Here’s the story.

And here’s a brief excerpt:

In 1971, scientists transplanted five adult pairs of the reptiles from their original island home in Pod Kopiste to the tiny neighboring island of Pod Mrcaru, both in the south Adriatic Sea.

…

After scientists transplanted the reptiles, the Croatian War of Independence erupted, ending in the mid-1990s. The researchers couldn’t get back to island because of the war, Irschick said.

…

The transplanted lizards adapted to their new environment in ways that expedited their evolution physically, Irschick explained.

The big and most interesting part of this story is how these amazing little saurians evolved new behaviours, a majour change in diet and they evolved a new physical characteristic (cecal valves in the intestine).

All of this happened in only 36 years!

Podarcis sicula; a representative of the species used in the study. Also, a bit of a show-off.

That’s not just amazing, it’s bloody phenomenal!

Prior to this study, the only thing that even came close (in tetrapods) was an “earlier” study by Jonathan Losos on Caribbean Anolis. In one study, Losos found rapid evolution of longer hindlimbs in introduced species of Anolis in as little as 14 years. The results were interesting, but were more a case of an amazing case of Natural Selection changing the frequency of a naturally occurring variation. This latest study is a little different. The kind of changes noticed here are normally the ones talked about in insects, or bacteria (i.e. large phenotypic changes).

It has been argued by some that this finding might be viewed as more fuel for the nutty creationist movement. Proving that evolution can occur quickly, means that creationists can argue better for a Young Earth. However, since the core tenet of creationism is that life does not evolve, this would do quite the opposite for them.

What this does bolster evidence for is Gould and Eldredge’s theory of Punctuated Equilibria.

The theory states that most of the time, populations of organisms remain fixed and stable, with very little evolution occurring. Then, when a portion of the population gets segregated and/or are forced to adapt to a different environment, evolution kicks into high gear. Change happens rapidly, and the new population becomes a new species.

That was a bit simplified, but you get the point.

Gould and Eldredge used fossil trilobites to support their case. Studies on plants and insects have also shown that this type of speedy evolution can happen. Now we have proof in a relatively large vertebrate as well.

I think these kinds of observations are good for the biological and paleontological sciences. I think that there is a tendency for paleontologists to “ride the brake” with evolution. Always insisting on measuring evolutionary change in millions and tens of millions of years. I don’t have a problem with this type of thinking when one is looking at changes in whole families and genera, but it seems very unlikely that many of the species seen in the fossil record were evolving so slowly from species to species (e.g. Tyrannosaurs, or mosasaurs). Showing that speedy evolution does happen, helps to better support a more “punctuated” view of evolution. One in which whole genera can arise in as little as a few thousand (or hundred thousand) years.

Geologically speaking; that’s pretty damned fast.

~Jura

Long story short, Windows Explorer crashed.

Then it restarted.

Then it crashed again.

Lather, rinse, repeat.

Somewhere along the lines a registry change occurred that didn’t get put back and so Explorer got stuck in an infinite loop. I had already dealt with this exact same problem when Explorer would keep crashing upon viewing the C drive. This time, though, it was on the desktop. This meant I couldn’t access most of the programs without doing long work arounds (e.g. opening programs in Firefox). It didn’t matter anyway. Even after a registry clean, or two, Explorer maintained its broken status. The only way to fix it would be to go into the registry, find the problem and manually change it. The only way to do that would have been to go through the command line interface (even Safe mode kept repeatedly crashing).

Well anyone who has hacked around with Windows knows how awkward it is to deal with their token command lines. In the end I wound up reverting back to the factory conditions.

Now I’m back in the states and my PC is Vista free. Like legions of other former Vista users, I “downgraded” to XP again. Now my PC runs faster, rarely crashes and has more free space.

Note to Microsoft: You might want to up the development of Windows 7 a little. As it stands now, Vista is pushing to take the crown away from ME as the worst MS operating system in history.

In other news Australia was a blast.

There still hasn’t been much in the way of herp news. Though there was a recent paper that came out on turtle origins that I feel the urge to talk about. We’ll see though.

For those still in the U.S. David Attenborough’s Life in Cold Blood series should just be starting up on Animal Planet. Sounds like a ripe time for me to pick up the series on DVD now. On the bright side, David Attenborough’s heavy involvement in the series should mean that American audiences should be treated to the same top notch narration that the U.K. got.

That’s it for now. For the Aussie locals, I’ll be killing time in Randwick Junction, Coogee Bay, and UNSW. If you guys have any suggestions on stuff to do, please feel free to drop me a line.

~Jura

Not like it hasn’t already been slow. During the past week, the only real news in the herp world seems to be that the news organizations have finally found the tuatara story.

Maybe I’ll get lucky, and some big herp news will come out during my interim.

~Jura

High speed pictures of Cosymbotus platyurus running up a vertical surface

I don’t know why, but for some reason herp news stories always seem to come in twos.

Announced today (or yesterday by the time I get this posted), scientists at UC Berkeley have found geckos to be one of the most agile climbing animals ever studied.

Jusufi, A., Goldman, D.I., Revzen, S. and Full, R.J. 2008. Active tails enhance arboreal acrobatics in geckos. PNAS. Vol. 105: 4215-4219.

Goldman et al studied geckos of the species Cosymbotus platyurus. Lizards were ran on vertical surfaces that had various degrees of traction. To induce slippage, some of the surfaces were equipped with a section of dry erase board which had been covered with dry erase ink.

Apparently geckos can’t grab onto everything after all.

By placing the lizards at various sections of these surfaces, the researchers were able to get them to either slightly slip, almost fall, or completely.

The results were interesting.

For starters, lizards ran up the surfaces with their tails off the “ground” the entire time. That is, unless they slipped. Immediately upon slipping, the tail would come down and act as a brace to keep the body from tilting back and falling off. The most dramatic case of this came from an experiment in which the researchers had dropped the lizards down straight on the dry erase board. The gecko in question fell backward, caught itself with its hindlegs, and tail. The body fell away from the wall about 60° before the tail fully caught the animal, and it was able to right itself again (see photo above).

By far the neatest test performed involved getting the lizards and placing them in a supine (belly up) position on a light polyethylene foil held together with four fishing lines. Then by gently shaking the platform (or waiting for the lizards to slip), they were able to dislodge the geckos and send them plummeting to their doom.

Doom, in this case, being an embellishment for safely padded landing area.

The lizards fell 2 meters down. High speed cameras recorded the first 23cm of that trip. These little guys were able to go from fully upside down to rightside up in only 106 milliseconds.

Let me make sure I’m getting the full effect of that result across:

These geckos were able to reorient themselves in 106 THOUSANDTHS of a second, or .00106 seconds!!

Geckos now hold the record for fasting righting time of a vertebrate without the aid of wings.

This unique feat is accomplished by rotating the substantial tail on these animals. As they fall, the tail is rotated counterclockwise. Physics does the rest. Conservation of angular momentum takes over and the entire body winds up turning clockwise, thus reorienting the animal. This phenomenon is known as: air righting with zero angular momentum. It’s the same effect that cats are often lauded for.

Cats, and other air righting mammals (e.g. rats) accomplish their air righting maneuvers by flexing and twisting their backs. Evolution removed the need/use for a large powerful tail in mammals, hundreds of millions of years ago.

No so with lizards. Thanks to this “fifth appendage” all the geckos needed to do was use their tail like a little propeller. There is, however, a caveat.

Cosymbotus platyurus, like most geckos, is capable of caudal autotomy (i.e. voluntary tail loss). Would lizards that have lost their tails still be able to right themselves?

Jusufi et al tested this scenario too. They carefully elicited the loss of the tails in some of their experimental animals, and then subjected them to the same tests as before. The results were striking. Tailless lizards were unable to keep themselves from falling in the vertical slip tests. When they were dropped supine, they still righted themselves, but the rate at which they did it was much slower. Tailless geckos relied on the kind of back flexion and twisting seen in mammals.

Taking things one step further, the authours decided to see how much of a role the tail plays during free fall. They placed the lizards in vertically oriented wind tunnels and “set them free.” The results were unequivocal; the tail acts as the main rudder in these guys. Geckos would rotate their tails counterclockwise to turn left, and clockwise to turn right, while the body remained a stationary airfoil.

The overall results demonstrated the incredible importance of tails in geckos. This is interesting given that so many geckos are also willing to part with their tails when in danger.

It seems that in the natural world it’s better to risk knocking oneself out from a fall, than to risk getting eaten by a bodypart that stubbornly stays on.
It’s unfortunate that the researchers didn’t test the air-righting ability of these geckos after their tails had grown back. Judging from the videos it appears that all the work is being generated by the proximal tail muscles; which stay even after autotomy. Theoretically then, it should still work in a regrown tail.

Oh yeah, did I forget to mention, Jusufi et al not only recorded everything, but they made them available for everyone to watch.

They’re all worth watching. It’s cool to see just how fast these little geckos are.

And so the “slow, sluggish reptile” stereotype, receives yet another nail in its coffin.

~Jura

The critter has been given the name: Guarinisuchus munizi, which translates out to: Muniz’s warrior crocodile. Despite the “crocodile” in its name, G.munizi was not that closely related to true crocodylians. It was more closely related to the giant pholidosaur Sarcosuchus imperator.

The neat thing about the paper, was not so much the crocodyliforme itself. At 3 meters, G.munizi was small for a dyrosaurid. Rather, it is the implications of this find that are intriguing.

Dyrosaurids first appeared in the Late Cretaceous Period (Maastrichtian age) . During this time they were very scarce, and hard to find. They were shallow marine predators, and in the Cretaceous that niche was already filled by another group of animals: the mosasaurs.

These ancient sea lizards had one of the fastest diversification rates of any vertebrate group studied. They went from nothing to dozens of species with a cosmopolitan distribution and domination of many ecological niches. All of this occurred in the space of only 25 million years! That’s faster than mammal diversification, and faster than dinosaur diversification.

Mosasaurs were showing no signs of slowing down right up to the K/T asteroid event. After that, they disappeared.

That’s when the dyrosaurids started taking over.

Analysis of Guarinisuchus munizi material has found that it is more closely related to African taxa than its geographically closer relatives in North America. This suggests that dyrosaurids had crossed the Atlantic ocean from Africa sometime before the K/T event. After said event, the vacant niches left by the mosasaurs were quickly snatched up by these dyrosaurids, as they moved up North, and eventually, worldwide.

It is interesting to see how this group of animals was apparently held back during their earlier evolution. Yet, if they hadn’t been held back; if they had out-competed mosasaurs for the top spot in the food chain, then they wouldn’t have survived the K/T event.

It’s funny - and completely make believe - but it almost appears as if dyrosaurids were already setting themselves up to take over. It’s almost as if they knew…

They didn’t of course, but it’s fun to pretend that they did. >:)

~Jura

I mean there are only so many ways that one can remix the same stuff.

As the meat of the site was meant to contain species information, I thought it would be nice if my first revamped species page, was a new one.

So I went and made one.

I had been meaning to write about Chlamydosaurus kingii (i.e. the frilled lizard) for a long time now. They have been a lacertilian favourite of mine. It’s rather sad that there is not much written about these guys, save for the occasional herpetocultural article, or the rather glib Wikipedia article.

Now, while I could have just gone and updated Wikipedia with this info, I wanted to have it on my site first. I mean, if I’m going to be the person to flesh out this species, then it’s only fair that I give my site first dibs.

Much of the article was culled from data in Shine & Lambeck, 1989. This was, and still is the most comprehensive review of this species. It is interesting to note that this reference is used in the Wikipedia article, but not for any of the more interesting info.

For example, as can be read in the article, frilled lizards are unique in being the only extant reptile that is an obligate biped. You’d think that would get more attention. Hmmph, it must be that distracting frill. :)

There you go. A new update with actual new content.

This might just become a pattern. :)

~Jura

Until then, let’s all congratulate Chrysemys picta bellii for becoming Colorado’s official state reptile.

More soon (hopefully)

~Jura

A recent report by the National Geographic Society suggests the the culprit is the food being fed to these animals.

They suggested that as the fish moved from polluted rivers into the Chambal, they ingested chemicals in their tissues. When the gharials eat the fish, these harmful substances pass into their systems.

One of the international vets who has been working on the case, Paolo Martelli, explained to the publication: “When cold temperatures came, the uric acid precipitated [separated into a fine suspension of solid particles] and began causing problems.

“So winter coupled with excess food could have made the gharials more susceptible to the toxin.”

One step closer, and none too soon either. 110 animals have died from this poisoning. Given that the wild population is estimated at 200, or less individuals this was a setback that these animals could not afford.

The first one is the biggest, as it received a news story.

Uriona, T.J., and Farmer, C.G. 2008. Recruitment of the diaphragmaticus, ischiopubis and other respiratory muscles to control pitch and roll in the American alligator (Alligator mississippiensis). J. Exp. Biol. Vol. 211: 1141-1147 doi: 10.1242/jeb.015339

Abstract

We used electromyography on juvenile American alligators to test the hypothesis that the following muscles, which are known to play a role in respiration, are recruited for aquatic locomotion: M. diaphragmaticus, M. ischiopubis, M. rectus abdominis, M. intercostalis internus, and the M. transversus abdominis. We found no activity with locomotion in the transversus. The diaphragmaticus, ischiopubis, rectus abdominis and internal intercostals were active when the animals executed a head-down dive from a horizontal posture. Weights attached to the base of the tail resulted in greater electrical activity of diaphragmaticus, ischiopubis and rectus muscles than when weights were attached to the head, supporting a role of this musculature in locomotion. The diaphragmaticus and rectus abdominis were active unilaterally with rolling maneuvers. Although the function of these muscles in locomotion has previously been unrecognized, these data raise the possibility that the locomotor function arose when Crocodylomorpha assumed a semi-aquatic existence and that the musculoskeletal complex was secondarily recruited to supplement ventilation.

Scientists at the University of Utah have discovered the unique internal subtleties that allow crocodylians to sink, rise, pitch and roll; all without disturbing the water (much). It turns out that the main muscles used for breathing, are also used to actually shift the lungs within the body!

That’s just crazy awesome. Uriona & Farmer’s work raises the question of how prevalent this ability is in other semi-aquatic animals (e.g. seals, terrapins, manatees). By shifting the lungs further back in the body, crocodylians are able to change their local density. This allows the front, or back of the animal to rise and sink separately from the rest of the body. So too does moving the lungs from side to side allow for rolling in the water. All of this can occur without the need to move any external body parts. This means no extra turbulence gets created in the water, thus allowing crocodylians to better sneak up on their fishy, or fleshy prey.

Baby crocodiles exhibiting their unique pulmonary powers.

If anything, it sure speaks to why crocodyliformes have held dominion over the semi-aquatic niche for over 200 million years. Uriona and Farmer do suggest that the ability of these respiratory muscles to do this might not be an exaptation. Rather, this might have been the initial impetus behind the evolution of these muscles. Only later would they have been exapted to help with breathing on land. Though the authours provide some good parsimonious reasons for why this may be (basically it would take less evolutionary steps to accomplish than the other way around), it doesn’t really jive with the fossil evidence. Part of the reason why the crocodylian diaphragm works, is because the pubis (the forepart of the hip bone in most animals, and the part that juts out so prominently in theropod dinosaurs), is mobile. This mobility occurred early on in crocodyliforme evolution, with the crocodylomorph Protosuchus having a pubis that was almost mobile. The problem arises when one looks at this early crocodylomorph. Protosuchus was obviously terrestrial. If Protosuchus was evolving a mobile pubis already, then it was doubtful that it was being used to allow lung shifting in the body (an ability that is helpful when underwater, but pretty pointless on land). Furthermore, Crocodylia proper is the umpteenth time that crocodyliformes have returned to a semi-aquatic existence. It is doubtful that all the numerous land outings that occurred during crocodyliforme evolution, would have retained the ability to move the lungs to and fro. It seems far more likely that this was an ability that evolved in Crocodylia, or somewhere close by on the evolutionary tree, in some taxa that was still semi-aquatic.

Protosuchus richardsoni. An example of an early crocodylomorph.

Of course it is also possible that crocodyliforme phylogeny is just all f-ed up. With the amount of convergence rampant in that lot, this remains a distinct possibility.

Either way this is a cool discovery, and one worthy of adding to the crocodylian pages.

The second paper also comes from the Journal of Experimental Biology. This one involves lizards.

McElroy, E.J., Hickey, K.L., Reilly, S.M. 2008. The correlated evolution of biomechanics, gait and foraging mode in lizards. J. Exp. Biol. Vol. 211: 1029-1040. doi: 10.1242/jeb.015503

Abstract

Foraging mode has molded the evolution of many aspects of lizard biology. From a basic sit-and-wait sprinting feeding strategy, several lizard groups have evolved a wide foraging strategy, slowly moving through the environment using their highly developed chemosensory systems to locate prey. We studied locomotor performance, whole-body mechanics and gaits in a phylogenetic array of lizards that use sit-and-wait and wide-foraging strategies to contrast the functional differences associated with the need for speed vs slow continuous movement during foraging. Using multivariate and phylogenetic comparative analyses we tested for patterns of covariation in gaits and locomotor mechanics in relation to foraging mode. Sit-and-wait species used only fast speeds and trotting gaits coupled with running (bouncing) mechanics. Different wide-foraging species independently evolved slower locomotion with walking (vaulting) mechanics coupled with several different walking gaits, some of which have evolved several times. Most wide foragers retain the running mechanics with trotting gaits observed in sit-and-wait lizards, but some wide foragers have evolved very slow (high duty factor) running mechanics. In addition, three evolutionary reversals back to sit-and-wait foraging are coupled with the loss of walking mechanics. These findings provide strong evidence that foraging mode drives the evolution of biomechanics and gaits in lizards and that there are several ways to evolve slower locomotion. In addition, the different gaits used to walk slowly appear to match the ecological and behavioral challenges of the species that use them. Trotting appears to be a functionally stable strategy in lizards not necessarily related to whole-body mechanics or speed.

I haven’t had a chance to read much more than what was written already. I do take a bit of offense to the authours referring to scleroglossan foraging technique as “slow,” but what are you going to do?

I do find it interesting that lizards seem to have lost the ability to “walk” numerous times. That almost seems bizarre. The study points out that ecology produces heavy pressures on lizards in terms of their locomotion type. This is extremely pertinent given how often one hears the old (and wrong!) adage about “reptiles” being incapable of intense aerobic activity.

According to the above study (among others), it all depends on the animals being tested.

There we go. Two really cool papers on reptiles, being released in one day.

~Jura

Yes, I know. I used jive. I’m sorry.