''Polycera quadrilineata'', is a sea slug, a species of

dorid ''Doridacea'' is a taxonomic grouping of dorid nudibranchs, shell-less marine gastropod mollusks.Bouchet P. & Rocroi J.-P. (Ed.); Frýda J., Hausdorf B., Ponder W., Valdes A. & Warén A. 2005''Classification and nomenclator of gastropod families ...

nudibranch. It is a

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

in the family Polyceridae. The specific epithet ''quadrilineata'' means four-lined and refers to the four longitudinal black lines present on the original specimen. This species is sometimes called the fourline nudibranch. In 2020 a integrative molecular and morphological study showed that ''P. quadrilineata'' was a complex of two species in the NE Atlantic and one of these species was given the new name '' Polycera norvegica''.

Distribution

This nudibranch was described originally from Norway. In the NE Atlantic it is a common species in shallow water.Picton, B.E. & Morrow, C.C., 2010
''Polycera quadrilineata''
n/nowiki> Encyclopedia of Marine Life of Britain and Ireland. It is distributed from Greenland to Norway and south along the European coasts into the Mediterranean Sea. It is found from the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species o ...

to 160 m. It has also been reported off the

South African __NOTOC__ South African may relate to: * The nation of South Africa * South African Airways * South African English * South African people * Languages of South Africa * Southern Africa Southern Africa is the southernmost subregion of the Afric ...

coast from the Atlantic coast of the Cape Peninsula to

Algoa Bay Algoa Bay is a maritime bay in the Eastern Cape, South Africa. It is located in the east coast, east of the Cape of Good Hope. Algoa Bay is bounded in the west by Cape Recife and in the east by Cape Padrone. The bay is up to deep. The harbour c ...

.Gosliner, T.M. 1987. ''Nudibranchs of Southern Africa'' The South African animals differ in having six instead of four papillae projecting from the frontal margin of the head, plus details of the coloration. These animals have been shown to be an undescribed species by studies in 2014 and 2020. Polycera-quadrilineata

Description

''Polycera quadrilineata'' is a smooth-bodied, variably coloured nudibranch. The ground colour is white or grey and there are usually black, yellow or orange stripes longitudinally along the notum, though these can be absent. The head has four or occasionally six yellow projections. The gills and rhinophores are translucent white, tipped with yellow. There are two processes at the sides of the gill cluster with glandular, orange or yellow pigmented tips matching the general orange or yellow colour of the body pigmentation.Thompson, T.E. 1988. ''Molluscs: Benthic Opisthobranchs'' Linnean Society of London. In the South African animals the gills and rhinophores are black, and may be spotted with yellow. Alongside the gills is a pair of yellow-tipped projections. The animal may reach 20mm in total length. It is distinguished from the

crowned nudibranch The crowned nudibranch (''Polycera capensis'') is a species of dorid nudibranch. It is a marine gastropod mollusc in the family Polyceridae. Distribution This species is found off the southern African coast from Luderitz in Namibia to Port Alfr ...

in having raised yellow spots on the mid-dorsal region.

Ecology

''Polycera quadrilineata'' feeds mostly on the bryozoans ''

Membranipora membranacea ''Membranipora membranacea'' is a very widely distributed species of marine bryozoan known from the Atlantic and Pacific Oceans, usually in temperate zone environments. This bryozoan is a colonial organism characterized by a thin, mat-like encrus ...

'' and ''

Electra pilosa ''Electra pilosa'' is a species of colonial bryozoan in the order Cheilostomatida. It is native to the northeastern and northwestern Atlantic Ocean and is also present in Australia and New Zealand. Description Colonies of ''Electra pilosa'' fo ...

''.

References

External links

* {{Taxonbar, from=Q1519574 Polyceridae Molluscs of the Atlantic Ocean Gastropods described in 1776 Taxa named by Otto Friedrich Müller