PORT PHILLIP BAY


Fan Worm 

Sabellastarte australiensis (Haswell, 1884)

View scientific description and taxonomy

Scientific Details

Family level description.
Sabellidae are aptly known as fan worms for the crown of feathery radioles which are used to filter particles from the water. The thorax has 8 segments in most sabellids, followed by a variable number of abdominal segments; the two regions are distinguished by a reversed arrangement of dorsal and ventral chaetal bundles. Sabellidae (except for one uncommon tropical genus) make flexible tubes of parchment or mucous. There is no operculum sealing the end of the tube when the worm retracts.

Species level technical description.
Branchial lobes fused dorsally. Radioles numerous, usually more than 8 pairs and increasing with size of worm. Palmate membrane present. Radiolar flange radiolar flange forming expanded rounded flanges at tips of radioles. Paired stylodes absent. Radiolar eyes absent. Anterior margin of peristomial ring unmodified, of low, even height all around. Narrow, about as long as wide. Distal end entire. Posterior peristomial ring collar present. Dorsal lips with dorsal radiolar appendages. Lacking dorsal pinnular appendages. Glandular girdle on chaetiger 2 absent. Thoracic and abdominal interramal eye spots present.. Pygidial eyes absent. Anal depression absent. Notochaetae of chaetiger 1 comprise a bundle of 2 rows similar to remaining thoracic notochaetae. Superior thoracic notochaetae elongate, narrowly hooded. Inferior thoracic notochaetae, anterior row (chaetiger 4) absent. Inferior thoracic notochaetae, posterior row (chaetiger 4) spinelike. Teeth of thoracic uncini equal in size in series above main fang. Breast well developed, resulting in a Z-shaped avicular appearance. Handle as long or slightly longer than length of neck of uncinus. Thoracic neuropodial companion chaetae absent. Abdominal notopodial uncini with a distinct main fang and several smaller teeth above. Breast well developed. Handle long. Abdominal neurochaetae in a C-shape (viewed end-on). Posterior abdominal neurochaetae, anterior row spinelike.

Taxonomy

Phylum:
Annelida
Class:
Polychaeta
Order:
Sabellida
Family:
Sabellidae
Genus:
Sabellastarte
Species:
australiensis

General Description

In members of this genus thoracic and abdominal interramal eye spots present while radiolar eyes are absent. Abdominal neurochaetae are arranged in a C-shape. In living specimens, identification is easy since the radiolar crown when expanded underwater appears as a tuft, not obviously helical (whereas in the introduced species Sabella spallanzanii it is a very obvious helix). Preserved specimens are more difficult to distinguish and require careful observation of chaetal arrangement. Body up to about 1 cm long.

Biology

Several different colour forms of this common, large, fan worm occur around south-eastern Australia. In eastern Victoria, specimens have a pale to white fan, while further west and in Port Phillip Bay specimens are brown-orange. Preliminary DNA studies indicate that several new species might one day be described.

Habitat

Port Phillip Bay and other similar coastal habitat, inshore and continental shelf.

Reefs

Soft substrates

Distribution guide

Southern Australia.

Species Group

Worms Fan worms

Depth

Shore (0-1 m)
Shallow (1-30 m)

Water Column

On or near sea floor

Max Size

1 cm

Diet

Plankton or particles

Commercial Species

No

Global Dispersal

Native to Australia

Identify

Conservation Status

  • DSE Advisory List : Not listed
  • EPBC Act 1999 : Not listed
  • IUCN Red List : Not listed

Author

article author Wilson, R.

Robin Wilson is a Senior Curator of marine invertebrates at Museum Victoria.

citation

Cite this page as:
Wilson, R., 2011, Fan Worm, Sabellastarte australiensis, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 29 Mar 2017, http://portphillipmarinelife.net.au:8098/species/11164

Text: creative commons cc by licence