Thieliana navis

Researched By	Nicola White	Data Supplied By	MarLIN
Refereed by	Dr Richard S.K. Barnes
Taxonomy
Scientific name	Thieliana navis	Common name	A hydroid
MCS Code	D260	Recent Synonyms	Clavopsella navis, Rhizorhagium navis
Phylum	Cnidaria	Subphylum
Superclass	Hydrozoa	Class	Leptolida
Subclass	Anthoathecatae	Order	Filifera
Suborder		Family	Bougainvilliidae
Genus	Thieliana	Species	navis
Subspecies
Additional Information	The systematic status of this species was revised recently by Stepanjants et al. (2000) who placed Clavopsella navis and Clavopsella quadrangularia in the new genus Thieliana.
Taxonomy References	Howson & Picton, 1997, Barnes, 1994, Millard, 1975, Gili & Hughes, 1995, Stepanjants et al., 2000
General Biology
Growth form	Turf	Feeding method	Passive suspension feeder, Predator
Mobility/Movement	Permanent attachment	Environmental position	Epifaunal, Epiphytic, Epilithic
Typical food types	No text entered	Habit	Attached
Bioturbator	Not relevant	Flexibility	High (>45 degrees)
Fragility	Fragile	Size	Very small(<1cm)
Height	Up to 5 mm	Growth Rate	Insufficient information
Adult dispersal potential	Insufficient information	Dependency	Independent
Sociability	Colonial
Toxic/Poisonous?	No
Additional Information	Size refers to length of hydranth.
Biology References	Millard, 1975, Eno et al., 1997, Boero, 1984, Gili & Hughes, 1995
Distribution and Habitat
Distribution in Britain & Ireland	Widewater lagoon, West Sussex.
Global distribution	Recorded from only 3 locations worldwide: Kiel Canal, Widewater lagoon in Sussex and attached to a ship's hull in South Africa.
Biogeographic range	Not researched	Depth range	Insufficient information
Migratory	Non-migratory / Resident
Distribution Additional Information	Thieliana navis is presumed to be an introduced species since it has only ever been recorded in the vicinity of ports and harbours. It is probably transported on ships hulls. It was first recorded in the UK in 1973 in Widewater Lagoon, Shoreham, West Sussex (Eno et al., 1997). It was last recorded there (as Clavopsella navis) by Sheader (1990) in 1990 when it was relatively abundant attached to algae. It is presumed extinct in South Africa as it has only been recorded from one ship's hull in 1959. The condition of the population in Kiel is not known.
Substratum preferences	Algae	Physiographic preferences	Isolated saline water (Lagoon)
Biological zone	Insufficient information	Wave exposure	Very Sheltered
Tidal stream strength/Water flow	Weak (<1 kn)	Salinity	Reduced (18-30 psu)
Habitat Additional Information	None entered
Distribution References	Barnes, 1994, Millard, 1975, Sheader & Sheader, 1990, Eno et al., 1997, Anonymous, 1999(s), Reise et al., 1999, Boero, 1984
Reproduction/Life History
Reproductive type	Gonochoristic	Developmental mechanism	Insufficient information
Reproductive Season	Insufficient information	Reproductive Location	As adult
Reproductive frequency		Regeneration potential	No
Life span	Insufficient information	Age at reproductive maturity	Insufficient information
Generation time	Insufficient information	Fecundity	Ca 8 eggs
Egg/propagule size		Fertilization type
Larvae/Juveniles Larval/Juvenile dispersal potential Insufficient information Larval settlement period Duration of larval stage Insufficient information
Additional Information	Female gonophores contain about 8 eggs, which develop directly into planulae. There is no free-living medusoid stage.
Reproduction References	Millard, 1975