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Sabellidae Family Sabellidae (sabellid/fan-worm)
Sabellida (Annelida: Polychaeta)
About Family Sabellidae polychaetes in New Zealand.  
How to recognise the family: The fan or feather-duster worms are so-called from the appearance of the feeding appendages, the radioles, which comprise a crown of two semicircular fans of stiff filaments projected from their tube. Each radiole has paired side branches called pinnules, forming a double-sided comb for filtering out food from the passing water. In some genera the radioles have additional external projections known as stylodes. Some small species have the ability to turn the crown directly onto the sediment to pick up particles. The crown is easily shed or lost in handling which is unfortunate as features such as the pattern of eyespots or presence of a connecting web are essential for identification. A low collar is usually present at the base of the crown. The rest of the body is characteristically very smooth and unornamented, but the last few segments may form a ventral spoon-shaped hollow. There are about eight thoracic chaetigers, sometimes fewer, followed by many abdominal chaetigers. The boundary between the thoracic and abdominal regions is marked only by a chaetal change, wherein the notochaetal capillaries and neurochaetal uncini of the thorax swap position for the remainder of the body. Uncini are usually compact Z-shaped toothed hooks. A separate subfamily, the Fabriciinae, includes some small-bodied forms in which the thoracic uncini are long and gently curved and there are only two or three pairs of radioles.

The sabellid tube is usually a thin, tough, bark-like composite of sediment and hard flexible mucoprotein secretions. Sabellids do not have an operculum to block the opening of the tube, and instead, as the animal withdraws, the top collapses or may roll up, thus sealing the entrance. However, some sabellids may just have flimsy sand-grain tubes and small motile species may have only a temporary mucous tube. Adult size: Some species are minute, others are up to 100 mm or more long and 15 mm in diameter.

How to recognise the New Zealand genera: In Megalomma species the eyespots are compound and only present at the ends of the radioles, whereas in Sabella and Pseudopotamilla there may be several simple eyespots on each radiole, and in Branchiomma, as well as usually bearing eyespots, the radioles have stylodes. In Pseudobranchiomma radiolar eyespots are absent and the stylodes are mere notches. Euchone species have a spoon-like posterior depression.
Quick pick shore species: Most sabellids are subtidal. A number of small, inconspicuous, unstudied species occur in sands and muds intertidally and subtidally, and amongst algal turf. Little is known about them.
Possible misidentifications: None
Distributions, lifestyle, and habitat: Throughout New Zealand, intertidal and subtidal to deep sea. The largest sabellids are subtidal and found amongst sessile marine growths, in crevices etc. A large subtidal Pseudopotamilla species sometimes occur in extensive beds that may foul trawler nets. Branchiomma curta can be very common on wharf-piles. Euchone limnicola is a small species recently found occurring densely in harbours and may be a species introduced via shipping. Sabella spallanzanii, an invasive species now in Australia, is not yet known for New Zealand
Abundance: Common, occasionally very abundant.
Taxonomic note: Also includes the former Caobangiidae and the Sabellongidae. Subtidal New Zealand species include Megalomma suspiciens (Ehlers, 1904), Megalomma kaikourense Knight-Jones, 1997, Branchiomma curta (Ehlers, 1901 as Daschone), Pseudobranchiomma serratibranchis (Grube, 1978), Pseudopotamilla alba (Knox, 1951) (a rock-boring species), Euchone pallida Ehlers, 1908, and Euchone limnicola Reish 1959, Eudistylia brevicomata (Ehlers, 1905). Additional species are known in genera Demonax, Amphiglena, Oriopsis, and some are yet to be described.
References: (Augener 1926: p245-270, f18), (Day & Hutchings 1979: p140-142), (Ehlers 1904: p62-67, P9.1-10), (Fauchald 1977: p135-141), (Fitzhugh 1989: p1-104, f1-34), (Fitzhugh 1991: p305-332, f1-13), (Hartman 1966: p203, pl6,f7-10), (Knight-Jones 1981: p183-202, f1-75), (Knight-Jones 1983: p245-295, f1-21), (Knight-Jones 1997: p320-321, f5), (Knox 1951b: p76-79, f18-23), (Schmarda 1861: p33, P22.186), (Whitley 1966: p97-102, P49-51).
(Full citations at Family pages literature cited list.)

Species in the guide: Rock Species: None for this family.
Sand Species: None for this family.
Shell Species: None for this family.

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Last modified by G. Read, 25/07/2004    (dd/mm/yy)