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Ymerana pteropoda Holthe, 1986

Forrige Opp Neste

Ymerana pteropoda can be up to 5 mm long. It can be found in deep parts of the Norwegian Sea and the Arctic Ocean at depths between 2000 and 4000 meters.

Type locality

Arctic Ocean, North of Svalbard, 81050’N 26034’E, 3270 m.

Key characters

Measurements: Up to 5 mm long.

Number of thoracic chaetigers: 14

Number of thoracic uncinigers: 11

Number of abdominal uncinigers: Unknown, at least more than 7.

Prostomium: Trilobed, middle lobe drawn out into horns; eyespots absent.

Mouth tentacles: Smooth.

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

Paleae: Absent.

Special features: 14th pair of thoracic notopodia achaetous and transformed into dorsolateral fan with pointed wings laterally connected by low ridge across dorsum.

Pygidium: Unknown.

Tube: Unknown.

Distribution

Deep parts of Norwegian Sea and Arctic Ocean; 2000–4000 m.

Similar species

The achaetous 14th pair of thoracic notopodia, which is transformed into a dorsolateral fan with pointed wings, makes it unlikely to confuse adult complete specimens of Ymerana pteropoda with any other Ampharetidae in Norwegian waters.

Remarks

In the original description, and in this key, the dorsolateral fan is referred to as achaetous notopodia of the last thoracic unciniger. It is, however, probably more correct to consider this structure as rudimentary notopodia on the first abdominal unciniger. Achaetous notopodia is by definition rudimentary and the neuropodium of this unciniger is of abdominal type. Ymerana pteropoda will thus have 13 thoracic chaetigers and 10 thoracic uncinigers (Jirkov 2001, Reuscher et al. 2009).

Sources

Holthe T (1986b). Polychaeta Terebellomorpha from the northern Norwegian Sea and the Polar Sea, with descriptions of Mugga bathyalis sp.n. and Ymerana pteropoda gen. and sp.n. Sarsia 71: 227-234.

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

Reuscher M, Fiege D, Wehe T (2009). Four new species of Ampharetidae (Annelida: Polychaeta) from Pacific hot vents and cold seeps, with a key and synoptic table of characters for all genera. Zootaxa 2191: 1-40. https://doi.org/10.5281/zenodo.189379

Personal observations, Alvestad T.

Siden siteres som:

Alvestad T og Budaeva N (2020). Ymerana pteropoda Holthe, 1986. www.artsdatabanken.no/Pages/299331. Nedlastet <dag/måned/år>