Anobothrus laubieri can be up to 10 mm long. It is ubiquitous in Norwegian waters at depths between 100 and 4000 meters.

Type locality

Greenland Sea, 76054’1N, 01049’8E, 3193 m.

Key characters

Measurements: Up to 10 mm long.

Number of thoracic chaetigers, excluding paleae: 15

Number of thoracic uncinigers: 12

Number of abdominal uncinigers: 12

Prostomium: Trilobed; eyespots absent.

Mouth tentacles: Smooth.

Branchiae: Three pairs of branchiae in transverse row.

Paleae: Long with filiform tips, 10–12 chaetae on each side.

Special features: Notopodia of 11th thoracic chaetigers slightly elevated and joined by ciliated ridge across dorsum.

Pygidium: Without cirri.

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

Distribution

Ubiquitous in Norwegian waters; 100–4000 m.

Remarks

Based on our unpublished genetic data, A. laubieri might be as many as 3 species in Norwegian waters.

Similar species

The small size of Anobothrus laubieri 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 Amythasides macroglossus. Anobothrus laubieri 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. Anobothrus laubieri can further be distinguished from A. macroglossus by having 15 thoracic chaetigers and many paleal chaeta (10–12 on each side). For comparison, A. macroglossus has 14 thoracic chaetigers and very few paleal chaeta (about five on each side).

Sources

Desbruyères D (1978). Melythasides laubieri gen. sp. nov. Ampharetidae (Annélides Polychètes sédentaires) abyssal de la mer de Norvège. Bulletin du Muséum d'Histoire Naturelle, Paris, 3e Série 514(Zoologie 353): 231-238. https://biodiversitylibrary.org/page/57913982

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

Personal observations, Alvestad T.