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

[Phil Bigelow <bigelowp@juno.com>]

As a footnote, when the seasonal supply of salmon dries up, coastal black
bears and grizzly bears consume vast quantities of clams.  Videos show
that the bears will hold the clam down on the sand, slip a manus claw
into the clam, and use their front teeth to pull up on the shell.  They
can pop open a lot of shells in an hour.

I would think that *any* medium sized theropod with a good set of sharp
front teeth and feet with nice sharp claws could do at least as good as a
bear. 

A taphonomic study of predation damage on large Mesozoic freshwater
mollusk shells would make a great masters thesis.

<pb>
--

On Fri, 27 May 2005 15:59:27 -0700 (PDT) "Jaime A. Headden"
<qilongia@yahoo.com> writes:
> Tim Williams (twilliams_alpha@hotmail.com) wrote:
> 
> <When Barsbold named _Conchiraptor_, he had all shelled molluscs in 
> mind (Gk 
> kogkhe, L. concha rather than just exotic undersea gastropods 
> (conchs).>
> 
>   Indeed, Barsbold in 1977 discussed some of the math involved in a 
> biting
> oviraptorid skull and determined the likelihood of eating was for 
> hard-shelled
> foods, and pointed at the plentitude of bivalves in "Senonian" 
> Mongolian beds
> as a ready source of food, as well as more readily available, than 
> seasonal
> eggs (apparently egg shell is easier to crack than bivalve shell, 
> thus physical
> adaptations to shell cracking would have been driven by harder 
> shells when the
> muscle output was far in excess of the integrity an egg should 
> muster. This of
> course led to him naming *Conchoraptor*. As a test, I am of the 
> driven need to
> duplicate Anne Schulp's "mechanic mosasaur" used to feed 
> *Carinodens* jaws as a
> test for materials and handling, only this will use a whole jaw 
> contraption. So
> far, study of the jaw anatomy implies an implicit crack and swallow 
> mechanism I
> do not think bivalves would be adequate to explain as a mechanism 
> for evolving
> such jaws.
> 
>   But then, there's not an animal living today [that I know of] that 
> adapts
> itself soly to consuming eggs nor do I think there ever was, despite 
> the
> African egg-eating snake *Dasypeltis* (less than 30% of its diet is 
> egg), so I
> am not sure what is required to drive a primary feeding adaptation 
> seemingly on
> par with the anteater's restrictive jaw morphology. However, 
> blue-tongued
> skinks show a specific muscular adaptation for eating gastropods, 
> giving the
> name snail-eating skink, as compared to other skinks, so there may 
> no be more
> than a 30% habitus needed to select for a feeding adaptation, 
> allowing
> generalists to possess specific adaptations for certain, seasonal 
> foods (like
> many snakes).
> 
>   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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