Amphicteis gunneri (M. Sars, 1835)

Synonyms:
Amphitrite gunneri M. Sars,1835
Amphicteis curvipalea Claparède, 1870
Amphicteis groenlandica Grube, 1860
Amphicteis gunneri japonica McIntosh, 1885
Amphicteis japonica McIntosh, 1885
Crossostoma midas Gosse, 1855

Distinguishing characteristics
Very large golden paleae.
Well separated two groups of four branchiae (gills) in rhomboid pattern.

Species description
Body thick, abdomen tapering towards pygidium. Prostomium with a pair of prominent glandular ridges and many eyespot. Branchiae in two well separated groups. Fourth branchiae of each group arranged in two transverse rows in a rhomboid pattern. Paleae very large, 8-22 on each side. 17 thoracic segments with notopodia with capillary chaetae, the posterior 14 also with neuropodia with uncini. 15 abdominal uncinigerous segments. Pygidium with two long lateral cirri. Tube - a thin layer of secretion incrusted with a thick, relatively firm layer of mud or clay, usually with plant fragments in characteristic ring like pattern.

Size
Worm up to 55mm long.

Color
Alive: yellowish or pink, branchiae greenish, body and branchiae with numerous light red and brown spots, on the branchiae giving the appearance of coloured rings.

Habitat
Many types of sediment, ranging from pure silt to coarse sand, including all types of mixed bottoms. Vertical distribution upper sublittoral to about 5000 m. Salinity range euhaline to mesohaline.
Species tolerant to excess organic matter enrichment. These species may occur under normal conditions, but their populations are stimulated by organic enrichment (slight unbalance situations).

Mobility
Sedentary.

Feeding
Surface deposit feeder.

Life cycle
Breeding takes place during summer.

Distribution
East Greenland, Svalbard, Barents Sea, Iceland, Jan Mayen, The Faeroes, Shetland, Norwegian Sea, entire Norwegian coast, North Sea, Skagerrak, Kattegat, the Øresund ant the Belts, western Baltic, Eastern North Atlantic, Mediterranean, South Africa, western North Atlantic, Gulf of Mexico, Mid-Atlantic Ocean, West Greenland, Canadian Arctic, Siberian Arctic, Bering Sea, Sea of Okhotsk, Japan Sea, North American Pacific, East India, Antarctic.