Melinna albicincta
Melinna albicincta can be up to 57 mm long. It can be found along the entire Norwegian coast at depths between 40 and 400 meters.
Type locality
Kosterfjorden, Sweden, 58o52.5’N 11o06.3’E, 60–80 m.
Key characters
Fig. 1. Head, dorsolateral view. br: branchiae, mt: mouth tentacles. Arrows denote postbranchial hook and dorsal crest.
Fig. 2. Anterior end, dorsal view Arrow denotes postbranchial hook.
Measurements: Up to 57 mm long.
Number of thoracic chaetigers: 18
Number of thoracic uncinigers: 14
Number of abdominal uncinigers: Up to 44–49.
Prostomium: With well-defined anterior and posterior parts, separated by pair of deep transverse nuchal grooves that nearly meet mid-dorsally; eyespots absent.
Mouth tentacles: Numerous, equally sized and smooth.
Branchiae: Four pairs in two basally fused groups; three branchiae in each group in oblique row slanting posteriorly towards mid-dorsum, fourth branchia in front of the middle one of the three; 35-40% of branchial length of inner- and anteriormost branchiae in each group fused together; within each group, inner anterior branchiae also fused similarly to inner posterior branchiae; remaining branchiae fused to a lesser extent; white bands on branchiae (can be difficult to see/faded away on fixed specimens).
Postbranchial hooks: Broad base and strongly curved tip.
Postbranchial depression: Wide
Dorsal crest: With serrations unequal in size.
Special features: Abdomen with small ciliated rudimental notopodia.
Pygidium: One pair of large dorsal lobes and 8–12 smaller ventral lobes.
Tube: Thin layer of organic secretion incrusted with mud and with shell fragments attached.
Distribution
Entire Norwegian coast; 40–400 m (Mackie & Pleijel 1995).
Similar species
Melinna albicincta is most similar to Melinna elisabethae. They can be separated by the width of the postbranchial depression, it is wide in M. albicincta while more narrow in M. elisabethae, and presence or absence of eyespots, as M. albicincta lacks eyespots while M. elisabethae has numerous. In addition, M. albicincta have white bands on the branchiae, however, these can be difficult to see or faded away on fixed specimens.
Sources
Mackie ASY og Pleijel F (1995). A review of the Melinna cristata-species group (Polychaeta: Ampharetidae) in the northeastern Atlantic. Mitteilungen aus dem Hamburgischen zoologischen Museum und Institut 92: 103-124.
Personal observations, Alvestad T.
Fig. 3. Posterior end, lateral view
Fig. 4. Melinna albicincta with tube.
Siden siteres som:
Alvestad T og Budaeva N (2020). Melinna albicincta Mackie & Pleijel, 1995. www.artsdatabanken.no/Pages/299318. Nedlastet <dag/måned/år>