Tianyulong

I'm not going to say much about this since Ed Yong has an excellent write-up, but a new feathered dinosaur has been discovered, called Tianyulong. As you can see in this image of the fossil, it was bristling with a fuzz of thin fibers — proto-feathers.

i-ffe71f424a82783f5c04dd1cd196d8b5-tianyulong_sm.jpeg
(Click for larger image)

a, Main slab of the holotype (STMN 26-3). b, Broken slab. The scale bar in b refers also to a. c, Close-up of skull and mandible. d, Interpretive drawing of skull and mandible. e, Close-up of dentition. Abbreviations: a, angular; aof, antorbital fossa; ca, caudal vertebrae; cv, cervical vertebrae; d, dentary; dv, dorsal vertebrae; emf, external mandibular fenestra; en, external naris; f, femur; h, humerus; isc, ischium; j, jugal; l, lacrimal; m, maxilla; n, nasal; pd, predentary; pf, prefrontal; pm, premaxilla; po, postorbital; pub, pubis; q, quadrate; qj, quadratojugal; scaco, scapulocoracoid; sa, surangular; tf, tibia and fibula.

There are a couple of noteworthy features in this creature. One is apparent: feathers just didn't bloom suddenly in evolution, but appeared in steps. This animal has 'feathers' that don't branch like those of modern birds, but instead form more of a furry coat than a set of flat blades.

The other cool thing is that this is an ornithischian dinosaur; most of the other dinosaurs that have been discovered to have feathers were saurischian. What that means might be made more clear by this diagram:

Feathered-dinos.jpg

It implies that just maybe the last common ancestor of the saurischia and ornithischia were also covered with proto-feathers, which means that feathers may be a primitive state in this lineage.


Zheng X-T, You H-L, Xu X, Dong Z-M (2009) An Early Cretaceous heterodontosaurid dinosaur with filamentous integumentary structures. Nature 458:333-336.

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Thanks PZ - one of the coolest things about this is that I, with almost no scientific training whatsoever, understand exactly what this means and how it fits in the bigger evolutionary picture.

By Wowbagger, OM (not verified) on 20 Mar 2009 #permalink

It implies that just maybe the last common ancestor of the saurischia and ornithischia were also covered with proto-feathers, which means that feathers may be a primitive state in this lineage.

So are the scaly-skin dinos in the diagram a convergent reversion, or is the implication here that maybe they weren't really scaly-skinned?

Fascinating.

PZ, could you tell us what the purpose of evolutionary advantage feathers would have been at this early state?

Damn! That quote from PZ was supposed to be in blockquote format.

So dinosaurs may have all been fuzzy? Of course! This would increase the comfort for the humans who rode them. What a marvelous feature to be intelligently designed!

I'll bet God made the ceratopsians after a lot of petitionary prayer for models with windshields...

Very cool and interesting. My mind wants to draw in that hypothetical "trunk" above the (great and helpful) diagram.

I always love waking up to science postings - thanks PZ.

I like the way some traits appear to be formed earlier than previously seen. Scales, hair, and feathers are probably very similar on the genetic level, with just some variation in th hox genes making the difference. (Enough babble, back to coffee.)

By Nerd of Redhead, OM (not verified) on 20 Mar 2009 #permalink

wow, that animal has some unusual teeth too!

maybe it was the young that had the 'feathers' and later groups just kept their baby fuzz on for longer.

By extatyzoma (not verified) on 20 Mar 2009 #permalink

The commenters are almost chortling with their glee over this find.

By FiveAcres (not verified) on 20 Mar 2009 #permalink

The function of proto-feathers? Thermo-regulatory perhaps? Anti-parasite?

By bybelknap, FCD (not verified) on 20 Mar 2009 #permalink

ed young says: "What happens when you find a feathered dinosaur that really isn't meant to have feathers?"

creationist says: "see, that just means its ONLY a bird kind, the scientist has it wrong, evolution didnt happen and that means that jesus does LOVE me."

hmm, thinking like a creationist is really, really uninteresting.

By extatyzoma (not verified) on 20 Mar 2009 #permalink

Stating the obvious perhaps, but I think calling these fibres "proto-feathers" is slightly misleading: the anti-evo brigade will argue "What use are non-functional feathers?" as if the fibres are on the way to becoming feathers but aren't ready yet.

Whatever these fibres are, they already had a use - keeping the creature warm (if it was warm-blooded, which I understand is still under debate), or protection from predators, whatever. But they had evolved to that point for a reason already. The fact that they continued to evolve into flight-capable feathers was merely another beneficial step. And that's evolution as I understand it; nothing is planned in advance, it's an entirely blind process. So "proto-feathers" is a bit misleading.

Elwood (posting this to prove that I'm not just here for the religion bashing!)

By Elwood Herring (not verified) on 20 Mar 2009 #permalink

Correct me if I am wrong but aren't feathers also a great defence against blows and bites?

By Dutch_labrat (not verified) on 20 Mar 2009 #permalink

ed young says: "What happens when you find a feathered dinosaur that really isn't meant to have feathers?"

creationist says: "see, that just means its ONLY a bird kind, the scientist has it wrong, evolution didnt happen and that means that jesus does LOVE me."

hmm, thinking like a creationist is really, really uninteresting.

By extatyzoma (not verified) on 20 Mar 2009 #permalink

Trold #6
That may be a joke, but I'm sure it's being added to the Discovery Institute's literature as I type.

Would be interesting to see some climate history or geology on this tree. Might show some correlations of feathers and bristles appearing/reappearing with warming and cooling climate periods. If only we could see the genomes of these creatures, maybe a palimpsest or two for feathers in the basal theropods.

So are the scaly-skin dinos in the diagram a convergent reversion, or is the implication here that maybe they weren't really scaly-skinned?

One of the possible implications certainly is that they weren't scaly after all...except, of course, for the tiny problem that we have direct fossil evidence of scaly skin for some dinosaurs (e.g., Carnotaurus (a theropod); several hadrosaurids (an ornithischian group)). So, it's very likely to be more complicated than what the current phylogenetic position of the origin of "feathers" might right this moment suggest (i.e., feathers, feathers, everywhere feathers). For example, a possible explanation for the current apparent distribution of feathers v. non-feathers within Dinosauria is a very "basal" origin of "feathers" and then subsequent losses of them in various groups.

But of course none of this will stop a good number of those who spend their time illustrating these animals from now breathlessly feathering the entire bloody Dinosauria.

Also interesting to note are the enlarged 'canines', just like many herbivores mammals.

Religion cannot hold a candle to science. Why do they keep trying? Their arguments become more and more incredibly absurd. Perhaps one day religious superstition will be in the backwaters of human foibles, where it truly belongs.

By reason be (not verified) on 20 Mar 2009 #permalink

On the "non-functional" feather idea above: As a layman perhaps this is naive, but I have always wondered why the focus on the development of feathers is always about flight. Feathers of various make and model surely contribute other advantages other than flight (temperature regulation, protection, etc.). The feathers of modern flightless birds aren't useless are they? Also, we certainly see flight developing independently without feathers. Would not it be more proper to think of flight being an incidental development flowing from the original introduction of feathers? (Understanding, of course, that once flight arrived "better" feathers more adapted for flight would be preferenced in later generations.)

By Edward Lark (not verified) on 20 Mar 2009 #permalink

So much for "no transitional fossils" ! I actually cannot believe how many transitional forms I've come across for the "dinosaur to bird" lineage in the past few months. They just keep coming out, it's insane! More of this is covered in Donald Prothero's "Evolution: What the Fossils Say and Why It Matters," but even though it was published in 2007 it's already out of date as the discoveries just keep coming. You should still buy the book, though.

It's hilarious because much of the creationist literature on this still only deals with "Archaeopteryx is just a bird!". Utter rubbish.

Ed, I'd have to agree with you; I also have read that the original purpose of feathers, or proto-feathers were to regulate temperature, add protection, and even help the animal to be more aerodynamic. Therefore I'd have to say the feathers of modern flightless birds are not useless, necessarily. But interestingly it is not just the feathers that animals like ostriches have managed to retain - they also have pneumatic bones.

Flight would probably be incidental, yes. Remember, the watchmaker is blind. I don't need to add anything more; you've summarized it quite nicely.

So much for "no transitional fossils" ! I actually cannot believe how many transitional forms I've come across for the "dinosaur to bird" lineage in the past few months. They just keep coming out, it's insane!

Yes... but you do understand there's a certain species of creonutter who'll report each and every discovery as 'two* more gaps discovered'...

/Mandatory, and sadly essentially true.

(That said, forgoing the downer focus on the pseudoscience brigade for a change: this is one groovy little fuzzball.)

*Yes, 'two' would actually be a fencepost error, since it's actually only a net increase of one additional gap per fossil, as each is technically a splitting of the previous gap... But no one ever accused these people of being terribly strong on math, either.

the use of feathers for insulation cannot be overestimated, you ever seen a defeathered small songbird?

By extatyzoma (not verified) on 20 Mar 2009 #permalink

If you ever let a bunch of chickens loose, you get to observe a great advantage that even non-flightworthy feathers confer - propulsion. I'm pretty sure they use their wingfeathers to scoot through the air and boost their running speed. I betcha a slightly faster population would leave more offspring in a natural environment.

I've always thought that was a great rebuttal to the lame "what good is half a wing" argument.

Maybe I'll ask my wife to pluck the wingfeathers of some of her hens and have the kids chase them and an unplucked control group to see if there's much of a speed difference. Or a plucked group vs. one with just "fuzz" to better model the protofeathers. Hmmm.

Hypothesis!
Experiment!
?????
Profit!

I don't suppose there's enough detail in the fossils (and we lack extant descendants to test genetically) to determine whether the proto-feathers are of the same construction in each group, ie are more likely to be a basal feature than another example of parallel/convergent evolution (like eyes and wings arose separately, multiple times).

my comment #29, my point was that the feathers constitute a significant portion of the birds survival repertoire, without them that scrawny little thing would cool very quickly.

betz, the creationist 'what use is half a...' always serves to demonsttate their lack of interest and imagination and their abundance of ignorance.

By extatyzoma (not verified) on 20 Mar 2009 #permalink

This could be quite a revolutionary find. We knew Psittacosaurus had filaments on its tail, but this is quite something. Of course, this doesn't mean that all dinosaurs had fuzz on their bodies all their lives, maybe just bearing this fuzz as hatchlings for insulation. Maybe just for a stage in their lives. And perhaps some lost them over evolutionary time. Still, this could mean there were fuzzy sauropod hatchlings, or even fuzzy ceratopsian hatchlings.

By Kevin Schreck (not verified) on 20 Mar 2009 #permalink

[T]he feathers of modern flightless birds are not useless, necessarily. But interestingly it is not just the feathers that animals like ostriches have managed to retain - they also have pneumatic bones."

This actually answers what would be my second question: How do we know that modern flightless birds evolved from flighted ancestors? Answer: The continued presence of vestigial adaptations for flight. Thanks, Mark.

By Edward Lark (not verified) on 20 Mar 2009 #permalink

Wow, I type too slow. I see that Edward & Mark are way ahead of me. Oh well, back to what I'm supposed to be doing!

I too am a layman but I’ve often thought that feathers could have arisen through sexual selection. Another thought is that they could have evolved to make smaller animals appear larger, thus discouraging some predators.

Pneumatic bones could also serve another purpose; lighter weight for more speed on the ground. The question then is did pneumatic bones evolve primarily to enable avian/dino flight or did avian/dino flight evolve because pneumatic bones enabled it? I suspect the later. Have we found fossils of any dinosaurs with pneumatic bones that don’t show other modern avian flight characteristics?

By DGKnipfer (not verified) on 20 Mar 2009 #permalink

Nerd #9
Retinoic acid injected into the scaly legs of chick embryos causes scales to develop as feathers.
RB

By Richard Bond (not verified) on 20 Mar 2009 #permalink

ppb #23:

what a terribly insensitive person!

egads! rickrolling isn't good enough for you? you gotta go that extra mile, turn the dial to eleven and barneyroll?

luckily, in cyberspace, no one can hear you scream.

Please to forgive rival fossil pimping, but as cool as Tianyulong is, see also this guy.

Just another anomalocaridid. <yawn> ;-)

So are the scaly-skin dinos in the diagram a convergent reversion

Possible.

could you tell us what the purpose of evolutionary advantage feathers would have been at this early state?

Insulation?

And before that, perhaps they started as porcupine-style quills. Who knows.

Anti-parasite?

The opposite!

The commenters are almost chortling with their glee over this find.

What else? Really, what else?

Stating the obvious perhaps, but I think calling these fibres "proto-feathers" is slightly misleading: the anti-evo brigade will argue "What use are non-functional feathers?" as if the fibres are on the way to becoming feathers but aren't ready yet.

Call them stage I feathers, because that's what they apparently are. They were predicted by evo-devo people in 2001 or so.

if it was warm-blooded, which I understand is still under debate

Less and less.

Correct me if I am wrong but aren't feathers also a great defence against blows and bites?

Sure.

Would be interesting to see some climate history or geology on this tree. Might show some correlations of feathers and bristles appearing/reappearing with warming and cooling climate periods.

Nah, it was warm all over.

direct fossil evidence of scaly skin for some dinosaurs (e.g., […] several hadrosaurids […])

Adult hadrosaurids, that is. Hadrosaur eggs have been found in Maastrichtian sediment in Kakanaut in northeast Siberia, which was very, very close to the North Pole at that time. No way these animals grew to a size at which they could migrate before the polar night came. They must have stayed there and survived the polar night in place.

Sure, it was warmer than today, but it did apparently freeze or nearly so.

We do have scaly skin impressions from titanosaur hatchlings -- but those come from a place in Argentina that was much, much warmer.

Also interesting to note are the enlarged 'canines', just like many herbivores mammals.

Yep, it's a heterodontosaurid.

I have always wondered why the focus on the development of feathers is always about flight.

In the scientific literature, it hasn't been for the last… at least 15 years. Feathers very clearly didn't evolve for flight; flight was able to evolve once the feathers were there.

But interestingly it is not just the feathers that animals like ostriches have managed to retain - they also have pneumatic bones.

This isn't surprising at all. It's linked to a breathing system that basically shows the mammals how improvements on the usual land-vertebrate condition are really done. Pneumatic bones are normal for Saurischia, and there's evidence from sauropods for the full set of air sacs. The necks of the biggest sauropods contained much more air than bone!

There've been posts here on Pharyngula about this.

Yes, 'two' would actually be a fencepost error, since it's actually only a net increase of one additional gap per fossil, as each is technically a splitting of the previous gap...

No, because -- like the vast majority of fossils -- isn't a direct ancestor of anything known. Thus, it introduces a new branching point into the tree, and this branching point splits the previous gap. You lose one gap and gain three (one on either side of the new branching point, one below it); net result -- two new gaps.

I'm pretty sure they use their wingfeathers to scoot through the air and boost their running speed.

No, they're trying to take off. Tie yourself to a car and see if you can run faster…

There are lots of other things that half a wing is good for.

I don't suppose there's enough detail in the fossils (and we lack extant descendants to test genetically) to determine whether the proto-feathers are of the same construction in each group, ie are more likely to be a basal feature than another example of parallel/convergent evolution (like eyes and wings arose separately, multiple times).

No differences to the predicted stage I feathers have yet been found, though of course the preservation is not that great either.

By David Marjanović, OM (not verified) on 20 Mar 2009 #permalink

There've been posts here on Pharyngula about this.

Namely this here.

By David Marjanović, OM (not verified) on 20 Mar 2009 #permalink

Does anyone here know if the very large dinosaurs had pneumatic bones? The usual estimates of the weight of the big dinos suggests that they were too heavy to move quickly.
Birds have not only pneumatic bones but internal air sacs which not only lighten the bird but increase the breathing efficiency. These same features would allow a dino to grow very large since its overall density would be less than one would expect from measurements of its skeleton.
Air sacs extending the lungs would help breathing for animals with very long trachea.

Retinoic acid injected into the scaly legs of chick embryos causes scales to develop as feathers.

A devo factor I presume. Learned many things new today. A good day so far.

By Nerd of Redhead, OM (not verified) on 20 Mar 2009 #permalink

Kevin,
check out Matt Wedel's stuff. Drop him an email and grab reprints. Good place to start if you're looking for actual literature.

http://www.westernu.edu/xp/edu/comp/faculty-mwedel.xml

Off the top of my head I don't know which books would be the best to check. David might have an opinion...

Goddammit. That was preview. Why did it submit? EERRRR.

David wrote:

Adult hadrosaurids, that is. Hadrosaur eggs have been found in Maastrichtian sediment in Kakanaut in northeast Siberia, which was very, very close to the North Pole at that time. No way these animals grew to a size at which they could migrate before the polar night came. They must have stayed there and survived the polar night in place.

And so you're presuming it's very likely that the hatchlings were fuzzed, yeah?

behold the wooly iguanodon? And flying hypsies? wow....

Thanks for that Josh, I had a creationist snort at me a few years ago on this issue and didn't know how to answer. : )

Assuming that your concluding sentence is true, PZ, which I am reposting, then this means that the Dinosauria are indeed a monophyletic group, and that the presence of proto-feathers (not feathers since we find feathers only in the coelurosaurian clade of theropods comprising Aves and, probably, even tyrannosaurids like Tyrannosaurus rex.) could be a symplesiomorphic trait:

"It implies that just maybe the last common ancestor of the saurischia and ornithischia were also covered with proto-feathers, which means that feathers may be a primitive state in this lineage."

By John Kwok (not verified) on 20 Mar 2009 #permalink

Kevin--happy to help. Wedel should be able to bury you in reprints/references if you drop him an email.

Exactly the kind of thing that indicates that nothing much interesting can be done in biology without evolution.

Someone like Behe would piggyback off of it, pretending that designed evolution would produce the same cladistic branchings, without any reason at all for this to be the case.

Even so, one has to wonder, if the ancestors of both branches of dinosaurs had "proto-feathers," why do later ornithiscians typically lack any apparent downy or feathery coverings?

It's really another good thing about having a meaningful theory, though, in that it can reveal apparent difficulties. Or again, the rule of thumb that theories should be falsifiable means that phenomena falling within that theory also become testable, falsifiable, and thus meaningful.

Glen D
http://tinyurl.com/6mb592

John wrote

...then this means that the Dinosauria are indeed a monophyletic group, and that the presence of proto-feathers

John, do you think there is a serious debate about there regarding dinosaurian monophyly? Have you read:

Benton, MJ, 2004, Origin and Relationships of Dinosauria. In: Weishampel, DB, P Dodson, and H Osmólska (eds.), 2004, The Dinosauria. 2nd edition. University of California Press, Berkeley. 833 pp.

From what I understand, mammals and dinosaurs had a common ancestor about 3e8 years ago, and from what I gather the origin of the genes required to make both hair, scales and feathers has been traced to there. If this dinosaur fossil shows a kind of fibers rather than real feathers, isn't it likely that this is what the last common ancestor had, which developped to scales in some lineages, feathers in birds and hair in mammals? Just a thought. I'm not a biologist, but I do find evolution incredibly interesting and I'm tingling with anticipation of seeing how this will play out.

By Anonymous Coward (not verified) on 20 Mar 2009 #permalink

@ Josh -

I am aware that some dinosaurian paleobiologists have concluded that Dinosauria is a monophyletic group, and that this isn't really a recent conclusion. Robert Bakker - whom I wouldn't necessarily cite as a superb example of a first-rate dinosaurian paleobiologist - made some compelling arguments more than twenty years ago, but since I am not someone who has a background in dinosaur paleobiology, I am not going to elaborate further (I am, by training, an invertebrate paleobiologist.). The presence of proto-feathers in at least one hadrosaurian lineage merely confirms IMHO that the Dinosauria are indeed a monophyletic group.

By John Kwok (not verified) on 20 Mar 2009 #permalink

A bunch of people have been predicting this for a long time, but this is the first real tangible evidence that it really is true, not just logical reasoning. You see, scutes which are found in both birds and crocodiles can be tricked into developing into feathers. This hints at the possibility that all archosaurian scutes are derived from an early protofeather-like structure. To add weight to the argument another lineage of archosaurs, the pterosaurs, also had hair-like filaments covering their bodies. The hypothesis was that protofeathers first appeared in the common ancestor of crocodiles, pterosaurs and dinosaurs, a primitive endothermic archosaurian or archosauromorph, and then retained in some lineages while lost in others (e.g. crocodiles, which strangely enough seem to have switched from endothermy back to ectothermy while preserving a 4 chambered heart).

By Sclerophanax (not verified) on 20 Mar 2009 #permalink

@ Sclerophanax -

Unless I am mistaken, crocodilians may lie near the basal stem of the Archosauria, and, if that is the case, then ectothermy would be a "primitive" trait, not one that was an example of reversion from endothermy.

By John Kwok (not verified) on 20 Mar 2009 #permalink

I'm actually going to plug a little here because I think this is interesting...I actually have a bunch of pictures I took at the Zigong Dinosaur Quarry in Sichuan Province. They have a crazy variety of animals, mostly species I've never heard of , and a dinosaur skin imprint of one that was probably not feathered. If anyone gets the chance to see one of these Chinese quarries, they're amazing. They also don't skimp on the geeky details or dumb down the captions at all.
http://www.flickr.com/photos/24332240@N03/sets/72157611954037884/

NO NO NO, YOUR LYING!!!

I DON'T SEE ANYTHING, LA LA LA LA LA!
/tard

By Pastor Chris Fox (not verified) on 20 Mar 2009 #permalink

@ #6,

Lol, Nice!

The crocodilian clade is indeed basal to pterosaurs & dinosaurs, but there are some pretty convincing arguments supporting ancestral endothermy and secondary ectothermy for the few crocs left today:

Seymour, R.S., Bennett-Stamper, C.L., Johnston, S.D., Carrier, D.R., and Grigg, G.C. (2004). "Evidence for Endothermic Ancestors of Crocodiles at the Stem of Archosaur Evolution", Physiological and Biochemical Zoology 77(6):1051-1067.

Hillenius, W.J., Ruben J.A. (2004). "Getting Warmer, Getting Colder: Reconstructing Crocodylomorph Physiology", Physiological and Biochemical Zoology 77(6):1068-72.

Seymour, R.S. (2004). "Reply to Hillenius and Ruben", Physiological and Biochemical Zoology 77(6):1073-1075.

I've come to think that ectothermy/cold-blooded vs. endothermy/warm-blooded is a false dichotomy for a bunch of reasons. Regional, facultative, ontogenetic, and evolutionary changes in "-thermy" are known in lots of extant animals, and although I (reluctantly) find myself more and more convinced that endothermy may have been widespread in dinosaurs, I also think it's foolish to insist on any sort of monotypic physiology for all dinosaurs, given their long tenure on the planet and the diversity of bodies they evolved.

By Sven DiMilo (not verified) on 20 Mar 2009 #permalink

"Even so, one has to wonder, if the ancestors of both branches of dinosaurs had "proto-feathers," why do later ornithiscians typically lack any apparent downy or feathery coverings?"
Posted by: Glen Davidson

Imagine that we didn't know that elephants and rhinos had hair and we found fossilized impressions of their skin. They would be considered hairless animals.

As large endotherms living in warm environments there's no need for insulating hair as it would hinder the animal's primary thermoregulation requirement; to expel waste heat generated by movement and digestion. The large ornithiscian dinosaurs likely had huge compost piles in their bodies to digest their cellulose rich diets and such bacterial decomposition also produces heat.

Since the ancestral dinosaur was a small bipedal active hunting carnivore that competed with our endothermic therapsid ancestors, it would surprise me if there weren't such thermoregulating mechanisms as hairlike/featherlike skin modifications developed by the ancestors of both the saurischian & ornithiscian lineages.

jaycubed is dead on.

By Sven DiMilo (not verified) on 20 Mar 2009 #permalink

Rather than "feathers" being a basal character, could this mean that the basal character is "the kind of scales that evolve into fluffy things quite easily", and the kind of feathers on this new guy is only analogous to the kind on truly feathered dinos and birds?

By Stephen Wells (not verified) on 20 Mar 2009 #permalink

BTW, given the dinosaur/birds transition, are we justified, when people bust out the "half a wing" argument, in looking at them with an expression of weary disgust and saying, as to a small and not especially bright child, "that would be an arm, with feathers on it"?

By Stephen Wells (not verified) on 20 Mar 2009 #permalink

Scrabcake, nice photos. Very cool looking museum. The stegosaur with mini-plates was way cool. The flying thing hanging from the ceiling is indeed a pteraosar of some kind and the "brontosaurus" is a sauropod but smaller than a real bronto. Also loved the long-necked swimming thing--David M. probably knows what it is.

By Sven DiMilo (not verified) on 20 Mar 2009 #permalink

pterosaur

By Sven DiMilo (not verified) on 20 Mar 2009 #permalink

John Kwok @49

Aren't you essentially repeating what PZ wrote, only using longer words?

ICBW. This particular article, related articles, and comments have had me chasing all over t'internet looking stuff up, reading, reading carefully, then reading again trying to understand what's going on here.

I hope I wasn't the only one who had to look up "symplesiomorphic" in the dictionary.

Dude! The Hurdia victoria link is awesome -- another new anomalocaridid! Anyone have a link to the original paper?

...Oh yeah. And feathered dinosaurs are cool too. The Mesozoic: now 100% fuzzier! I wonder when that showed up...well, I guess we're going to be finding out better and better, too, what with all this excellent new material coming out of China.

John Kwok @54, I'm an invertebrate paleontologist too, so IANAVP but I don't think that the important thing about this is its confirmation that Dinosauria are monophyletic. Isn't a more interesting point more about the feature, rather than the phylogeny -- that feathers may go back a fair long way further than we thought? I think some chick in vitro studies about the dev. bio. of feathers is in order!

Jaycubed, #61

The next time you're at the zoo see if you can get a close look at the elephants, rhinos, and hippos. You'll notice one thing, they all have hair. Widely scattered hair, but hair.

Now, just to be contrary, I present an alternative.

We think of genetic transference among multicelled life as being a vertical process. That is, from parent to child. Such scalawags as bacteria can get away with horizontal transference because bacteria are not like us.

Yet in the last few decades we have learned that horizontal DNA transference does occur among plants and animals and even slime molds. For the most part mediated by viruses, though bacteria are thought to play some role, and even eukaryotes may play a role.

To make matters even worse, sometimes it would appear the newly installed DNA actually performs a service in its new cell, or may be coopted by the cell into performing a services.

So I'm thinking, a feathered saurischian came down with a viral infection one day. One virus accidentally picking up the DNA for feathers, then subsquently went on to great reproductive success. A few of those progeny finding lodging in an ornithiscian dinosaur. They, accidentally of course, injected the feather DNA into the animal's cells, a few of those cells being germ stem cells in ovary or testes. The DNA got expressed and so feathers were spread from lizard hipped to bird hipped dinosaurs.

So what's the difference between these proto-feathers, and the downy non-flight feathers you see in birds?

A couple of years ago (can't find the reference) I read a paper that essentially explained that the 'down' type feathers and flight feathers were very similar in make up - a very small change, and one became the other.

"Jaycubed, #61
The next time you're at the zoo see if you can get a close look at the elephants, rhinos, and hippos. You'll notice one thing, they all have hair. Widely scattered hair, but hair."

Posted by: Alan Kellogg

You completely miss the point of my comment. I am well aware that elephants, rhinos & hippos have hair on their body. My comment specifically referred to the fossilization of skin, where it would be extremely unlikely to find any hair preserved on any random piece of skin impression, because most of the skin's surface is hairless.

For this reason one cannot assume that the "scaly" skin seen in those rare large ornithiscians whose skin impressions have been found are definitive of a lack of feathers/"hair".

PS. What's with all the blatantly racist RPG stuff on your mythusmage site?

"Ed, I'd have to agree with you; I also have read that the original purpose of feathers, or proto-feathers were to regulate temperature, add protection, and even help the animal to be more aerodynamic."
Not to mention helping to attract mates and intimidate rivals.

By Titanis walleri (not verified) on 20 Mar 2009 #permalink

I really wish that the feathered T.rex meme would die. There are skin impressions from T.Rex that show that the adults at least were definitely scaly.

By Knight of L-sama (not verified) on 20 Mar 2009 #permalink

Off the top of my head I don't know which books would be the best to check. David might have an opinion...

What? Books? No books. Just Wedel's papers.

Well, there's the Ostrom Symposium volume from 2001, which has something on the origin on the air-sac system, but that book may not be easy to get. Very good-quality paper, very heavy, very expensive last time I checked.

And so you're presuming it's very likely that the hatchlings were fuzzed, yeah?

Well, it would fit very nicely. The climate was harsh, at least in winter; crocodiles, champsosaurs, squamates, and AFAIK amphibians have not been found there or in the sites on the north slope of Alaska that have the same age.

then this means that the Dinosauria are indeed a monophyletic group

Of course. That hasn't been doubted since the late 1980s or the early 1990s at the latest.

and that the presence of proto-feathers [...] could be a symplesiomorphic trait

Yes, it could be an autapomorphy of Ornithodira -- that's the smallest clade that contains the dino- and the pterosaurs, and pterofuzz could easily be stage I feathers, too...

Even so, one has to wonder, if the ancestors of both branches of dinosaurs had "proto-feathers," why do later ornithiscians typically lack any apparent downy or feathery coverings?

See comment 61. Also, Psittacosaurus lived at the same time as Tianyulong.

If this dinosaur fossil shows a kind of fibers rather than real feathers, isn't it likely that this is what the last common ancestor had, which developped to scales in some lineages, feathers in birds and hair in mammals?

Not at all, no.

1) The homology between all three (and teeth, and taste buds, and limbs...) is only at a very basic level. Beyond that, feathers are lengthened scales that grow away from the skin, but hairs apparently aren't scales at all.
2) The common ancestor you mention was a lizard-shaped and -sized, cold-blooded animal. Insulation is counterproductive for cold-blooded animals, because it prevents them from regulating their temperature behaviorally (like by basking).

The presence of proto-feathers in at least one hadrosaurian lineage [ARGH! Ornithischian! Hadrosaurs are ornithischians, but not the other way around!!!] merely confirms IMHO that the Dinosauria are indeed a monophyletic group.

Well, it adds one character to another dozen... :-|

Unless I am mistaken, crocodilians may lie near the basal stem of the Archosauria

They are the last survivors of one of the two basic archosaur branches (Crurotarsi), with the birds being the last survivors of the other (Ornithodira).

Rather than "feathers" being a basal character, could this mean that the basal character is "the kind of scales that evolve into fluffy things quite easily", and the kind of feathers on this new guy is only analogous to the kind on truly feathered dinos and birds?

Sure it could, but that's less parsimonious.

That would be this one, right? That's a weird champsosaur, and champsosaurs are already weird by definition... they're diapsids, probably basal archosauromorphs. And did I mention how weird they are? Very bad fossil record before the Early Cretaceous -- there's a Late Jurassic animal that almost certainly is a champsosaur, and a Late Triassic one that could also be one; the youngest ones are Eocene Oligocene Miocene Pliocene in age. Also, they're weird.

I think some chick in vitro studies about the dev. bio. of feathers is in order!

Already done. That's how the stage I feathers were predicted.

"As you can see in this image of the fossil, it was bristling with a fuzz of thin fibers — proto-feathers.

That is NOT certain:

Well, Charlie the Banned, you have just embarrassed yourself. Let's see:

- Collagen fibers are part of the inner layers of the skin. The feathers on all these fossils stick out of the skin.
- The exact same feathers are found on every single bird from those sites, just like how hair is found on every single mammal, scales are found on every single well-preserved lizard and champsosaur and Psittacosaurus, and outlines of naked skin are found on every single frog and salamander (and they've got insane amounts of salamanders).
- Collagen fibers that, when frayed, look vaguely similar to badly preserved stage I and II feathers are only known from highly specialized swimmers: sharks, ichthyosaurs, plesiosaurs, sea snakes, dolphins. What are they doing "in" the skin of a dinosaur?

I've said it before in public under my real name, and I'll say it again:

That paper is the biggest failure of peer-review I've seen so far.

And for the three reasons listed above, even you, Charlie, should have noticed this right away, even though you are neither a vertebrate paleontologist nor any other kind of anatomist.

I suggest you start reading here and then just follow the thread. It's hilarious. Like watching a trollboy dance.

(You might miss most of the sarcasm, though, because you haven't been following the "discussion".)

The second paper you cite is likewise a glaring failure of peer-review. I offer this (note the sarcasm in the 2nd-to-last paragraph, Charlie), this, and this.

This seems like the proper thread to put this in: They’ve found a baby tuatara in New Zealand.

Too cool!!! Will be interesting to find out if it's a new species, or one that is so far only known from (sub)fossils.

So I'm thinking, a feathered saurischian came down with a viral infection one day. One virus accidentally picking up the DNA for feathers, then subsquently went on to great reproductive success.

Highly improbable, because we're talking about several genes that may not even be on the same chromosome, plus their entire regulatory apparatus, which (we're talking about eukaryotes here) has to be humongous. Doesn't even all fit into a single virus.

So what's the difference between these proto-feathers, and the downy non-flight feathers you see in birds?

These here don't branch.

I really wish that the feathered T.rex meme would die. There are skin impressions from T.Rex that show that the adults at least were definitely scaly.

On small, unidentified parts of their bodies, yes. Also, there's Dilong.

By David Marjanović, OM (not verified) on 20 Mar 2009 #permalink

I just wrote a long comment with lots of links that take care of the two papers Charlie the Banned cited. It's stuck in moderation.

By David Marjanović, OM (not verified) on 20 Mar 2009 #permalink

JayCubed, #74

Touchy little toad, aintcha? I swear, you're pricklier than a porcupine in a pineapple patch. And what does my Mythus blog have to do with anything? Or does confusing fantasy with reality serve some purpose in your mind?

If it weren't for those jaw bones, I would think that this was some sort of proto-carnivorid that somehow got misplaced in the geologic strata. As it is, those 'canines' are a fantastic example of convergent evolution. I wasn't aware that there was much tooth specialization that far back.*

*thus betraying the sketchiness of my paleontological knowledge...

*jumps up and down rabidly waving his hands in the air and shouting*

I TOLD YOU SO I TOLD YOU SO I TOLD YOU SO!

feathers are a primitive trait in all dinosaurs, and feather-loss is a secondary adaption!

By arachnophilia (not verified) on 21 Mar 2009 #permalink

I really wish that the feathered T.rex meme would die. There are skin impressions from T.Rex that show that the adults at least were definitely scaly.

Partially scaly. For all we know, T. Rex may have had a few vestigial tufts of feathers/protofeathers in places not preserved by our collection of tyrannosaurid skin impressions. Maybe, for example, it had a feathered crest running down its neck?

For all we know, T. Rex may have had a few vestigial tufts of feathers/protofeathers in places not preserved by our collection of tyrannosaurid skin impressions.

Yes--for all we know. But does it make more sense to apply feathers in those instances where we actually have data, or does it make more sense to feather animals on the basis of a prediction?

Too cool!!! Will be interesting to find out if it's a new species, or one that is so far only known from (sub)fossils.

Alas, it is neither. It's a reintroduciton attempt; tuataras were taken from their native islets and released in a mammal-proof-fenced sanctuary on the mainland. The news is that they are successfully reproducing there.

By Sven DiMIlo (not verified) on 21 Mar 2009 #permalink

As it is, those 'canines' are a fantastic example of convergent evolution. I wasn't aware that there was much tooth specialization that far back.

That's where the name Heterodontosaurus comes from.

BTW, the upper-jaw "canines" of heterodontosaurids are not on the same bone as the mammalian ones. They're on the bone that carries our incisors.

But does it make more sense to apply feathers in those instances where we actually have data, or does it make more sense to feather animals on the basis of a prediction?

Dilong.

It's a reintroduciton attempt

Oh. Well, better than nothing :-|

By David Marjanović, OM (not verified) on 22 Mar 2009 #permalink

More dynamic visuals needed.

Ken Cope? :)

Dilong isn't T. rex.

Feathering T. rex on the basis of Dilong is still a prediction. And it assumes, among other things, that the current phylogentic position of Dilong is correct.

does it make more sense to apply feathers in those instances where we actually have data, or does it make more sense to feather animals on the basis of a prediction?

Any phenotype is a prediction in the absence of data, including "no feathers". You're right to suggest caution, but it should be about the relative strength of the predictions, not about refusing to predict at all.

You're right to suggest caution, but it should be about the relative strength of the predictions, not about refusing to predict at all.

Caution is all that I was advocating. And I agree 100% about the relative strength of the prediction being important.

I guess I was saying that, with the following statements all being accurate:

1. to my knowledge, only one anatomical treatment of Dilong having been done so far,
2. two possible/likely subclades existing within Tyrannosauridae,
3. something like 58-50 million years separating Dilong from T. rex (almost as much time as T. rex has been gone from the world),
4. other tyrannosaurids known that don't appear to have feathers,
5. at least one other phylogeny not resolving Dilong as a tyrannosaurid*,

feathering T. rex based on what we currently know is a prediction that probably has some fairly significant error bars around it.

*Tuner et al., 2007, A Basal Dromaeosaurid and Size Evolution Preceding Avian Flight. Science 317:1378-1381.

something like 58-50 million years separating Dilong from T. rex (almost as much time as T. rex has been gone from the world)

And even a much shorter time should potentially be enough for major changes, considering modern elephants and rhinos vs. their extinct woolly relatives.

Exactly...

"JayCubed, #74
Touchy little toad, aintcha? I swear, you're pricklier than a porcupine in a pineapple patch. And what does my Mythus blog have to do with anything? Or does confusing fantasy with reality serve some purpose in your mind?

Posted by: Alan Kellogg

I'm not the one who promotes crude racist fantasies for players in RPGs on their website. You are. The racist descriptions of human beings present on your site are merely standard racist classifications slightly modified by mixing in some simplistic fantasy plotlines of the alternative history genre.

Racist and banal.

What does your blog have to do about anything? It speaks to your character; displaying your own words & ideas.

JayCubed, #91

After reading Niven and Pournelle's Escape From Hell it occurred to me that they were describing Hell as an Ethical singularity. That is, the deeper into Hell you go, the greater the gravity of the offense.

You have shown yourself not only to be intellectually dense, but morally dense as well. From what you're accusing me of I have to wonder about your thinking regarding other races and ethnicities. You, sir, not only project, you do it poorly.

For those of you not into seeing the worst in people, what JayCubed is honking and blathering about has to do with an RPG known as Mythus. The official game setting is a world known as "Ærth", which is a lot like our own Earth, only with landmasses that never existed, a hollow interior, and fantastical creatures. That is, the sort of world as presented in adventure stories, pulp fiction, and tales of wonder.

And a pre-modern view of the races, where hue and physiognomy determined affinity instead of genetics. In alphabetic order you have; Black People, Brown People, Red People, White People, and Yellow People. They are people. Some are good, some are bad. Some embraced the abyss, others were forced into it in order to survive.

The game does have an Æropan (European) focus because Gary Gygax -the original author- felt that most people playing it would be of European extraction, and because he knew the European aspect better, being of European descent himself. (On a side note, the Gygaxes of Switzerland are said to be the gnomes of Zurich, and the Gygax family has been connected with the Gyges of Greek legend and myth. By this you can see that the family has been a bunch of troublemakers for thousands of years. :) )

Now Ærth does have one ethnicity of dubious morality. These are the Lemurians. Based, I do believe, on one of Blavatsky's Lemurian races more than on any real world race. They are arrogant, cruel, cannibalistic, and worship deities that the comparatively gentle cephalopod gods of the A-tlan-tl have bad dreams about.

JayCubed very simply decided he needed something to hate me for, and chose the most ludicrous thing he could find. JC not only has trouble distinguishing reality from make believe, he thinks this reflects on him positively.

One more thing before I close. Vargaard (our North America) as of the year 1009AAF (After A-tlan-tl's Fall, our 2009) is not only far from being conquered by the Æropans, the Iroquois Nation is on it's way to conquering the Æropan kingdoms on Vargaards A-tlan-tic shores.