Re: lizard jaws

["King, Norm" <nking.ucs@smtp.usi.edu>]

Thanks to those who responded.  Graeme Barden's observations on Komodo 
dragons suggests that while the construction of their skulls/jaws 
theoretically (read that: "in my ignorance of what they're actually 
like")
would allow them to work like snake jaws (to a degree, anyway), the 
animals don't actually use their jaws that way.  So much for inferring 
behavior from anatomy!

Aaron Feuk seems to have some references.  I'd love to have them, and I 
can pursue it in the literature myself.  A direct line would be 
appropriate.

Nick Pharris' response made me go back to my initial posting to see where 
I went wrong.  I don't want to trouble anybody to tell me what I already 
know--that's just a waste of time.  I'll try to word my questions more 
precisely.  I know their anatomy, but was hoping to find out what they 
ACTUALLY do.

Here is some more background, in case anybody else is interested.  
Squamates MAY have as many as eight kinetic joints in their skulls (my 
sources differ on the count).  It's my understanding that the jaw 
condyles aren't actually disjointed.  Instead, the joint itself spreads 
apart by virtue of other kinetic joints in the skull (corrections, 
anybody??).  

Perhaps it is no surprise that large lizards that depend on strong bites 
to subdue prey, like the Komodo dragon (corrections?) don't use their 
kinetic ability, or have lost it (????).  On the other hand, snakes, with 
little dependence (there is _some_) on biting to kill prey, have 
well-developed kinesis. Incidentally, the skulls of birds are kinetic in 
much the same way as those of lizards.

Komodo dragons may be unique because of their large size.  Gila monsters 
may be the best comparison with sphenodonts.  Does anybody have any 
suggestions as to why sphendonts seem to have been so completely 
outcompeted by lizards?  Is there anything besides skull kinesis that 
seems likely?  Is my premise right--i.e., have they indeed been 
outcompeted by LIZARDS?  How would we know?


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Norman R. King                                       tel:  (812) 464-1794
Department of Geosciences                            fax:  (812) 464-1960
University of Southern Indiana
8600 University Blvd.
Evansville, IN 47712                      e-mail:  nking.ucs@smtp.usi.edu