Cephalopod parasites

[N.Monks@xxxxxxxxx (Neale Monks)]

Dear All,

I have recently come accross some very odd ammonite fossils, in which the
internal moulds of the adult body chamber strongly suggests that there were
structures rather like 'attached pearls' on the iside of the shell.

They are small ovals (about 0.5mm long).

Are there any parasites that cause the host mollusc to produce a blister on
the inside face of the shell, ultimately placing nacre over the blister and
sealing it off? It is VERY odd that only adult chambers show these, and
even then only a tiny proportion of all individuals.

Beneath the pearl, there is no evidence to suggest that a perforation to
the external face of the shell ever existed. The  nacre and prismatic
layers are intact.

Thanks for any help or ideas,

Neale.



>From  Neale Monks' PowerBook, at...

Department of Palaeontology, Natural History Museum, London, SW7 5BD
Internet: N.Monks@nhm.ac.uk, Telephone: 0171-938-9007

"...now Nature is having the last laugh. The freaky stuff is turning out to
be the mathematics of the natural world"

from 'Arcadia', by Tom Stoppard