Truncatella subcylindrica

Researched By	Nicola White	Data Supplied By	MarLIN
Refereed by	Dennis R. Seaward
Taxonomy
Scientific name	Truncatella subcylindrica	Common name	Looping snail
MCS Code	W398	Recent Synonyms	None
Phylum	Mollusca	Subphylum
Superclass		Class	Gastropoda
Subclass	Prosobranchia	Order	Mesogastropoda
Suborder		Family	Truncatellidae
Genus	Truncatella	Species	subcylindrica
Subspecies
Additional Information	Abscission of the earlier part of the shell is presumably an adaptation to an interstial habitat. The taxonomy of the Gastropoda has been recently revised (see Ponder & Lindberg 1997, and Taylor 1996). Ponder & Lindberg (1997) suggest that Mesogastropoda should be included in a monophyletic clade, the Caenogastropoda.
Taxonomy References	Howson & Picton, 1997, Barnes, 1994, Fretter & Graham, 1978, Ponder & Lindberg, 1997, Taylor, 1996
General Biology
Growth form	Cylindrical	Feeding method	Sub-surface deposit feeder, Surface deposit feeder
Mobility/Movement	Crawler	Environmental position	Epifaunal, Interstitial
Typical food types	Vegetable detritus and small algae	Habit	Free living
Bioturbator	Not relevant	Flexibility	None (< 10 degrees)
Fragility	Robust	Size	Very small(<1cm)
Height	Up to 5 mm	Growth Rate	Insufficient information
Adult dispersal potential	100-1000m	Dependency	Independent
Sociability	Gregarious
Toxic/Poisonous?	No
Additional Information	It has a peculiar looping gait and moves along by alternately attaching the foot and snout to the substratum (Seaward, 1988). The species is found at moderate densities in narrow, linear habitats.
Biology References	Killeen & Light, 1998, Seaward, 1988
Distribution and Habitat
Distribution in Britain & Ireland	Recorded from Pagham Harbour, West Sussex; The Solent, Isle of Wight, The Fleet, Dorset and St Mawes Bay, Cornwall.
Global distribution	From the Channel coasts of France and Britain to the Mediterranean, the Black Sea, and on the Canaries, Madeira and Azores.
Biogeographic range	Not researched	Depth range	Insufficient information
Migratory	Non-migratory / Resident
Distribution Additional Information	Formerly known from 12 sites in Britain, from Porthcurno along the south coast to the rivers Orwell and Deben, Suffolk. Presently known to be living in only five locations. It is a southern species which reaches its most northerly distribution in Britain. Paludinella litorina, Ovatella myosotis and Leucophytia bidentata are associates.
Substratum preferences	Gravel / shingle, Mud	Physiographic preferences	Estuary, Isolated saline water (Lagoon)
Biological zone	Upper Littoral Fringe, Lower Littoral Fringe	Wave exposure	Sheltered
Tidal stream strength/Water flow	Very Weak (negligible)	Salinity	Variable (18-40 psu)
Habitat Additional Information
Distribution References	Barnes, 1994, Killeen & Light, 1998, Fretter & Graham, 1978, Seaward, 1991
Reproduction/Life History
Reproductive type	Gonochoristic	Developmental mechanism	Oviparous
Reproductive Season	Insufficient information	Reproductive Location	As adult
Reproductive frequency	Insufficient information	Regeneration potential	No
Life span	Insufficient information	Age at reproductive maturity	Insufficient information
Generation time	Insufficient information	Fecundity	Insufficient information
Egg/propagule size	Eggs 0.75-0.80mm in diameter	Fertilization type	Insufficient information
Larvae/Juveniles Larval/Juvenile dispersal potential <10m Larval settlement period Insufficient information Duration of larval stage Not relevant
Additional Information	Egg capsules are laid of 0.75-0.80mm diameter, which are spherical and surrounded by a thick wall. Each capsule contains one egg and they are attached singly to pieces of detritus in the habitat in which the adults live. Small snails are hatched with a shell of 0.65mm (Fretter & Graham, 1978)
Reproduction References	Fretter & Graham, 1978