Re: Mollusk eating (was Re: Sauropod necks????)

["Jaime A. Headden" <qilongia@yahoo.com>]

Dann Pigdon (dannj@alphalink.com.au) wrote:

<Only the turtle headed sea snake, and that feeds on soft fish eggs. They lack
teeth completely.
 
http://www.jcu.edu.au/school/tbiol/zoology/herp/Emydocephalusannulatus.PDF>

  My comprehension on this matter is that most egg-eating snakes, such as
desypeltines and some viperids, as well as some booids, which consume
hard-shelled eggs, do not use their jaws in bringing the egg further into the
esophagus, but only the muscular contraction of the throat itself. Observations
by Gans in 1954 on *Dasypeltis* precluded any involvement of the teeth itself,
suggesting to him that teeth had little functional effect on the animal eating
eggs. Durophages typically loose or reduce teeth, or produce robust teeth but
reduce their count, possibly due to enlargement of the said teeth (e.g.,
pycnodont fish, placodonts, globidontine mosasaurs) whereas other faculative
durophagous animals that do not use their teeth but crush using the palate also
reduce their teeth (e.g., aardwolves, aardvarks, anteaters) as effectively
unneccessary. The steps taken to swallowing soft-shelled (or in this case
unshelled) eggs most likely did not involve any required occlusion of teeth,
and thus can be selected for their loss as in other edentulous animals (e.g.,
birds) which may have crushed food before swallowing, or developed means of
processing food that made teeth obsolete (i.e., a gizzard or other gastric
mill).

  Unfortunately, my more concise statements must wait for the paper, which I am
currently working on background data for with regards to mechanisms in jaw
function, diet, and their corrolations.

  Cheers,

Jaime A. Headden

  Little steps are often the hardest to take.  We are too used to making leaps 
in the face of adversity, that a simple skip is so hard to do.  We should all 
learn to walk soft, walk small, see the world around us rather than zoom by it.

"Innocent, unbiased observation is a myth." --- P.B. Medawar (1969)


                
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