Antedon bifida

Researched By	Jacqueline Hill	Data Supplied By	MarLIN
Refereed by	This information is not refereed.
Taxonomy
Scientific name	Antedon bifida	Common name	Rosy feather-star
MCS Code	ZB10	Recent Synonyms	None
Phylum	Echinodermata	Subphylum
Superclass		Class	Crinoidea
Subclass		Order	Comatulida
Suborder		Family	Antedonidae
Genus	Antedon	Species	bifida
Subspecies
Additional Information	Antedon bifida may be confused with another feather-star species Antedon petasus which has a more northerly distribution around the British Isles. Antedon petasus is larger and has 50 or so short cirri on the undersurface of the disc.
Taxonomy References	Fish & Fish, 1996, Hayward & Ryland, 1995b
General Biology
Growth form	Pinnate, Radial	Feeding method	Passive suspension feeder
Mobility/Movement	Crawler	Environmental position	Epibenthic, Epifaunal, Epilithic
Typical food types	Particulate matter such as detritus and plankton.	Habit	Free living
Bioturbator	Not relevant	Flexibility	High (>45 degrees)
Fragility	Fragile	Size	Medium(11-20 cm)
Height	Insufficient information	Growth Rate	Insufficient information
Adult dispersal potential	1km-10km	Dependency	Independent
Sociability	Gregarious
Toxic/Poisonous?	No
Additional Information	Mobility Feather-stars are also able to swim short distances by moving the arms up and down through the water.
Biology References	Fish & Fish, 1996, Hayward & Ryland, 1995b
Distribution and Habitat
Distribution in Britain & Ireland	Antedon bifida is found around most of Britain and Ireland but is apparently absent from the southern part of the east coast of England.
Global distribution	Widely distributed in north-west Europe from Shetland to Portugal.
Biogeographic range	Not researched	Depth range	from ELWS to 450m.
Migratory	Insufficient information
Distribution Additional Information	No text entered
Substratum preferences	Algae, Bedrock, Large to very large boulders	Physiographic preferences	Open coast, Offshore seabed, Strait / sound, Enclosed coast / Embayment
Biological zone	Sublittoral Fringe, Upper Infralittoral, Lower Infralittoral, Upper Circalittoral, Lower Circalittoral, Circalittoral Offshore	Wave exposure	Moderately Exposed, Sheltered, Very Sheltered
Tidal stream strength/Water flow	Moderately Strong (1-3 kn)	Salinity	Full (30-40 psu)
Habitat Additional Information
Distribution References	Fish & Fish, 1996, Hayward & Ryland, 1995b, La Touche, 1978
Reproduction/Life History
Reproductive type	Gonochoristic	Developmental mechanism	Planktotrophic, Brooding
Reproductive Season	Possibly all year. See additional information	Reproductive Location	As adult
Reproductive frequency	Annual episodic	Regeneration potential	No
Life span	Insufficient information	Age at reproductive maturity	1-2 years
Generation time	Insufficient information	Fecundity	Insufficient information
Egg/propagule size	Insufficient information	Fertilization type	External
Larvae/Juveniles Larval/Juvenile dispersal potential Insufficient information Larval settlement period Insufficient information Duration of larval stage 2-10 days
Additional Information	Mature individuals can be recognised by swollen genital papillae at the base of the arms. Eggs escape through splits which appear in the pinnule walls, and adhere in groups to the external wall of the pinnule where fertilization takes place. The embryos are held on the pinnules in a mucous net during which time the female holds its arms close together in what has been described as brooding behaviour, allowing spawned females to be readily identified. Embryos remain attached in groups of up to 20 for four or five days (Chadwick, 1907 cited in Nichols, 1991). The embryos hatch as free-swimming larvae which, after a short pelagic phase, attach to the substratum and develop a short stalk. At this stage they are known as pentacrinoid larvae. The pentacrinoids eventually detach and by this stage the small, prehensile cirri have developed on the undersurface of the disc. The season of spawning for Antedon bifida is universally stated as May to July. However, Nichols (1991) observed that mature oocytes and active sperm were present in every month of the year although a spawned out condition is seen in samples every so often. Therefore, although shed embryos have only been seen in the period May to July, it is possible that, like the congeneric Antedon mediterranea, Antedon bifida reproduces all year. Other evidence leads Nichols (1991) to suggest that Antedon bifida may have two shedding strategies, also shedding directly into the seawater as in the case of the congeneric Antedon petasus. In later work Nichols (1994) suggests that the maintenance of gonads at a high level of maturity throughout the year is a life-history trait developed to tolerate the predation of expendable and easily-regenerated gonads. Brooding female comatulids are almost insensitive to mechanical stimuli (Lahaye & Jangoux, 1984).
Reproduction References	Fish & Fish, 1996, Nichols, 1991, Nichols, 1994