Amythasides macroglossus can be up to 11 mm long. It can be found along the entire Norwegian coast at depths between 30 and 300 meters. 

Type locality

Kosterfjorden, Sweden, 58°52.335N 11°05.641E, 30-50 m.

Key characters

Measurements: Up to 11 mm long.

Number of thoracic chaetigers, excluding paleae: 14

Number of thoracic uncinigers: 11

Number of abdominal uncinigers: 12

Prostomium: Trilobed; eyespots absent.

Mouth tentacles: Smooth, relatively large.

Branchiae: Three pairs of branchiae in transverse row; bases of branchiae completely fused, forming characteristic and well-marked edge above head in frontal view.

Paleae: Long with filiform tips, very few, about five chaetae on each side.

Special features: None.

Pygidium: Without lateral cirri.

Tube: Thin layer of organic secretion covered with loose layer of mud.

Distribution

Entire Norwegian coast; 30–300 m.

Similar species

The small size of Amythasides macroglossus makes it difficult to see characters and the species can be confused with other small-sized species and juvenile specimens of larger ampharetids, in particular, with Ampharete undecima and Anobothrus laubieri. Amythasides macroglossus can be separated from A. undecima by having three pairs of branchiae and 12 abdominal uncinigers compared to four pairs of branchiae and 11 abdominal uncinigers in A. undecima. It can be further differentiated from A. laubieri by having 14 thoracic chaetigers and very few paleal chaeta (about five on each side). For comparison, A. laubieri has 15 thoracic chaetigers and many paleal chaeta (10–12 on each side)

Sources

Eliason A (1955). Neue oder wenig bekannte schwedische Ampharetiden (Polychaeta). Göteborgs Kungliga vetenskaps- och vitterhets-samhälles handlingar (B) 6 (16): 1-17.

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

Personal observations, Alvestad T.