Polycera quadrilineata (O. F. Müller, 1776)
Arctic to Mediterranean. (GBIF map). Common, and sometimes abundant in early spring, on hard substrate shores all around Britain and Ireland. (U.K. interactive distribution map.NBN.)
On lower shore and sublittorally to 60m. Large and most easily found in February and March. Feeds on Electra pilosa (often on Fucus serratus) (EML), Membranipora membranacea (often on Laminaria) (EML), Callopora dumerilii, Celleporella hyalina and Tegella unicornis. Simultaneous hermaphrodite. Short curved ribbon of spawn attached by edge to Fucus and Laminaria fronds in most months. Shelled veliger larvae live as plankton before metamorphosing.
Polycera faeroensis
- No elongate papillae at base of rhinophore.
- Oral veil with six to twelve yellow elongate processes.
- No medial dorsal pigment marks between gills and rhinophores.
- Anterior of foot expanded into propodial tentacles.
Trapania maculata, T. pallida & T. tartantella
- One or two backward pointing elongate papillae at base of each rhinophore.
- One elongate papilla on either side of the gills.
- Anterior of foot expanded into propodial tentacles.
- Two forward pointing elongate papillae at base of each rhinophore.
- No yellow elongate processes on anterior edge of head (but has white oral tentacles)
- Several erect elongate papillae on either side of the gills.
- No propodial tentacles or extension on foot.
Alder, J. & Hancock, A. 1845-1855. A monograph of the British nudibranchiate mollusca. London, Ray Society.
Thompson, T.E. & Brown, G.H. 1984. Biology of opisthobranch molluscs 2. London, Ray Society.
Current taxonomy: World Register of Marine Species (WoRMS)
Irish distribution maps and prey organisms:
Picton, B.E. & Morrow, C.C., 2010. Encyclopedia of Marine Life of Britain and Ireland (EML)
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