Polycera norvegica Sørensen, Rauch, Pola & Malaquias, 2020
Superdomain | Biota | |
Kingdom | Animalia | |
Phylum | Mollusca | |
Class | Gastropoda | |
Subclass | Heterobranchia | |
Infraclass | Euthyneura | |
Subterclass | Ringipleura | |
Superorder | Nudipleura | |
Order | Nudibranchia | |
Suborder | Doridina | |
Infraorder | Doridoidei | |
Superfamily | Polyceroidea | |
Family | Polyceridae | |
Subfamily | Polycerinae | |
Genus | Polycera | |
Species | Polycera norvegica Sørensen, Rauch, Pola & Malaquias, 2020 | |
Classification according to Bouchet et al. (2017) Taxonomic source: World Register of Marine Species (AphiaID: 1451585). |
Synonyms
- Polycera capitata (Alder & Hancock, 1854) > nomen dubium
- Thecacera capitata Alder & Hancock, 1854
Description
Body elongated, up to 14 mm long, limaciform, with a distinct marginal ridge. Body is highest and widest in the middle part, close to anus, gills and papillae, and ends in tappered tail. Body surface smooth, covered with scattered flattened tubercles, which are variable in number and size. In specimens with dotted morphotype these tubercles tend to be colored in light yellow. There is an frontal veil on the anterior part of the body, with 4-7 digitiform, yellow or orange coloured processes with whitish tips that point forward. Specimens with dotted morphotype often with only yellow spots scattered on a whitish translucent body background. Rhinophores are not retractile and have 6-10 lamellae, with stems slightly leaning forward and a cylindrical mucron in the distal end. Eyespots are on the notum, right behind the rhinophores, almost indistinguishable in some specimens. Gill is formed by 7–11 pinnate leaves that could be of different sizes. They are partially retractile into a pocket in the notum. There is an elongate and narrow papillae on each side of the gills, pointing backwards or laterally, that are shorter and stubby with rounded apical tip on individuals with dotted morphotype, and slender with sharper apical tips on individuals with yellow / orange morphotype.
There are two main colour morphs present:
- Dotted colour morph (Figure A) – base colour translucent white with black, dark brownish or grey dots scattered over entire surface. Brown/orange patches present on head region or sometimes randomly along body surface. Rhinophores translucent white; lamellae sometimes with a weak hint of light yellow pigmentation; stem sometimes dark brown or grey (Figure B). Frontal veil processes translucent white, with few scattered yellow patches randomly distributed. Posterior papillae white with yellow tips; sometimes white basal part dotted with yellow or black patches. Gills whitish with yellow, orange, or black spots along rachis and tips.
Colour forms of Polycera norvegica by C.G.Sørensen
- Yellow/orange colour morph (C), but in the studied specimens the rhinophore stems were always whitish lacking black pigmentation. Faint greyish tiny spots may be present on head region and gills.
Biology
Sublittoral species occurring between 2–15m depth, often on kelp (Laminaria spp.).
Etymology
- Polycera. From Greek “polys”, many + “keras”, horns.
- Norvegica. From Latin “norvegicus”, of or pertaining to Norway.
Distribution
European Atlantic shores from Norway to Spain and Portugal, common around the British Isles and Ireland.
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Abundance
Western Mediterranean: | ☆☆☆☆☆ |
Eastern Mediterranean: | ☆☆☆☆☆ |
Atlantic Ocean: | ★☆☆☆☆ |
More pictures
Bibliography
Further reading
Cite this article as:
Pontes, Miquel (2023) "Polycera norvegica" in OPK-Opistobranquis. Published: 09/02/2023. Accessed: 30/03/2023. Available at (https://opistobranquis.info/en/Bc1ly)