Jncc coastal Directories Project Region 11 The Western Approaches

5.4  Rare sea-bed species
101
Table 5.4.1  
‘Nationally rare’ and ‘nationally scarce’ marine benthic species found in the region (continued)
Species
Type of
Area(s) of
Habitat/associations
Comments
Useful
organism
occurrence
reference
Typton spongicola*
The sponge
shrimp
Isles of Scilly
Subtidal.  Living in
sponges to 90 m.
Southern species.
Cryptic, therefore may not
be as rare as current
records suggest.
Hayward &
Ryland (1990)
Clibanarius
erythropus*
A hermit
crab
Lizard Point (?),
Porthleven (?), Marazion
(?), Great Hogus Reef (?),
Battery Rocks (near
Penzance)
Intertidal pools and
subtidal to 40 m.  Seems
to favour dogwelk shells.
Southern species.
Formerly at scattered
locations in S. Devon &
Cornwall.  Appears to
have declined
substantially.  See text.
Southward &
Southward
(1988), Ingle
(1993)
Cestopagurus
timidus*
A hermit
crab
Isles of Scilly
Low shore to about 70 m
Southern.  Also
Mediterranean and
Canary Islands.
Northernmost limit
appears to be SW
Scotland.  Therefore may
not be as rare as the dearth
of records suggests.
Ingle (1993)
Dromia personata
Sponge crab
or sleepy
crab
Off Portreath, Lundy
Rocky or stony ground
from 10-30 m
Cautiously regarded as
scarce.  Many old,
scattered records exist
from southern coasts in
GB (Clark 1986).
Elsewhere south to W.
Africa, Azores and
Mediterranean.
Hayward &
Ryland (1990)
Achaeus cranchii
Cranch’s
spider crab
Fal Estuary, Isles of Scilly,
Lundy
On hydroids, bryozoans
and sea squirts from
about 5-70 m
Known from scattered
locations from south and
west GB to SW Scotland
Ingle (1993)
Leptochiton scabridus* A coat-of-
mail (chiton)
Helford (Prisk Cove)
On stones in coarse sand.
Recently from maerl bed
(J.M. Baxter pers. comm.
1994).
Thought to be southern
but recent record from
Orkney maerl may
indicate that it occurs
more widely (J.M. Baxter
pers. comm. 1994).
Jones & Baxter
(1987)
Jujubinus striatus*
A sea snail
Fal Estuary, Helford River,
Isles of Scilly
Low water to 200 m.
Often associated with
weeds (Zostera, Ulva,
Codium).
Southern species.
Populations seem to have
crashed early this century
and appear not to have
recovered (D.R. Seaward
pers. comm. 1995).
Graham (1988)
Alvania cancellata
A sea snail
Helford River
Low water to 90 m
Southern species.
South from English
Channel.
Graham (1988)
Paludinella littorina*# A sea snail
Martinhoe
Upper shore.  In shingle,
caves and crevices.
Southern species.
Mediterranean and from
Britain to Madeira.
Killeen &
Light (1994),
Bratton (1991)
Bittium simplex*
A sea snail
Isles of Scilly
Poorly known
Taxonomic confusion may
have resulted in a degree
of under-recording.
Graham (1988)
Ocinebrina aciculata*
A sea snail
Porlock (Somerset)
Often with barnacles.  On
rocky shores from low
water to 15 m.
Southern.  Elsewhere
south to the
Mediterranean.
Graham (1988)
Tritonia nilsodhneri
The fan slug
Falmouth Bay, Manacles,
off Lizard, Mount’s Bay,
Isles of Scilly, Newquay,
Kellan Head, Lundy
Occurs and feeds on pink
sea fan Eunicella verrucosa
in GB
South-western species.
Also known south to
Spain.  Prone to
substantial population
fluctuations.
Hiscock (1994),
Picton &
Morrow (1994)
Okenia elegans*
Yellow skirt
slug
Lundy
Feeds on the sea squirt
Polycarpa rustica
Wide-ranging records from
Devon to Scandinavia.
Recent British records are
from the SW.
Picton &
Morrow (1994)

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Region 11  Chapter 5  Important species
102
Table 5.4.1  
‘Nationally rare’ and ‘nationally scarce’ marine benthic species found in the region (continued)
Species
Type of
Area(s) of
Habitat/associations
Comments
Useful
organism
occurrence
reference
Trapania pallida
A sea slug
Isles of Scilly, Lundy
Usually found amongst
bryozoans, hydroids and
sponges.  Rocky subtidal
areas from 10-20 m.
Also W. Scotland to
Atlantic France and Spain.
Picton &
Morrow (1994)
Greilada elegans*
Blue spot
slug
Lundy
Associated with and feeds
on the bryozoans Bugula
turbinata and B. flabellata
Southern species.
Populations are known to
fluctuate considerably at
Lundy (see Hiscock 1994).
Picton &
Morrow (1994)
Atagema gibba*
A sea slug
Porthkerris Point,
Isles of Scilly
Known from steep rock
between 8-15 m.  Often
with sponges.
Southern (?).  Elsewhere
from Mediterranean.
Picton &
Morrow (1994)
Tenellia adspersa* #
Lagoon sea
slug
Portishead
(Bristol Channel)
Intertidal & shallow
subtidal.  Normally
brackish, feeding on a
range of hydroids.
May prove to occur more
widely in GB.  Elsewhere
globally distributed.
Populations fluctuate
widely in The Fleet
(Region 9).
Picton &
Morrow (1994)
Caloria elegans*
A sea slug
Lundy
Found on various
hydroids
Southern, also occurring
south to the
Mediterranean
Picton &
Morrow (1994)
Atrina fragilis
Fan mussel
Helford River (also old
and shell records from
other parts of the region)
Point of shell down in
mud, sand and gravel.
Shallow subtidal to
considerable depths.
Sometimes gregarious.
Widely distributed in GB
but rarely encountered.
N. of Scotland to Iberian
Peninsula.  May have
declined owing to sea-bed
disturbance and collection
(Holme 1995).
Aggregations may be of
importance.
Tebble (1976)
Pteria hirundo*
Wing-shell
Between Nare Head and
Dodman Point
Often on pink sea fan
Eunicella verrucosa
Southern.  Also off-shore
but overall rare in British
seas.  Elsewhere south to
Iberian Penninsula and
Mediterranean.
Hayward &
Ryland (1990)
Lucinella divaricata*
A bivalve
Porthcurno
Muddy gravel sand.
Intertidal.
Southern.  South to the
Mediterranean and the
Black Sea, Madeira and
the Canary Is.
Tebble (1976)
Galeomma turtoni*
Weasel-eye
shell
3/4 mile SE of Anthony
Lighthouse
Low on shore to about
37 m.  Sometimes
attached to sea bed by
byssus threads.
Southern.  Elsewhere
Channel Islands and
south to Mediterranean,
Black Sea and African
coast to Senegal.
Tebble (1976)
Acanthocardia
aculeata*
Spiny cockle
or red nose
Isles of Scilly (also recent
fresh shells collected from
Fal Estuary and Helford
River)
Infaunal.  Also occurs
offshore but not
commonly.
Southern.  Also occurring
S. to Mediterranean and
NW Africa.  Collected as
food in past.  Seems to
have declined.
Hayward &
Ryland (1990)
Callista chione*
A bivalve
Amsterdam Point -
Carricknath Point (Fal
Estuary), Helford River,
Isles of Scilly (old and
shell records also).
In sand.  Occurs offshore
also (to 100 m but not
known to be common off-
shore).
Southern species.
Elsewhere south to the
Mediterranean, Canary
Islands and Azores.
Hayward &
Ryland (1990).
Victorella pavida*#
Trembling
sea mat
Swanpool (S. Cornwall)
Brackish water on a
variety of substrata
Known in the UK only
from this lagoonal site.
Also known from
locations between the
Baltic and the
Mediterranean and other
scattered sites around the
world.
Barnes (1992)

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