I know what your thinking, and I have no idea what happened to May either.? Things have been busy for me IRL, but I didn’t want to leave the site hanging.
Anyway, I have some time off coming,? so I’ll be posting something new soon.
Till then: R.I.P. George Carlin. You will be missed, but never replaced.
I’m a little behind on this now 3 day old story. It’s been hard to get back into the proverbial swing of things. I believe part of it has to do with the large dearth of nothing that occurred during my “vacation.” The other part probably has to do with being bloody busy. >:)
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!
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
Herrel A, Huyghe K, Vanhooydonck B, Backeljau T, Breugelmans K, Grbac I, Van Damme R, Irschick DJ. (2008) Rapid large-scale evolutionary divergence in morphology and performance associated with exploitation of a different dietary resource. Proc Natl Acad Sci U S A. 105(12):4792-4795.
The last few days of my Sydney trip were spent in relative internet silence. During my stay Windows Vista had incurred one of those OS crippling problems that it is so often known for. In this case, I was trying to watch a video of something that wouldn’t open in anything short of Windows Media Player. I had had the media player open to play some music at the time (Tool FTW!), and Vista couldn’t seem to decide which application had priority (*Hint* it would be the one that I am repeatedly trying to open).
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.
I was hoping I would have been back in the saddle by now, but not so much yet. I’m spending the rest of this week in Sydney, Australia (beautiful place, even if I did come at the wrong time of year).
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
I’ll be off for the next couple of days. I have an overseas trip to take. Once I’ve settled in, things should be back to normal. Till then, the site is going to be slow…
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
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.
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
Recently published in Proceedings of the Royal Society B, scientists in Brazil have found the remains of a prehistoric crocodyliforme that used to roam the oceans of the Paleocene.
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.
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
So I’ve been working on dragging the rest of my site into the 21st century. While most of this work has been just transcribing of old code to new code, I didn’t want to just wind up rehashing all of my old info.
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.
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
It has been a painfully slow week in terms of herpetology and paleo. I’ve noticed that when I tend to talk about things being slow, there is usually a sudden surge in topics. Here’s hoping that will happen this time too.
Until then, let’s all congratulate Chrysemys picta bellii for becoming Colorado’s official state reptile.
More soon (hopefully)
~Jura
Astute observers may remember the news story about the mysterious death of gharials in the Yamuna river.
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.
