''Berthella plumula'', commonly known as yellow-plumed sea slug, is a gastropod mollusc usually found on rocky coasts in the

infralittoral The littoral zone, also called litoral or nearshore, is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely flood ...

zone and which can live up to 30m depth.

Description

''Berthella plumula'' is an oval-shaped

sea slug Sea slug is a common name for some Marine biology, marine invertebrates with varying levels of resemblance to terrestrial Slug, slugs. Most creatures known as sea slugs are gastropods, i.e. they are Sea snail, sea snails (marine gastropod moll ...

with an internal shell, which can be up to long. The body is up to and has a cream to orange colour and often displays reticulate markings. The head is flat and a large oral veil lies between the propodium and the mantle. The

rhinophores A rhinophore is one of a pair of chemosensory club-shaped, rod-shaped or ear-like structures which are the most prominent part of the external head anatomy in sea slugs, marine gastropod opisthobranch mollusks such as the nudibranchs, sea hare ...

are protruding and enrolled. The species has acid glands in the skin which secrete sulphuric acid for protection in case of danger.

Distribution

''Berthella plumula'' is found in the north-eastern

Atlantic The Atlantic Ocean is the second largest of the world's five oceanic divisions, with an area of about . It covers approximately 17% of Earth's surface and about 24% of its water surface area. During the Age of Discovery, it was known for se ...

, the

Mediterranean Sea The Mediterranean Sea ( ) is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean basin and almost completely enclosed by land: on the east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

, the

English Channel The English Channel, also known as the Channel, is an arm of the Atlantic Ocean that separates Southern England from northern France. It links to the southern part of the North Sea by the Strait of Dover at its northeastern end. It is the busi ...

and the

North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...

Behavior

Diet

''Berthella plumula'' is a slow moving predator which scrapes its

radula The radula (; : radulae or radulas) is an anatomical structure used by mollusks for feeding, sometimes compared to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters ...

on rocks to feed on colonial

ascidians Ascidiacea, commonly known as the ascidians or sea squirts, is a paraphyletic class in the subphylum Tunicata of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer test or "tunic" made of the polysaccharid ...

of the genus '' Botryllus'' as well as on ''

Oscarella ''Oscarella'' is a genus of marine sponges. The genus can be found off the coast of every continent, in every ocean except the Arctic. Species Subtaxa include: * '' Oscarella aurantia'' Stillitani, Ereskovsky, Pérez, Ruiz, Laport, Puccine ...

'' sponges.

Reproduction

The species is

hermaphrodite A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

and the two individuals reciprocally fecundate each other by exchanging their sperm. The reproductive period occurs in spring. The laying is tube-shaped and the eggs are displayed in spiral.

Similar species

''Berthella plumula'' can be confused with '' Berthella stellata'', which is smaller and displays a small white mark on its back, and with '' Berthellina edwardsii'', which is usually bigger and more red. File:Berthella plumula DSC 0231.jpg, Three specimens of ''Berthella plumula'' in Pula, Croatia File:Berthella plumula DSC 0245.jpg, Spiral eggs of ''Berthella plumula'' in Pula, Croatia File:Berthella plumula DSC 0498.jpg, Yellow-plumed sea slug in Pula, Croatia

References

{{Taxonbar, from=Q5063374 Pleurobranchidae Molluscs of the Atlantic Ocean Molluscs of the Mediterranean Sea Gastropods described in 1803 Taxa named by George Montagu (naturalist)