Ampharete octocirrata can be up to 13 mm long. It constructs a mud tube with a characteristic anterior end which curls up like a party horn when the worm retracts. It can be found along the entire Norwegian coast at depths between 50 and 500 meters.

Type locality

Glesvær and Florø, Western Norway.

Key characters

Ampharete octocirrata. Anterior end. br: branchiae, pa: paleae, pr: prostomium.

Ampharete octocirrata. Abdominal neuropodium, ndc: neuropodial dorsal cirrus, nrp: neuropodium.

Measurements: Up to 13 mm long.

Number of thoracic chaetigers, excluding paleae: 13

Number of thoracic uncinigers: 11

Number of abdominal uncinigers: 15–18

Prostomium: Trilobed; one pair of eyespots.

Mouth tentacles: Papillose.

Branchiae: Four pairs of branchiae in two well separated groups; branchiae in each group arranged in nearly transverse row.

Paleae: Short with filiform tips.

Special features: Long neuropodial dorsal cirri from third abdominal segment.

Pygidium: With two long lateral cirri and several small rounded papillae.

Tube: Narrow and cylindrical; thin layer of organic secretion incrusted with mud; thin anterior end which curls shut when the worm retracts.

Distribution

Entire Norwegian coast; 50–500 m. 

Similar species

Ampharete octocirrata is most similar to Ampharete borealis. They can, however, be easily separated by the length and placement of the branchiae and the number of abdominal uncinigers. Ampharete octocirrata has longer branchiae with all the pairs in a more or less transverse row and 15 to 18 abdominal segments. Ampharete borealis has shorter branchiae with one pair located slightly behind the others and 12 abdominal uncinigers.

Sources

Holthe T (1986a). Polychaeta Terebellomorpha. Marine Invertebrates of Scandinavia 7: 1-192.

Sars M (1835). Beskrivelser og Iagttagelser over nogle moerkelige eller nye i Havet ved den Bergenske Kyst levende Dyr af Polypernes, Acalephernes, Radiaternes, Annelidernes og Molluskernes classer, med en kort Oversigt over de hidtil af Forfatteren sammesteds fundne Arter og deres Forekommen. Bergen, Thorstein Hallagers Forlag hos Chr. Dahl, R.S., xii + 81 pp., 15 plates. https://doi.org/10.5962/bhl.title.13017

Personal observations, Alvestad T.

Ampharete octocirrata. Posterior end. lc: lateral cirrus.

Ampharete octocirrata. Uncini from abdominal neuropodium.

Ampharete octocirrata. Thoracic neuropodium with uncini.