Sosane wahrbergi is a very small species, only up to 4 mm long. It can be found along the entire Norwegian coast at depths between 20 and 300 meters.

Type locality

Koster Islands, Sweden, 20–80.

Key characters

Measurements: Up to 4 mm long.

Number of thoracic chaetigers, excluding paleae: 12

Number of thoracic uncinigers: 9

Number of abdominal uncinigers: 12

Prostomium: Trilobed; one pair of eyespots.

Mouth tentacles: Smooth.

Branchiae: Three pairs of branchia in two widely separated groups; branchiae arranged in triangles.

Paleae: Small with filiform tips; 15–20 chaetae on each side.

Special features: 12th pair of thoracic notopodia elevated and laterally enlarged; chaetae usually crossing mid-dorsally.

Pygidium: With long lateral cirri.

Tube: Thin layer of organic secretion incrusted with mud.


Entire Norwegian coast; 20–300 m.

Similar species

Sosane bathyalis and Sosane wahrbergi are morphologically very similar, particular since fixed specimens of S. wahrbergi quite often miss eyes. Sosane bathyalis are generally smaller than S. wahrbergi and occur much deeper.


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

Personal observations, Alvestad T.