''Berthella stellata'' is a species of sea slug in the family

Pleurobranchidae The Pleurobranchidae are a taxonomic family of sea slugs, marine gastropod molluscs in the clade Pleurobranchomorpha. Characteristics Species in the family Pleurobranchidae have a prominent mantle and an internal shell that becomes re ...

. It is found in shallow water in the Mediterranean Sea, the western Atlantic Ocean and the tropical and subtropical Indo-Pacific region.

Taxonomy

This sea slug was first described in 1826 by the French-Italian naturalist Antoine Risso. He gave it the name ''Pleurobranchus stellatus'', but it has since been moved to the genus ''

Berthella ''Berthella'' is a genus of sea slugs, marine gastropod mollusks in the family Pleurobranchidae. Species Species within the genus ''Berthella'' are: ''Species inquirenda In biological classification, a ''species inquirenda'' is a species of d ...

'', becoming ''Berthella stellata''. It has a very wide distributional range, and morphological studies and molecular evidence suggest that it is a species complex consisting of at least eight species. These form a

monophyletic In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...

group if ''

Berthella strongi ''Berthella'' is a genus of sea slugs, marine (ocean), marine gastropod mollusks in the family Pleurobranchidae. Species Species within the genus ''Berthella'' are: ''Species inquirenda'' * ''Berthella dautzenbergi'' (R. B. Watson, 1897) * ''B ...

'' from the eastern Pacific Ocean is included.

Description

''Berthella stellata'' is a slightly domed oval shape and can grow to a length of about . It has a translucent whitish or golden-brown mantle through which the thin, flattened internal shell, and the brownish visceral mass can be seen. The rhinophores are tubular and divided along their length; they and the buccal membrane extend far beyond the foot and are the same colour as the rest of the animal. The

mantle A mantle is a piece of clothing, a type of cloak. Several other meanings are derived from that. Mantle may refer to: *Mantle (clothing), a cloak-like garment worn mainly by women as fashionable outerwear **Mantle (vesture), an Eastern Orthodox ve ...

surface is finely reticulated with white lines surrounding low raised areas. In the centre of the dorsal surface is a white cross, with short white diagonal lines lying between the arms of the cross; these markings are more visible in young individuals, with older specimens often having only the diagonal lines.

Distribution and habitat

First described from the Mediterranean Sea, this sea slug has been recorded under various names from around the world including from the western Indo-Pacific, Réunion, New Caledonia, Brazil, the Caribbean, the Red Sea, south-eastern Australia, Baja California, Hawaii, the Marshall Islands and Japan. It occurs on rock surfaces from the intertidal zone down to about . It is nocturnal, and hides in crevices and under stones during the daytime.

Ecology

''Berthella stellata'' probably feeds by grazing on encrusting sponges in the family Oscarellidae. Scattered white spots on the surface of the mantle are glands that secrete acidic mucus to deter

predators Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

. This sea slug is a

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...

, the genital openings being on the right side. A pair of slugs will orientate themselves so that the openings are in alignment, and fertilise each other. The eggs are laid in a whitish, coiled cylindrical, jelly-like ribbon about long.

References

{{Taxonbar, from=Q6776042 Pleurobranchidae Molluscs of the Atlantic Ocean Molluscs of the Indian Ocean Molluscs of the Mediterranean Sea Molluscs of the Pacific Ocean Animals described in 1826 Taxa named by Antoine Risso