Feathery Dinosaurs

OK! I have stopped ranting about Paleontology and the internet.

Now (as an amateur) it seems to me that through cladistics, the case is pretty well proven that dinosaurs and birds are closely related. From what I have read, (The Mistaken Extinction - Dinosaur Extinction and the origin of birds - by Lowell and Dingus) they seem to point firmly at Deinonychus as one of the closest 'maniraptors' to the early birds. The closest thing to a link.

I can see the wisdom in the 'ground up' theory of flight, especially as all other 'flying' creatures that are obviously 'trees down' fliers are gliders, and don't flap.

We knew that Archyoptrix was a bird due to the impression of feathers in the extremely fine mud that the specimens found in Germany were preserved in.

There is one giant leap, from the idea of a scaled skin maniraptor, running so fast after prey, that it might take off, and the development of the feather. I know that a feather is essentially a scale - however radically evolved.

By using these facts (and I am sure there are more that I have missed - be kind, I am an amateur), it must logically follow that the feather must predate flight. Why? Because for the 'ground up' theory of flight to be true, there must have been a maniraptorian dino with feathers, that suddenly 'realised' the potential of feathers for not only keeping it warm, but helping it cross distances faster after it's prey (picture if you will a swan taking off from water - essentially running across the surface) and holding it in the air for a while.

When I first got interested in dinosaurs (aged approx. 6) it was because they were 'big and scary', but now I love paleontology, because of it's 'revisionary' nature. I believe that although I am not qualified to do so, the door is open for me to postulate theory. And where better than here?

So. The crux of my point is this. If you agree that the feather predates flight in dinosaur/birds, can we say when it started? Do we need a new model of Veloceraptor (or a close relative?) complete with feathers? Afterall, isn't it only recently that we got detailed skin imprints of early dinosaurs from Argentina?

I would go so far as saying that even with the drawings we have of dinosaurs currently available, while anatomically correct, leave a little to be desired in the colour front?

Debate!!

Oh, and Merry Christmas and a prosperous new year to all too!!

Greg Paul stuck feathers onto the Velociraptors illustrated in his book (Predatory Dinosaurs of the World) over 10 years ago. Where to put them, and how many, were obviously up to the imagination, then as now. I agree with you, and Paul, that it is reasonable to imagine small, agile Jurassic predators as bearing feathers in some form. Paul's book is still in print, and often referenced. It would probably be worth the effort to locate a copy. Larry

Among non-avian theropods, skin impressions preserved in situ along with bone fossils are known for _Carnotaurus_, _Sinosauropteryx_, _Protarchaeopteryx_, and _Caudipteryx_. The first shows no feathers or feathery integument whatsoever, the second shows 'proto-feathers', and the last two show true feathers.

The most commonly accepted cladogram for these would be:

Thanks Mike, that's not only interesting, but also exciting, do you, or anyone else, know of any artists drawings that might represent a feathery dinosaur?

Is it possible to have a debate about coloration, or is it just considered taking a stab in the dark and not worthy of consideration? Can we not look at the feathery fauna about us today, see where their 'nook' in the scheme of life is, and devise some sort of rule about coloration? Or is this a no-go area?

Of course Martin and Feduccia argue that these are not proto-feathers at all but collagen rods supporting a flap of skin on the back. Compsognathus, which is closely related to Sinosauropteryx, shows no trace of either feathers or protofeathers even though it is found at Solnhofen, where Archaeopteryx is also found.

I am not convinced they are feathers. Even if they are, they may just be birds (which is what Martin and Feduccia think they are). Since they lived after Archaeopteryx, the appearance of secondary ground birds is not surprising.

A cladogram is only as good as the characters upon which it is constructed. The cladogram above is constructed upon a set of characters which are most likely homoplastic, which means the group of animals depicted above is likely to be polyphyletic.

I will wait for the news. My hunch is that it will be dated in the Cretaceous, long after the appearance of Archaeopteryx.

Alas there is not one shred of physical evidence that any of these beasts had anything remotely resembling feathers.

Again, there is not one shred of physical evidence for that either.

But no one has ever found any feather on deinonychosaurs.

Again, no evidence of such was ever found.

None has been shown to have anything resembling feathers.

It is amusing to me that all sorts of unsupported and fantastical speculations on dinosaurian body coverings have been made on the basis of nothing more than a cladogram that most likely depict an unnatural polyphyletic group. The characters used are most likely adaptations to digging (which is similar to the wing flapping motion) in theropods and bipedal running. In fact, Zhou pointed out that many of the characters identifying Mononykus as a bird are also found in burrowing moles (Mammalia).

Many. Greg Paul and Bob Bakker were some of the first. You can find some at the gallery on my site: http://www.gl.umbc.edu/~tkeese1/dinosaur/gallery.htm

So far, no-go. Artists usually base coloration on extant animals and

Strangely enough, everyone who's actually *examined* the specimens up close seems to agree that they are simple, feather-like structures. Seeing as they extend down the sides of the body, I find it difficult to see how they would form a single flap of skin.

Liaoning preservation is better than Solnhofen. The non-contour feathers of _Archaeopteryx_ were not preserved, so we would not expect _Compsognathus_' fluff to be there. In fact, the contour feathers of _Archaeopteryx_ were barely preserved in some cases

Martin and Feduccia examined the specimens closely and they don't subscribe to the proto-feather claim. They may be feather-like, but most likely not feathers.

So what is your claim? That Compsognathus had feathers despite the lack of evidence in support of that claim?

What would it take? More evidence. Martin and Feduccia obviously believe that they are feathers, but I still have some doubts and I need more evidence.

This I agree. Archaeopteryx is probably more bird than reptile. That would mean a rather early ancestry for birds, too early for many of the theropods to be considered likely bird ancestors.

I have many good reasons not to like it. It is based on superficial similarities and a methodology that sends systematics back into the pre-Linnaean dark ages of facile diagnosis.

Doesn't recent argon dating place Confuciusornis and Liaoningornis at about 121 million years old? That means Protarchaeopteryx and Caudipteryx are some 29 million years younger than Archaeopteryx. Fossils that live 29 million years after the first known bird cannot possibly be bird ancestors.

Not the same. All tetrapods have intestines for example. Most tetrapods have tongues and eyes. Far fewer of them have feathers. To show that theropods had feathers, we require much more evidence than that required to show they had intestines. We need more than phylogenetic bracketing, and definitely a much better phylogenetic hypothesis than the bird-theropod link, which is based on the cladistic analysis of a set of questionable characters.

So you think deinonychosaurs may not have skin? I think the evidence for skin is much stronger than the evidence for feathers in these dinosaurs.

Not all birds fly. So even if all theropods are adapted for digging, not all of them may be diggers. Their *ancestor* may be adapted for digging and their morphology reflects that ancestry.

Do you think convergence is impossible?

Not quite sure what you mean.

Have you read Zhou and Chiappe et al.'s reply to Zhou? How do cranial features establish Mononykus as a bird? Eoalulavis, a hatchling bird fossil from Northern Spain, dated 135 million years old, has a fixed upper jaw and well developed wings. Is it a bird based on cranial features?

Please read Zhou (1995 The Auk 112:958-963). He never said that the skull of Mononykus looks like that of moles. Zhou pointed out that Perle et al. used such characters as the large, longitudinally oriented, ossified sternum, sternal carina, prominent antitrochanter on ilium, undivided femoral trochanteric crest, and a fibula that does not reach the tarsus to diagnose Mononykus as a bird. None of these characters are cranial features. And many of these characters are convergently found in moles. So you must have remembered things incorrectly or you are simply barking up the wrong tree.

Oops! My apologies to Dr. Feduccia for misrepresenting his view. He calls these fossils 'interesting' but did not claim that they are birds. Only Dr. Martin did. Martin thinks that these are birds that just resemble dinosaurs. But both of them agree that these fossils are too late in the timescale to be bird ancestors. Since these beasts lived 1 million years AFTER such advanced birds as Confuciusornis and Liaoningornis, and 30 millioin years after Archaeopteryx, I would have to agree with Dr. Martin and Dr. Feduccia.

Caudipteryx and Protarchaeopteryx may have feather-like structures but not everyone thinks they are feathers.

The photos show that the 'flap of skin' in the fossil impressions does not consistently follow the ridge of the backbone

Forgot to mention, but Feduccia and Martin said that decomposition had taken place. That could account for any observed imperfect alignment perhaps.

But most likely not feathers. Even fully evolved feathers did not keep some Mesozoic birds warm. So feathers did not evolve as insulation. And since Sinosauropteryx is a ground dweller, protofeathers would have done it little good.

The barbs in true feathers are held together to form vanes by interlocking barbules. Sometimes these barbules unhook and adjacent barbs are pulled apart to form wedge-shaped spaces. A good illustration of this is the first feather found at Solnhofen. Now look closely at the pictures of 'feathers' of Caudipteryx and Protarchaeopteryx (or try to remember what you saw at the exhibit). There is no evidence of separated barbs in the photos because there is no wedge-shaped space between the 'barbs' in the 'feathers' of Caudipteryx or Protarchaeopteryx. All of the 'barbs' are neatly arranged next to each other and evenly spaced. As such they look like they are not held together by barbules (which can unhook), but instead they seem to be supporting structures for perhaps a flap of skin.

That may be why Feduccia said they were 'interesting' instead of conceding that they were birds. And that is one reason I have not made up my mind about them. One thing I am sure. They cannot be the missing link between theropods and birds. These animals lived at least 30 millions years too late for that.