Amphicteis sundevalli can be up to 75 mm long. It can be found in the Arctic Ocean at depths between 2 and 350 meters. Although Svalbard is the type locality of the species there are no recent records of the species in Norwegian waters. 

Type locality

Whalers Point, Spitsbergen, Svalbard (Entire North West corner of Spitsbergen is littered with places used by whalers, none of these places are called Whalers Point today), 30–50 m.

Key characters

Measurements: Up to 75 mm long.

Number of thoracic chaetigers, excluding paleae: 17

Number of thoracic uncinigers: 14

Number of abdominal uncinigers: 18–20

Prostomium: With longitudinal ridges and transverse nuchal grooves, numerous eyespots.

Mouth tentacles: Smooth.

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

Paleae: Long with filiform tips; 17–19 chaetae on each side.

Special features: All abdominal segments with rudimentary notopodia.

Pygidium: With two long lateral cirri.

Tube: Not known.

Distribution

Arctic Ocean; 2–350 m (Jirkov 2001).

Remarks

There are no recent records of the species in Norwegian waters. This might be due to very little sampling of Arctic shallow soft bottom habitats. 

Similar species

Amphicteis sundevalli can be confused with three other species of Amphicteis occurring in Norwegian waters. However, Amphicteis sundevalli has 18–20 abdominal uncinigers while Amphicteis gunneri, Amphicteis ninonae and Amphicteis wesenbergae have 15 abdominal uncinigers. 

Sources

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

Jirkov IA (2001). [Polychaeta of the Arctic Ocean] (In Russian). Polikhety severnogo Ledovitogo Okeana. Yanus-K Press. Moscow, 632 pp.

Malmgren AJ (1866). Nordiska Hafs-Annulater. [part three of three]. Öfversigt af Königlich Vetenskapsakademiens förhandlingar, Stockholm 22(5): 355-410, plates XVIII-XXIX. https://biodiversitylibrary.org/page/32339631

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