Odontochelys, a transitional turtle

i-e88a953e59c2ce6c5e2ac4568c7f0c36-rb.png

Now this is an interesting beast. It's a 220 million year old fossil from China of an animal that is distinctly turtle-like. Here's a look at its dorsal side:

i-3186cb40a1f71a5523546ff7fc6f09fa-odontochelys_fossil.jpeg
a, Skeleton in dorsal view. b, Skull in dorsal view. c, Skull in ventral view. d, Body in dorsal view. Teeth on the upper jaw and palatal elements were scratched out during excavation. Abbreviations: ar, articular; as, astragalus; ca, calcaneum; d, dentary; dep, dorsal process of epiplastron; dsc, dorsal process of scapula; ep, epiplastron; fe, femur; fi, fibula; gpep, gular projection of epiplastron; hu, humerus; hyo, hyoplastron; hyp, hypoplastron; il, ilium; ipt, interpterygoid vacuity; j, jugal; ldv, last dorsal vertebra; m, maxilla; n, nasal; na, naris; op, opisthotic; p, parietal; phyis, posterolateral process of hypoischium; pm, premaxilla; po, postorbital; prf, prefrontal; q, quadrate; sq, squamosal; st, supratemporal; sv1, 1st sacral vertebra; ti, tibia; ul, ulna; vot, vomerine teeth; I, V, 1st and 5th metatarsals.

Notice in the skull: it's got teeth, not just a beak like modern turtles. The back is also odd, for a turtle. The ribs are flattened and broadened, but…no shell! It's a turtle without a shell!

Flip it over. There's another specimen, and we can look down on its ventral side, and there it is — a plastron, or the belly armor.

i-ac302d0673410627d99a95b54119baf8-odontochelys_belly.jpeg
a, Skeleton in ventral view. b, Body in ventral view. c, d, Skull in ventral and slightly lateral views. Abbreviations as in Fig. 1, plus: ao, anal opening; bo, basioccipital; bs, basisphenoid; cav, caudal vertebrae; che, chevron; ent, entoplastron; hyis, hypoischium; is, ischium; meso I and II, mesoplastra 1 and 2; pr, prootic; prq, pterygoid ramus of quadrate; pt, pterygoid; pu, pubis; qj, quadratojugal; qrp, quadrate ramus of pterygoid; ra, radius; trpt, transverse process of pterygoid; xi, xiphiplastron; I, IV and V, 1st, 4th and 5th digits.

So, what we have here is a long-legged, toothed reptile with an elongate body, and it also has a plastron like a turtle, and hints in the bony structure of the spine of the carapace-to-be. It also fits perfectly with the embryology: modern turtles form the plastron first, and the carapace second. This is a beautiful transitional form. I'd love to have some swimming in the streams near me. And here's a reconstruction of what they would have looked like, way back in the Triassic.

i-d4a3388ce7380bf49c902e0304770a42-odontochelys.jpeg

Li C, Wu X-C, Rieppel O, Wang L-T, Zhao L-J (2008) An ancestral turtle from the Late Triassic of southwestern China. Nature 456: 497-501.

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Has this feller been named yet?

By Brownian, OM (not verified) on 26 Nov 2008 #permalink

But it's not also feathered, and has no gills. It's still just a shell-less turtle, and so remains within the same kind.

This really shows nothing at all.

By CrypticLife (not verified) on 26 Nov 2008 #permalink

Awesome....I love it :-)

Damn. Now I see the title of the post.

In my defense, the first sign that PZ has posted an entry with binomial nomenclature is a runaway italics tag...

(Sorry about scapegoating you to compensate for my own shortcomings PZ. I blame it on overexposure to Christians on this site, making me act more like them every day.)

By Brownian, OM (not verified) on 26 Nov 2008 #permalink

One additional gap, but the two gaps are different from the old one, so strictly speaking, it does create two new gaps.

The name is in the title. Full binomial: Odontochelys semitestacea.

Wait, I'm confused. It looks like this is mostly inference. And worse than that, it involves drawings mostly, NOT evidence. This reminds me of Colin Powell's farcical performance before the United Nations. You know which one I'm talking about.

Also, @Mrs Tilton, indeed! lol

There used to be one gap, now there are two. One additional, two total.

Oh, no. Now Brownian is going to start harrassing the administrators at my U, is going to turn me in to the Muslims, and is going to flood my mailbox with impotent death threats.

They already have soft-shell turtles. This proves nothing you morons. And you guys claim to be "skeptics"... laughable

By Karl Hungus (not verified) on 26 Nov 2008 #permalink

How about we call the second one, the one on it's back, Brian, in honour of my grandson's father who is the slowest and laziest twit I know.

Two new, but smaller gaps. This can go on forever, but I'm sure the creobots will never agree that the transformation took place even with only very fine and easily seen transformation remaining.

Great find PZ.

By Nerd of Redhead (not verified) on 26 Nov 2008 #permalink

We would expect the plastron to develop first because, as P.Z. notes, during the development of the turtle embryo we see first the appearance of the plastron followed by the growth of the carapace. This suggests that the plastron had evolved first while the carapace was only tacked on later.

They already have soft-shell turtles. This proves nothing you morons. And you guys claim to be "skeptics"... laughable

Yes and they already have those with smaller brain size such as yourself. Where did you find that time machine mr. Australopithecus afarensis?

Those lovely creationist chaps
Will be chortling into their caps
It's a real crocoduck!
Ah, but see, damn the luck,
Seems the record just grew two new gaps!

Nit: The link in "Fig. 1", above, is bad, lacking the domain name of nature.com.

By Owlmirror (not verified) on 26 Nov 2008 #permalink

Ah, thank you Meur, I had no idea. So then I guess as the plastron conferred additional defense to those lucky enough to have it, those who then developed the top shell got even more defense, and voila, natural selection in action.

This shit is cool.

Hmmm. That dorsal side fossil just makes me think of Bill the Cat. Let's call him Bill.

By PlainJane (not verified) on 26 Nov 2008 #permalink

Cuttlefish does limericks too! Nicely done as always!

Oh Karl Hungus, even a lowly computer scientist like myself, not versed in biology, zoology, or taxonomy, can easily do a search online and find that "Soft-shelled" turtles still possess a carapace (though only centrally and not all the way across the back) and some even have dermal bones in the plastron. I can even find that they are called soft-shelled, not because they lack hard tissue shells, but because they don't have the bony scutes that hard-shelled turtles have.

Thanks for playing, do some research and try again later.

>>The name is in the title. Full binomial: Odontochelys semitestacea.

That's kind of a mouthful. Could us non-biologists just call it Steve.

Really cool. I'll be showing my kids tonight as they love this kind of thing.

By Marcus Christian (not verified) on 26 Nov 2008 #permalink

When confronted with knowledge, trolls become defensive and spit bile at the offending information.
Run away little trolls, the adults are having fun.
I wonder, will we one day discover a transitional fossil from the time that trolls lost the ability to feel shame?

Karl Hungus: You want a Poe? I can get you a Poe, believe me. There are ways, Dude. You don't wanna know about it, believe me. Hell, I can get you a Poe by 3 o'clock this afternoon...with nail polish. These fucking amateurs.

By Brownian, OM (not verified) on 26 Nov 2008 #permalink

Way cool! Can't wait to read the whole article. Serves me right to cancel class today and stay home where I don't have access to Nature!
Can anyone tell me if they comment on the phylogenetic position? Most recent molecular phylogenies place turtles with the archosaurs.

By Snakewoman (not verified) on 26 Nov 2008 #permalink

Jesus, Walter. calm down, wouldja?

Wow. How pathetic. I feel so untrolloved.

Admittedly, it did feel rather dishonest and slimy, and I couldn't put my full heart into it.

By CrypticLife (not verified) on 26 Nov 2008 #permalink

I am a bit confused here, are some of the posters actually denying our evolution?

Sorry, im swedish, I did not know there was actually people denying facts like this. Does not american schools have basic evolutionary education in pre/highschool? Shouldn't be to hard to learn.

It makes me wonder, the people denying this, living in some sort of isolated bubble, are they vaccinated?

By guy fawkes (not verified) on 26 Nov 2008 #permalink

Could us non-biologists just call it Steve.

Really cool. I'll be showing my kids tonight as they love this kind of thing.

I think "Leonardo" or "Raphael" are really rather better choices.

By CrypticLife (not verified) on 26 Nov 2008 #permalink

Can't CJO. They're playing the TBL tomorrow night at a local art-house cinema here, and I'm so excited it's all I can do to not micturate upon the rug right here in my fair office.

Seeing the name 'Karl Hungus' didn't help.

By Brownian, OM (not verified) on 26 Nov 2008 #permalink

I reckon it should be named "A'Tuin" after the world turtle from Pratchett's Discworld.

By Paul Hands (not verified) on 26 Nov 2008 #permalink

CrypticLife
If you want troll love I could tell you that you'll be tortured for eternity for not agreeing with my worldview, but point out that my imaginary friend loves you.
That's how it works, right?
Ah, troll love. Missionary position of course.

Guy Fawkes
One is just playing around and the other is batshit crazy.
That's the technical term of course.
You may need to wiki it.

So, who's going to send this to Harun Yahya, collect the $Trillion prize money?

Meur:
This suggests that the plastron had evolved first while the carapace was only tacked on later.

Tacked on "at the end", specifically. Why not "at the front"? I don't see how that really answers the original question.

(And mine is a rhethorical question - I would guess that the answer is something along the lines of that a change in early development is (way!) more likely to upset something that is already established as vital, whereas a change that sets in during later development is relatively free to modify what's going on. But that really is just an educated guess.)

OK, this may be a dumb question...

Why would the plastron have evolved before the carapace? It just seems to me that a carapace is a better defense, even though your vital organs are ventral, because most creatures that want to eat you are bigger than you. Therefore Death from Above is more of a threat than Death from Below, when on land anyway.

In the water both are equal threats, but horseshoe crabs know which way to bet.

Re #8:

Remember, Brownian: If you fight Christians long enough, you will become a Christian.

I'd rather become a dragon, really.

Full binomial: Odontochelys semitestacea.

How do you pronounce that?

By FishyFred (not verified) on 26 Nov 2008 #permalink

One note of caution about the carapace: in the "News & Views" commentary, Reisz & Head note an alternative hypothesis: "We interpret the condition seen in Odontochelys differently -- that a carapace was present, but some of its dermal components were not ossified. The carapace forms during embryonic development when the dorsal ribs grow laterally into a structure called the carapacial ridge, a thickened ectodermal layer unique to turtles8. The presence of long, expanded ribs, a component of the carapace of all turtles, indicates that the controlling developmental tissue responsible for the formation of the turtle carapace was already present in Odontochelys. The expanded lateral bridge that connects the plastron to the carapace in other turtles is also present, implying that the plastron was connected to the laterally expanded carapace. Thus, an alternative interpretation is that the apparent reduction of the carapace in Odontochelys resulted from lack of ossification of some of its dermal components, but that a carapace was indeed present."

That said, the skull is damn primitive (margin teeth, for instance!). It would be nice to see this critter plunked into a big-ass matrix of parareptiles and eureptiles, to see if we can sort out where turtles fit in the phylogeny.

Two new, but smaller gaps.

That's the problem with all this palaeontology stuff, you just create more gaps. How about filling them in!

[To anyone who doesn't think that's humor, I apologize. It's hard to lampoon some forms of stupidity.]

I believe a partial answer to your question #4, Richard Wolford, would be that based on indicated embryological development, the plastron appears to signal a more archaic structure in development than the shell. It's similar to the development of the gill arches in mammalian embryos. I believe the article related to snake's venom fangs a month or so ago also illustrates that in embryological development, the rear teeth beds are the first to arise, followed by the frontal, regardless of where the venom fangs are eventually located in the developing snake species. It would be like asking why the rear fangs develop first. Because in this instance, the Sonic Hedgehog gene is known, we can infer that a duplication event eventually resulted in the formation of the frontal fangs. As far as the plastron, it's relation to the dorsal shell is not based on a duplication event, but analysis of embryological development does show the approximate primordial structures that result in the plastron occurring first.

By Helioprogenus (not verified) on 26 Nov 2008 #permalink

Re Thomas, at 43:
I have to say I'm really looking forward to any future paper titled "Plunking Odontochelys semitestachea into a big-ass matrix of parareptiles and eureptiles"!

But did it taste good in a soup?

@40
Perhaps their method feeding exposed them to an attack from below more often than an attack from above? If they spend a significant amount of time near the surface in any depth of water predation may have come in the form of other larger fish or water reptiles attempting to attack from the river/pond floor.

By RiftPoint (not verified) on 26 Nov 2008 #permalink

Posted by: Apikoros | November 26, 2008 3:55 PM
OK, this may be a dumb question...

just a guess, but... a terrestrial critter first moving into water would benefit from hull plating when venturing just offshore to feed on seaweed, or other food near the surface?

What a fine demiturtle. If, contrary to all likelihood, there is a god, it clearly finds creobots as mockable as we do.

By Nick Gotts (not verified) on 26 Nov 2008 #permalink

how very interesting. I wonder what advantage a hard belly first had in survival? I mean why the ventral first? I do not know of any animal that has a hard belly and a "softer" back. Could there be parts missing?
Did the animal have to walk on very rough ground? What danger from below would not also be above, not jaws I would think? More questions. I do love a mystery!!

By uncle frogy (not verified) on 26 Nov 2008 #permalink

My guess would be that the plastron evolved before the carapace for reasons having nothing to do with the defensive capabilities of the shell.

The plastron would be useful to an air-breathing aquatic animal simply because it is dense and located in the animal's ventral position, assisting in providing neutral buoyancy (together with the apparently dense bone structure shown in the pictures). This would allow the creature to stay underwater with a minimal amount of energy, and with a slight head down tilt for efficient feeding on bottom dwellers.

That's no soft-shelled turtle.
Looking at the photographs and drawings, it's hard for me to see if the scapula are located underneath the ribs. Or are they far enough forward that "above or below" aren't applicable?

There are no transitional fossils.

"We would expect the plastron to develop first because, as P.Z. notes, during the development of the turtle embryo we see first the appearance of the plastron followed by the growth of the carapace. This suggests that the plastron had evolved first while the carapace was only tacked on later.

What? Is this correct? This rings of Haeckel to me. Can someone with linkable credentials verify this?

Discovered in China? That's not a plastron, it's a lizard in a wok.

By Stephen Wells (not verified) on 26 Nov 2008 #permalink

This animal is fascinating but nothing will convince a creationist. They have already demonstrated that evidence and logic don't matter--only the "holy book" The only way to convince them is a new bible in which god says "by the way, I didn't create all this stuff; it just happened." The LDS church has managed to convince millions of people of utterly preposterous things with a new bible, maybe we need a John Smith of atheism. Maybe I have some brass plates buried in my back yard? Yes, "The Book of Dawkins"

If evilution were true, we'd see turtles with half a shell.
What use is half a shell?
Checkmate Atheists!

There is no Matt7895.

If evilution were true, we'd see turtles with half a shell.
What use is half a shell?
Checkmate Atheists!

I didn't know EdwardCurrent commented here.

What use is half a shell?

Umm.. It's a handy implement for serving oysters?

-jcr

By John C. Randolph (not verified) on 26 Nov 2008 #permalink

Dear Ron Gove,

A minor point, but it was Joseph Smith who came up with the Mormon scam.

It is interesting to note that Ol' Joe Smith, Brigham Young & the rest of the original Mormon patriarchs, who would have considered it ungodly to not have a full beard, have been shaved in modern representations, such as at BYU.

Kel
I stole the line from Ed.
It just seemed to fit so well.

I assumed you where joking ggab? I mean, no one has that little knowledge of the world, right?

I tried to explain to a creationist that ALL fossils or living beings are Transitional, as all is related to eachother. But they continue claiming "no transitional forms", yet they are infront of them. And then when they find these terrific examples thats so visually clear, they just run back in there shell and cries wolf.

By guy fawkes (not verified) on 26 Nov 2008 #permalink

maybe we need a John Smith of atheism.

I don't think that atheism has any need for a charismatic leader.

-jcr

By John C. Randolph (not verified) on 26 Nov 2008 #permalink

#40

Posted by: Apikoros | November 26, 2008 3:55 PM

OK, this may be a dumb question...

Why would the plastron have evolved before the carapace? It just seems to me that a carapace is a better defense, even though your vital organs are ventral, because most creatures that want to eat you are bigger than you. Therefore Death from Above is more of a threat than Death from Below, when on land anyway.

Keep in mind that evolution isn't just contingent on need, there's also opportunity. No matter how much pressure there may be to have an armored back, natural selection cannot produce one until it has the right mutation to select.

Two more gaps in evolution tree, two more beasts on Noah's Ark

By Mad§cientist (not verified) on 26 Nov 2008 #permalink

Guy Fawkes
Yeah, I was just playing around.
Good luck with the "all fossils are transitional" arguement.
Creationists aren't known for their ability to grasp logic and reason.

If evilution were true, we'd see turtles with half a shell.

Yes, there are transitional forms as features evolve, but the fossil record is incomplete, ie we don't have a fossil of every step of evolution for every species, but we have enough fossils including transitional forms, to prove evolution beyond a reasonable doubt.

What use is half a shell?

Anything that provides additional protection is an evolutionary advantage. A proto-turtle with a partially developed shell would have an advantage over his unarmored lizard relatives.

By Bureaucratus Minimis (not verified) on 26 Nov 2008 #permalink

Guy Fawkes @67

That's a tough one, isn't it? The people you're explaining this to have to be able to imagine very large numbers (or quanities?) and realize that there are variations within those numbers. Long time spans, large populations, and extremely complicated molecules certainly stretch my imagination to its limits, and I have a pretty good imagination. Couple that with the idea that both the environment and the organisms are changing however they can manage, and it's little surprise that they run back to their shells.

Madscientist
"two more beasts on Noah's Ark"

I never thought of that.
I love it, totally stealing it.

@#58 Techskeptic:

From the paper:
"Odontochelys provides documentation that in turtles, the plastron evolved before the carapace. This corresponds to the ossification of plastral before carapacial elements in embryonic turtles12, 13, 14."

Refs in question are:
12 Rieppel, O. Studies on skeleton formation in reptiles. Patterns of ossification in the skeleton of Chelydra serpentina Linnaeus (Reptilia, Testudines). J. Zool. 231, 487-509 (1993)

13 Scheil, C. A. Osteology and skeletal development of Apalone spinifera (Reptilia: Testudines: Trionychidae). J. Morphol. 256, 42-78 (2003)

14 Sheil, C. A. & Greenbaum, E. Reconsideration of skeletal development of Chelydra serpentina (Reptilia: Testudinata: Chelydridae): evidence for intraspecific variation. J. Zool. 265, 235-267 (2005)

Just beautiful animals - thanks PZ. Posts like this are one of the reasons I read Pharyngula!

Posted by: Last Hussar | November 26, 2008 4:49 PM
It is obviously a fully formed animal, ergo it isn't a transitional. Still no transitionals then.

My left nut hasn't dropped yet, what does that make me?

Blast you, ggab. I wasted a perfectly good response for nothing. Pbbbbt! And to think I was just muttering about the inability of Pharyngulites to tell parody from fact. Harumph.

By Bureaucratus Minimis (not verified) on 26 Nov 2008 #permalink

Newfie
My condolences on the left nut.
Is it like when a blind man develops extra sensitive hearing?
Is your right nut like a giant extra-sensitive supernut?

Bureaucratus
Sorry, feeling playful today.
If you use the same response against a real creationist, I won't tell.

Hang on. I'll call Denyse O'Leary right away.

I'm not so big on the artist's rendering. I wouldn't be surprised if there were thicker keratinous scales, particularly on the back. One could then imagine that cartilaginous, then bony, tissue could evolve as a support structure until it fused. I'm not sure how the carapace develops, but I'm sure someone could make a prediction from this.

Also, check out this cool image of a soft-shell turtle that's fixed: http://www.nmnh.si.edu/rtp/students/2006/images/zoo_day_herps1.jpg
I would imagine that the soft-shelled phenotype is either a derived trait, or less likely that they split off the before the 'main' branch had developed a boned carapace (assuming that cartilage came first). Anyone know of a cladogram of the turtles? I couldn't find a good one quickly.

P.Z.,

Can you confirm that this animal is anapsid. It appears to be from the drawing, but this is not made explicit.

As this is a definitive characteristic of chelonians, there would be little doubt about Odontochelys s. and its place in turtle evolution if it is an anapsida.

Oh-don-toe-chay-lease sem-eye (or sem-ee)-test-ay-see-a

I took enough Latin to know that that biologistws have no clue how to pronounce Latin, but still, can we at least *try*?

;-)

I was kidding, ggab. Either that, or I'm off to the rodeo. :P

Karl Hungless @ #13:

Hey Moron,

Do you even know exactly what a soft-shelled turtle really is? It has the full carapace of solid bone underneath it's skin, it just does not have the hard scutes that make up the external armor of a 'normal' turtle. It also has a flexible leathery 'skirt' at the edges of the carapace that makes it look like the whole shell is soft and floppy, but it is not - it does have the same skeletal structure as any other modern turtle. Next time you set critical (and stupid) fingers to keyboard, do at least a little cursory research:

http://en.wikipedia.org/wiki/Trionychidae

Oh, I forgot. Creo-F**k-tards don't read. It might actually edermakate them...

This is all well and good, but can it grasp a banana? Have you ever looked at how well the human hand grasps a bana....

Oh hell...I can't even stomach the sarcasm anymore.

great!
now you just need to find a quarter-shell turtle and a three-quarters-shell turtle....and of course eventually a 1/8 and 3/8 and 5/8 and 7/8 shell ... the sixteenths come next

By the great and … (not verified) on 26 Nov 2008 #permalink

Alex
Don't forget the non-slip skin of the banana, and the stem/tab for removing the peel.
Ah, just thinking about it makes me want to grasp my banana.
How Comfort-ing.

Okay guys, pardon my questioning here (consider this open for all), but how can people deny evolution when its a fact? I mean, there is no doubts or somesuch, we know how humans evolved, for example, and we can show how this has happened.

You got dogs, cats, horses etc, we can show how these evolve, how does it work with these people that deny this? Do they live completely secluded ignoring reality? Why? Whats the point of lying to yourself?

Further on, we, as humans are evolving NOW, we can PHYSICALLY SHOW that we are evolving into something different, and in 50 thousand years, you would SEE this by your naked eye, but you dont need to, you can just check the microscope today, if it interest you.

I just dont get this, is thi for real? And why are people saying these ignorant things even bothered with? Obviously they are uneducated and ignorant living in the middle ages, I mean, anyone that lives in a civilized society knows about a imple thing like our biological evolution, not to mention the medicins we manage to produce BECAUSE of the knowledge about it.

I dont get it.

By guy fawkes (not verified) on 26 Nov 2008 #permalink

@#84 Jaycubed: The temporal fenestration condition is not apparent in the illustration, as there aren't any good lateral views. It does seem to be anapsid, though.

Nevertheless, the authors of that paper are among several groups who consider turtles to be derived from the diapsid condition, so a diapsid basal testudinate is not out of the question. (Personally, I think that turtles lie within the parareptiles, but I recognize that some morphological and molecular analyses place turtles as eureptiles.)

@#83 jolthoff: http://research.amnh.org/users/esg/ is an excellent interactive turtle phylogeny. It doesn't include the very latest stuff, but is otherwise up-to-date.

I vote we name it "Yertle the Turtle" in honor of Theodor Geisel aka Dr. Seuss who was indefatigable champion of children's education and healthcare.

By mayhempix (not verified) on 26 Nov 2008 #permalink

Guy
You can't imagine how I feel.
I live near Ken Hamm's creation museum.
Ken has said openly that he believes creationism because to say that Genesis isn't true could mean that the rest of the Bible isn't true.
They have to deny it or they feel like they are denying GOD!
Didn't you know that science is the work of Satan?

#90

ggab,

You really ran with that one. Nice *hand* job there. Comfort-ing indeed.

Posted by: guy fawkes | November 26, 2008 5:23 PM
Okay guys, pardon my questioning here (consider this open for all), but how can people deny evolution when its a fact?

Doesn't work with their religious dogma, which in their minds, is truth. That, mistrust of anything that counters their dogma and stupidity.... you can't cure stupidity.

For the Creobots, evolution made simple:

Anapsida, Anapsid, Anapsi, Anapse, Anatse, Anatle, Auatle, Tuatle, Turtle, Turtles.

This simple one letter change pathway could be replicated with a random letter generator and a group of 'sorting (natural selection) programs.' Examples, sort programs that might favor fewer letters, but still two syllables. Sort programs that kill 'a's', Sort programs that favor T insertions at the beginning of syllables. Many differing selection pressures going on simultaneously and all effortless, seamless and mockingly godless. :)

As I write this, Odontochelys is on NPR where they state (my loosely paraphrased summary): the plastron developing first is one reason they believe this creature to be aquatic in origin- aquatic animals are more likely to be attacked not from the sides, but from below, where you weren't even looking.

Why the plastron should be developed before the carapace is an interesting question, I think, but it may not really have an answer. Since evolution works by natural selection on random mutations, if this mutation occurred first by chance and was beneficial, then the plastron would've developed first.

I'm still relatively new here, but I have learned not to have a reflexive screed toward any poster. A couple of days ago, I was gearing up for a snarky reply and saw the poster was Brownian, OM. Needless to say, I canceled my snark. Sometimes our regulars are the best at breaking the irony meters. So being a little cautious with the snark is warranted.

By Nerd of Redhead (not verified) on 26 Nov 2008 #permalink

"...aquatic in origin- aquatic animals are more likely to be attacked not from the sides, but from below, where you weren't even looking.

So then why didn't they just evolve a pair of eyes on their stomach then mr. I'm-going-to-hell-because-I-hate-god-and-try-to-make-evilution-real-by-pretending-I'm-smarter-than-everyone-else?

Newfie
Sorry, didn't see your reply earlier.
I knew you were kidding. I just couldn't pass up the opportunity to say giant supernut.

This is interesting. fossils are always interesting. I dont see how it "debunks" any creationist "argument" because they are immune to debunking. Those who choose to belong to the american literalist religious community decided they werent going to "believe" evolution before they were even sure they "believed" in god. Its a group identity thing. They may know deep inside that biblical literalism is anithetical to ojective reality, but they dont care. All of their "beliefs" are rooted in primal emotional urges. They need a strong group identity and the fundamentalist community provides one they can join immediately. They dont think they are giving anything valuable up to belong, and the benefits of the tribe membership confers, they suppose, better protection from the larger group they are abandoning. Keep in mind this operates mainly on a psychological level where it belongs,but what haapened when these folks realized they really ARE in a large tribe, and they were invited into the political process. Facts historical. biological and geological have almost nothing to do with their reality.

By Marcus_solerso68 (not verified) on 26 Nov 2008 #permalink

I just couldn't pass up the opportunity to say giant supernut.

*shakes head sadly*

Clearly, the Devil made you do it.

By Owlmirror (not verified) on 26 Nov 2008 #permalink

#100

Well done. You'll get to know the regulars. And if you do cross one, it's usually not a big deal if one is gracious by pointing out one's indiscretion.

Apparently Alex is also feeling playful today.
We're all in a good mood because the War On Christmas traditionally starts after Thanksgiving.
It's an exciting time for we godless.

Alex, Alxe, Axle, xale, xael, xeal, exil, exile. . .yup, yer a goin' to hell. (Note, I did not choose the shortest evolutionary pathway), I do not believe in parsimony either.

Fawkes: You're Swedish, so I can understand your incredulity with regards to evolution deniers. There are lots of them in America, and they are very vocal, due to the forces of modernity eroding away their hegemony over culture and thinking. The short answer to your question is: Yes, these people are insulated. By culture and by choice.

Alex #105

And if you do cross one, it's usually not a big deal if one is gracious by pointing out one's indiscretion.

I have made my share of apologies, which is I am more careful these days. When in doubt, I let others make the call. Always something to learn, like with the above article.

By Nerd of Redhead (not verified) on 26 Nov 2008 #permalink

"We're all in a good mood because the War On Christmas traditionally starts after Thanksgiving."

Oh that's right! It slipped my mind. I'll login to our Anti-xmas portal to get the details. I think I'm running with the 4th Brigade this year - the desecration division. Last year was awesome.

So then why didn't they just evolve a pair of eyes on their stomach [...]?

Ever seen turtles mating? (Usually there is plenty of time to observe!) They'd probably go blind or at least get a few scratches on their corneas.

P.S. If turtles don't have corneas please don't ruin this lame attempt at a joke.

What a cool little critter. Must have been a lot of environmental pressure for him to evolve into a turtle though. Somehow I look at those things as being easy prey in the Triassic period.

By woodstein312 (not verified) on 26 Nov 2008 #permalink

Mothra @ 107

Heh heh heh.

Down at the communist/islamic/Satanic praise and worship center, where i went to hang up Barrak Obama posters, I encountered one of the transexual preists, who is a member of nambla and teaches science courses at the local community college, and he offered me the rank of colonel in the war on christmass.so, as much as id like to be on here baiting fundies and talking about the cretaceous era, i have to be off now to distribute santa clause coloring books and tell everyone HAPPY HOLLIDAYS!!!

By Marcus_solerso68 (not verified) on 26 Nov 2008 #permalink

Newfie @97:

.... you can't cure stupidity.

Yes you can. It's called "education." You know, they have that stuff all over Europe now. They certifiable religious wackos it, too. That's why they wage war on public schools.

Also, isn't the last part sem-eye(or sem-ee)test-a-kay-a? I was taught to always pronounce Latin with hard c's.

Nice eye Brownian! Or is it a Brownian Eye? Haha

By Karl Hungus (not verified) on 26 Nov 2008 #permalink

The problem is that I dont know which one of you who's ironic/satirical, and who is for real.

I mean, seriously.

By guy fawkes (not verified) on 26 Nov 2008 #permalink

Posted by: Rey Fox | November 26, 2008 5:52 PM
The short answer to your question is: Yes, these people are insulated. By culture and by choice.

.. and live in a country with a two party system where one party panders to them, and gives them some (in their own minds, at least) credibility.
I had to give up talking with an old high school friend earlier this year. She'd been a classmate of mine from Kindergarten to HS graduation in a non religious school system. She's a young earth creationist, and even though she knows a lot of the scientific theory, she chooses to ignore it, because she loves Jesus so much. So, instead of telling her that the Jesus character was made up, based on previous sun gods, and point her in the direction to get actual information... I just stopped talking to her. Devout faith must have an effect on the brain when it comes to reason and logic... so, maybe there is something to be said for the power of religion and belief on the human brain, if it can overpower such overwhelming evidence.

Alex!!
"I think I'm running with the 4th Brigade this year - the desecration division. Last year was awesome."

Alex from last years Desecration Division?
It's Gary! I was the one tainting the holy water.
Do you remember the guy in vinyl chaps and the pope hat?
That was me. I had the 70's pornstache.
Last years War On Christmas was the best ever.

"P.S. If turtles don't have corneas please don't ruin this lame attempt at a joke."

And if they do have corneas then why did they evolve eyes on their stomachs that need corneas? They should have evolved cornea-less eyes!....or longer *bananas* so they wouldn't need to be so close when mating.

#115 CJ:

Scientific Latin isn't quite like Church Latin or Classical Latin. "Tes-tay-see-a" is the way nearly all biologists would pronounce "Testacea". (Note: British ones actually make the effort to match Classical Latin, but not so much in other countries).

Happy Thanksgiving, Pharyngula Pholks;I'm heading home. Got to get ready to cook the Mealagris gallopavo tomorrow.

guy

It is pretty hard to tell the difference because no matter how hard people try, their parody just can't out crazy the creationists.

@117, Guy Fawkes. I'm not for real, aka. I am imaginary and will only occasionally appear as a a few lines of text on a not-so-obscure website.

Seriously though, It is difficult to differentiate between the satirical/ironic, the brilliant humor and the ignorant/ deluded posts. When I decide to respond to a particular commenter, I go back and read all their other posts on the thread to be sure I am interpreting remarks correctly.

Any kid who has seen "Finding Nemo" will only recognize this turtle as "Crush" or "Squirt".

By bunnycatch3r (not verified) on 26 Nov 2008 #permalink

Nice eye Brownian! Or is it a Brownian Eye? Haha

ugh

so weak

Anyone want to take a swing at who Karl's other pseudonyms are?

He's pretty much par for the course for the drive by troll exhibiting little to no intelligence or balls.

Are you a eunuch Karl?

CJ @115: You can cure ignorance through education, but stupidity is harder to deal with.

So if we have softshell turtles, hardshell turtles, and now proto-turtles, how long will it be until double-decker turtles (with a soft shell encasing the hard shell) evolve? It almost sounds like (from #87 above) that we might already have them. The very existance of softshell turtles would seem to be a bit of an evolutionary mystery, since the soft shell not only isn't protective but would tend to hold the rest of the organism together when bitten, making it more convenient to eat. What advantage does the softshell turtle gain in compensation? Why were they favored? Perhaps the softshell gene is linked to the forgot-to-hand-out-spicy-sauce-packet gene, thus making the softshell turtle less palatable.

Guy
It's usually a little easier to tell.
There are more of us goofing around than usual today.
I would suggest checking their name to see if it's a link to a personal blog.
The blogs tell all.

#123

Good advice mothra. Also Guy Fawkes, you'll notice more and more regulars engaging the *disruptive* poster until it turns into a dog pile. At that point it becomes clear that the disrupter is not interested in engaging in honest debate by their dodgy repetitive remarks, lack of citation, use of debunked canards, etc.. It's actually interesting how predictable those scenarios unfold.

Just doing a little research in the area of Poe's Law. It held!

By Karl Hungus (not verified) on 26 Nov 2008 #permalink

chuko in #99: Why the plastron should be developed before the carapace is an interesting question, I think,

For surfin', of course.

but it may not really have an answer.

Bingo. Let's all remember that the just-so stories are only that, and aren't why anything develops or evolves. Just people making educated guesses about how some feature might have been useful enough to give critters a reproductive advantage--and that has to do with personal survival long enough to get more youngsters off to a good start, and habits and habitats that result in more offspring and/longer survival for them. Lather, rinse, repeat; or mutate, sift, disperse.

And it's enough for any feature not to confer a reproductive disadvantage, really. It doesn't have to make sense to us; we just feel better about it when it does. And of course we keep trying to make sense of it, as that hones our reasoning.

@127 said ". . .The very existance of softshell turtles would seem to be a bit of an evolutionary mystery. . ."

Sorry for the direct quote mine. Answer: Only for the cognitively impaired, un[der]educated, or the deluded. 1) You have obviously never seen a soft-shell turtle in its natural habitat. 2) You obviously no nothing about its ecology, 3) You obviously have not even bothered to simply google the beast. If YOU find a softshell turtle, make sure to pick it by the front of the shell so as to learn about its defenselessness.

Tim H @ 127

The double-decker turtle with cheese lacks the spicy-sauce gene because they go better with ketchup.

Joking aside, their central carapace is still somewhat bony and protective. The softshell strategy though has been to jettison a lot of mass, and as a result they can accelerate rapidly. They can actually sprint short distances on land. The leathery shell acts like an aquatic wing allowing them to glide through the water like a ray. It helps them bury themselves in sand. It also provides a large respiratory surface. Trionchids are a rather successful group. Unfortunately for them, they make good soup.

"Unfortunately for them, they make good soup."

They can cook? Why is that unfortunate? I wish I could make good soup.

@133, beautiful response! I was too snarky in my reply to Tom H. It was the phrase 'evolutionary mystery' that set me off. A phrase used by creos and telegraphic shorthand for: I have never bothered to think about the idea, have never tried to educate myself, am clueless, deluded, or all of the above.

Aquatic turtles can't swallow food unless they're submerged. So they spend all this time preparing a hearty meal and when it comes time to eat, it just gets flushed into their surroundings. Totally maladaptive.

@127 said ". . .The very existance of softshell turtles would seem to be a bit of an evolutionary mystery. . ."

Sorry for the direct quote mine. Answer: Only for the cognitively impaired, un[der]educated, or the deluded. 1) You have obviously never seen a soft-shell turtle in its natural habitat. 2) You obviously no nothing about its ecology, 3) You obviously have not even bothered to simply google the beast.

1) is correct
2) is correct
3) is correct
Cognitively impaired would apply. I burned my leg on a lightbulb and am treating it with a 40% alcohol solution, taken internally. It's a joke about Taco Bell, mothra. Thank you, C Barr, for the info.

Wow. This is getting absurd. Sorry PZ. And thank you.

Newfie I was just Poeing. It's depressingly easy.

My thoughts were the same as the earlier poster- You don't get to choose your evolution- I guess the plastron mutation happened first.

Guy Fawkes:

You have discovered the phenomenon known as Poe's Law, which states: "Without a winking smiley or other blatant display of humor, it is impossible to create a parody of Fundamentalism that SOMEONE won't mistake for the real thing."

Polls suggest that something close to 50% of Americans deny evolution in some form. You're lucky; you live in a part of the world where you can reasonably expect that your neighbor accepts reality. Around here it's a crapshoot (and it's socially acceptable to be a reality-denialist, at least on this topic).

By chancelikely (not verified) on 26 Nov 2008 #permalink

Seriously, though, I suspect the carapace vs plastron question has a lot to do with the fact that a turtle breathes air. A trilobite had a hard carapace-like shell because it is was bottom-dweller that could hunker down and outwait predators on the bottom. A turtle has to surface sometime, exposing its ventral side. In fact, it can stay surfaced, using its plastron for defence without needing a carapace. Does that make sense?

having just watched the neil shubin video yesterday (at work no less) it seems that those early tetrapods found the ability to do a "push up" very adaptive...possibly for nipping at the underbellies of prey. Perhaps this is why our very old turtles seem to be evolving a plastron first and a carapace later. (arms race?)

By stephanie (not verified) on 26 Nov 2008 #permalink

And perhaps there is some developmental connection between the two. So if the signals for plastron development are activated, then they in turn will tend to activate signals that lead to carapace development down stream.

@Apikoros, #40

"why would the plastron have evolved before the carapace? It just seems to me that a carapace is a better defense, even though your vital organs are ventral, because most creatures that want to eat you are bigger than you. Therefore Death from Above is more of a threat than Death from Below, when on land anyway.

In the water both are equal threats, but horseshoe crabs know which way to bet."

I don't think both are equal threats. It depends on the way of living/swimming. Crabs live directly on the ground, so most danger has to come from above. The ground is their plastron so to speak.
AFAIK Turtles live more in the upper areas and don't dive too deep. So, there is more water with big predators under them, than over them. Makes sense then, to have the protection below.

@ Tom H., see the last paragraph of my comment #108, excerpted from an NPR interview with one of the scientists involved in the fossil turtle discovery. And, I apologize for being waay too snarky. Happy Thanksgiving.

Tim H #142

Read TR Holtz #43
There's a good argument that this animal did have a functional carapace. Those prominant bony lateral processes must have served some function, and in modern turtles they attach to the carapace. I don't think the artist's reconstruction shows how broad and flat these guys were either.

By the way, softshells are the goofiest looking things. They have lips and pig noses.

One additional gap, but the two gaps are different from the old one, so strictly speaking, it does create two new gaps.

All this time spent debating creationists, and you still don't understand how they think?

See, the new fossil does indeed create two additional gaps, but as a creationist you must deny the existence of the new form in situations where it's existence is inconvenient (such as the filling of a gap). Therefore, there are now three gaps.

CJ @115: You can cure ignorance through education, but stupidity is harder to deal with.

With only the shell on front, this is reminiscent of fencing garb.

I say we call him Touche' Turtle

"...as a creationist you must deny the existence of the new form in situations where it's existence is inconvenient..."

Not only that, their idea of a valid transition is a crocoduck!

They're not even wrong about their conceptions on Evolution.

Posted by: Last Hussar | November 26, 2008 6:56 PM
Newfie I was just Poeing. It's depressingly easy.

I know. I thought it was a good point for me to jump in and be facetious. I haven't posted here a lot, but I think I have a feel for the place... unless some of the biology experts here have fun with terminology and processes that I wouldn't know enough about to spot the intent.
I do enjoy the place, and learn quite a bit here though.. like the "sonic hedgehog" ... not having studied embryology or even much biology for that matter, it stuck out, so I wiki'd it.

Quoting Thomas R. Holtz:

That said, the skull is damn primitive (margin teeth, for instance!). It would be nice to see this critter plunked into a big-ass matrix of parareptiles and eureptiles, to see if we can sort out where turtles fit in the phylogeny.

Well, they claim that they've run this thing in the matrix of Rieppel & DeBraga (1996) and continue to recover it as a diapsid. Now, that's not to say that Rieppel & DeBraga's dataset is complete, and it's certainly not to say that the phylogeny of basal amniotes is anything remotely resembling complete, from basal captorhinomorphs and 'araeoscelids' to derived late Permian diapsids. Regardless, any such analysis would require a hearty sample of Triassic diapsids, many of which are either poorly known or are only just now receiving attention.

@ Guy Fawkes --

The creationist culture in the USA is an interesting one. And quite frustrating. I'm not quite sure why creationism showed up, but it seems to have started just before the turn of the 20th century.

As others have noted in these comments, creationists ignore any and all science that they need to, in order that their literalist beliefs not be violated. (I find it interesting that they routinely avail themselves of technologies resulting from the very sciences that they deny. But I digress.)

I was raised in the Catholic Church (I got better...) then at some point ten years ago joined an evangelical church to please my now-ex-wife (relapse and subsequent double recovery). During my period in that evangelical church I became quite interested in "apologetics" and became a part-time troll here. (Apologies for that period; I hope I was not *too* obnoxious.)

I discovered that the religious in this country have a tremendous need for certainty in their lives. They do not want questions or the inherently tentative nature of scientific knowledge. They want permanent answers. And they do not let facts get in the way of a perfectly good belief system.

I hope this helps. I think I'll move to Sweden.

By complex field (not verified) on 26 Nov 2008 #permalink

Ahh yeah...the Triassic. Back when the turtles still had teeth. Edentulous vertebrates kinda bore me.

mothra-
Perhaps my original post, which was intended to be humorous, only made sense to fast-food frequenters. I fully approve of snarkiness directed at real creationists, and yours was very good. My only real knowledge of softshell turtles is that the reptile book I owned in 4th grade said they made bad pets because they were evil-tempered. No apology necessary. I will be sure to use caution should I ever encounter one. Happy Thanksgiving. Time for more leg medication.

For those of you, like Guy Fawkes, wondering what it's like here in America and why we worry about creationists, check this graph. Among modern industrialized nations, only Turkey exceeds our ignorance on the subject of evolution. Yes, you're reading it right. Only about 40 percent of the U.S. population "believe" in evolution.

In Why People Believe Weird Things, Dr Shermer pointed out that the figures are more damning than that. If you break it down, out of those who believe in evolution, the vast majority believe that God had a hand in it - in the sense that God intervened at key moments. The figure is really that only 9% of the American population believe in evolution in the same way that 99% of scientists know it to be.

Joke: How many fossils does it take to fill a gap.

Duane Gish: 'fossils are creatures excluded from the ark.'

Ken Ham: 'There are no fossils.'

Ken Homvid: 'Fossils are manifestations of Satin!

Michael Behe: 'the complexity we see in the modern world cannot be explained by fossils.'

Mike Huckabee: 'I for one, don't believe that fossils support evolution.'

Pope Bene 'I accept that fossils exist, but they never experienced ensoulment.'

Oh, never mind, I guess it isn't a joke.

Scooter- My prev post was originally eaten by the internets. I mentioned that until I read this post a 'plastron' was a arm/chest guard worn under the fencing jacket- like a 1/4 t-shirt.

By Last Hussar (not verified) on 26 Nov 2008 #permalink

Tim H #158

I think I owned that same book. Softshells got a bad rap. As a kid I read the literature and was scared to be bitten. I finally donned leather gloves and let my softshell bite my finger. No problem. Tried it again bare handed. No worse than any other turtle. So instead of holding him by the rear of his carapace, I supported his body with my hand underneath and he stopped trying to bite me. I think they get their bad reputation because the long necks allow them to suddenly snake out and strike at a surprising distance. Between scratching and biting, there's not much in the way of a safe handhold. Of course you don't want to get tagged by any large turtle. You might lose some flesh.

complex field
They do not want questions or the inherently tentative nature of scientific knowledge. They want permanent answers. And they do not let facts get in the way of a perfectly good belief system.

Also, because of their ignorance of the scientific method, they think that the adherents to science have "all" the answers, which isn't the point. The point is to further understanding of the physical universe. Some of today's scientific "facts" may one day be dropped as new evidence and understanding replace what we know. *See string theory, or Theodoric of York.

According to Li et al., turtles are closely related to Sauropterygia within Diapsida (there's disagreement on this, I know, I know; Tom Holtz said above he favoured a parareptile origin, my colleague Mike Lee supported an origin within derived pareiasaurs, also within Parareptilia; and David Marjanovic will be along any time soon to tell us that he's looking into the question in exhaustive length and detail: bring it on!).
If you look at a typical sauropterygian skeleton (plesiosaur or such) you see that the pectoral and pelvic girdles form expanded, nearly flat plates meeting along the ventral midline and enclosing the odd fenestra. It's not hard to see this as the incipient stage of a plastron.
The 'other' armoured sauropterygian group, Placodontia, also have a notably flat belly in the primitive deep-bodied forms, though more derived ones had armoured, wide and low carapaces (different in structure from those of turtles). Methinks the flat belly is convenient for resting on or scooting along the bottom (see also marine iguanas, and water dragons), and also when emerging from water to lay eggs. Or mating.
Without those needs, open-water turtles might have evolved plastra and carapaces deeper than wide, and become laterally compressed like fish.

By John Scanlon FCD (not verified) on 26 Nov 2008 #permalink

Oh, Guy, dear, dear, Guy. I always knew that Sweden was some kind of paradise (except for maybe the black winters...but that's what Aquavit is for, right?)and you're just throwing fuel on that fire.
/jealous

By Beerinacan (not verified) on 26 Nov 2008 #permalink

#165 Newfie.

or perhaps your lack of cross-disciplined studies prevents you from comprehending coherent arguments that 1. don't take unreasonable leaps of inference and 2. that do not admit assumptions that leave them as vulnerable to attack from above as this turtle.

happy thanksgiving
:)

By breadmaker (not verified) on 26 Nov 2008 #permalink

This just proves further that "it's turtles all the way down!!".

By gr8googlymoogly (not verified) on 26 Nov 2008 #permalink

1. perhaps
2. we've already had our Thanksgiving, I have to work tomorrow. :(

but, enjoy your gobblebird. :)

John Scanlon #166

Fascinating post. Thanks.

I think that flat belly is important for negatively buoyant swimmers like sharks, plesiosaurs and turtles. It provides lift during the gliding phase of their swimming, allowing them to travel farther with less effort. For those who as you say "scoot" along the bottom this is especially adaptive because of the "ground effect" where the supporting fluid is compressed underneath the swimmer. We've all experienced the ground effect when a thrown frisbee drops close to the asphalt then just glides forever a half inch above the surface. In an aquatic environment, well you might have had the experience as a kid of dropping a swim fin in the shallow end of a pool and watching it glide smoothly along the bottom down into the deep end.

A domed carapace resists the crushing jaws of predators but is poorly streamlined. A flat profile is streamlined for swimming and allows bottom dwellers to travel within the low velocity bottom boundary layer, underneath the faster current. Of all the North American softshells, the river dwelling Smooth Softshell Turtle, Apalone muticus has the flattest body profile.

newfie -- I think you misunderstood my phrase, "the inherently tentative nature of scientific knowledge". I was not criticizing science or the scientific method. In fact, I use the latter everyday in some rather pitched battles against the fundagelicals.

Or were you simply directing me to some very (very) good parody?

Physics rocks. That was my major in college.

By complex field (not verified) on 26 Nov 2008 #permalink

I may be exposing my ignorance here, but a Swede with the moniker 'guy fawkes'? Any particular reason why you're using an English handle? Just curious.

Fuck. There I go, I read the paper, and in the meantime there are already 166 comments here, and it's half past three in the fucking morning!

OK, so just a few things before I read all comments tomorrow:

I would say that the carapace is in fact there, or rather, all of its parts are present. The small plates above the vertebrae are there (as the paper says, and the photos clearly show), and the plates above the ribs are also there, they just aren't sutured to each other or to the plates above the vertebrae. The paper says the ribs are broadened, but (via some convolutions through modern turtle embryogenesis and through the recently described Triassic turtle Chinlechelys tenertesta) this probably amounts to the same thing.

They already have soft-shell turtles. This proves nothing you morons. And you guys claim to be "skeptics"... laughable

It is better to be thought ignorant than to open one's mouth and prove to be egnorant.

The soft-shelled turtles have lost the horn (keratin) plates above the bony shell. The bony shell is still there. It has holes, granted, but the parts are all fused together, unlike in Odontochelys. Also, have a look at its toothed jaws, its palate, and a long list of other features that exist despite you not having the slightest inkling of them.

Question: why would we expect the plastron to develop first?

We might, because it consists of evolutionarily old bones -- the collarbones, the interclavicle, and the gastralia. Also, comments 16 and 76.

It would be nice to see this critter plunked into a big-ass matrix of parareptiles and eureptiles, to see if we can sort out where turtles fit in the phylogeny.

The temporal fenestration condition is not apparent in the illustration, as there aren't any good lateral views. It does seem to be anapsid, though.

And the authors say so, though they also seem to say that the suborbital fenestra in the palate could be present.

Scientific Latin isn't quite like Church Latin or Classical Latin. "Tes-tay-see-a" is the way nearly all biologists would pronounce "Testacea".

...nearly all biologists who have English as their first language, you mean. Most others don't even go to such lengths when speaking English.

If YOU find a softshell turtle, make sure to pick it by the front of the shell so as to learn about its defenselessness.

Disgusting, mothra. I had no idea what a sadist you were.

David Marjanovic will be along any time soon to tell us that he's looking into the question in exhaustive length and detail: bring it on!)

I'm still constructing the not merely big-ass but outright megalomaniacal matrix; I can't add any taxa yet. Eliminating duplicate and quintuplicate characters that have accumulated because I throw a dozen sources together will take up the rest of the year, and then some months, I suppose. But then I'll add Odontochelys, Chinlechelys, and lots more...

If you look at a typical sauropterygian skeleton (plesiosaur or such) you see that the pectoral and pelvic girdles form expanded, nearly flat plates meeting along the ventral midline and enclosing the odd fenestra. It's not hard to see this as the incipient stage of a plastron.

Yes, but all these animals lack cleithra and IIRC even interclavicles...

By David Marjanović, OM (not verified) on 26 Nov 2008 #permalink

Okay guys, pardon my questioning here (consider this open for all), but how can people deny evolution when its a fact?

A variety of reasons. How can anyone believe L. Ron Hubbard is a space alien god. Or Bush is a good president. Humans just are prone to believe weird stuff.

For creos, the median IQ is 100, meaning that 150 million US citizens are below IQ 100. Millions of 70's and 80's walking around. With that giant pool of morons and near morons, anything no matter what it is, will always find a group of believers. Creationism is the domain of the stupid and the crazy, neither of which are rare.

And a blockquote failure. Hooray! Grmpf. "Indeed, see below" is by me...

Good night.

By David Marjanović, OM (not verified) on 26 Nov 2008 #permalink

complex field
Or were you simply directing me to some very (very) good parody?

I was agreeing with you. And pointing out that human knowledge is always building upon itself, and sometimes, a new idea comes along that changes the way we look at things. Copernicus, Newton, Einstein, etc. String theory may lead to a better understanding of quantum theory, and eventually lead to a unification with relativity, giving us a better understanding of physics... maybe even show us how something like gravity actually works.
And then a comedic twist on that idea with the SNL reference.

As this is a definitive characteristic of chelonians, there would be little doubt about Odontochelys s. and its place in turtle evolution if it is an anapsida.

This is just one character. Though it doesn't happen often (...extremely rarely in fact), skull windows can close.

I would imagine that the soft-shelled phenotype is either a derived trait, or less likely that they split off the before the 'main' branch had developed a boned carapace (assuming that cartilage came first).

It is highly derived. There's a nice series of fossil transitional forms... :-)

And no, cartilage did not come first. There is no cartilage in the carapace of soft-shelled turtles either.

Does not american schools have basic evolutionary education in pre/highschool?

Short answer: no. It's not mandatory in every state, and even where it is, many teachers either are creationists themselves or don't dare teach evolution because they're afraid of creationist parents.

It makes me wonder, the people denying this, living in some sort of isolated bubble, are they vaccinated?

Not all of them...

By David Marjanović, OM (not verified) on 26 Nov 2008 #permalink

gr8googlymoogly

Well right about that time, people,
A fur trapper
Who was strictly from commercial
(Strictly Commershil)
Had the unmitigated
audacity to jump up from
behind my igyaloo
(Peek-a-Boo Woo-ooo-ooo)
And he started in to
whippin' on my fav'rite
baby seal
With a lead-filled snow shoe . . .
I said:
With a lead
LEAD
Filled
LEAD-FILLED
A lead-filled snow shoe
SNOW SHOE
He said Peak-a-boo
PEEK-A-BOO
With a lead
LEAD
Filled
LEAD-FILLED
With a lead-filled snow shoe
SNOW SHOE
He said Peak-a-boo.
PEEK-A-BOO
He went right up side
the head of my favourite
baby seal
He went WHAP!
With a lead-filled snow shoe
An' he hit him on the
nose 'n he hit him on fin
'n he . . .
That got me just about as evil
As an Eskimo boy can be .
. . so I bent down 'n I
reached down 'n I scooped
down
An' I gathered up a
generous mitten full of
the deadly . . .
YELLOW SNOW
The deadly Yellow Snow
from right there where the
huskies go
Whereupon I proceeded to
take that mitten full
Of the deadly Yellow Snow Crystals
And rub it all into his
beady little eyes
With a vigorous circular motion
Hitherto unknown to the
people in this area,
[ Find more Lyrics at www.mp3lyrics.org/VIC ]
But destined to take the
place of THE MUD SHARK
In your mythology
Here it goes now . . .
THE CIRCULAR MOTION . .
. (rub it) . . .
(Here Fido . . . Here Fido)
And then, in a fit of anger, I . . .
I pounced
And I pounced again
GREAT GOOGLY-MOOGLY
I jumped up 'n down the
chest of the . . .
I injured the fur trapper
Well, he was very upset, as
you can understand
And rightly so
Because
The deadly Yellow Snow Crystals
Had deprived him of his sight
And he stood up
And he looked around
And he said:
I CAN'T SEE
(DO . . . DO DO-DO DO DO
DO . . . YEAH!)
I CAN'T SEE
(DO . . . DO DO-DO DO DO
DO . . . YEAH!)
OH WOE IS ME
(DO . . . DO DO-DO DO DO
DO . . . YEAH!)
I CAN'T SEE
(DO . . . DO DO-DO DO DO
DO . . . WELL!)
NO NO
I CAN'T SEE
NO . . . I . . .
He took a dog-doo sno-cone
An' stuffed it in my right eye
He took a dog-doo sno-cone
An' stuffed it in my other eye
An' the huskie wee-wee,
I mean the doggie wee-wee
Has blinded me
An' I can't see
Temporarily
Well the fur trapper
Stood there
With his arms outstretched
Across the frozen white wasteland
Trying to figure out what he's gonna do
About his deflicted eyes
And it was at that precise
moment that he remembered
An ancient Eskimo legend
Wherein it is written
On whatever it is that they
write it on up there
That if anything bad ever
happens to your eyes
As a result of some sort of conflict
With anyone named Nanook
The only way you can get it fixed up
Is to go trudgin' across
the tundra . . .
Mile after mile
Trudgin' across the tundra . . .
Right down to the parish of
Saint Alfonzo . . .

newfie -- gotta admit, Steve Martin is one of a kind. Is it me or has he gotten a bit conventional in the last fifteen years?

At least no one expects the Spanish Inquisition....

By complex field (not verified) on 26 Nov 2008 #permalink

Is it me or has he gotten a bit conventional in the last fifteen years?

He's concentrated more on acting, and banjo playing than comedic writing and performing. I was a guitarist in the 80s, but if you don't keep it up, you lose your chops. I've found other interests and outlets though, no regrets.

@ Alan Kellogg

delta S = Q/T

By complex field (not verified) on 26 Nov 2008 #permalink

guy fawkes,

I am a bit confused here, are some of the posters actually denying our evolution?
Sorry, im swedish, I did not know there was actually people denying facts like this.

I envy you.

The problem is that I dont know which one of you who's ironic/satirical, and who is for real.

That's why they invented Poe's law

I imagine you feel like we would if we were in room with some of the people insisting the world was flat, not being able who was joking or who was not. I would sympathize with your dilemma, but I'm just too damn envious.

P.S. What's up with a Swedish person having the name 'guy fawkes'?

By Feynmaniac (not verified) on 26 Nov 2008 #permalink

No benefit for a half shell? Yeah right! Tell that to Raphael, Michelangelo, Leonardo and Donatello. Turtle Power!

Awww, it's so cute! I'm with PZ: I'd love to have these swimming in the creeks near my house!
Yay for transitional fossils!

By darkseraphina (not verified) on 26 Nov 2008 #permalink

Crocodilians are archosaurs that branched off early, birds are archosaurs that branched off late. The intermediate archosaurs between crocs and ducks are dinosaurs.
Wouldn't one of the feathered therapods be a pretty good candidate for "crocoduck"? Oh, no, that would make too much sense.

What use is half a shell?

At the time, it wouldn't be half a shell. It would be the latest, greatest, most cutting-edgiest shell available. Just because the never-ending prey/predator arms race later led to even more armor-plating doesn't diminish the usefulness of that shell, at that time, in that place.

In the land of the blind, the one-eyed man is king

HumanisticJones @ #28

This here's the plastron,
emblem of our band,
you can wear it on your belly,
you can stroke it with your hand

By Disfunky Monkey (not verified) on 26 Nov 2008 #permalink

Unfortunately the photos don't show a lateral view, but they sure look flat to my eye. In the artist's rendering the hypoplastron and epiplastron bend up into a vertical orientation along the sides of the animal's torso. In the fossils these bony projections appear to stick out laterally. I think those animals were flatter and broader than shown.
Of course the skeletons could have been squashed from burial under sediments.

Amen, #189/190.

We can say in hindsight that the "half-shell" isn't any good when they could have had a complete shell... but how does the "blind watchmaker" know that? People really should read some Dawkins.

Egad! You mean to say that it's not turtles all the way down?

LOVELY transitional form!

Every new discovery of a transitional form has added an additional gap. If we run this state of affairs backwards (uh, de-evolve it), we inevitably arrive at a time at which there must have been only One Original Gap: that separating every organism alive today from scientific curiosity.

Behold the One True God in All His Undiluted and Singularly Naked Glory...the one that presides over nothing, no data, no information and no evidence whatsoever.

No wonder people of faith find it so easy to believe in The Big Blank. It resonates excellently with the giant cavity in their minds, like an echo chamber. It requires no effort at all.

By Arnosium Upinarum (not verified) on 26 Nov 2008 #permalink

Edentulous.

Thanks for the new word, Josh!

Brownian happy =)

By Brownian, OM (not verified) on 26 Nov 2008 #permalink

Posted by: Feynmaniac | November 26, 2008

P.S. What's up with a Swedish person having the name 'guy fawkes'?

Because he wants to blow up Parliament?

By Janine ID AKA … (not verified) on 26 Nov 2008 #permalink

In Why People Believe Weird Things, Dr Shermer pointed out that the figures are more damning than that. If you break it down, out of those who believe in evolution, the vast majority believe that God had a hand in it - in the sense that God intervened at key moments. The figure is really that only 9% of the American population believe in evolution in the same way that 99% of scientists know it to be.

This is nitpicking but the latest polls show that 14% of Americans accept evolution without invoking the Magic Fairy to guide it. 14% is a disgracefully low percentage, but better than the 9% it probably used to be.

I just visited a Tennessee news website. A creationist wrote in a letter to the editor about a "Lack of transitional fossils" and a few other creationist lies I've seen before many times. Creationists keep repeating the same nonsense over and over again, no matter how many times somebody explains why they're wrong. I will never understand why so many millions of Americans can be so hopelessly stupid.

I Want One! GIMME GIMME! I don't CARE if they have to genetically reverse-engineer it, i want one! They're so flippin' awesome!

Silly creotards, Zeno's paradox doesn't apply to lifeforms lol. If it did, how would they ever explain the holes in all those Biblical geneologies, hmmmm?

This is nitpicking but the latest polls show that 14% of Americans accept evolution without invoking the Magic Fairy to guide it. 14% is a disgracefully low percentage, but better than the 9% it probably used to be.

Nitpicking is always welcome, especially when it's new data. The survey in the book was from 1991 or 1992 so it's most likely out of date. Good to see things are improving - however slightly.

I think they look great ! ...and you can really see in this case how the armor plating started of at the belly .
Reminds me of a catcher in a baseball game .

Come on guys, the reason for the development of the bottom plating first is extremely clear:

flat bottom = good for surfing
good at surfing = more turtle chicks
more turtle chicks = more offspring

It is sexual selection, no? :P

Lindsey @188,

birds are archosaurs that branched off late

I see what you mean, but I'm not sure that's the right way to say it. AIUI the birds didn't branch off from the dinosaurs, they emerged from within them -- specifically, out of the Euraptoridae. This might seem hair-splitting, but it's not. Had birds branched off from dinosaurs, then all dinosaurs would be more closely related to every other dinosaur than any of them was related to birds. As it happens, birds and (say) velociraptors are more closely related to each other than either is to a triceratops or T. rex. It's just that velociraptors, triceratops, T. rex etc. died off, leaving only the birds to shit upon statues in the park.

Under the principles of phylogenetic systematics (and we are all cladists now), "dinosaurs" is only a valid clade if it includes the ur-dinosaur and all its descendants (and nobody else). So you can't talk about "dinosaurs" as a group separate from "birds".* This is what is behind pedantic cladists insisting that, unless you prefix "dinosaur" with "non-avian", they don't know whether you mean T. rex or Foghorn Leghorn, and behind your kids bursting in, breathless with excitement, to tell you they have learned that birds are really dinosaurs.

* Well, you can, really; we all do so every day in the real world. But in systematic terms, the labels "Aves" and "Dinosauria" (at least as classically used, with the former being a taxon unrelated to, and higher level than, the latter) are illegitimate. Come to think of it, so is "Reptilia" itself, unless perhaps we were to include ourselves in it.

Mrs Tilton,

what you said about birds and reptiles....I believe you...

The really important question however: Whats the weather like back home?? LOL

Creationist here.
Its not a transition. its just what it is. A kind of turtle. lots of them now and in the past. Flexible to changing as needed. this creature was fossilized during the biblical flood.
it was killed in the prime of life by what encasses. Sediment moved by water and made into stone by the pressure above of sediment/water.
Finding bits of features doesn't change its a turtle. Other options can be invoked for adaptation in creatures.
By this reasoning some present living seals are transitions from other present living seals with different leg abilities on land.
They are in fact just minor adaptions unrelated to ideas of evolution and not evidence of evolution.
There is no evidence of any worth for the great claims of evolution as the origin of great life biology.
If there was all men would be persuaded especially in the smarter countries like North America.

By Robert Byers (not verified) on 26 Nov 2008 #permalink

Creationist here.
Its not a transition.

What a surprise. And Archaeopteryx was just a bird or was that dinosaur? Maybe a dinobird. And Tiktaalik was just an amphibian, I mean freshwater-fish I mean a fishapod.

Silly creationist, talking moron doesn't get you anywhere in life.

Thanks for the new word, Josh! Brownian happy =)

Ha! I made Brownian happy. That's absolutely terrific. Today was not the best day ever, but just made it. You're very welcome.

In other news:
I just visited a Tennessee news website. A creationist wrote in a letter to the editor about a "Lack of transitional fossils" and a few other creationist lies I've seen before many times.

Do you have the URL? This doesn't have the sense of immediate gratification one gets from crashing a silly internet poll, but I think a concerted campaign of letters to the editor might in order. We're pretty good at "fighting the good fight" with the godbots and creotards that show up here--patiently (sometimes) explaining the same things over and over and over again to multitudes of different folks. I think few of us expect it to help much in the short run. But we're willing to try and chip away at the mantle of stupid again and again, happy with that faint hope of dislodging even the tiniest of fragments. Considering the energy invested and the number of characters we write in those efforts, an editorial page seems to me to be an objective we could assault from "geography" we currently occupy. It (well, the $$ helped too...) worked with pretty well with Kay Hagan's "opponent."

Creationist here.
Its not a transition. its just what it is. A kind of turtle. lots of them now and in the past. Flexible to changing as needed. this creature was fossilized during the biblical flood.

Your comment is important to us.

Yes indeed, a lovely critter.

Anyone daunted by Swedish winters can just come to Austria, where we also believe in evolution. Or pretty much anywhere in Europe.

Guy Fawkes- I sympathize. When the thin line between cold stone fucking craziness and satire of the same broadens to a river, it becomes harder and harder to tell the one from the other. In my way of thinking, in a way, there's actually no real difference: anyone who denies evolution at this point in the twenty-first century is performing satire, whether they realize it or not. That's fine with me, as long as they keep their satire out of public schools and government.

"semitestacea" - half a nut?

So would a viable hypothesis be that these critters were more prone to get attacked from below than above? Or is it just not possible to build a carpace without a plastron?

And my apologies if this has already been answered somewhere among the trollery upthread.

Creationist here. Its not a transition. its just what it is. A kind of turtle. lots of them now and in the past. Flexible to changing as needed. this creature was fossilized during the biblical flood.

Your comment is important to us.

lol, laugh of the night there.

I wonder what is wrong with Robert Byers brain, does he think that saying such absurd shit will endear anyone to him at all? It's almost as if he's trying to invoke a sense of pity in the way a stray dog does.

*Sigh*
Robert. It's a transition. Let it go. Seriously. You don't get to redefine scientific terms in a blog comment any more than I get to redefine the authorship of one of Paul's letters. There are venues for altering the definitions of scientific terms. This isn't one of them.

this creature was fossilized during the biblical flood.

Evidence that Odontochelys comes from a flood deposit? Not a flud deposit, but any flood deposit? You do realize that not all sediments are flood-lain, right? But seriously, I'm curious as to your source. Nature has a notoriously short format and vertebrate paleontologists tend to care much more about synapomorphies than they do about all that icky taphonomy stuff, so while I haven't yet read the article in question, I rather doubt that a lot of words were devoted to discussing the formation in which the animal was found. But of course you wouldn't be making an unfounded assertion, right? That would be walking rather close to bearing false witness, wouldn't it?

Sediment moved by water and made into stone by the pressure above of sediment/water.

This is nit picky, but then science is about precision and accuracy.

A. A stone is a building material. The word you want to use is "rock."
B. Geologically speaking, there's essentially no difference between unconsolidated sediment and sediment that has been lithofied. Sedimentary rocks aren't classified on the basis of how indurated they are. You get a pass on this one though, since pretty much every text book you see below the graduate level gets it wrong.

It does appear to keep its scapulae under its ribs. If you look at the first figure and find the humerus (hu) follow it towards the centre line and you will come to the head which abuts a structure which is labelled dsc (dorsal process of the scapula). Not all of this can be seen since it disappears under the anterior ribs. Which would I suppose be further evidence that odontochelys had a carapace since you would have no need to keep your scapulae inside your rib cage unless they would foul on a carapace. Merely fusing the dorsal ribs does not foul the scapula.

By Peter Ashby (not verified) on 26 Nov 2008 #permalink

There is no evidence of any worth for the great claims of evolution as the origin of great life biology.

If there was all men would be persuaded especially in the smarter countries...

like
North
America.

Robert= poe

It's a croc with rickets.

Rickr0ll

Unfortunately not, Bobby Bubba Byers is for real!

By CosmicTeapot (not verified) on 26 Nov 2008 #permalink

I too am afraid Robert is not poeing us: poers usually have better grammar...

What a beautiful animal. And as a fossil, almost too good to be true!

As for the creationist - you believe whatever you need to, dear.

Byers the Delusional:

There is no evidence of any worth for the great claims of evolution as the origin of great life biology.
If there was all men would be persuaded especially in the smarter countries like North America.

There is no evidence for the great claims of Xianity either.

If there was, all men and women would be persuaded. Guess what, Byers. The majority of the world isn't xian. Xians run around 30% of the world's population. Using your (faulty) logic, you have just falsified xianity.

This is neat. Another fossil to add to the bookmark folder. Hoping if I keep track of enough of them I can convince family members this stuff is real. Thanks :)

Evidence for the Biblical flood please Robert. Geologists maintain the geology of the world would be very different if there was any 'Great Flood'

By Last Hussar (not verified) on 27 Nov 2008 #permalink

"If there was all men would be persuaded especially in the smarter countries like North America."

The smarter part of North America is.

Credit please, #180, to a great American composer, Mr. Frank Zappa, for the folks who didn't recognize the lyrics.

On transitional forms - this is not original, but I can't remember the source: Want to see transitional forms? Just look at your children.

PZ, thanks for passing along the article on Odontochelys. Fascinating.

@#203 Mrs. Tilton:

A minor quibble: "Euraptoridae" should be "Eumaniraptora". Just a minor point, but since the authorship of the name is "Padian, Hutchinson & Holtz 1999", one that I care something about...

Bird is in the oven now.

Seriously guys, I am trying. I see no difference between the ones that are "joking" and is a nutcase.

Okay, fine, you lack basic education, I am very well aware of the poor education in United States, i unfortunately spent alot of time there, but never have I gotten a chance to ask about these strange and deluded beliefs, it seems they simple never wanted to "talk bout it". My Ex girlfriends mother (american) thought it was horrible I was an atheist as that meant I was evil and had no 'moral', but as a contradiction, she loved me, as woman do, and did not understand how I could be such a nice guy AND an atheist....

For the real people here, that seriously believe this, Get an education. There is a reason to why the most advanced nations on the planet are secular. We live in prosperous free countries, we have low violence and low poverty. The U.S, your country, is a third world nation compared to any northern european country in almost every sense, and as our Austrian friend told us, the rest of Europe is pretty much all above you in education and healthy society. Should you not take a CUE from this? Secularism make by statistics the best nations on the planet.

With your own nation in the bottom. Not because of the religion, but because of the poor education and cultural fenomene that causes the belief in UFOs, Unicorns, Gods and other deranged fantasies, this belongs in the story books, movies and fun-time for the kids, its not real.

Stop insulting your fellow americans by showing this ridicolous stupid behaviour denying facts. You Are Wrong! There is no debate about this, it does not exist, it seems only these kind of religious folks in your country have told their minons its a 'debate' about evolution, obviously, you would not know what it is if you say that.

Listen to your fellow americans here, they clearly are educated, do you question a painter? Your dentist? No, why? Because he knows it better then you, it is the same here. These people do not 'wing it' and spout random bullshit, but have a basis of knowledge they are taking from, and are prepared to SHARE this knowledge if you want it, you need more of these countrymen if you want your nation to survive because else people like you, uneducated and clearly violent , start wars and hurting people because of your belief in some sort of god that told you this, please dont make the world unsafe because of your own ignorance, you got the whole internet at your feet, dont be afraid to use it.

As a helpful hint to you other educated americans (not the nutcases here), you could always move to Australia/New Zealand, even the moderated religious folks. They ae HIGHLY religious in both the countries, But they do not deny facts, so you can still live in the comfort of your sky daddy, and yet use the medicins and knowledge we produce because of our 'evil secular lust' for truth.

*Guy Fawkes tried to blow up the British Parlament so.. I.. erh... oh crap I hot busted there didn't I?

By guy fawkes (not verified) on 27 Nov 2008 #permalink

Guy Fawkes: yes. Unfortunately, you are pretty much preaching to the choir here: that means, most everyone here will agree with you anyway. But it's nice to hear from you.

Look me up if you're ever in Vienna, and the drinks are on me. My email is: fydylstyks "affenklammer" ("ape parenthesis"- that's what we call the @ sign) utanet dot at.

That goes for the rest of you, too- creationists included.

cheers from wintry Vienna, zilch

Guy Fawkes
there are only two things you need to know:
1. America! Fuck Yeah! The greatest country in the world. (most who think this have never ventured out of their own state, let alone country)
2. http://www.freerepublic.com/home.htm (the stupid there is overwhelming)

It may not help you to understand any better, but it will be enough for you to think it best to not even bother trying to understand their mentality. You'd have better luck trying to teach a dog to cook breakfast. You'll only injure your own brain if you try to rationalize the irrational.

Guy Fawkes, there are a few crackpots like Robert Byers, a Canadian crackpot, that make drive-by posts. You just have to learn their names.

I think they see Pharyngula as the equivalent of mental pron. They know they shouldn't look, but they always do. They don't stick around because they don't have the mental equipment to argue with us, and they get very frustrated if they try, so hit and run is their game.

By Nerd of Redhead (not verified) on 27 Nov 2008 #permalink

Creationist here.

Might as well say

"Idiot here."

But from your other comments you can say

Racist here.
Homophobe here.
Frightened little boy here.

Its not a transition. its just what it is. A kind of turtle. lots of them now and in the past. Flexible to changing as needed. this creature was fossilized during the biblical flood.

Evidence please?

it was killed in the prime of life by what encasses. Sediment moved by water and made into stone by the pressure above of sediment/water.

In less that 6000 years too I'm sure.

Finding bits of features doesn't change its a turtle. Other options can be invoked for adaptation in creatures.

Oh rly? Please explain.

By this reasoning some present living seals are transitions from other present living seals with different leg abilities on land.

Are you drunk?

They are in fact just minor adaptions unrelated to ideas of evolution and not evidence of evolution.
There is no evidence of any worth for the great claims of evolution as the origin of great life biology.

Ok not drunk, just stupid.

If there was all men would be persuaded especially in the smarter countries like North America.

And there's that racism and a little more stupidity thrown in.

If that were true Robert how do you explain yourself?

North America is a country?

Hey chimp- if Africa is a country, then North America is too, no?

Good morning all.
Guy, are you still here trying to figure out American ignorance? Good luck fella.
And Robert stopped by with creationist drivel.
Happy Thanksgiving Robert. Enjoy your dinner of feathered Dino.

clinteas @204,

Whats the weather like back home?

Grey. Nasty. Cold, but not refreshingly so. The usual.

sili @210,

"semitestacea" - half a nut?

More likely "half-shelled., I'd think, from testa rather than testis.

Thomas @225,

"Euraptoridae" should be "Eumaniraptora". Just a minor point, but since the authorship of the name is "Padian, Hutchinson & Holtz 1999", one that I care something about...

Correction gratefully accepted, and its inherent coolness factor duly noted. And you should care about it, because no taxonomic point is minor.

Bird is in the oven now

Well, thank goodness it didn't manage to gut you with those massive hind claws before you wrestled it into the roasting pan.

#40 Apikoros

"Why would the plastron have evolved before the carapace? It just seems to me that a carapace is a better defense, even though your vital organs are ventral, because most creatures that want to eat you are bigger than you. Therefore Death from Above is more of a threat than Death from Below, when on land anyway."

If the lineage of protospecies leading to Odontochelys were ecologically identified by shallow water or intertidal niches, then positive selection for defending the underside against environmental hazards other than predators could lead to a stronger plastron.

Robert Byers @125 offered:

Its not a transition. its just what it is. A kind of turtle.

And snakes are just legless lizards, and lungfish are just fish with lungs, and horses are just unicorns that don't have horns...

By castletonsnob (not verified) on 27 Nov 2008 #permalink

#220 Raven
"Using your (faulty) logic, you have just falsified xianity."

It's possible to dismiss xtianity without resorting to false logic. Applying the real thing does the job adequately, as I'm sure you know.

I wonder what is wrong with Robert Byers brain, does he think that saying such absurd shit will endear anyone to him at all? It's almost as if he's trying to invoke a sense of pity in the way a stray dog does.

Think "Poe's Law"?

http://research.amnh.org/users/esg/ is an excellent interactive turtle phylogeny. It doesn't include the very latest stuff, but is otherwise up-to-date.

Said very latest stuff, however, overthrows some of the basics of this tree. For example, Gaffney still has Proterochersis as a pleurodire and Kayentachelys and the meiolaniids as cryptodires and the protostegids next to the dermochelyids, but work from the last 2 years shows otherwise.

If turtles don't have corneas

Of course they do. All vertebrates that don't live underground or in the deep sea or something have corneas.

how long will it be until double-decker turtles (with a soft shell encasing the hard shell) evolve? It almost sounds like (from #87 above) that we might already have them.

Exactly. That's what a soft-shelled turtle is: it's soft on the outside because the horn scutes are missing.

What advantage does the softshell turtle gain in compensation? Why were they favored?

Their shell is a bit like a bulletproof vest and at the same time much lighter than conventional turtle armor.

captorhinomorphs and 'araeoscelids'

There is no such thing as a captorhinomorph (unless you give that term a definition quite different from previous usage), but there is such a thing as an araeoscelidid (Araeoscelis, Petrolacosaurus, Zarcasaurus, Kadaliosaurus).

please please talk about this in a future post:
http://www.youtube.com/watch?v=ypPxGL62dUY&feature=related
monks fist fighting in front of Jesus tomb

This is not news anymore. It has constantly been mentioned in the comments here for several weeks.

Awww, it's so cute! I'm with PZ: I'd love to have these swimming in the creeks near my house!

They'd greatly prefer a warm sea over an absurdly cold creek...

Unfortunately the photos don't show a lateral view, but they sure look flat to my eye.

Well, it's a crushed fossil, as usual. There basically is no lateral view. :-| Three-dimensionally preserved fossils are rare and don't occur in this kind of rock.

Edentulous.

Thanks for the new word, Josh!

Brownian happy =)

Oh yeah. That's the term that the mammalologists (note the LOL in there) use for fossil jaws where the teeth have fallen out, and everyone else uses for jaws that never had teeth to begin with whenever they feel too elitist to just say "toothless". :-)

So would a viable hypothesis be that these critters were more prone to get attacked from below than above? Or is it just not possible to build a carpace without a plastron?

As I said above, I think all of the parts of the carapace are there, they just aren't sutured to each other.

birds are archosaurs that branched off late

I see what you mean, but I'm not sure that's the right way to say it.

Indeed not...

Anyway, under the somewhat more common of the two definitions of Archosauria, Archosauria arose at the split between the ancestors of crocs but not birds on the one side and those of birds but not crocs at the other. All dinosaurs, birds included, are part of the latter branch.

They are in fact just minor adaptions unrelated to ideas of evolution and not evidence of evolution.

No, my friend. No. We evolutionary biologists own the word evolution. It's our technical term. You can't simply make up another definition for it and claim ours is wrong. That's simply not how it works.

it was killed in the prime of life

We don't know that. It could have been sick, ridden with tapeworms even, whatever, and we couldn't tell from the skeleton.

this creature was fossilized during the biblical flood.

This is not a flood sediment, ignoramus. It is finely laminated fine-grained sediment, the kind of thing deposited in still water. No sign of movement.

Did you really believe the whole fucking science of sedimentology didn't exist?

(Well, to answer my own question, of course you did. After all, if you can't tell the difference between a rock and another rock, then there cannot be any difference. Right? Creationism is all about "me, me, me".)

Finding bits of features doesn't change its a turtle.

How do you define "turtle"? B-)

There is no evidence of any worth for the great claims of evolution as the origin of great life biology.

This merely shows that you haven't understood what the "great claims" are.

If there was all men would be persuaded especially in the smarter countries like North America.

So you had no idea that the USA and Turkey are the only halfway First World countries with any significant number of creationists at all?

Eh, of course you didn't know that. After all, you don't know anything -- otherwise you wouldn't be a creationist in the first place!

I have to stop now. The more often I look at comment 206, the more mistakes I find. I could spend the rest of the day on it.

"semitestacea" - half a nut?

Half-shelled or -bowled. Testa "shell, bowl" is also where the Italian and French words for "head" come from (compare "noggin").

It does appear to keep its scapulae under its ribs. If you look at the first figure and find the humerus (hu) follow it towards the centre line and you will come to the head which abuts a structure which is labelled dsc (dorsal process of the scapula). Not all of this can be seen since it disappears under the anterior ribs. Which would I suppose be further evidence that [O]dontochelys had a carapace since you would have no need to keep your scapulae inside your rib cage unless they would foul on a carapace.

The ribs are too disarticulated and the whole fossil too squashed for me to tell. However, keep in mind that, while turtles have the shoulder girdle inside the carapace, they do not have it inside the ribcage. More on that later.

I'd say the preservation is consistent with the shoulder girdle being in front of the ribcage, but, as I just said, I can't tell for sure (and the paper doesn't say).

By David Marjanović, OM (not verified) on 27 Nov 2008 #permalink

I think they see Pharyngula as the equivalent of mental pron. They know they shouldn't look, but they always do.

=8-)

By David Marjanović, OM (not verified) on 27 Nov 2008 #permalink

Peter Ashby @#213 answering question @#56

I finally donned reading glasses and agree with your analysis of the positioning of the scapula under the ribs. It has been an evolutionary question about how the shoulder assembly moved from outside the ribcage to inside in turtles. It either happened in a short time, with a major mutation repositioning the scapula from outside to in, or gradually with development of a carapace requiring the scapula to move forward to still allow the shoulder to function, until it was forward of the anteriormost ribs and able to drop down into the body cavity. It is interesting that in the first specimen the anteriormost ribs appear swept back which would have allowed the gradual migration of the scapula to more easily occur. You're right ... Why reposition the scapula unless there was a carapace?

...and everyone else uses for jaws that never had teeth to begin with whenever they feel too elitist to just say "toothless". :-)

Oh bite me, David. It's a perfectly cromulent word...

And Sarah Palin and Joe the motherfucking plumber already think I'm elitist (real Americans don't have PhDs, don'tcha know), so I guess there's no additional harm done in using whatever damn word I want.

Whoa, David M posted #239 while I was writing. I look forward to your next post.

Tyler Lyson: How did the turtle get its shoulder girdle inside its ribcage, or did it?, Journal of Vertebrate Paleontology 28 (supplement to issue 3), 109A

The apparent relationship of the shoulder girdle inside the ribcage of turtles has puzzled neontologists, embryologists, and paleontologists for centuries. Unlike other extant amniotes where the scapula lies dorsal to several thoracic ribs, the turtle scapula appears to lie inside the thoracic ribs and thus inside the ribcage. However, while the shoulder girdle clearly lies inside the shell, its precise relationship to only those portions of the shell that are considered homologous with other amniotes' ribs and vertebrae remains untested. The neural and costal bones, which make up the majority of the turtle shell, undergo both endochondral and intramembranous ossification and the whole structures have been hypothesized by some to be homologous to the endochondrally ossified ribs and vertebrae of other amniotes. However, fossil, histological, and some embryological data indicate that only the endochondrally ossified portion of the costal and neural [bones] is homologous to the ribs and vertebrae. Computed Tomography images manipulated to show only the endochondral portion of the costals and neurals of a sample that covers the full extant tree space of turtles clearly indicate that the turtle scapula does not lie inside the shell [oops -- ribcage], but rather frames the neck and lies anterior to the thoracic ribs. This relationship is homologous to the condition found in basal amniotes ([and their closest relatives,] e.g. Limnoscelis paludis). In addition, the position of the coracoid is similar to other amniotes in that it lies underneath the ribcage poster[...]odorsally to the clavicle and interclavicle. These observations indicate that turtles essentially retained the shoulder girdle of basal amniotes and that the position of this girdle "within" the ribcage is an illusion created by secondary dermal ossifications.

"Endochondral" means that a bone forms first as cartilage and then turns into bone; vertebrae and ribs, for example, form that way (except for the vertebrae of salamanders).
"Dermal" means that a bone forms in the deep layers of the skin, directly from connective tissue, without a cartilaginous precursor.
"Intramembran(e)ous" means the same, only that it's not necessarily the skin that's involved.
The scapula and the coracoid are two bones of the shoulder girdle; most mammals (such as us) have greatly reduced the coracoid.
The clavicles are the collarbones, the interclavicle is something that we've more or less lost. All three form the front part of the plastron.

Any more questions? :-)

By David Marjanović, OM (not verified) on 27 Nov 2008 #permalink

Way cool. Thanks David

It's always fun when the experts explain the data. Great brain food.

By Nerd of Redhead (not verified) on 27 Nov 2008 #permalink

Wow, that's amazing. Thanks for the summary, PZ!

I know I should leave this alone, but I am strangely compelled. Robert said:
it was killed in the prime of life
and I have to agree. I mean, look at how happy and healthy the two of those prototurtles look, cavorting underwater, in that nice color photo.

"and I have to agree. I mean, look at how happy and healthy the two of those prototurtles look, cavorting underwater, in that nice color photo."

Of course it's a photo.
It was easy to make a camera 6,000 years ago.
They just had to model it after the eye that god gave us, fully formed.

I forgot to capitalize God.
Poe FAIL!!
I'd make a lousy creationist.

it was my understanding that the blade of the scapula formed as dermal bone with only the articulations having cartilage precursors. That seems to be how it forms in mice anyway. You see the muscles such as supra and infra spinatus arise before the blade.

By Peter Ashby (not verified) on 27 Nov 2008 #permalink

No, no, the scapula is endochondral. The clavicle, interclavicle and cleithrum are dermal... do the muscles merely form before ossification, but after chondrification?

By David Marjanović, OM (not verified) on 27 Nov 2008 #permalink

This post is doing my head in. New and fascinating transitional fossils are found and although some people are doing their best to explain where they fit in the tree of life and what their significance is (and this seems way complicated - I guess science is just inherently difficult so maybe I should pray for enlightenment) but the post gets clogged up with pretend creationists, and at least one genuine one. I mean surely no one here needs to pretend to be stupid? No wonder G Fawkes is baffled.
So who can explain to me simply: how do we know that this is a precursor to all modern turtles, and what does it show us?
Oh, and to the real creationist - if you don't understand reality, fuck off. And when you get ill, I really hope you just pray to get to get better, rather than bothering doctors - just the kind of science-based expert you take no notice of.

Of course, one must always bow to the superior intellect of people called David :)

In future, I will refer to human remains with total tooth-loss as "postdentulous"

Hope the USian ilk are having a fine Thanksgiving!

and this seems way complicated - I guess science is just inherently difficult so maybe I should pray for enlightenment

Nah. It's merely a lot of work because of all the convergence. :-)

how do we know that this is a precursor to all modern turtles

It combines characters that all turtles -- even the ones closest to the origin of turtles, especially Proganochelys -- have with characters that they lack but other animals have and with characters that both have and more derived turtles lack.

and what does it show us?

That the plastron was already there before the teeth were lost; and apparently that the carapace was assembled stepwise as predicted. Just two examples off the top of my head.

By David Marjanović, OM (not verified) on 27 Nov 2008 #permalink

Ah, I see. 8) Thanks

Of course, one must always bow to the superior intellect of people called David :)

Quite so.

By David Marjanović, OM (not verified) on 27 Nov 2008 #permalink

David Marjanovic, Anthony K:

Nearly forgot to mention this, but with respect to the comment:

how do we know that this is a precursor to all modern turtles

The most precise answer of course is that we don't! This particular creature or its descendants probably is not ancestral to all modern turtles. The odds that the species Odontochelys has any living descendants aren't that great. But it does show transitional features between other species in the fossil record, transitions which are predicted on the basis of comparative anatomy to modern turtles and which quite plausibly could've been shared with other related species that may have existed for which no fossil record is yet known.

Sorry to nitpick, but I'm just fresh off a radio show where the host threw out canards like 'missing link' and the presumption that he was related to a stromatolite....:)

The most precise answer of course is that we don't! This particular creature or its descendants probably is not ancestral to all modern turtles. The odds that the species Odontochelys has any living descendants aren't that great.

Correct. I didn't want to interpret "precursor" as strictly "ancestor".

And yep, the host is related to every single cyanobacterium in every single stromatolite in the world.

By David Marjanović, OM (not verified) on 27 Nov 2008 #permalink

Sorry to nitpick, but I'm just fresh off a radio show where the host threw out canards like 'missing link' and the presumption that he was related to a stromatolite....:)

Yeah, I heard that. And the caller who was all indignant about science being all uppity and continuing to add knowledge to the world, saying, "First we were decended from an ape, and then a fish, and now a rock?!"

I had a similar issue listening to my grandmother relate my family history. I was all like, "Woah! First you tell me I'm descended from Dad, then you tell me that I'm descended from you and Granpa, and now you tell me I'm descended from Great-Granpa and Great-Grandma, and that I'm related to Uncle Barrie and Auntie Liz? What the fuck have you been smoking, you senile crone?!"

By Brownian, OM (not verified) on 27 Nov 2008 #permalink

It has also been reported on the BBC yesterday -
http://news.bbc.co.uk/1/hi/sci/tech/7748280.stm
as was my earlier link re the Burgess shales, which was also on the 'Today' programme- one of the main serious news programmes in the UK.

Were there any reports in the US in the Godless Liberal Christian-Hating pro-evolution fag-loving 'MSM'

By Last Hussar (not verified) on 27 Nov 2008 #permalink

Thanks David, and Scott - and by a coincidence I was just reading your blog, and of your encounter with a silly creationist. I do wonder a bit that you don't find pharyngula a little - uh - liony as a forum, you being a christian and all. Still I'm glad that sensible people of faith like you aren't put off by all the vitriol you get here. There does seem to be a lot of intolerance about religion on this site - but then I guess that unlike in Britain religion really had a terrible effect on the US. Reading ex-Christian.net gives many examples of people totally traumatised by their upbringing. But in case it sounds as if I'm in any way superior the main reason that we aren't still in the grip of religious mania is that we've been there already...best of luck spreading the science message!

As a helpful hint to you other educated americans (not the nutcases here), you could always move to Australia/New Zealand, even the moderated religious folks. They ae HIGHLY religious in both the countries, But they do not deny facts, so you can still live in the comfort of your sky daddy, and yet use the medicins and knowledge we produce because of our 'evil secular lust' for truth.

We still have some nutcases in Australia, it's comforting to know though that we are an exporter of nutcases - America just loves to import them. ;)

We still have some nutcases in Australia, it's comforting to know though that we are an exporter of nutcases - America just loves to import them. ;)

for fuck's sake

PLEASE STOP

We have enough home grown ones

We still have some nutcases in Australia, it's comforting to know though that we are an exporter of nutcases - America just loves to import them.

(Pondering briefly the mental image of a trade balance correction involving shipping Ken Ham in chains to Botany Bay, with a sign attached to him: DO NOT WANT)

By Owlmirror (not verified) on 27 Nov 2008 #permalink

Supply and demand my good Reverend. It's like importing oil, it's a symptom of the excessive demand versus the ability to supply. You may grow your own creationist preachers, but think of it like owning an American car. If American cars suck, would you forsake owning a shinier slicker European / Asian car just so you can drape the American flag over it?

(Pondering briefly the mental image of a trade balance correction involving shipping Ken Ham in chains to Botany Bay, with a sign attached to him: DO NOT WANT)

lol. It'd only return to you with the sign: NO RETURNS

"Woah! First you tell me I'm descended from Dad, then you tell me that I'm descended from you and Granpa, and now you tell me I'm descended from Great-Granpa and Great-Grandma, and that I'm related to Uncle Barrie and Auntie Liz? What the fuck have you been smoking, you senile crone?!"

ROFL! I'm totally using this next time I hear that "what'll those crazy scientists say next" crap.

#216Posted by: Kel | November 27, 2008 5:33 AM

Robert= poe

If only.
---+----
Whoops, my optimism is showing again! How embarassing lol.

I better wait until this thread slows down before i tackle it.

I am curious as to whether this creature has the articulating connection between neck vertebrae which allow a turtle to retract its head. This feature is only useful if you have a carapace.

Exporting religious nutters to America is a bit like cricket ... we started it, then the Aussies got hold of it and started beating us at it.

Exporting religious nutters to America is a bit like cricket ... we started it, then the Aussies got hold of it and started beating us at it.

lol

I am curious as to whether this creature has the articulating connection between neck vertebrae which allow a turtle to retract its head.

No, the ability to retract anything evolved long after the carapace -- twice independently, in fact. 50,000 years ago there were still turtles in Australia that were unable to retract anything. (They had horns instead, and other bone spikes on neck, limbs and tail.) For an example that's only some 20 million years younger than Odontochelys, go here and check out Proganochelys.

By David Marjanović, OM (not verified) on 28 Nov 2008 #permalink

To Jaycubed, Yes, of course it was "Joseph Smith" who created the Mormons. I must have had a brain fart that made it come out "John Smith." A

David, thanks for the link. Gaffney's website looks fascinating.

I'm still pondering the artist's reconstruction which shows these animals with rounded bellys (comment #92). The fossil with a ventral view shows a concave plastron which in a modern turtle would be interpreted as a typical male form. Of course this is likely to have been pushed in by an overburden of sediments. Still, the shadows in both photos show the specimens demonstrate considerable three dimensionality.

Again looking at the dorsal view photo, the shadow along the left side of the plastron (right side of photo) shows a clear shadow which outlines what appears to be a very flat and elongate elliptical belly, with a defined sharp bend along this outline. On the animal's right side the crushing sediment overburden caused the plastron plates to fail inward of this outline. In the four laterally projecting bones of the hyo, hypo, and mesoplastra on each side, I see no sign of the curvature shown in the artist's rendering which has these bones curling up like fingers along the animal's torso. Yes they could have been flattened, but the right side of the specimen shows these bones failing along definite lines as contrasted with bending under pressure.
It seems that based upon the assumption the animal had no carapace, the artist gave the animal a gently curving convex belly when there is really no evidence for such. To my mind, the fossils make more sense interpreted as showing a typical broad aquatic turtle shell, but with a carapace that lacks the modern sutured bony plates.
Where the heck is Sven? He's a turtle guy.

Crap!

"Again looking at the dorsal view photo ..." NOT!

ventral view, ventral view

If the plastron is too flat, the animal can't move its forelimbs anymore -- look where they are in the ventral-view photo.

but with a carapace that lacks the modern sutured bony plates.

With a carapace that lacks the sutures between the bony plates -- the costal plates are, I think, all there, only the peripherals, nuchal & pygal are missing.

By David Marjanović, OM (not verified) on 28 Nov 2008 #permalink

Oh for crying out loud.

"I'm still pondering the artist's reconstruction which shows these animals with rounded bellys (comment #92)"

comment #192 my friends.
I'm going back to bed now.

"If the plastron is too flat, the animal can't move its forelimbs anymore -- look where they are in the ventral-view photo."

In the dorsal-view photo, the distal portions of both humeri lie ventral to the hyoplastron as does the left humerus in the ventral-view. But yes, with a completely flat plastron this would require the humerus to be oriented ventrally making for an inefficient swimming stroke. So taken as evidence that in both specimens the plastron has been flattened by burial, I would interpret that the animal had a flat elongate elliptical belly as described above, with the lateral processes of the plastron bending sharply upward along that elliptical outline. In the ventral-view specimen the right hand side of the plastron failed both medially and distally of that outline because of burial pressure. The left hand portion of the plastron failed distal to that elliptical outline, bending ventrally. I still see no reason to interpret these animals as having convexly curved bellies. Shadows in the ventral-view show a sharp dorsally oriented bend in the plastron along the animal's left side. This cannot be explained by deformation from burial.

David, thank you for you patient corrections and explanations.

Quoting David Marjanović, OM:

There is no such thing as a captorhinomorph (unless you give that term a definition quite different from previous usage), but there is such a thing as an araeoscelidid (Araeoscelis, Petrolacosaurus, Zarcasaurus, Kadaliosaurus).

Are we going off of Muller and Reisz's recent analysis? Or something else? The mess of captorhinids+protorothyridids+acleistorhinids+parareptiles+pareiasaurs seems to be remotely well-supported, for whatever reason that may be, although that clade could certainly represent some sort of methodological artifact. "Araeoscelidids" may represent a clade, or may represent a basal assemblage of diapsids that appear to form a distinct clade due to heterogenous sampling of diapsid taxa in space and time in the late Paleozoic.

But then, we get right back to the same set of major problems with Paleozoic tetrapod phylogeny that we've discussed before.

The mess of captorhinids+protorothyridids+acleistorhinids+parareptiles+pareiasaurs seems to be remotely well-supported, for whatever reason that may be, although that clade could certainly represent some sort of methodological artifact.

What do you mean? I haven't seen such a clade in any paper I've seen. At least some of the "protorothyridids" have been found to be more closely related to the diapsids than to the captorhinids ever since the late 80s, and the first paper to do so declared the name Captorhinomorpha to be history; it hasn't been used since.

"Araeoscelidids" may represent a clade, or may represent a basal assemblage of diapsids that appear to form a distinct clade due to heterogenous sampling of diapsid taxa in space and time in the late Paleozoic.

Well, there's a reason I didn't mention Spinoaequalis, though that needs more testing, and Reisz (pers. comm. at the SVP meeting) is still "comfortable" with it as an araeoscelidian. But Araeoscelis and Petrolacosaurus keep coming out as sister-groups -- not only when they're the only diapsids in the matrix, like in Müller & Reisz 2006 --, and that's based on a fairly long list of synapomorphies.

The very poorly known Zarcasaurus and the... apparently drastically underresearched Kadaliosaurus have never been entered into a data matrix, though apparently they share the list of araeoscelidid autapomorphies.

Do you happen to know what the latest paper on Kadaliosaurus is, BTW?

By David Marjanović, OM (not verified) on 29 Nov 2008 #permalink

Just revisited Muller and Reisz, and you're right. My memory was definitely off on that one.

Regardless, my point about "araeoscelids" is that we have a really limited diapsid sample from the Paleozoic, and most of that sample is pretty contentious. Beyond the "araeoscelids" and a small sample of late Permian taxa (e.g. Youngina, Hovasaurus, etc.) there's little to suggest that we're looking at a sample we can assume to be representative of early diapsid taxonomic diversity.

As for Kadaliosaurus, I haven't been significantly following the early diapsid literature beyond the whole "it's a phylogenetic hellhole" issue. Someone really needs to simply go through all of the basal amniote material and just start affixing "nomen dubium" to anything that lacks a skull or highly diagnostic postcranial elements (e.g. Lupeosaurus is okay, but scrap Clepsydrops) and produce a consistent monographic treatment of all amniote material earlier than the Russian and Karoo series. The current specimen-by-specimen approach is highly problematic and is leaving way too much junk sitting around with old Cope/Case/Williston names.

Shucks, late to the turtle thread. Have been going sans-laptop this weekend as an inducement to grade freakin lab reports...anyway.
That abstract David M. posted @#244 is the coolest thing I've learned in weeks...that's brand-new stuff, people; I can't find that abstract anywhere else on the web, including the JVP website.
As for Odontochelys, very cool with the teeth and plastron. I'm not buying the artist's conception though; I've seen tortoise skeletons at all stages of weathering and there's just no way to know what overlaid those flattened ribs. From the bridge-like structures of the plastron, I'd guess there was a nice turtley carapace. Thanks to T. Holtz for posting early and confirming my already-nagging suspicions.

Yo, PZ! More turtles, please!

By Sven DiMilo (not verified) on 30 Nov 2008 #permalink

that's brand-new stuff, people; I can't find that abstract anywhere else on the web, including the JVP website.

Technically, SVP meeting abstracts count as published once the talks/posters have been presented; they are printed in the supplement to each year's September issue of the JVP. It's strange that the website still restricts access to SVP members (...well, maybe not, access to the journal is restricted the same way -- but then, it's an abstract!).

Incidentally, the abstracts themselves are not password-protected; only the path to them from the main page is.

there's just no way to know what overlaid those flattened ribs.

As mentioned above, I think the ribs aren't flattened, they're fused to costal plates -- except for the peripherals/nuchal/pygal, the carapace is there, its parts just aren't sutured to each other.

there's little to suggest that we're looking at a sample we can assume to be representative of early diapsid taxonomic diversity.

Of course.

The current specimen-by-specimen approach is highly problematic and is leaving way too much junk sitting around with old Cope/Case/Williston names.

Yep.

BTW, Robert Reisz has a skeleton of Varanops and/or Varanodon in his office; someone else has an abstract about new information on Varanops, which beast apparently hasn't been redescribed since Romer & Price 19-fucking-40 (we have a facsimile of that book in the lab, and I'm using it, for crying out loud); and Reisz & coauthors have an abstract on the previously enigmatic Permian diapsid Lanthanolania (now known from much more material), and two of his students have two abstracts about a new "enigmatic parareptile" each. Also, if you know what Apsisaurus is, you actually don't; reality is much more boring. Stay tuned.

By David Marjanović, OM (not verified) on 30 Nov 2008 #permalink

I think the ribs aren't flattened, they're fused to costal plates -- except for the peripherals/nuchal/pygal, the carapace is there, its parts just aren't sutured to each other.

I see what you mean.
Looking forward to results of running your megamatrix. In the meantime, I'm not giving up ancestrally anapsid turtles without good reason. Some of these molecular studies bother me, though.

By Sven DiMilo (not verified) on 30 Nov 2008 #permalink

What lovely creatures they were, no matter what their position in the evolutionary parade. Step back from the minutae and look.

I do not doubt that they were lovely--I take a back seat no one in my regard for turtles--but I do not pretend to have the slightest idea what they looked like, artist's conception notwithstanding.

By Sven DiMilo (not verified) on 30 Nov 2008 #permalink

I would be interested to know what the orientation of these fossils were during burial. Did the dorsal view specimen lie upright during decomposition and burial?

Teh Google; Somebody might find these articles interesting.

This study used computed tomography to analyze the shoulder girdle
http://www.yale.edu/ceo/Projects/Students/TurtleGirdle.html

This study found the softshell to hold the humerus relatively horizontal during the power stroke. The slider had a more vertical component to the forelimb power stroke, with the humerus angled downward. The authors concluded that the slider's forelimb motion provided more stability than propulsion while swimming.

Comparative kinematics of the forelimb during swimming in red-eared slider and spiny softshell turtles
http://jeb.biologists.org/cgi/content/figsonly/204/19/3261

Geez, It was Tyler Lyson in both. Same work. Nothing to see here, move along. Some day I'll make a post without having to add a correction. Sorry.

BTW, Robert Reisz has a skeleton of Varanops and/or Varanodon in his office;

Color me unsurprised.

[quote]someone else has an abstract about new information on Varanops, which beast apparently hasn't been redescribed since Romer & Price 19-fucking-40 (we have a facsimile of that book in the lab, and I'm using it, for crying out loud);[/quote]

Good, on the same scale of "good" as Jason Anderson getting into all of Carroll's old microsaur material.

[quote]and Reisz & coauthors have an abstract on the previously enigmatic Permian diapsid Lanthanolania (now known from much more material), and two of his students have two abstracts about a new "enigmatic parareptile" each.[/quote]

Saw most of these.

[quote]Also, if you know what Apsisaurus is, you actually don't; reality is much more boring. Stay tuned.[/quote]

If it's following the trend in recent years, I'm guessing "varanopid."

Ignore the poor markup.

Thank you, ggab, particularly with comments #26 and #61, wherever the comment may have originated. You have helped contribute to a growing movement for lethargy and cognitive stagnation.

Just a thought...If I really am a troll (for as you have specified, I am an Atheist and neo-Darwinist, while I add that I am currently using the full potential of having an astonishing ratio of brain to relative body mass), I promise, I still feel shame for I unfortunately have to admit existence in the same species as ggab; yes, that would be Homo sapiens (sapiens), which, yes, is a further manifestation of our acknowledgement (not faith) of evolution (spelt with an "o").

This is a science blog and the lack of science in your argumentation is (a) inappropriate, (b) appalling, and (c) hardly compensative to the answering of the proposed question, the which you haven't even acknowledged or at least proposed a new question you feel is a more appropriate one. Thank you for justifying cynicism.

Josh:

This is a science blog and the lack of science in your argumentation is (a) inappropriate, (b) appalling, and (c) hardly compensative to the answering of the proposed question, the which you haven't even acknowledged or at least proposed a new question you feel is a more appropriate one.

No.
This is PZ's blog, one of many in ScienceBlogs.
Your indignancy is based on a misunderstanding.
This blog is for Evolution, development, and random biological ejaculations from a godless liberal and any commenters who wish to opine.

I am currently using the full potential of having an astonishing ratio of brain to relative body mass

Let me guess, you're a scrawny, macrocephalic multiple amputee.

By John Morales (not verified) on 02 Dec 2008 #permalink

Looking forward to results of running your megamatrix. In the meantime, I'm not giving up ancestrally anapsid turtles without good reason.

Seconded.

If it's following the trend in recent years, I'm guessing "varanopid."

I'm not telling. :-)

BTW, I finally read the Chinlechelys paper today. Quite impressive; clearly supports the idea that the costals are not part of the ribs.

By David Marjanović, OM (not verified) on 02 Dec 2008 #permalink

I am currently using the full potential of having an astonishing ratio of brain to relative body mass.

Seems that "ratio" and "relative" a) are redundant, b) begin with the same letter, and c) are hardly dispositive to the question at issue, which is what species of tree did the giant stick up your ass come from?

BTW, I finally read the Chinlechelys paper today. Quite impressive; clearly supports the idea that the costals are not part of the ribs.

I think there are two questions: are the costals derived from the ribs, and are the costals initiated and patterned by the ribs? The former is pretty clearly not the case. The latter seems to be decently supported by the evo-devo work out of, say, Scott Gilbert's lab. Is the carapacial ridge capturing the ribs and redirecting them into the ectoderm? Yeah, it seems like it is. Does this mean that these redirected ribs contribute to the costals? No. Does this mean they pattern the costals? Possibly.

Do we need to start looking at Triassic diapsids in a LOT more detail? Absolutely.

Seems that "ratio" and "relative" a) are redundant

Unless Josh means that his relatives are few and scrawny.

Yeah, it seems like it is. [...] No. [...] Possibly. [...] Absolutely.

Agreed.

By David Marjanović, OM (not verified) on 03 Dec 2008 #permalink

hardly compensative to the answering of the proposed question, the which you haven't even acknowledged or at least proposed a new question you feel is a more appropriate one

Say what?

By Sven DiMilo (not verified) on 03 Dec 2008 #permalink

John Scanlon FCD in #166 compares turtle evolution of belly armor with dorsal boniness in sauropterygians, which I also find instructive. Hardening of their undersides could have developed in order to promote underwater locomotion as well as to protect vulnerable bodies.

By John Tillman (not verified) on 04 Dec 2008 #permalink

As per John Scanlon's comment #166, he refers to open water turtles. Marine turtles have a unique highly specialized swimming style, using their forelimbs synchronously and simultaneously in subaquatic flight, unlike the drag based propulsion of more generalized turtles (like this specimen?) which mimics the alternating limb motion of walking. Plesiosaurs may have utilized underwater flight also. This method of locomotion may have benefitted from a flat bony ventral surface in several ways. The extra bone mass may have given the animal negative bouyancy (interestingly, plesiosaur skeletons have been found with swallowed stones in the stomach region). A rigid skeletal torso would not consume energy by flexing if the propulsive force and timing of forelimbs and hindlimbs were not equally matched. A rigid belly would prevent oil-canning which wastes energy during a thrust stroke (why you should not store your kayak resting on it's bottom).

Odontochelys does not have any adaptations to underwater flight, however.

By David Marjanović, OM (not verified) on 08 Dec 2008 #permalink

You are correct. Hence my comment

unlike the drag based propulsion of more generalized turtles (like this specimen?) which mimics the alternating limb motion of walking.

My discussion of this was in response to John Scanlon's reference to plesiosaurs in his mention of sauropterygians.

Religion in Australia from the 2006 Census:

No religion: 18.67% (16% in 2001)
Christian 63.89% (71% in 2001)
Other 3.46% (Hinduism and Buddism doubled since 2005)
Not Stated 11.2%

A lot of people I've spoken to who ticked Christian only did so as that's how they were raised. They certainly don't go to church or believe creationist non-sense, so the number of people actually non-religious would I feel be a lot higher.
http://www.censusdata.abs.gov.au

However, not good news today that a christian high school in NSW has been cleared of teaching creation in science classes, not a good precedent:
http://www.smh.com.au/news/national/school-in-clear-over-teaching-creat…

Anyways, we're getting there!
http://www.secular.org.au/index.php

I have to say I'm really looking forward to any future paper titled Plunking

Just discovered this site and could not resist a post. Looks like interest has expired in this exchange, but here goes.

Creationist arguments are just tired. First, you cannot support creationist hypotheses with any kind of hard data. Trying to make negative arguments against someone else's hypotheses without any supporting evidence of your own is just garbage science.

Second, don't try to engage in real exchanges with working scientists without knowing more about the subject. In the U.S., we tend to have the outlook that everyone gets their say, no matter how absurd. However, this just wastes time that real scientists do not have.

For instance, arguing over transitional forms is just an old, tired excuse for avoiding real thinking. The concept of transition is pure hindsight. All of the transitional forms were real species that were adapted to specific environments in their time. Their status as transitional comes from the fact that they gave rise to somewhat different descendants who in turn achieved the same thing BEFORE they became extinct. Most species out of the many millions that have existed in various slices of time in the last few billion years have been "dead ends." Only a few have given rise to radically different descendants by experiencing mutations affecting development of some body part, life cycle stage, or physiological process.

Evolution is a complex process with many twists and turns--not the simplistic vision of creationsists. If any one thing bores the crap out of me about creationists it is their relentless simplemindedness. A creationist universe would be just too DULL for words.

By the way, discovery of this fossil creature is a piece of great good fortune. Creationists out there: go look up punctuated equilibrium. Transitions from one sort of creature to another appear to happen quite rapidly in geological time, so partially evolved creatures like Odontochelys semitestacea (toothed turtle with part of a shell in Latin and Greek) are going to be rare because they existed in a rather small slice of time.

Here are some answers to everyone's questions:

Why would the plastron evolve more quickly than the carapace? The plastron is derived from scales (sections of dermis), which will evolve more quickly because not much change in development is required to make them bigger and thicker. Lots of reptiles, like crocodiles, have thick dorsal scales for protection. Evolution of the carapace, by constrast, involved a change in development of the entire rib cage--not something that will likely happen every day.

What advantage do "soft-shelled" turtles gain from their partially degenerate dorsal shell? They are lighter and more mobile. Learn about their lifestyle: these are turtles that specialize in a lifestyle that involves relatively rapid swimming in open water. A heavy shell would just slow them down. The tradeoff is that they are faster and better able to evade their own predators. Also, some of them are LARGE (this alone is protection).

Why would the partial carapace of the fossil turtle be an advantage in natural selection? Even a partial bony shield over the internal organs would have given this guy an edge relative to its predators compared to reptiles with just thickened scales.