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New Papers: The Megalania Chronicles.



I didn't want to take away the thunder from this month's upcoming blockbusters, 
so I went for a TV reference instead.

This one just came out in PNAS.

http://www.pnas.org/content/early/2009/05/15/0810883106.abstract

A central role for venom in predation by Varanus komodoensis (Komodo Dragon) 
and the extinct giant Varanus (Megalania) priscus.

Bryan G. Fry, Stephen Wroe, Wouter Teeuwisse, Matthias J. P. van Osch, Karen 
Moreno, Janette Ingle, Colin McHenry, Toni Ferrara, Phillip Clausen, Holger 
Scheib, Kelly L. Winter, Laura Greisman, Kim Roelantsi,
Louise van der Weerd, Christofer J. Clemente, Eleni Giannakis, Wayne C. 
Hodgson, Sonja Luz, Paolo Martellin, Karthiyani Krishnasamyo,Elazar Kochva, 
Hang Fai Kwok, Denis Scanlon, John Karas, Diane M. Citronr, Ellie J. C. 
Goldstein, Judith E. Mcnaughtan and Janette A. Norman.

Abstract:

he predatory ecology of Varanus komodoensis (Komodo Dragon) has been a subject 
of long-standing interest and considerable conjecture. Here, we investigate the 
roles and potential interplay between cranial mechanics, toxic bacteria, and 
venom. Our analyses point to the presence of a sophisticated combined-arsenal 
killing apparatus. We find that the lightweight skull is relatively poorly 
adapted to generate high bite forces but better adapted to resist high pulling 
loads. We reject the popular notion regarding toxic bacteria utilization. 
Instead, we demonstrate that the effects of deep wounds inflicted are 
potentiated through venom with toxic activities including anticoagulation and 
shock induction. Anatomical comparisons of V. komodoensis with V. (Megalania) 
priscus fossils suggest that the closely related extinct giant was the largest 
venomous animal to have ever lived. 

++++++++++++++++++++++++++++++++++++++++++++++++++++++

The paper is really neat, and not just because I have a slight bias in favour 
of it (though not as much as Tim :)), but because it's the first time an 
extensive anatomical study on the venom glands of a non-traditional venomous 
lizard, has been studied. Turns out 
 remarkably potent, and the "toxic bacteria" angle is more an urban legend than 
anything else. 

I'm not a fan of the continued use of the contentious Toxicofera, and I do 
doubt that Megalania was venomous (though it is a neat idea to entertain), but 
overall this study gives one an idea of the type of comprehensive studies that 
can be done on modern and extinct taxa, using new techniques (i.e. MRIs and FEA 
are more than just pretty pictures). 

My only real worry about this study is that the erroneous view of oras as "bite 
and release" killers will be further propagated. On the bright side, the 
authors do attempt to quell this notion. 

Fry even gave Science News this little "sound bite":

http://www.sciencenews.org/view/generic/id/43907/title/It%E2%80%99s_not_their_dirty_mouths

"Whatâs more, rare sightings of the lizards hunting didnât fit with this 
method. Victims typically died quickly and quietly after going into shock, the 
authors say. âNo oneâs actually seen a Komodo dragon track a prey for three 
days until it dies of septicemia,â Fry says. âItâs an absolute fairy 
tale.â"

Jason

http://reptilis.net

"I am impressed by the fact that we know less about many modern [reptile] types 
than we do of many fossil groups." - Alfred S. Romer