurs - why would the fact that dinosaurs are like birds help any argument to the contrary?
Secondly, it seems that ALL feathered dinosaurs (aside from Archaeopteryx) date from the same period as they are from the same Chinese formation. They are from the Barrremian stage of the Early Cretaceous? Correct me if I'm wrong.
Well, that's controversial; since there are several claimed discoveries of feathers in dinosaurs elsewhere. The fossil deposits in Liaoning are of exceptional quality; which is why so much there is preserved that the arguments related to other fossil sites can be avoided.
But you need to keep track of the arguments here. Your position requires dinosaurs to be descended from feathered birds. If there were no feathered dinosaur before the Cretaceous it doesn't help your position.
His theories are current and he published a 2014 journal article on the issue.
NOT REFUTED AT ALL!
The fact that someone is publishing recently is not relevant to the correctness of their views. Despite the fact that Feduccia is still publishing today; there is one thing he has not published - a cladistic analysis. The 'methods' section of that paper is the quite frankly hilarious length of 112 words. Even that's longer than necessary - I would have saved space and simply written 'we looked at the fossil'
Now, looking at a fossil, or living organism, and searching for some key classificatory feature that would allow you to declare where it belongs on the tree of life is exactly how these things were figured out in the 1940s. Thankfully, science marches on, and a lot of bright minds have spent the last seven decades figuring a better way; using statistical techniques to try and avoid the simple mistake of simply searching for features to support a presupposed idea, which project Feduccia is still sadly involved in,
Cladistic analyses all recover Scansoriopteyx as a theropod; usually as a maniraptoran.
Re: PaulK on the run. Won't respond to 2014 journal (nobody will).
I had not read this post before replying, since you post a lot of words. Having read it I felt the urge to expand on my post:
EDIT: Classification has more to do with man's convenience. The recognition of something having major features that clearly predate the origins of something else is the issue. It is origins and not arbitrary classification.
No, that's not how it works. You're looking at 19 characters - 19! Whether they're correctly coded is irrelevant; as this is precisely the sort of cherry-picking to support a preconceived conclusion I mentioned in the previous post.
Phylogenetic analysis is done with hundreds of characters, not 19. If simple numbers are enough to convince you, then have a look at this 2012 cladistic analysis of coelurosaurian theropods. I recommend this since it's open access; and since they conveniently include the character matrix in the same pdf as the article; even conveniently listing synapomorphies supporting each clade in their analysis.
You can then entertain yourself looking through the 51 shared characters in their matrix that support scansoriopterygids as paravians.
Re: Since 99% of what I say gets ignored (especially by PaulK):might have to be selective
The more I respond to, the more I get ignored (PaulK, especially, is setting a record for ignoring everything, then claiming that he has covered an issue).
You post an enormous amount. There are several things I can see are wrong; but often I can't grasp why; and it can often involve a lot of work to figure out where you're coming from and try to explain why I think you're wrong. When you post a quick stream of such statements I don't have the time to answer everything, on account of having a job, a family, and hobbies. I don't just sit here on EvC all day.
Some of what I ignore is just because I haven't the faintest idea what point is being made. Take the post I'm replying to; which includes a quote from the article I pointed you to discussing the definition of bird. There's no explanation why you posted it, and you seem to think it explains itself; but it doesn't. I have no idea why that's in your post, or how it's supposed to relate to the rest.
This is why I liked Phat's comment. Your interpretations of what you read are almost always different to mine. Maybe that's because you don't understand things properly, maybe that's because you understand things I don't. But either way, your cuts-and-pastes do not communicate your argument. Less pasting; more trying to explain what you think and why.
All that being said, you write
And I note that the 13 pre Theropoda features in Scansoriopteryx are still being ignored.
but that was specifically what I was trying to address with the discussion of cladistics. You can't figure out the relationships of organisms by just picking a small selection of features and considering that this settles it. Why do these 13 matter more than all the rest (or this 19, if we're including the six you mentioned shared with birds)?
You later go on to quote from Czerkas, who seemed intent on demonstrating that he was profoundly ignorant of things he must have known. I don't understand his motivations. He tells us that the description "arboreal theropod" was
an apparent contradiction in terms as according to definition, “theropods” do not climb.
But, of course, that's got nothing to do with the definition of theropod. Even back when they were originally named it never did - Marsh defined theropods as carnivorous dinosaurs.
It's even been argued by some palaeontologists that deinonychosaurs used their claws for climbing. This is almost certainly wrong, but the idea that an arboreal theropod is wrong by definition is just silly. All their saying is that this is an unusual theropod. Lots of organisms are unusual.
It's been standard for decades, of course, to define groups or organisms in terms of descent. Theropods have definitions like "Everything that shares a more recent common ancestor with sparrows than with sauropods" (loosely adapted from the definition given in the 2nd edition of The Dinosauria. Specific features or behaviours are not part of how we define clades, because of a little thing called evolution - these can change,
Czerkas goes on to briefly mention the few skeletal characters you're so excited about, and then declares
quote:Therefore, Scansoriopteryx is more parsimoniously regarded as being a saurischian of “pre-theropod” status, instead of as a true theropod.
This here is a hypothesis. And yet, for some reason, he doesn't seem interested in testing that hypothesis. He seems to think the work is done once he's stated it.
That is, of course, deeply antithetical to the point of science. And that was why cladistics was developed in the first place - all the way back in the 1940s and 50s. The core of cladistics is a way of testing the parsimony of different evolutionary scenarios - using statistics to turn the classification of organisms from informed speculation into science.
It's come a long way since simple parsimony techniques; but for some reason the 'birds are not dinosaurs' gang still haven't reached the 1950s.
I will "ignore" your other points for now, since addressing one point properly takes time.
Re: Birds, Reptiles, Frogs, and evolution with hybridization.
The scientists who carried out the cladistic analysis you object to our more work into “getting it right” than Feduccia.
Let's be clear, not 'analysis'. I posted one because I found an open-access pdf which included all the supplementary material. There are many analyses including scansoriopterygids - all find them to be theropods (though admittedly most aren't really testing that); most find them close to birds.
Of course; there are innumerable studies finding birds to be deeply nested in theropods, and theropods deeply nested in dinosaurs.
As a quick aside and not a reply to you, I'm a bit lost what the point of the hybridisation discussion is supposed to be, but there was some mention of DNA. To be clear; DNA is not used to figure out the relationships of extinct organisms - we don't have any DNA from the Mesozoic. Palaeontologists need to use morphological features (for dinosaurs and their relative this usually just means bones).
Re: Birds, Reptiles, Frogs, and evolution with hybridization.
There's a whole lot of confusion here. I don't think your scenario of birds evolving faster through hybridisation makes sense; but we don't need to go in to that, since the conclusion you draw from it is clearly wrong:
The cladistics analysis will see birds as having more evolved features, while Dinosaurs look more archaic (except there will be fossils that complicate the picture like the one we keep talking about that Czerkas named). The relationship between the two (birds and one line of dinosaurs) clearly exists. But which one truly (and ultimately) comes from the older line?
You seem to be envisioning that cladistics finds birds to have evolved from dinosaurs because birds are 'more evolved', and so must have come later. But that's not how cladistics works. It's nothing to do with figuring out who has evolved the most - it's about looking into evolutionary changes shared between groups.
The simple idea is to take a bunch of characters; and then code a bunch of organisms for them. Simple parsimony techniques then look at the collection of coded characters; and figure out how to construct a family tree with the fewest changes of character. The key point is that this doesn't tell you that one thing is descended from another. All the organisms used in your analysis are treated as the end products - they're all sisters and cousins, not ancestors and descendants.
We see birds as being evolved from dinosaurs because they come out as nested within dinosaurs, not because they're more evolved from them. Like so:
The point here is that some dinosaurs are more closely related to birds than they are to other dinosaurs. The most recent common ancestor of two dinosaurs is, of course, a dinosaur, and it's in this sense that we see birds to be evolved from dinosaurs.
Now, if we accept your strange scenario in which birds evolve unusually quickly; the very last thing we would expect is to find birds spuriously placed within dinosaurs. In fact, the opposite is more likely. One of the best known sources of systematic errors in cladistic analysis is the problem of long-branch attraction. This is caused when you have organisms which evolve very quickly, or which have no close relatives. They are said to be on a long branch; since on the branch which separates them from their nearest relatives there will be a lot of changes of character. All these changes tend to 'overwrite' the signal of shared ancestry; and long-branched taxa tend to be spuriously drawn to the base of a tree; not to deep within it.
In a dinosaur-bird tree; a long branch would artificially pull birds towards crocodiles - not because of similarities but simply because crocodilians are also separated from dinosaurs by their own long branch. It would make it more likely that we would find the scenario (I think) you're arguing for; even if it wasn't true.
But we don't find that. Birds always come out as nested deep, deep within dinosaurs; because of all the things they share in common with theropods. And, more, the things they share with some theropods to the exclusion of other theropods.
Not sure if I explained this at all well, but too tired to try to rewrite now
Re: Let us stay on topic. Caffeine went back to a good spot to start: post 34
I'm starting to wonder if this is a windup, but I'm willing to give you the benefit of the doubt.
Pay close attention to this below.
Okay. I did. I agree with Arnold. Somewhere on these forums there's a post from me explaining why I think the Biological Species Concept is a minority view almost never employed by taxonomists in the real world. I think I used the example of persistent gene flow from baboons into geladas.
The next step would be for you to explain why you wanted me to read this, and why you think the existence of hybridisation is relevant to your argument.