Distomus variolosus

Researched By	Dr Paul Somerfield & Prof. Richard Warwick	Data Supplied By	PML
Refereed by	This information is not refereed.
Taxonomy
Scientific name	Distomus variolosus	Common name	Lesser gooseberry sea squirt
MCS Code	ZD121	Recent Synonyms
Phylum	Chordata	Subphylum	Tunicata
Superclass		Class	Ascidiacea
Subclass		Order	Pleurogona
Suborder	Stolidobranchiata	Family	Styelidae
Genus	Distomus	Species	variolosus
Subspecies
Additional Information
Taxonomy References	Millar, 1970, Berril, 1950, Hayward & Ryland, 1995b, Gibson et al., 2001, Howson & Picton, 1997
General Biology
Growth form	Globose	Feeding method	Active suspension feeder
Mobility/Movement	Permanent attachment	Environmental position	Epifaunal
Typical food types	Phytoplankton, detritus	Habit	Attached
Bioturbator		Flexibility	Low (10-45 degrees)
Fragility	Fragile	Size	Very small(<1cm)
Height	Up to 1 cm	Growth Rate	Not researched
Adult dispersal potential	Not researched	Dependency	Independent
Sociability	Colonial
Toxic/Poisonous?	No
Additional Information
Biology References	Fish & Fish, 1996
Distribution and Habitat
Distribution in Britain & Ireland	Recorded in west Sussex, south Devon and Cornwall, Lundy, south and south-west Wales, south-east and western Ireland, north Wales, Isle of Man and the sound between Gighay and Hellisay in the Outer Hebrides.
Global distribution	Found in north-west Europe from south-west British coasts south to the coasts of Portugal.
Biogeographic range	Temperate.	Depth range	Lower shore to 20 m.
Migratory
Distribution Additional Information
Substratum preferences	Bedrock, Large to very large boulders, Algae	Physiographic preferences
Biological zone		Wave exposure
Tidal stream strength/Water flow		Salinity
Habitat Additional Information
Distribution References	Millar, 1970, Berril, 1950, Hayward & Ryland, 1995b, Picton & Costello, 1998, JNCC, 1999, NBN, 2002
Reproduction/Life History
Reproductive type	Budding	Developmental mechanism	Viviparous (No Care)
Reproductive Season	July to September	Reproductive Location	As adult
Reproductive frequency		Regeneration potential	Yes
Life span	1-2 years	Age at reproductive maturity	Insufficient information
Generation time	Not researched	Fecundity	3-4
Egg/propagule size	Up to 0.6 mm	Fertilization type	Internal
Larvae/Juveniles Larval/Juvenile dispersal potential Not researched Larval settlement period July to September Duration of larval stage <1 day
Additional Information	It is hermaphroditic although the exact type of hermaphroditism has not been recorded.
Reproduction References	Berrill, 1948b