''Berthellina edwardsii'' is a species of
sea slug, a
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
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 native to the northeastern Atlantic Ocean and the
Mediterranean Sea.
Description
''Berthellina edwardsii'' is a large sea slug, growing to a length of . The head bears a pair of smooth, rolled
rhinophores at the top, but the triangular buccal veil and a pair of low-lying
tentacles are less discernable. There is a small flattened internal shell which looks whitish when viewed through the translucent tissue, and there are dark spots visible through the dorsal surface which are the digestive glands. The foot is broad, and the
gill is located on the right side of the body, between the foot and the mantle. The colour varies from whitish or lemon yellow to deep orange-red.
This sea slug is very similar in appearance to ''
Berthella aurantiaca
''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 ...
''; there are no distinctive external features distinguishing the two, but ''B. aurantiaca'' has a much larger internal shell. Another similar species is ''
Berthella stellata
''Berthella stellata'' is a species of sea slug in the family Pleurobranchidae. 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 Sp ...
'', but that is rather smaller, transparent or whitish, and has a star-shaped opaque pattern in the centre of its back.
[
]
Ecology
''Berthellina edwardsii'' is mainly nocturnal, hiding during the day in a crack or under a rock. Glands on its mantle secrete a white acidic fluid which is distasteful to fish.[ The bright colouring serves as a warning of its toxicity to potential ]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 ...
.radula
The radula (, ; plural radulae or radulas) is an anatomical structure used by molluscs 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 ...
. Breeding takes place in autumn. Each individual 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 ...
, and a pair of slugs will orientate themselves so that their genital openings are close together, and exchange sperm. The eggs are numerous but tiny, and are laid in a whitish, coiled cylindrical, jelly-like ribbon, stuck to the substrate.[
File:Berthellina edwardsii DSC4002.jpg, ''Berthellina edwardsii'' in Pula, Croatia
File:Berthellina edwardsii DSC3920.jpg, Two specimens of ''Berthellina edwardsii''
File:Berthellina edwardsii DSC2641.jpg, ''Berthellina edwardsii'' in Pula, Croatia
]
References
{{Taxonbar, from=Q13438951
Pleurobranchidae
Molluscs of the Atlantic Ocean
Molluscs of the Mediterranean Sea
Molluscs described in 1897