Amphicteis wesenbergae can be up to 12 mm long. It can be found in deep parts of the Norwegian Sea at depths between 1000 and 2500 meters.

Type locality

East Norwegian Sea, 69o13′N 08o23′W, 1889 m.

Key characters

Measurements: Up to 12 mm long.

Number of thoracic chaetigers, excluding paleae: 17

Number of thoracic uncinigers: 14

Number of abdominal uncinigers: 15

Prostomium: With longitudinal ridges (less obvious than in other Amphicteis species in Norwegian waters) and transverse nuchal grooves; eyespots absent.

Mouth tentacles: Smooth.

Branchiae: Four pairs of branchiae in two groups separated by distance equal to one branchial base diameter; four branchiae in each group arranged in rhomboid pattern.

Paleae: Long with filiform tips; 8–10 chaetae on each side.

Special features: All abdominal segments with rudimentary notopodia; posterior most thoracic and all abdominal neuropodia with long dorsal cirrus.

Pygidium: With two long lateral cirri.

Tube: Thin layer of organic secretion incrusted with layer of loose mud and attached foraminiferans.

Distribution

Deep parts of the Norwegian Sea; 1000–2500 m.

Similar species

Amphicteis wesenbergae can be confused with three other species of Amphicteis occurring in Norwegian waters. However, A. wesenbergae have abdominal neuropodia with long dorsal cirri while Amphicteis gunneri, Amphicteis ninonae and Amphicteis sundevalli have abdominal neuropodia with short dorsal cirri.

Sources

Parapar J, Helgason GV, Jirkov I, Moreira J (2011). Taxonomy and distribution of the genus Amphicteis (Polychaeta: Ampharetidae) collected by the BIOICE project in Icelandic waters. Journal of Natural History 45(23-24): 1477-1499. https://doi.org/10.1080/00222933.2011.558640

Personal observations, Alvestad T.