This is Gigantoraptor erlianensis, a newly described oviraptorosaur from late Cretaceous of China. It’s a kind of nightmare version of Big Bird — it’s estimated to have weighed about 1400kg (1½ tons for non-metric Americans).
Histological examination of the growth structure of the bones suggests that this fellow was a young adult, about 11 years old, and that they grew rapidly and reached nearly this size by the time they were 7. And since it is a young adult, there were probably bigger gigantoraptors running around. They also compared limb length to other dinosaurs, like the tyrannosaurs—gigantoraptor had longer, slimmer legs and was more of a runner than they were.
There’s no sign whether it was covered with bright yellow feathers.
Xu X, Tan Q, Wang J, Zhao X, Tan L (2007) A gigantic bird-like dinosaur from the Late Cretaceous of China. Nature advance online publication, 13 June 2007.
wow!
That guy standing there must have had huge cojones! He’s one brave dude!
Oh wait! you mean he’s not a fossil? not contemporaneous?
LIAR!
(sorry just pre-empting the fundie, creobot response) Now we’ve got that out of the way we can proceed to lerned discource on big ass birds….
obviously having a poblm wit my kyboad!
My pardon!
Of course I meant ‘lurned’ ;-)
How many coconuts do you suppose it needed on its 40-day ark voyage?
Wow, i’d already read 2 articles about these things, but i hadn’t realized they were THAT big.
Was another one that caught my attention. Been playing too much Evercrack II, so my first thought was, “They got the coloring and wings all wrong.” lol
http://www.livescience.com/animals/070612_gliding_reptile.html
http://images.livescience.com/images/070612_glider_reptile_02.jpg
EQ2 Faydark Drake:
http://img183.imageshack.us/img183/5282/eq2fdh01ec6.jpg
Wow. I’m looking at the tree in my yard and thinking about how this thing was taller than that.
How many coconuts do you suppose it needed on its 40-day ark voyage?
I’m thinking T-Rex would have to help as this guy doesn’t have the teeth, but I’m sure ol’ T-rex would be willing to help out one of his buddies when he wasn’t combing the knots out of the lamb’s wool.
Awesome!
Oh, come on! What’s wrong with you people! You see a giant raptor and the first thing you think about is stupid fundies? Giant raptors are awesome in their own right! Now, if you’ll excuse me, I’ve got to figure out how best to use the mutant computer-controlled clones of this thing…
Actually
some of the first things that came to mind were “wow – awesome – cool – big – yummy”
but since this isn’t a ‘free association therapy session’
the first printable thing that came to mind was how can I make fun of some fundies with this — especially given the recent posts on the Ken Ham’s freak show (aka the creation museum)
And so it goes
I do have one, semi-rational comment…
Why are bird-like fossil reconstructions always shown doing the ‘strut’…. It’s like all of the artists are channelling Jurassic Park or something.
“and reached nearly this time by the time they were 7.”
Should the first instance of “time” be “height” in the quote above?
As a non-scientist, if dinosaurs went extinct, how did birds evolve from them?
e-lad, most dinosaurs went extinct. Not all of them. Some populations survived and their descendants became birds.
That’s not a dinosaur. That’s obviously a parrot crossed with a giraffe ;-)
Moreover, e-lad, they evolved into birds (or, at least, early birds) _before_ the Cretaceous extinction.
umm…
I’m in ur Cretaceous
kickin ur dudez
i’d like to see the raptor-shaped cutout on the Ark for this monster to fit in.
seeing large species like this still being discovered tells me that there needs to be orders of magnitude more funding for paleontology, before all the good digging areas are built over with condos or strip malls.
the first printable thing that came to mind was how can I make fun of some fundies with this — especially given the recent posts on the Ken Ham’s freak show (aka the creation museum)
Well, obviously, this new find means that not only was “The Flintstones” a documentary, but so is “Seseme Street”.
My first reaction was, “What will xkcd make of this?”
How did they detail the wing/forelimb, especially the clawed digits? The image indicates which bones were found and which interpolated. There is clearly enough on hand to declare the animal a new find and to lay out its size. But the image shows no limb bone fossils.
Arrrr…now THERE’s a parrot that would make a pirate proud!
..or make a pirate into a meal, anyway.
No wonder they could never find snuffelupagus.
Tastes like chicken!
greensmile,
There is no Key to the illustration, so maybe the white bones are the ones recovered and the grey are those missing? I don’t know — can someone clear this up?
Probably. Of course, since the deceased, nay, gone to the fjords oviraptorosaur is so large it could be heleven.
Probably. Of course, since the deceased, nay, gone to the fjords oviraptorosaur is so large it could be heleven.
Here’s the description of the holotype:
The white parts in the diagram are the bits they’ve got.
The white bones are the ones God loves… the darker ones are the ones God was angry with and made darker. And no- that isn’t racist… it’s Mormon. And being part of a religion exempts it from such criticisms.
There’s your key.
I wish we could get some of this things’ DNA. Oh, man to have gigantoraptor steak…
e-Lad, don’t make such questions. Just accept the received Darwinian wisdom. If it is hard for you to imagine reptiles “transforming” into birds….well…just have faith.
Here are other questions you are not suposed to ask:
1) How did the avian lung evolve?
2) How did feathers evolve?
3) Which dinosaurs gave rise to which birds?
4) Which model is the right one: the cursorial one, or the arboreal one? Why one and not the other?
5) How could we falsify the dino-to-bird story?
Dammit! There goes my hopes of cloning and riding a giant chocobo.
Here are other questions you are not suposed to ask:
are you asking, mats?
’cause if so, then you would be a scientist, and could look at the data readily available to address your questions.
otherwise, questions posed in order to verify your ignorance don’t do much, do they.
so, again, are you asking?
hey, I’m an ichthyologist, not a paleontologist, but i already know that it wouldn’t be hard to find actual paleontologists who have published data attempting to answer those very questions.
so, if “darwinists” insist we not ask the questions, why then are they insistent on asking the same questions themselves, and publishing the results of their explorations in the literature?
must be some sort of back-handed consipiracy where, instead of trying to cover up issues, they are working double time to clarify things.
Thanks to all except “Mats” for the info. I needed a starting point on this.
I’m a four year mech eng and at 56 y/o I am doing some remedial paleontology/ biology because it is so available of the net these days !
I was still in grade school when I figured out my main reason for not believing in supernatural BS is all the contradictions, inconsistencies, and absurdities in “the inerrent word of god.”
Mats, there are valid psychological reasons why certain people do not trust science. If you are interested you can read the basics here:
http://www.edge.org/3rd_culture/bloom07/bloom07_index.html
Hey Mats, there are these neat buildings in most every town called libraries. In those libraries are all these stacks of paper covered with information and conveniently bound together, I believe they’re called books. When you have questions about the collective body of information discovered and postulated by people, oftentimes these books have answers in them, or at least the educated opinions of people who have studied the same questions. There are even people who work there who can help you find what you’re looking for!
Well done, E-lad.
~ K-lass
Prove that all the feathered dinosaurs we have discovered, such as Sinornithosaurus, are hoaxes. That would be an important first step.
Birds are dinosaurs. They never went extinct, they just started looking funny.
Baratos,
It is so fascinating at how we all (including the anti-mules)got here !
I am wondering if gigantus hopped like some birds, or had a leg-after-leg stride.
Rey, Mats don’t need no steenking libraries! He performs all his own research, and finds the Answers to be particularly comforting, in that they enable him to completely ignore information that might contaminate his hermetically-sealed beliefs.
well, doesn’t that just prove how diabolical the conspiracy is?
uh-oh, I’ve said too much already…
I bet that took you less than 5 minutes to put that together, Kseniya.
If mats would take 5 minutes to google his “questions” (even better, try google scholar), I’d bet he would find lots of research looking at the answers to his “questions”.
like you say, though, he isn’t interested in answers that differ from his preconception that scientists are nothing but materialists, intent on destroying his little fantasy.
Lad, that’s an interesting question. Have you ever seen a large, flightless bird that hopped like a sparrow? I haven’t. I’d go with “stride” for this big fellah. There may be other clues (such as, in the structure of the hip, for example) but I’m not equipped to elaborate on that…
Ichthyic – yes, exactly. I’d love for Mats to prove us wrong, though. Wouldn’t that be cool?
Bastard. I was drinking soda when I read that. :(
K-girl,
I thought that maybe the humans that lived at the time could have outrun him if he hopped.
Ichthyic – yes, exactly. I’d love for Mats to prove us wrong, though. Wouldn’t that be cool?
mats could actually turn his driveby into an interesting discussion about the current status of a couple of those questions…
if he’d just ask.
heck there are a couple there I might like to spend some time bringing myself up to date.
like maybe extending his question on feather evolution to looking at the latest collection of fossils indicating the existence of feathers, and who is currently working on them.
I haven’t looked at the issue in a few years now, and likely there are some great finds out there I’m unaware of.
seems especially applicable given that this latest find is a raptor.
If only he would ask the questions he is not supposed to ask…
why you such a hater, mats?
E-lad’s comment echos my own observation, wasn’t a precursor to the ratites the top carnivore during the Eocene? This completely f’s up the extinction narrative of K-T boundary.
Mike
“5) How could we falsify the dino-to-bird story?”
Just find a 300 million year old bird. In the fundy universe, where all dating methods are flawed, that should be a simple task.
funny, but Lou over on ATBC just now posted this link:
http://news.lycos.com/dynamic/stories/F/FEATHERED_DINOSAURS?SITE=LYCOS&SECTION=SCIENCE&TEMPLATE=DEFAULT&CTIME=2007-06-13-17-50-00
oh mats…
perhaps you might like to visit the display so you can not ask your questions there?
@33 Rey Fox
We don’t have those in my town. Instead we’re given a wanna be starbucks, with lots of magazines, empty shelves and computers. They call it a homework location, and keeps hours of 3 to 5.
Mike/mgr,
I’m so happy that my comment preceded and initiated your post !
Dale
“This completely f’s up the extinction narrative of K-T boundary.”
I thought according to you creationists the K-T layer was put down by everyone on the Ark having the runs from bad soup on day 35, or something.
Wouldn’t it be cool if the Gigantoraptor’s direct genetic descendent turned out to be swallows?
One could always hope that there is a group of kangaroo-parallel dinosaurs waiting to be discovered? But probably they wouldn’t be quite as big as this one. The largest (extinct) hopping kangaroo was around 500 pounds.
“it’s estimated to have weighed about 1400kg (1½ tons for non-metric Americans).”
Sorry for my nitpicking, but aren’t both tons and kg a part of the metric system, and isn’t saying that “about 1½ tons” = 1400kg, the equivalent of the creationists saying that 1/3 = 30%?
The jiggle factor alone, at that weight could cause trauma.
We see this in mature females.
Y’know what they say, Ichthyic (and I think I just said it yesterday @ AtBC),
Timing is everything.
Happy to help.
While in the shower a moment ago, I devised a theory; well, let’s call it a hunch, that I could start a new religion based on the premise that the value of pi is actually three point zero, zero.
And the religion of the scientists has altered it slightly to show their superiority.
Never mind, I just saw the article on Scientific American’s homepage, where it appears that they are both just rough estimates.
Dibs on the drumstick. For me and my neighbourhood.
So from the time Adam got smart until Noah, things like this were living on the same planet as humans? No wonder that they thought He was a vengeful God.
Ken Ham is getting rich off of stupid.
Hey, Matt!
You asked, I answer:
> 1) How did the avian lung evolve?
Incrementally. Saurischians other than birds (non-avian theropods, sauropods, basal sauropodomorphs) have the pleurocoels associated with the modern avian air sac system (an important element in the avian flow-through lung). More problematic evidence for air sacs lie in various pockets (but not true pleurocoels) in erythrosuchids and other dinosaurs.
However, the pelvic pump of the avian lung system is clearly present until Ornithothoraces (enantiornithines plus ornithuromorphs).
> 2) How did feathers evolve?
Incrementally. Basal coelurosaurs (Sinocalliopteryx, Sinosauropteryx (unlike what certain recent papers suggest!), Dilong, etc.) show rather simple fluffy structures. Maniraptorans such as Caudipteryx, Microraptor, Sinornithosaurus, Archaeopteryx, etc. show fully avian plumes.
For the evo-devo perspective on it, check scholars.google.com for references by Prum.
> 3) Which dinosaurs gave rise to which birds?
Birds are nested among the eumaniraptorans. Their closest relatives are deinonychosaurs (raptors).
See http://www.geol.umd.edu/~tholtz/G104/10424arch.htm for eumaniraptoran relationships and http://www.geol.umd.edu/~tholtz/G104/10423coel.htm for more basal coelurosaurs.
>4) Which model is the right one: the cursorial one, or the arboreal one? Why one and
> not the other?
Neither, and both! One of the most compelling recent discoveries in this field is the existence of Wing Assistend Incline Running, a behavior present in basal modern birds in which a front-and-back motion of the wings to generate traction against a vertical substrate, allowing them to literally run up a tree.
WAIR may have been present in basal maniraptorans on up. Basal eumaniraptorans (Epidendrosaurus, primitive deinonychosaurs, Archaeopteryx) show some limited arboreal traits. Above these forms you have more aerial locomotion traits.
So it seems as if the early phases were cursorial, and the later parts arboreal.
> 5) How could we falsify the dino-to-bird story?
At this point, roughly comparable to falsifying the carnivoran origin of seals or the primate origin of humans! However, in principle, you would need a comprehensive set of potential outgroups whose morphology and stratigraphic position is even more compelling than the dinosaurian origin of birds. In other words, unlike the media portrayal of Science, a single discovery doesn’t do it: it is a case made by the gathering of a mass of consilient data.
Hope this helps,
From the Miami museum exhibition article referenced by Ichthyic above,
This got me to wondering about creationists and undersized hearts that may not pump enough blood to the brain…
Has anyone looked into this?
Polly want a cracker!
Right. Freakin’. Now!
Re 46,
Thanks for the info link! Guess where I’m taking my kid next weekend. You know living close to Miami ain’t all bad after all.
BobL said:”I thought according to you creationists the K-T layer was put down by everyone on the Ark having the runs from bad soup on day 35, or something.
Wouldn’t it be cool if the Gigantoraptor’s direct genetic descendent turned out to be swallows?”
Comprehension problem?
What I was referring to is the scientific narrative that dinosaurs were on the way out at the K-T boundary, and note that the therapsid line potentially carried on into the Eocene, and I am a creationist?–ouch!
Don’t assume that Walter Alvarez’s account of the iridium line at the K/T boundary is the end all of the narrative, not with the outgassing issue associated with the Ghats still being considered as a factor, and that the only sharp extinction at that line is a large foraminifera.
Mats–as to the falsification question, what was the claudogram for T Rex at Hell’s Creek all about? If the DNA was inconsistent with the avian sequences, this could have been such evidence, but it is not.
Mike
Polly want a cracker!
Right. Freakin’. Now!
LOL
Re 46,
Thanks for the info link! Guess where I’m taking my kid next weekend. You know living close to Miami ain’t all bad after all.
yeah, I’m on the other side of the country, but figure eventually it will make it to the LA Natural History Museum.
I hope.
oh, and thank Lou:
http://www.antievolution.org/cgi-bin/ikonboard/ikonboard.cgi?s=46708077c21b510a;act=ST;f=14;t=5066
The illustration would be way more awesome if the human-shape-for-scale was reeling back in terror, B-movie poster style.
Its not just the birdie dinos in the news today, there’s also Eocursor a basal ornithiscian that’s just turned up. If anything it’s arguably more important than Gigantoraptor as it tells us about the very early evolution of the other big dinosaur group.
The PDF is freely avaliable from the Royal Society’s website
And there should be a small fullness in the rear of his pants…
The illustration would be way more awesome if the human-shape-for-scale was reeling back in terror, B-movie poster style.
here ya go:
http://home.earthlink.net/~tjneal/gigantoraptor2.jpg
Tom, between the metric and the English systems, there are three different units called “ton” (yeah, I know, homonymy’s a bitch, especially in knowledge representation…).
A long ton is 2,240 lb/1,016.0469088 kg; a short ton (the usual here in the US) is 2000 lb/907.18474 kg; and the metric ton (sometimes written “tonne” to distinguish it) is 2,204.6lb/1000 kg.
…the therapsid line potentially carried on into the Eocene…
Potentially? We are here, aren’t we? ;)
Is it just me or is this obviously a transitional fossil between a brontosaurus and an ostrich?
PZ, “Late Cretaceous” is a proper name with a strict definition (http://www.stratigraphy.org/gssp.htm).
YES YES YES YES!!!!
That’s not going to happen to the Gobi desert…
Dr. Holtz gave the fossil side, let me give the rest: Today’s crocodiles have a couple of air sacs connected to the lung. Enlarge and multiply those air sacs and let them invade the skeleton, and that basically is it.
Birds are monophyletic, that is, the last common ancestor of all birds was itself a bird. Birds evolved only once. At least that’s by far the most parsimonious interpretation of the evidence.
PZ, “Late Cretaceous” is a proper name with a strict definition (http://www.stratigraphy.org/gssp.htm).
YES YES YES YES!!!!
That’s not going to happen to the Gobi desert…
Dr. Holtz gave the fossil side, let me give the rest: Today’s crocodiles have a couple of air sacs connected to the lung. Enlarge and multiply those air sacs and let them invade the skeleton, and that basically is it.
Birds are monophyletic, that is, the last common ancestor of all birds was itself a bird. Birds evolved only once. At least that’s by far the most parsimonious interpretation of the evidence.
Argh. The second blockquote should of course end after its first paragraph.
Argh. The second blockquote should of course end after its first paragraph.
That’s not going to happen to the Gobi desert…
hey, I live in CA. It’s already happened here to a great extent.
so i’ll adjust and say MOST instead of ALL.
;)
Second? It’s the fifth blockquote. Must go to bed.
Second? It’s the fifth blockquote. Must go to bed.
Thanks for the picture, PZ! I was jumping up and down when I saw this news story earlier today. I’ve gt a large interest in bird evolution, I even wrote a paper on it for my Evolution class. One of the most interesting things is how big this bloody thing is. The next biggest bird-like fossil is the “thunder bird” from Australia, which was at least half the size of this thing.
Tom, between the metric and the English systems, there are three different units called “ton”
You forgot frieght ton, register ton and displacement ton. I’m sure there are more than I haven’t heard of.
Here in metric-land the metric “ton” is always spelled “tonne” to make things non-confusing.
Dear “Mats”
If you care to write me at acantho@mac.com I will go over avian evolution with you in some detail. Your questions show you are far FAR from educated in that particular field.
I will explain modern avian osteology and such, and compare this to the fossil record to reveal the obvious stepwise development of birds from non-volant theropod dinosaurs…
First let me thank Lou as requested by Ichthyic for the info link to the exhibit at the Miami museum of science.
I would also like to thank Mats for the questions to which he didn’t want answers. The answers given in the above posts were very elucidating indeed, so a heartfelt thank you to all of the knowledgeable people who provided them. Thanks!
By the way, the WAIR bit, seems a tad silly to me, as it always has, as the traits needed to produce the effect are not seen in basal birds, or theropods closely related to them.
Said another way, they are traits of an advanced neornithine pectoral girdle that brings about WAIR and are simply not seen in say, Archaeopteryx…
Neato.
My first thought when I read about this earlier today was to wonder whether we’d finally solved the mystery of where Deinocheirus‘s arms came from. Looking at the illustration, though, this guy seems to have (relatively) shorter forelimbs. (I know the arms are thought to be from an ornithomimosaur, but with an oviraptorosaur this size I thought it might be possible.) I guess there’s still a giant ostrich dino waiting to be found somewhere out there…
Thanks tons, Graculus :) — I hadn’t heard of any of those others before.
Aye, thanks for the many explanations on the whole “ton”-issue. I think I got a little wiser. I could of course have done a little research before making my comment, but I weren’t familiar with the many different kinds of “ton”s, so I assumed it was an error…. And who am I to question the infallibleness of PZ! I feel so very ashamed.
It’s wonderful when an anti-evolutionist shows up and (refuses to?) ask some good questions. I learn so much!
“Comprehension problem?”
Yep, mixed you with Mats, Mike. My woops.
I will explain modern avian osteology and such, and compare this to the fossil record to reveal the obvious stepwise development of birds from non-volant theropod dinosaurs…
well, I know mats didn’t actually have any questions, since he was reading from a script, but I’ll take you up on that, if you have time, as I’ve been curious about bone anatomy for a bit now:
When and with what fossils did the characteristics that make modern bird bones so light start appearing?
Was it before the raptors, after, or did it appear within that group? Did it start with hollowing, or something else?
thanks
I think this is my mother.
Heh, Cyan, I spent a good part of the afternoon reading up on reptile, amphibian, and mammal skin because a troll named Jeff on the “maelstrom” thread was all “I know all about dermatology and we *so* don’t need evolution”. Like you describe, the troll caused me to learn something new.
Now I’m going to take those articles I read and model that anatomical and physiological knowledge in an information system. That’s my new incentive–every time a troll misuses an anatomical example, I’m going to model that troll’s example correctly in my system. In that way, they’re advancing the knowledge representation and dissemination of evolutionary transformation. I’m helping them, like Mats here, not be useless, in spite of their best efforts. :)
@Thomas R. Holtz, Jr. (#57):
i’ve heard some thought that parrots are actually more closely related to this guy (oviraptors) than other maniraptors, what with the similarities in bizare head-shapes. but i’m not sure what to think about that.
@David Marjanović (#72):
well, i suppose i should direct the question to you as well, since you seem to something of an authority on the matter. i’ve heard some chattering about evo-devo and the evolution, secondary loss of, and re-evolution of flight, and that birds might indeed be polypheletic (with things like psittachiformes and ratites coming more directly from their similar-looking dinosaurian ancestors than from archaeopteryx), or that we should perhaps push the definition of “aves” further back on the cladogram. my paleontology prof indicated something about herrerasaur tracks that seem to indicate flight, but i haven’t seen or heard of anything remotely like that.
any validity to any of this? is there any legitimate debate, or is this all fringe-thinking and cracked pottery?
@Ichthyic (#86):
well, as thomas holtz indicated above, pleurocoels appear even in sauropods, so it would have been a condition present in basal saurischians. since pleurocoels are essentially what makes the skeleton hollow, i would say they started at least as early as the first saurischian. in other words, “very early in the dinosaurian line, if not before.”
i don’t think we have skeletons that are hollow to an avian extent until the maniraptors, such as archaeopteryx. but i could be mistaken about that. but the characteristics, like other avian characteristics, started appearing long before birds and long before flight.
thanks.
yeah, I figured it had to be a while back, but was wondering just when and to what degree; thanks for the bit of clarification.
Not quite sure why I’m so curious about this specific thing; maybe it’s the size/weight biomechanics issue.
Hollow bones in theropods is quite basal, relatively speaking. I don’t not mean just a little bit hollow, but hollow in very similar ways we see later in Aves…
Also, we have no clue if “birds” are monoplyletic. Do modern birds share a common origin? I would bet almost certainly (too many shared similar derived traits not to assume so as a default). But anything that was a derived volant theropod that one might call bird? We simply do not know, and claims that they are monophyletic is just opinion. I do suppose though that was actually meant was all birds, extinct and extant, find their origins in “nested among the eumaniraptorans”, which seems very well supported in my opinion, though I have debated some weird people who claim eumaniraptorans are not monophyletic themselves, with some being true dinosaurs, and other, non-dinosaurian archosaurs that only “look” a bit like theropods…
“i’ve heard some thought that parrots are actually more closely related to this guy (oviraptors) than other maniraptors, what with the similarities in bizare head-shapes. but i’m not sure what to think about that”
Parrot skeletons are very much modern in build, and are far FAR more similar to other modern birds, than to any Oviraptor. For them to be separately derived (modern birds in general, and Parrots), and have so many very similar traits in common, does not only contradict the basic idea of parsimony, it murders it with a dull axe and buries it under the shed.
@Lago (#92+93):
ignore those people. well, really, person singular, alan feduccia. and a bunch of creationists that think his crackpot rejection of dinosaur paleontology in favor of the kinds of incredibly coincidental convergence you describe above is some kind of problem for the theory of evolution.
feduccia is to paleontology what behe is biochemistry. mention his name in a paleontological community, and watch the blood boil.
that’s sort of what i figured. it requires that a number of blatantly obvious adaptations like the carpometacarpus and the specific plate-like fusing of the hip bones be totally convergent to the point of perfect coincidence. its not quite was “murderous” as that “no it only looks exactly like a dinosaur” argument above, but it’s in the same vein.
i’d just heard a (competant, working) paleontologist bring it up — granted, he doesn’t work with dinosaurs.
Every discovery such as this is another feather in the evolutionary cap and another nail in the creationists coffin I hope.
As I understand it all the Coelurosaurs (the group that includes the deininychosaurs and tyrannosaurus, among others) have extensive bone hollowing (“Coelurosaur” means “hollow-tailed lizard” I believe). Scientific American had an article about this a while back, but I don’t recall it offhand. Apparently the weight reduction from hollow bones has been implicated as a possible enabler of the unusual size of certain tyrannosaurids, too…
As for oviraptor as an ancestor of parrots, that seems enormously unlikely. It’s much more likely that they convergently evolved similar head shapes due to similar diets or some such.
e-lad
I don’t know anyone who “doesn’t trust science”. I mean, even saying such things shows how far you are from reality. Perhaps you mean “people who don’t believe in unguided evolution”? Please, don’t confuse disbelief in unguided evolutionism with mistrust in the scientific enterprise.
Lago,
In fact, the anatomical traits for WAIR **do** seem to be present in basal maniraptorans, as it uses a different stroke than the vertical one used in aerial flight (which does indeed require a bunch of adaptations not found in even basal avialians).
AdamK,
Nope, this critter is most definitely NOT Deinocheirus. The humeral and hand morphology and proportions are entirely different. So yes, there is still a bigass ornithomimosaur out there to be found!
Ichthyic,
The hollowing of bones works in steps. (Wow, amazing! It is almost as if evolution proceeded by the stepwise acquisition and modification of traits… :-). Hollowing of the vertebrae starts with simple pockets, becoming changers in some, becoming complex spongy chambers in some of those. Hollowing of the limb bones occurs early, but actually pneumatopores to the limb bones occurs later.
So oviraptorosaurs, deinonychosaurs, Archaeopteryx, and various basal birds have vertebrae and limb bones which are somewhat less pneumatic than found in ornithurine birds.
Arachnophilia,
No, oviraptorids are no more closely related to parrots than they are to seagulls, hummingbirds, chickens, Hesperornis, Archaeopteryx, or (for that matter) than to Velociraptor or Troodon. The similarity between the beaks of advanced oviraptorosaurs (the caenagnathoids) and parrots is convergence, as basal oviraptorosaurs and most Mesozoic birds have very un-parroty jaws.
Shorter Mats: Despite all my best efforts to undermine the basic science it’s based on, if I ever need what medical science has to offer, I’ll be all over that in a New York minute.
Please, don’t confuse disbelief in unguided evolutionism with mistrust in the scientific enterprise.
Why not, it’s the same thing.
Eocene parrots have pretty normal bird heads. The similarity between oviraptorosaurs and parrots is limited to gross head shape on the one hand and characters all maniraptorans have in common on the other hand.
Not all hollow bones are pneumatic. The hollow tail vertebrae that Coelurosauria is named for usually just contained bone marrow (as shown by the lack of a pneumatopore = hole big enough for an air sac diverticle to pass).
Pneumaticity evolved in a very gradual manner. Most Mesozoic birds, AFAIK, don’t have pneumatic upper arm and thigh bones, while today’s birds do.
Quite obviously.
The same almost certainly holds for the short-tailed birds (Avebrevicauda): the surviving clade of birds (Neornithes), the rest of Euornithes, Enantiornithes, Confuciusornithidae, Sapeornis, and probably Omnivoropteryx which still hasn’t received a serious description.
All that are currently thought to have been able to fly belong to Avebrevicauda, except for Microraptor, Archaeopteryx, Rahonavis, Shenzhouraptor, Jixiangornis, and Dalianraptor (I hope I haven’t forgotten any), and the scansoriopterygids if the adults were volant.
When and how often flight evolved is not quite clear, though “at the origin of Eumaniraptora or Maniraptora” and “once” sound good to me at the moment.
Phew… let’s just do it the other way around: let’s define Aves first. Then we can find out if, say, oviraptorosaurs or for that matter Archaeopteryx are birds. :-)
That’s Czerkas trying to do cladistics with a single character in his frankly embarrassing description of Scansoriopteryx. Then there’s Feduccia who keeps talking about dinosaurs other than neornithine birds but knows hardly anything about them, and a few other such people.
Mats, evidence for guidance, Please.
Eocene parrots have pretty normal bird heads. The similarity between oviraptorosaurs and parrots is limited to gross head shape on the one hand and characters all maniraptorans have in common on the other hand.
Not all hollow bones are pneumatic. The hollow tail vertebrae that Coelurosauria is named for usually just contained bone marrow (as shown by the lack of a pneumatopore = hole big enough for an air sac diverticle to pass).
Pneumaticity evolved in a very gradual manner. Most Mesozoic birds, AFAIK, don’t have pneumatic upper arm and thigh bones, while today’s birds do.
Quite obviously.
The same almost certainly holds for the short-tailed birds (Avebrevicauda): the surviving clade of birds (Neornithes), the rest of Euornithes, Enantiornithes, Confuciusornithidae, Sapeornis, and probably Omnivoropteryx which still hasn’t received a serious description.
All that are currently thought to have been able to fly belong to Avebrevicauda, except for Microraptor, Archaeopteryx, Rahonavis, Shenzhouraptor, Jixiangornis, and Dalianraptor (I hope I haven’t forgotten any), and the scansoriopterygids if the adults were volant.
When and how often flight evolved is not quite clear, though “at the origin of Eumaniraptora or Maniraptora” and “once” sound good to me at the moment.
Phew… let’s just do it the other way around: let’s define Aves first. Then we can find out if, say, oviraptorosaurs or for that matter Archaeopteryx are birds. :-)
That’s Czerkas trying to do cladistics with a single character in his frankly embarrassing description of Scansoriopteryx. Then there’s Feduccia who keeps talking about dinosaurs other than neornithine birds but knows hardly anything about them, and a few other such people.
Mats, evidence for guidance, Please.
Of course I did: Yandangornis may have been able to fly. Very interesting animal. If only a halfway decent illustration of it existed, and if only its description weren’t so short and superficial.
Of course I did: Yandangornis may have been able to fly. Very interesting animal. If only a halfway decent illustration of it existed, and if only its description weren’t so short and superficial.
The wisest person is the one who can learn from the most foolish.
Kick ass. Where can I buy one?
WAIR has only been shown by observations in modern birds with distinctly different traits found in the wrist, elbow joint, and shoulder joint. The birds showing these abilities differ from basal birds and the theropods they are believed derived from in ALL of these points, and I am sure you know this quite well Mr Holtz. WAIR is a square peg being hammered into a round hole.
And Dave
When it comes to flight developing only once, we have NO idea if this is in fact the case, as numerous pre-flight species probably had the right stuff for selection to choose from. There is simply no good evidence that Archaeopterygiformes are actually in line with modern birds through whatever huge bush developed. They could very well have developed flight separately along with numerous other theropods, one of which giving rise to the line that gave us what we know as birds. Or on the other hand, Microraptors could be very close to Archaeopterygiformes and both could be defined as “Birds” if one wanted to, and modern birds could have found their roots shared with both of these, but, many still think Microraptors are on a side branch away from the development of flight that modern birds eventually sprung from. If this is true, I see no reason why we cannot call both Microraptors “birds” along with the rest, despite an independent development of flight in each, as they really have all the basic qualifications to be called “Bird” (at least they have as much as Archaeopteryx does).
Let’s not confuse popular dogma, with the facts, as so many did when they didn’t desired to see Microraptors with asymmetrical flight feathers because of their “Pre-flight” evolutionary position, despite the obvious fact that had them, and well-developed ones as well.
I, too, have to thank mats for inspiring such an enlightening thread and then leaving so as not to get in the way.
Crunchy – I like.
Tom @ 51
Metric is kg & tonnes.
Ton is an imperial, non-metric weight.
Wierdly though, metric.& non-metric tons/tonnes are pretty close in mass to be interchangeable for everyday use…
I would look it up- but I’m reading this (& reponding) on my blackberry! Single tasking sux
@David Marjanović (#101):
don’t most people generally place archaeopteryx in aves?
where should we define aves, anyway?
The hollowing of bones works in steps. (Wow, amazing! It is almost as if evolution proceeded by the stepwise acquisition and modification of traits… :-)
uh, I was indeed asking for specific discoveries, so I’m a bit confused about what seems to be a bit of condescension on your part here. but otherwise, thanks. Perhaps I worded the question to ambiguously?
I’m an ichthyologist. I know quite a bit about fish evolution, biology, and especially behavior, but relatively little about dino/avian evolution.
was just curious as to the specifics; which individuals first started exhibiting specific traits, etc.. I suppose just visiting the exhbit from China when it comes to my neck of the woods would end up satisfying my curiosity in a more visceral sense.
cheers.
Hee. Cute. Also: Bird and cephalopod, together at last.
before all the good digging areas are built over…
not to worry Ichthy, nobody builds housing in a bombing range [allthough a few bombing ranges moved to residential neighborhoods in Iraq but that is a different blog] so some fossil finds will be left in the sunshine, carefully excavated by explosives.
Arachnophilia,
Oooh, you have stumbled across one of the great current debates in paleontological taxonomy (and phylogenetic taxonomy, too). One school of thought is to restrict Aves to the crown group of birds: that is, all living birds, their most recent common ancestor, and all descendants of that common ancestor. This would encompass tinamous, ratites, and neognaths, but not Ichthyornis, Hesperornis, Gansus, the enantiornithines, Confuciusornis, Archaeopteryx, etc.
Another school of thought is to use the name “Neornthes” for the modern bird, and extend Aves to a more inclusive group. Subschool of thought A is to hang the name on the clade comprised of all descendants of the most recent common ancestor of Archaeopteryx and modern birds. Subschool of thought B is use it for modern birds and everything closer to them than to Deinonychus. Note that if it is discovered that Archaeopteryx is more closely related to Deinonychus than to modern birds (a non-zero chance!), or if Archaeopteryx lies outside a Deinonychus-modern bird clade (another non-zero chance), than Deinonychus is in Aves under definition A, but neither it nor Archaeopteryx would be in Aves under definition B.
Lago,
More precisely, WAIR is fitting a round peg into a hole whose actual parameters are not known (i.e., the historical sequence of the evolution of avian flight). I may remind you that even hatchling birds who have not yet developed the full complement of derived pectoral and forelimb adaptations are capable of this behavior. It is through ontogeny (which includes, among several other aspects, the development of those traits) that the angle of ascension increases. No one is claiming that this behavior was fully developed ab initio (well, okay, maybe creationists are…), only that an early version of this would have been feasible given the known forelimb excursions, feather pattern, and hindlimb morphology of basal maniraptorans.
Thanks PZ. I think I had it backwards because of a photo with the NYT article showed a skull. That made me assume the grey bones were the ones found but apparently the skull was a model since they say they only had the jaw.
not to worry Ichthy, nobody builds housing in a bombing range
I’ve seen so many good fossil sites I used to collect in here in CA built over with condos (e.g., Simi Valley), or storage structures (e.g., Santa Cruz), one can only wonder what might have been.
sure there will always be relatively “safe” (ironic?) collection locales, but that doesn’t diminish the MANY MANY sites that have already been lost and will be lost to development, or damming.
so yeah, my fears are actually based on experience. don’t see how a couple here can legitimately say there is nothing to worry about. If you want to restrict all future locales to sites that are essentially non-buildable (like unstable beach cliffs), you’re consigning the vast majority of potential sites to the dustbin.
I’ll remind you of this when the military base that uses your locale as a bombing range is long closed, the land “reclaimed”, and then built over.
Please don’t even try to tell me THAT never happens. I lived in Monterey during the entire time that Fort Ord land was being transferred to private use (about 10 years).
as soon as the land becomes more valuable for development than as a bombing range, it’s amazing how fast things start to change.
just something to think about.
Ichthyic,
Sorry if you thought the condescension was aimed at you: it was at certain others in the reading chain, and I accidentally flared it off in the wrong direction.
Pneumatic cervicals are present in basal sauropodomorphs, sauropods, and basal theropods. Pneumatic dorsals are present in sauropods, some coelophysoids, ceratosaurs, and tetanurines (spinosauroids, carnosaurs, and coelurosaurs).
Pneumatic sacrals show up in some sauropods, some ceratosaurs, some carnosaurs, and some coelurosaurs. Pneumatic caudals are found in a subset of each of the former.
Pnematicity of the pectoral and pelvic girdle is present in some carnosaurs and coelurosaurs, but is highly variable.
Pneumaticity of the long bones is way up in the avialians.
Hope this helps,
Holtz,
We both know that, even hatchlings of modern birds have a pectoral girdle, bone for bone, angle for angle, joint surface for joint surface, that is, far, FAR more like that of later derived birds (Crown Birdies), than basal birds and related non-volant theropods. A newly hatched extant bird skeleton, most of the time, is OBVIOUSLY modern and very distinct from all of which you mentioned (Not counting Apteryx, or crap like that)…
I know you know these things, but let’s be honest about what that implies, K?
Sorry if you thought the condescension was aimed at you: it was at certain others in the reading chain, and I accidentally flared it off in the wrong direction.
ah, no worries, I was just a bit confused.
Hope this helps,
yes, that’s exactly what I was looking for.
now I’m off to see if I can dig up some photos of sections to get a visual picture of the list you gave me.
thanks again.
Thinking back, I think my interest in this specifically started with a class I took in Biomechanics ages and ages ago. mostly a size/weight issue.
For some reason, I just got a bug up my butt to want to get a good visual picture of exactly how this trait changed over time. probably the same curiosity that got me interested in the evolution of swim bladders and the rete mirabila system in fishes.
I know you know these things, but let’s be honest about what that implies, K?
what, that ontogeny recapitulates phylogeny?
sorry, just had to.
:p
Ichthyic,…
I feel bad, as I know what it is like to want to see the progression, so here is quicky bit to get the conversation going with everyone…
First, start with a relatively small theropod…
Next you have an elongation of the arms. This is supposed by many to be due to predation, some other as allowing to grasp branches, and other people both ideas are present. Other people will have more varied opinions that they can state to add to this conversation…
Next, the size of the muscles on the chest increase a bit as they will continue to do over the evolution of birds. This basically starts a trend where the hips go from thin side to side, to much wider as the organs move back to balance off the animal. The distal aspect of the pubes eventually stop articulationg, and then later on, the distal aspect of the ischia as well…
Energy is lost in flight if you have too many joints (sorta like throwing a spear with springy joints in it) so another trend of fusion starts to increase over time, as in the development of the synsacrum by the addition of caudal and thoracic elements to the sacrum. The amount of vertebrae in the dorsal region also decrease helping to firm things up.
The coracoid gets longer overtime as a region of the deltiods grows down on to a rearward expanding sternum, which gives more and more leverage for the upstroke…
There is a belief I follow that the “belly ribs” of the basal forms that was common to theropods as well, was used to help drive air in and out of the airsac system of the basal birds, but that this task was taken over by the developing sternum…
The femur becomes less important in locomotion, and the knee becomes the joint where most of the range of motion of the back leg occurs. This is, in my opinion, due to several selective factors, with the widening pelvis being top of the list. To make up for this reduced motion of the femur, the tibia is selected for greater length to make up the stride distance….
As the foot develops a reverse big toe, and the birds brain develops (is selected for) for greater balance, the arms are used less as a brace in trees. Many people will argue that this is a particular position that is opinion, and I grant them that. However, we do tend to see, as the front limbs fuse up more and lose their claws, a development of a more kinetic skull and more mobile neck.
The skull kinetics are based on the loss of some elements loosening up the skull, and the development of a strut like series of interconnections based on what is left over. The neck gets more mobile by having the vert centra become more saddle shape…
I need to go, but I hope this starts you off, and maybe gets a few people discussing these details, well..more in detail. I also hope they add their own favorite trends as well that I have left out…
Be back to see how things work out…
(sorry if this post is a mess, I wrote it fast as I am rather busy at the moment)
Next you have an elongation of the arms. This is supposed by many to be due to predation,
because of being prey, or hunting prey? I’ve heard the ideas about elongation and grabbing prey. Is there something associated with elongation and predator evasion?
does gigantoraptor have arms shorter than expected?
Energy is lost in flight if you have too many joints (sorta like throwing a spear with springy joints in it) so another trend of fusion starts to increase over time, as in the development of the synsacrum by the addition of caudal and thoracic elements to the sacrum. The amount of vertebrae in the dorsal region also decrease helping to firm things up.
back up a sec… I’m unclear here, are you talking about changes in fusion before or after flight evolved?
If so, what are the proposals as to the function of fusion prior to flight? general stability for faster and more efficient running? using your spear analogy, increasing longitudinal stability could easily be envisioned to be more energy efficient for running as well.
It’s the most parsimonious option that’s compatible with the currently known data. Sure, that’s no proof — but I wouldn’t call it “no idea” either.
Fine. That would mean Utahraptor and Achillobator are probably birds. Is that OK with you?
Aves is not a fact, it’s a name. How to define it is not a question of science but a convention (or, at present, a lack thereof).
Yes. How much sense that makes is a difficult question (I’m in subschool B).
This, though, happened very late.
Quite so! We can see the sacrum growing one vertebra after another in the fossil record.
Rather the shortening of the tail, which happened early and moved the center of gravity to a position in front of the hips, where only the knees could reach it.
It’s the most parsimonious option that’s compatible with the currently known data. Sure, that’s no proof — but I wouldn’t call it “no idea” either.
Fine. That would mean Utahraptor and Achillobator are probably birds. Is that OK with you?
Aves is not a fact, it’s a name. How to define it is not a question of science but a convention (or, at present, a lack thereof).
Yes. How much sense that makes is a difficult question (I’m in subschool B).
This, though, happened very late.
Quite so! We can see the sacrum growing one vertebra after another in the fossil record.
Rather the shortening of the tail, which happened early and moved the center of gravity to a position in front of the hips, where only the knees could reach it.
“because of being prey, or hunting prey? I’ve heard the ideas about elongation and grabbing prey. Is there something associated with elongation and predator evasion?”
Being hunters was the original idea for the length, and many hold to it still. I hold to climbing, as well as prey grasping. The fact that Archaeopteryx has slightly curved phalanges seems to indicate grasping of branches (many animals that climb show this trait), along with using them as predacious tools.
“does gigantoraptor have arms shorter than expected?”
I did not know they were expecting a certain length, and the length shown seems sorta typical, or at least not way off average for the type of theropod it was…
“back up a sec… I’m unclear here, are you talking about changes in fusion before or after flight evolved?”
Archaeopteryx had a curved back in some fossil specimens showing it was rather loose as compared to todays birds, and well in-line with what would have been seen in your average non-flying theropod of the day. The cranial bones were not nearly as fused as in modern birds. The carpus and tarsus is far more fused in modern birds. Cervical ribs. pelvis, caudal elements etc…
Fusion was used to fine-tune energy loss as well as for several other possible reasons…
“If so, what are the proposals as to the function of fusion prior to flight? general stability for faster and more efficient running?”
As Holtz will tell you, the larger theropods did use fusion to stabilize, and quite possible to assist in more efficient running, but most fusion found in birds today started after theropods started their take-off into the air, evolutionarily speaking…
“using your spear analogy, increasing longitudinal stability could easily be envisioned to be more energy efficient for running as well.”
It would, and did take place to a degree in theropods, but modern birds are far more fused than running theropods ever were. Modern bird bone fusion has been taken to the point of an extreme…
It has the longest arms of any oviraptorosaur whose arms are known.
Most of the fusion happened after the origin of flight, but the stepwise change from 2 to 5 (if not 6) sacrals happened earlier in saurischian history.
Likely.
Not that I know of. Well, if you assume climbing, it should work, but then there are no climbing adaptations in any dinosaur before the 1st toe starts to reverse within short-tailed birds.
It has the longest arms of any oviraptorosaur whose arms are known.
Most of the fusion happened after the origin of flight, but the stepwise change from 2 to 5 (if not 6) sacrals happened earlier in saurischian history.
Likely.
Not that I know of. Well, if you assume climbing, it should work, but then there are no climbing adaptations in any dinosaur before the 1st toe starts to reverse within short-tailed birds.
It has the longest arms of any oviraptorosaur whose arms are known.
looks can be deceiving I guess; looking at the skeletal diagram above, I would have guessed those as “short”. It looks like only the metacarpals make it out of the body cavity?
which reminds me, I need a bigger picture, damnit, I can’t hardly tell what’s going on from the minuscule diagram above. Is there a full-sized pic somewhere?
“It’s the most parsimonious option that’s compatible with the currently known data. Sure, that’s no proof — but I wouldn’t call it “no idea” either.”
I think it is far from most parsimonious. There is a point where Ockham’s Razor become Ockham’s Bulldozer…
“Fine. That would mean Utahraptor and Achillobator are probably birds. Is that OK with you?”
Why not?
“Aves is not a fact, it’s a name. How to define it is not a question of science but a convention (or, at present, a lack thereof).”
I never said “Aves” is a fact. I basically said, in translation, that these terms are ill defined, and many definitions are in contradiction with themselves when people later find out associated traits were not as once thought. In other words, the basic definition of bird that we used to use as a feathered, egg laying vertebrate, that either flies, or evolved from an ancestor that flew, can be applied to many species that are still not considered birds by many professional and laymen alike.
In other words, claiming all “birds” evolved at once is an extremely loaded statement that one should not really make at this point in time. If it is your opinion that they probably did, then fine, but the evidence is far from in to decide such with any degree of certainty.
“This, though, happened very late.”
The separation of the pubes so only the distal aspect were in contact (as in the loss of a well-developed pubic apron) started VERY early on…
“Quite so! We can see the sacrum growing one vertebra after another in the fossil record.”
Wow we agree…that’s cool…
“Rather the shortening of the tail, which happened early and moved the center of gravity to a position in front of the hips, where only the knees could reach it.”
The weight of the tail was minimal as compared to the new weight of the muscles of growing pectoral region. Pointing to the tail as the only, or even main selective force here for the lengthening of the tibia seems, in light of this new weight, odd at best..
ahh paleo arguments…
takes me back. there were still punc eq arguments going on between some of the paleos and the zoos when I was at Berkeley.
either of you guys ever hang in the paleo dept. or mvz at Berkeley?
@Thomas R. Holtz, Jr. (#112):
not so much stumbled, i was aware there was some debate, though my interest is far from professional or well educated. personally, i don’t know what side to take. some days, i want to take your first option and only call living birds and their most recent common ancestor aves. some days, i just fail to see much reason why aves and theropoda (or even dinosauria) shouldn’t be synonymous. some days, i’m just tempted to call anything with feathers a bird, and let it sort itself out. it’s quite a complicated picture when you look at it.
this is perhaps why i get my feathers a little ruffled when i hear the creationists downplaying the dinos-to-birds evidence, because the similarities are so blindingly obvious that the only real debate is where to draw the arbitrary line that divides them.
this is the position i hear the most often — i had gathered this was the mainstream. but, for me, archaeopteryx has way too much in common with deinonychosaurs to not include them too, and the differences are far to subtle to base a huge distinction like aves on. which, i suppose is where this paraves business comes from.
actually, i would say that’s a good deal greater than simply “non-zero” as archaeoptryx does not have a reversed hallux as previously thought, and its second toe is hyperextendable — a classic deinonychosaur feature. the suggestions i’ve heard recently (and these ones sound more convincing to me) indicate that archaeopteryx might actually be a basal deinonychosaur (the more derived ones evolving from flying ancestors such as archie).
though archaeopteryx has a number of characters in common with modern birds that say velociraptor does not. which, to me, would indicate that the clade containing archaeopteryx and modern birds comes out of maniraptora as a sister group to other deinonychosaurs (as commonly thought)
we also see some correlation between archie and microraptor, as it has reduced leg feathers running part-way down it’s leg. but genetics (on chickens) has told us that the feather loss on the feet was a secondary adaptation, which would seem to indicate that archaeopteryx is more highly derived than microraptor. which doesn’t seem right with the above arrangement of the cladogram. maybe microraptor’s copy of that gene was recessive?
i’m not really sure what to make of things like this.
it’s nice, of course, to able to hear from people who actually know what they’re talking about, working the correct field. apparently, unlike my paleo prof. ah well.
I don’t really have anything to add to this discussion, but it’s been awesome to read. It’s like I’m still in my honors dinosaur class in college.
*waves at Dr. Holtz* Sorry I’m not contributing to your paycheck anymore. :)
madmolly,
*Waves back* Don’t forget: the alumni association will NEVER EVER LET YOU ALONE, so they’ll keep on trying to help you contribute to the paycheck fund…
Posted by: David Marjanović | June 14, 2007 09:36 PM
“….. but then there are no climbing adaptations in any dinosaur before the 1st toe starts to reverse within short-tailed birds.”
David, I’m not directing this personally at you. I simply believe that this view seems just a tad bit dogmatic. As such, it needs to be questioned…
I need something explained to me… Why is it, that a theropod is automatically banned from the trees unless its first toe is reversed???
Is there some sort of written law that I’ve missed that states that none of those other claws found on the fingers and toes can be used to scramble up a tree? Is it because the curvatures of the claws are not EXACTLY PERFECT as compared to expert climbers, so therefore climbing is forbidden? When it comes to perching, one usually requires a greater degree of curvature because the foot alone is doing the grasping. But in an animal that uses both the foot and hand, the curvature doesn’t need to be as great.
Using a modern perching bird as the standard from which to base conclusions on the climbing abilities of basal birds is stretching it just a bit don’t you think?
On that note, what about the curved phalanges in the manus of Archaeopteryx? Why can’t these be interpreted as an indication of climbing? After all, monkeys and squirrels have the same trait. Also, the orientation of the unguals on the manus, as well as an increased range of motion for the shoulder joint in basal birds and their kin, look to me like something that would come in handy when climbing… And what about the pecs? Primates = big pec selection, so why not the same in some smaller theropods??? Big pec selection in theropods = pre-evolved state for powering flight.
And furthermore, WHY would the 1st toe reverse if the theropod wasn’t already in the trees??? I mean seriously… did some fluffy little monster decide one day to give birth to other fluffy little monsters with reversed 1st toes so that they could climb a tree even though the parent couldn’t? Is that what we are saying here?… The toe magically reversed for no reason, and then theropods decided to climb? How is that not the implication of what you are saying?
Selection only works if there is a need… How did the need for a reversed toe start if theropods were not up in the trees before they needed the reversed toe to be up in the trees???
And perching…. Perching… Perching is not the same as climbing. I’m sorry, but you might need the reversed toe to perch WHEN YOU ARE A BIRD… but a reversed toe isn’t required equipment for climbing up trees and holding onto branches…. especially when you have something called fingers. Let’s avoid using todays heavily derived state to indicate what a basal state should look like.
Maybe… just maybe… a certain group of theropods were scrambling up into trees… using their feathered arms with their big’ole fingers and sharp claws… to cling to branches while being assisted by their feet. But eventually, as the feathered arms became wings, and the fingers faded away… the feet completely absorbed the job of clinging to the branches… leading to selection favoring the reversed 1st toe. Why would such a scenario not be possible?
Given how these animals are preserved, with the added complication of how that toe attaches, isn’t it possible that due to the nature of the fossil record, we might never be able to tell from the that it was on its way to being reversed (especially if the toe was mobile, which depends on how firmly the toe was attached to metatarsal 2 by the ligaments)…. That is until it was nearly completely reversed. And by then, with no wing claws, it had to be reversed if the animal was arboreal… Awfully convenient too, since so many ended up in the trees only after they were evolved to allow such behavior, right?
this thread appears to be dying the death of the “back page”, so before it sinks completely under the waves, can I ask that anybody who manages to see the chinese exhibit post back and tell us how it was?
and if it makes it into PZ’s neck of the woods, also suggest a visit and new thread devoted to it?
this being one of the most interesting and (at least up to recently) contentious issues in paleontology IMO, it deserves another thread or two.
as I find some decent sites with osteo cross-sections available on-line, I’ll post the links here.