<i>Najash rionegrina</i>, a snake with legs

Posted 19 April 2006 by PZ Myers

It's a busy time for transitional fossil news—first they find a fishapod, and now we've got a Cretaceous snake with legs and a pelvis. One's in the process of gaining legs, the other is in the early stages of losing them.

Najash rionegrina was discovered in a terrestrial fossil deposit in Argentina, which is important in the ongoing debate about whether snakes evolved from marine or terrestrial ancestors. The specimen isn't entirely complete (but enough material is present to unambiguously identify it as a snake), consisting of a partial skull and a section of trunk. It has a sacrum! It has a pelvic girdle! It has hindlimbs, with femora, fibulae, and tibiae! It's a definitive snake with legs, and it's the oldest snake yet found.

Continue reading "Najash rionegrina, a snake with legs" (on Pharyngula)

52 Comments

Anton Mates · 19 April 2006

Yeah, well, obviously this snake is just LOSING the INFORMATION needed to make legs. And also it's gradually getting closer to the ground than its ancestors, which is consistent with the second law of thermodynamics. Doesn't prove anything.

Stevaroni · 19 April 2006

2 new gaps!

Anton Mates · 19 April 2006

From Pharyngula's comments:

PZ, you are too optimist and don't understand how their mind works. Expect creationists to come out at any moment saying that this is a confirmation of Genesis 3.14, in which the serpent is punished by God making it crawl on its belly (implying it had legs before the Fall). Posted by: Alejandro | April 19, 2006 02:20 PM Oh, dang, right. They're going to use this to date the Fall now. Posted by: PZ Myers | April 19, 2006 02:26 PM

improvius · 19 April 2006

This is pretty exciting, even aside from the evo/creo debate. I keep snakes as pets (see my website) , so I'm always interested in news like this. This seems to strongly support the study from a couple of years ago that tended to rule out mosasaurs as snake ancestors based on DNA evidence. That earlier study leaned heavily towards land-based reptiles as their ancenstors, and this could pretty much nail it down. Very cool!

normdoering · 19 April 2006

Are there a lot more people looking for fossils now? I don't remember new species being found at a rate of a couple a week before now.

wamba · 19 April 2006

Yeah, but it's still a ~~snake~~ ~~lizard~~ ~~demon~~ reptile.

wamba · 19 April 2006

Are there a lot more people looking for fossils now? I don't remember new species being found at a rate of a couple a week before now.

I think that since Kitzmiller, every announcement is hyped as proof of evolution by the researchers and the media. I suppose it could have something to do with the schedules of granting agencies, but I'm not positive which agencies would be involved.

Henry J · 19 April 2006

Re "Yeah, but it's still a snake lizard demon reptile."

Not to mention tetrapod, vertebrate, chordate, animal, and eukaryote.

(But does it taste like chicken?)

John Y. Jones · 19 April 2006

To quote shamelessly from the below LiveJournal post, "snakes on a plain!"

http://community.livejournal.com/blindwatchmaker/49741.html

normdoering · 19 April 2006

I think that since Kitzmiller, every announcement is hyped...

You mean they've been finding two new species a week before now and I didn't know?

alienward · 19 April 2006

wamba wrote:

I think that since Kitzmiller, every announcement is hyped as proof of evolution by the researchers and the media. I suppose it could have something to do with the schedules of granting agencies, but I'm not positive which agencies would be involved.

My guess is since these announcements seem to be coming from researchers at universities that aren't in the U.S., those researchers might not even know about Kitzmiller. But maybe every granting agency on the planet gives out their grants on the day U.S. taxes are due...

harold · 19 April 2006

normdoering -

"Are there a lot more people looking for fossils now? I don't remember new species being found at a rate of a couple a week before now."

There are two non-mutually exclusive possibilities.

The first, and the one I favor, is sheer coincidence. There are always a lot of people looking for fossils all the time, and although the "easy pickings" gradually disappear, the sophistication of the seekers expands, so it's hard to say whether major finds will increase or decrease in frequency over time. As far as the timing of the finds, I think this is the explanation. More or less coincidence.

The amount of media attention in the US may be a different matter. Although these finds clearly would have been in the media anyway - it's easy to forget that the US has millions and millions of science lovers, and that major fossil finds always generate news stories - the US media may be especially alert for pro-evolution pieces these days.

Remember, the media actually started to see the light at the Kansas kangaroo trial. Reporters flocked to it, because ID was still perceived as a valid controversy. As members of the general public always are, they were disappointed in what they say. Kitzmiller may have accelerated the trend.

noturus · 19 April 2006
What are they going to say about that slight delay though? "God told the snake it was going to have to walketh on its belly and yea, through a process of each generation of snake getting smaller and smaller legs over a period of millions of years lo! it finally came to pass?"

noturus · 19 April 2006
What are they going to say about that slight delay though? "God told the snake it was going to have to walketh on its belly and yea, through a process of each generation of snake legs getting smaller and smaller legs over a period of millions of years lo! it finally came to pass?"

fnxtr · 19 April 2006
Makes me wonder what the reproductive/survival advantage was to losing legs... has there been any speculation on this front?

Jason · 19 April 2006
See? Genesis and Gerard Schroder are right!

Glen Davidson · 19 April 2006
Makes me wonder what the reproductive/survival advantage was to losing legs... has there been any speculation on this front?
In the past it was speculated that snakes lost their legs to be able to move more readily underground, through smaller tunnels, etc.--in their pursuit of burrowing rodents and the like. Legless lizards seem to have done this in some cases, though it occurs to me that the best examples that I know about involve legless and nearly legless lizards burrowing through sand, not through tunnels bored by other animals. Actually, to speak of the hyping of "missing links", we have apparent intermediates today in the lizards that seem to be on the way to losing their small and not very functional legs (of course whether or not they really are "intermediates" to some snake-like external forms depends on future selective pressures). It might be of some value to start publicizing the evolution that is existing all around us, rather than focusing on the poor remains of long-dead bones of past evolutions. Presumably other explanations than burrowing, whatever the media, are quite possible for the evolution of leglessness. I'd assume that predators living in very dense vegetation might tend to lose legs. Perhaps tree climbing, particularly along very thin and consequently weak branches could also be helped through leglessness and the very long bodies possible in snakes. Still, we seem to be watching burrowing lizards losing their legs at this time, which makes the burrowing hypothesis a good one. Glen D http://tinyurl.com/b8ykm

Peter Henderson · 19 April 2006
Expect something to appear on the AIG website with the line "Its still only a KIND of snake" or something similar (this is what they usually say when these fossils turn up).
It may take a few days this time since Ham and co. are in the UK at the moment attending our version of the Mega-Conference in Derbyshire. (Is anyone from the Panda's Thumb doing a report on this by the way ?)
He says on his blog that he's staying on in the UK for a few days after the event, apparently to do some TV interviews. Mr. Ham didn't say which channels he's on but I'd keep an eye on Sky News, News 24 and the Heaven and Earth show this Sunday morning on BBC 1. Also, he may well appear on Revelation TV around 9 PM next week (Sky Digital 765) at some stage !

normdoering · 19 April 2006
fnxtr wrote:
Makes me wonder what the reproductive/survival advantage was to losing legs... has there been any speculation on this front?
There may not be an advantage in itself, rather lack of enough disadvantage if you're abdominal muscles will let you crawl like a snake can. Snakes can move fast. There is a possibility that lack of limbs let the first snakes crawl into the boroughs of very small creatures the legged ones couldn't fit into thus giving them an extra niche for meal eating their limbed cousins didn't have.

'Rev Dr' Lenny Flank · 19 April 2006
This is pretty exciting, even aside from the evo/creo debate. I keep snakes as pets (see my website) , so I'm always interested in news like this. This seems to strongly support the study from a couple of years ago that tended to rule out mosasaurs as snake ancestors based on DNA evidence. That earlier study leaned heavily towards land-based reptiles as their ancenstors, and this could pretty much nail it down. Very cool!
Where's Dr Fry to say "I told you so!!". ;) Actually, I want to see a skull first -- I want to see if it really has any "burrowing adaptations".

'Rev Dr' Lenny Flank · 19 April 2006
Makes me wonder what the reproductive/survival advantage was to losing legs... has there been any speculation on this front?
If they were burrowers, losing legs makes it easier to burrow (there are also some living lizards that spend most of their tiem burrowing and lost all their legs). If they were swimmers, streamlining makes them better and faster swimmers.

Glen Davidson · 19 April 2006
I found a link showing one of the lizards that is losing its legs, and in fact its legs are considered "vestigial". And it does spend its time in the debris and burrowing in detritus and apparently the ground as well. Not a great picture, but still a great specimen of evolution:
http://tinyurl.com/ry69n
Glen D
http://tinyurl.com/b8ykm

Steviepinhead · 19 April 2006
And if they were beer drinkers, they could fit more of themselves in the vat, pitcher, or schooner, all the while displacing less of the nectar with their dwindling limbs...

'Rev Dr' Lenny Flank · 19 April 2006
I keep snakes as pets (see my website)
Nice to see a fellow herper. :)

Pizza Woman · 19 April 2006
Pinhead said:
And if they were beer drinkers, they could fit more of themselves in the vat, pitcher, or schooner, all the while displacing less of the nectar with their dwindling limbs...
Nice to see a fellow burper. :-)

Shalini · 19 April 2006
God of the gaps, here we go again!

KiwiInOz · 19 April 2006
As opposed to Pizza Women and Stevie Pinhead's god of the vats?

Zim · 19 April 2006
And if they were beer drinkers, they could fit more of themselves in the vat, pitcher, or schooner, all the while displacing less of the nectar with their dwindling limbs...
— steviepinhead
Obviously, there's more than one way to get legless.

Stuart Weinstein · 19 April 2006
Yeah.. but its still a snake...

Alan Kellogg · 19 April 2006
If you helped an anaconda with a gassy stomach by patting it on the back would you be a herper burper?

Alan Kellogg · 19 April 2006
Yeah.. but its still a snake...
— Stuart Weinstein
Upgrades from early reptile to advanced primate take more than one day in the shop.

minusRusty · 19 April 2006
And if they were beer drinkers, they could fit more of themselves in the vat, pitcher, or schooner, all the while displacing less of the nectar with their dwindling limbs...
— steviepinhead

Obviously, there's more than one way to get legless.
— Zim
The selection pressure clearly works in favor of minimizing or eliminating damage from cranial/granite impact after extended feeding! *Hoist*

Shalini · 19 April 2006
"As opposed to Pizza Women and Stevie Pinhead's god of the vats?"
Exactly.
;-)

MrDarwin · 20 April 2006
Any minute now the Discovery Institute will put out something saying that (1) "Intelligent Design" doesn't have a problem with transitional species, and doesn't necessarily predict there WON'T be transitional species; (2) for some convoluted reason this ISN'T a transitional species; and (3) every discovery like this just reminds us how few transitional species evolutionary biologists can come up with.
I have to wonder just what it will take before the creationists and IDers will accept something as truly "transitional". I think they really expect us to produce a living and breathing critter that is half-fish and half-monkey, like those taxidermic monstrosities that are displayed at Ripley's Believe It Or Not! museums.

Gordon · 20 April 2006
As a fellow herper, I think snakes that are arboreal move more swiftly through trees and the brush without legs hindering them too.
A pizza girl? Has Lenny change pizza genders? I hope she has the same beer wit. What is her vita? Hic!

Keith Douglas · 20 April 2006
I seem to remember that fossils of snakes with pelvises (or was that extant species?) had been found previously. Is that correct?

Anton Mates · 20 April 2006
I have to wonder just what it will take before the creationists and IDers will accept something as truly "transitional". I think they really expect us to produce a living and breathing critter that is half-fish and half-monkey, like those taxidermic monstrosities that are displayed at Ripley's Believe It Or Not! museums.
— MrDarwin
Nah, they'd just assume scientists whipped it up, in flagrant violation of our federal anti-manimal policy. One of the wonderful things about creationists is that they believe biologists are too dumb to know that their theory violates fundamental laws of physics and logic, but simultaneously are so smart that they're already pumping out human clones and man-animals left and right.

Anton Mates · 20 April 2006
I seem to remember that fossils of snakes with pelvises (or was that extant species?) had been found previously. Is that correct?
— Keith Douglas
According to the paper, other fossil snakes have been found with hindlimbs, but they lacked a fully developed pelvis (no sacrum).

The Sanity Inspector · 20 April 2006
It's a definitive snake with legs
[insert lawyer joke here]

Gordon · 20 April 2006
It's a definitive snake with legs [insert lawyer joke here]
— The Sanity Inspector
Humm....Lawyer jokes, I know some. What do you call a snake with legs? Creationist: The snake that trick Adam. ID Creationist: A "kind" with an Irreducibility Persecution Complex. Scientist: Ancestor of modern snakes. Red Neck: Does it taste like chicken with Lenny's beer? Lawyer: A liability Appendage Lawsuit. Q: What's the difference between a lawyer and a snake? A: You don't know either? A blind snake meets a blind rabbit. To figure out what kind of creature it has come across, the snake coils itself around the rabbit. "You're warm and fluffy, you have long ears, strong hind legs and a cold, twitching nose. You must be a bunny rabbit!" "Right," says the rabbit. "Now let me try to feel what you are." The rabbit cuddles up next to the snake. "You're cold, you're scaly, and you have a forked tongue," the rabbit says. "You must be a lawyer!" Q - What's the difference between a dead lawyer in the middle of the road and a dead snake in the middle of the road? A - The dead snake has skid marks in front of it.

k.e. · 20 April 2006
Hah ....a snake with legs ?
Get out of here, next you'll be saying it can talk!!!(Gen. 3)
Of course talking animals are just a figment of the imagination, but I did like the Herper Burper joke.

'Rev Dr' Lenny Flank · 20 April 2006
I seem to remember that fossils of snakes with pelvises (or was that extant species?) had been found previously. Is that correct?
Yes and no. Fossil snakes have indeed been found with vestigial rear limbs, and living pythons still have them. And they have vestigial pelvic bones. What they DON'T have, though, is a sacrum that attaches their limbs to the spinal column.

Steviepinhead · 20 April 2006
k.e.:
Of course talking animals are just a figment of the imagination, but I did like the Herper Burper joke.
I've come up with a "slurper" post, but I was holding that in reserrve that for the very final dregs of the "latest religious war" thread...

Henry J · 20 April 2006
Anton,
Re "One of the wonderful things about creationists is that they believe biologists are too dumb to know that their theory violates fundamental laws of physics and logic, but simultaneously are so smart that they're already pumping out human clones and man-animals left and right."
Yep. How anybody could claim that tens of thousands of scientists, working over several decades, could manage to both overlook basic principles and still produce massive amount of usable results - well, the "logic" of that escapes me as well.
Henry

Randy · 21 April 2006
Just when you think Najash is adding evidence for Snake evolution, along comes a story showing snakes are designed:

Pa. Professor Develops Snake-Like Robots By DANIEL LOVERING, Associated Press Writer
[Note: the Pa prof in question is not famous ID advocate Michael Behe]
For most people, snakes seem unpleasant or even threatening. But Howie Choset sees in their delicate movements a way to save lives.
The Carnegie Mellon University professor has spent years developing snake-like robots he hopes will eventually slither through collapsed buildings in search of trapped victims. In recent weeks, Choset and some of his students got the remote-controlled devices to climb up and around pipes....
for the rest of the story see http://news.yahoo.com/s/ap/20060419/ap_on_hi_te/snake_robots_1
(don't jump on me, I'm just kidding, but of course ID advocates have used the "engineers are mimicking nature's designs, therefore natural desing must be intelligent design" agument for a long time, so lets see if they pick this up.)

kidotre · 21 April 2006
People tend to forget that we only grasp glimpses of the real picture through rare and scarce discoveries like this one.
For all we know snakes could have very well come out of an aquatic environment, evolved towards having legs instead of a swiming gear to loose them at a later stage. Dolphins and whales are here to remind us that such a loop has already happened.
This is an interesting discovery but it does not prove anything it just strenghen the likelihood of snakes being the evolution of a terrestrial lizard. This is the boldest statement we can make as a result of this discovery.
Evolution is like a huge puzzle with billions of pieces and we only possess a few thousands of them.
And why do you people even bother mentioning creationism? Fanatical idiots are not worth mentioning in what should be a scientific discussion.

steve s · 21 April 2006
Najash rionegrina, a snake with legs PZ Myers posted Entry 2224 on April 19, 2006 02:08 PM.
Najash rionegrina aeroplanus: a snake with legs, on a Motherf*cking plane.

Peter Henderson · 22 April 2006
Here we go again:
http://www.answersingenesis.org/docs2006/0421legs.asp

k.e. · 22 April 2006
AiG is cautious about comparing this fossil snake to the serpent in Genesis 3:14. First, we really don't know much about the serpent's anatomy anyway. Yet we can offer a reasonable guess that it apparently was once able to crawl or walk; after the serpent was cursed, it was pronounced that "on thy belly shalt thou go," suggesting that it previously moved using appendages.5 Also, this fossil probably resulted during Noah's Flood, an event that took place about 1,500 years after the serpent was cursed to crawl on its belly.
Cautious? Oh come now why be so coy? A talking snake would have to have tonsils and it is well known that tonsils don't fossilize so there is no evidence to NOT support talking snakes. Of course legs would have been useful for AiG's talking snake, its easier to lean against a bar when you proposition a girl, easier to get a 'leg over', better for walking and toes are useful to put between ones teeth when you want to whistle Eve. Psst.....hey Eve did you hear about the snake with the golden tonsils? Why no Mister Snake .....(big eyes) pray do tell (giggle). Hrmmm ....well come back to my place and I'll show you. OK Mister Snake but it better be good.

Anton Mates · 22 April 2006
Yeah, well, obviously this snake is just LOSING the INFORMATION needed to make legs.
— Attempting to parody creationists, I

Even if it could be shown that snakes at one time had legs, this actually fits within the creationist model. The loss of features like legs is a type of degeneration, which is the opposite of molecules-to-man evolution (which requires new genetic information for advancement)
— Answers in Genesis proved that I shouldn't have bothered when they
Oh, and I note that this article is dated April 21, and they say:
With such a new claim, AiG researchers will need to devote some time to evaluate the Nature article when it appears.
Meanwhile, the Najash article actually came out in the April 20 issue. At least creationists are consistent about being stuck in the past....

Henry J · 23 April 2006
Re "Yeah, well, obviously this snake is just LOSING the INFORMATION needed to make legs."
But gaining the information needed to sidewind across sand, or crawl using just its scales, or climb trees without having claws to grip with.
Could a lizard that lost its limbs in an accident do those things? I rather doubt it.
Henry

'Rev Dr' Lenny Flank · 23 April 2006
Now that Dr Fry is here, I'll repeat my earlier post:
Where's Dr Fry to say "I told you so!!". ;)