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Re: Last Supper Hypothesis
Gerrit Hanenburg (ghanenbu@inter.nl.net)
Sat, 26 Aug 1995 18:06:54 GMT
"wally@mfs.duke.edu" <wally@mfs.duke.edu> wrote:
>I think these SEMs are still simply showing neat grooves and pits from
>ages ago. I still cannot agree with you that dental microwear will "give
>a resonably accurate image of the overall diet." Especially, when, as
>you put it, teeth exhibiting a "tough gritty surface, will lead to a
>conclusion that the diet was tough and gritty." What about
>parafunctional habits, sand incorporated into foodstuffs, etc.? Don't
>you think there is more to it?
The choice seems to be between:the microwearpattern will give you no
information about the diet of fossil species (your position?) and it will
give some information about the diet (my position).
Since teeth are mainly used in foodprocessing I think it's reasonable to
assume that most of the wearpattern is caused by the diet.After an animal
dies there will be no more occlusal events and since enamel is very resistant
to decay the pattern on the fossilized tooth acquired during life will be
preserved.(unless the tooth is badly eroded).So what you have is a
wearpattern caused by occlusal events during the animals life.
I agree with you that some wear may be caused by activities and processes
that are not directly related to diet (e.g.dental caries) but SEM can be
helpfull in distinguishing between patterns caused by these different
activities.Without the SEM you've got no image at all and you cannot even
begin to make inferences.
With SEM you can correlate microwear and diet in extant species with a known
diet so you have a basis of comparison for use with fossil species.
Thus I think the SEM image together with knowledge of the anatomy of the
masticatory apparatus,the mechanics of chewing and microwearpatterns in
extant species can give you a fairly accurate impression of what happened in
the occlusal plane of fossil species and,by inference,of their diet.
Even if there is no correlation between diet and wear you will need SEM to
arrive at that conclusion.
SEM is as valuable a scientific tool in trying to figure out what caused a
certain microwearpattern in fossil teeth as it is in inferring what caused a
certain pattern of microwear in extant species (with less certainty because
of the historical character of the fossil;you can't actually see what it ate)
The pits and scratches caused by sand incorporated into foodstuffs is
informative about diet.They tell you that the hominid in question possibly
ate sandy food like tubers and roots.But it would be wrong to jump to this
conclusion on the basis of only one specimen.If the same pattern recurs in
other specimens of the same species the conclusion is reasonably justified.
See also:
F.E.Grine,Dental evidence for dietary differences in Australopithecus and
Paranthropus;a quantative analysis of permanent molar microwear.
Journal of Human Evolution 15 (1986),p 783-822.
Gerrit.
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