The major larger claw is always on the left side nearest the apex
of the adopted shell when viewed from the front.
Crab on the left is Diogenes pugilator with the major claw on the
Similar species: Pagurus
cuanensis (CD-ROM ONLY)
interested in your recent find of a couple of Diogenes.
It is a species with an interesting distribution and interesting habits.
Some years ago I supervised at least two summer MSc projects on it. Since
I think MarLIN have yet to do a page
on it I thought you might be interested in a few comments.
distribution round Britain and Ireland is or was generally southwestern.
In the Irish Sea it comes up the Welsh coast as far as the
coast of Anglesey. Here it occurs commonly on certain flat slightly
beaches and just offshore from them. For example at Aberffraw I can
20 - 50 in a few minutes if I go at an evening LW in July and August
they are active and out of the sand. The distribution is clumped -
sexual activity rather than fighting for shells. Most are only in
deep water at this time so are easy to see. Although quite abundant
the right sort of beach on the west coast of Anglesey they do not as far
I know extend round to the east side of the island. There are no records
the east coast of Ireland but there are on suitable beaches in
Bay, Carmarthen Bay and Gower. Interestingly, the illustration in
"Stalk-eyed Crustacea" is one from Rhosslli in Gower.
all the beaches where I know of them in Wales are flat beaches
medium / fine sand and where the waves spill rather than curl when
Diogenes burys rapidly and our hypothesis is that the south-paw
of the chelae is connected with burying. They seem to use the
chela as an anchor to stabilise the shell while digging themselves
the sediment. In some circumstances they can be seen using the major
in such a way was to limit the rolling of the shell in the wave
If you have Pagurus and Diogenes together in similar shells,
become active after disturbance much more quickly. An adaptation
re- bury quickly.
the distribution in the SW and English Channel. The MNCR
did not have any records from the north side of the SW peninsula,
counting the Scillies, but on the S side they had them as far east as
Bay. Like several other things they did not normally seem to get past
Bill. This makes your Sussex record particularly interesting. On a
near Plymouth (name forgotten) thety were sufficiently abundant to be
as test animals for dispersant toxicity at the time on the "Torrey
However on the French side of the Channel they seem to be abundant
least as far as the Straits of Dover. I know less of the French
but in August this year we were doing work in the Channel on
habitats and found them abundant in a small mesh beam trawl at a depth
17m off Le Touqet. As in North Wales most were in Hinia shells.
the record, they were found in a few places on the west coast of
as far north was Donegal in the Irish equivalent of the MNCR. These
the furthest N I know of in the British Isles.
most Britsh records are from beaches, off S Spain and Portugal they
to be common subtidally on sandy grounds to judge from the literature
their reproduction etc I have turned up.
I would be interested in any more you find and in the types of
they come from.
low tide on Lancing beach revealed my very
first discovery of the South-claw Hermit
Diogenes pugilator, on the
Sussex coast. This Hermit Crab was discovered in knee depth water in the
sandy shallows below the low tide mark on the equinoctial spring tide,
receding below Chart Datum. They occupied
the empty shells of the Netted Dogwhelk, Hinia.
Hermit Crabs for the younger student (NE Atlantic
Information wanted: Please send any records of this crab, with
location, date, who discovered it, how it was identified, prevalence, common
name and any other details to
Project EMail Glaucus@hotmail.com.
All messages will receive a reply.