Ferran,

Holes made by octopuses (or is it octopi?) usually have irregular edges and
there may be more than one hole per shell. Would humans have made multiple
holes on shells? On the other hand, holes made by predatory gastropods are
more regular in shape & usually have beveled sides. If you know what tools
humans may have used to make holes in shells, then you can figure out what
the holes made by those tools look like & compare them with octopus or
gastropod holes. In the Mediterranean, drilled shells are common in the
nests of octopuses.

Aydin


These references may be useful:
Wodinsky, American Zoologist 9:997-1010, 1969. Penetration of shell and
feeding on gastropods by Octopus

Nixon, Malacologia 18:431-443, 1979. Hole-boring in shells by Octopus
vulgaris in Mediterranean

Nixon et al., J. Zool. 191:75-88, 1980. Effects on shells of drilling by
Octopus

Bromley, Acta Geologica Hispanica 16:55, 1981. Concepts in ichnotaxonomy
illustrated by small round holes in shells

Ambrose et al., J. Zool. 214:491-503, 1988. Characterization of boreholes by
Octopus dofleini in bivalve Saxidomus giganteus

Ponder & Taylor, J. Zool. 228:317-328, 1992. Predatory shell drilling by 2
species of Austroginella

Carriker, American Malacol. Bull. 14:121-131, 1998. Predatory gastropod
traces...


 -----Original Message-----
From: Ferran Bayés [mailto:[log in to unmask]]
Sent: Thursday, September 28, 2000 8:00 AM
To: [log in to unmask]
Subject: Pierced shells



Dear Members,

Could anyone give a practical criteria to distinguish between holes pierced
in shells by predators (gastropods, octopus...) and human-made holes? I'm
involved in archaeology, not mallacology, and in the iberian and roman sites
of Spain always appear some exemplars of pierced shells (glycymeris,
callista chione,...), mostly pierced in the umbo. Some of them also have the
body deeply "engraved", I suppose by the action of an organism unknown to
me. Does it means that the shell was collected after his death?

Thanks in advance,

Ferran