On Sun, Sep 27, 2009 at 10:58 AM, Thomas Eichhorst <[log in to unmask]> wrote:
> I also have a Nautilus pompilius with these scars, in this case they are
> healed over and the continued growth of the shell shows two deep parallel
> grooves on the remainder of the shell.  When this shell was sent to me I was
> told this was shark damage with the curve of the shell preventing more teeth
> from impacting and damaging the shell.  Whatever the truth, it is neat
> looking.
>
> Tom Eichhorst in New Mexico (USA)


Nautiluses with scars are common and are selling for crazy prices as
"freaks"... or rather, the sellers are ASKING crazy prices (hopefully
nobody's buying!).

Crabs are probably the main culprit of the mantle damage that resaults
in a spiral scar. The scar may or may not start with a chip in the
shell lip.

Sharks, if they are biting seriously, will crush a Nautilus shell
easily... their bites rate in tonnes of pressure.

As to nacre being perforable by point-pressure, I find that this may
be so, but the shell isn't just nacre. Nautilus shells have a thick
nonnacreous outer layer which is brittle and shatters into sizable
chunks.

Speaking of Nautilus, I have recently prepared an extremely nice
specimen from the middle Eocene of NZ (that's about 40 million years
old). It has open umbilicuses which are partly masked by posterior
lappets extending from the umbilical margin of the lip. Coiling is
about as involute as N. macromphalus but the whorl sections exposed in
the umbilical walls are much more convex. Like N. macromphalus, the
shell is much more inflated than the slightly compressed N. pompilius.

--
Regards
Andrew Grebneff
Dunedin, New Zealand
Fossil preparator
Mollusc, Toyota & VW van fanatic

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