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Re: The Megalania Chronicles



Jason/Jura <pristichampsus@yahoo.com> wrote:


> 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.


Just an update... the paper is now officially out in print form.

 
> The paper is really neat, and not just because I have a slight bias in 
> favour of it (though not as much as Tim :)), 


:-)  My sole contribution to the work was moral support, as spouse of one of 
the co-authors.  


> 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), 


I'm skeptical of any clade based predominantly on molecular phylogenetic 
evidence.  But the claim that _Megalania_ (now sunk into _Varanus_) was "the 
largest venomous animal to have ever lived" is certainly a neat idea.  

Mosasaurs also fall within the Toxicofera, suggesting that venom glands were 
primitive for mosasaurs too (*if* the Toxicofera hypothesis is valid).  I'm not 
necessarily saying mosasaurs were venomous, but applying phylogenetic 
bracketing implies that venom was at least present in their ancestors.  
Apparently, the idea of venomous mosasaurs is not new...

http://scienceblogs.com/tetrapodzoology/2009/04/tongues_venom_goronyosaurus.php


This reminded me of reports of a venomous theropod from the Cretaceous of 
Mexico.  The hypothesis is based on a single tooth.

http://dml.cmnh.org/2002Aug/msg00551.html
http://dml.cmnh.org/2004Jul/msg00042.html

Given that the tooth in question was only ~ 2cm long, there's little chance of 
the theropod (even if venomous) outranking "_Megalania_".

The Late Permian therapsid _Euchambersia_ (Therocephalia) has also been 
regarded as venomous, on more solid grounds.  The venom-producing glands would 
have been held in a recess behind the canine teeth, which were grooved.  I 
don't know how large _Euchambersia_ was, but a close relative (_Moschorhinus_) 
has been said to have "skull dimensions [that] range from those of a large 
monitor lizard to those of a lion" (Van Valkenburgh & Jenkins, 2002).



Cheers

Tim