''Simnia spelta'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a marine

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 Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Ovulidae Ovulidae, common names the ovulids, cowry allies or false cowries, is a family of small to large predatory or parasitic sea snails, marine gastropod molluscs in the superfamily Cypraeoidea, the cowries and the cowry allies. MolluscaBase eds. ...

, the ovulids, which are

cowrie Cowrie or cowry () is the common name for a group of small to large sea snails, marine gastropod mollusks in the family Cypraeidae, the cowries. The term ''porcelain'' derives from the old Italian term for the cowrie shell (''porcellana'') d ...

allies sometimes called "false cowries". It was first described in 1758 by the Swedish naturalist

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

Description

''Simnia spelta'' grows to a length of about . The shell is roughly egg or cigar-shaped with a flattened base. It is strong, thick, smooth and glossy, with inrolled edges at the sides of the long aperture on the underside. The colouring varies according to the species of gorgonian on which it is living. The background colour of the shell is white, yellow, pink or orange, often with white spots or dark spots, marbling or streaks, providing

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...

. As is commonly the case in '' Simnia'' species, the colour of all the visible soft parts normally matches the colour of the gorgonian on which the snail is grazing, as the pigment from the gorgonian is retained in 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 ...

of the mollusk.

Distribution

''Simnia spelta'' was at one time considered to be

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the western

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 north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

and the

Adriatic Sea The Adriatic Sea () is a body of water separating the Italian Peninsula from the Balkan Peninsula. The Adriatic is the northernmost arm of the Mediterranean Sea, extending from the Strait of Otranto (where it connects to the Ionian Sea) to t ...

, but it is now known to occur also in the eastern Atlantic Ocean between the

Bay of Biscay The Bay of Biscay (), known in Spain as the Gulf of Biscay ( es, Golfo de Vizcaya, eu, Bizkaiko Golkoa), and in France and some border regions as the Gulf of Gascony (french: Golfe de Gascogne, oc, Golf de Gasconha, br, Pleg-mor Gwaskogn), ...

, the

Canary Islands The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Morocc ...

and

Angola , national_anthem = " Angola Avante"() , image_map = , map_caption = , capital = Luanda , religion = , religion_year = 2020 , religion_ref = , coordina ...

. Its normal habitat is living on gorgonians, or sea fans, at depths down to about .

Ecology

''Simnia spelta'' is a specialist

predator 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 th ...

on gorgonians of the genera ''

Eunicella ''Eunicella'' is a genus of coral in the family Gorgoniidae family. Species The World Register of Marine Species lists the following species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, a ...

'', ''

Paramuricea ''Paramuricea'' is a genus of gorgonian-type Octocorallia, octocorals in the Family (biology), family Plexauridae. Species The World Register of Marine Species lists these species: *''Paramuricea aequatorialis'' Wright & Studer, 1889 *''Param ...

'' and '' Lophogorgia''. It feeds on the polyps and the

coenenchyme Coenenchyme is the common tissue that surrounds and links the polyps in octocorals. It consists of mesoglea penetrated by tubes (''solenia'') and canals of the gastrodermis and contains sclerites, microscopic mineralised spicules of silica or of ca ...

, the living connective tissue that surrounds the horny skeleton, but does not graze excessively and therefore does not kill its

host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman * Michel Host ...

. The sexes are separate in this species, and fertilisation is internal. Eggs are laid on the branches of the host species and resemble the natural warty appearance of the stems. The white gorgonian '' Eunicella singularis'' is one of the sea fans with which this snail associates. On this host the snail is normally white and mimics the twigs in appearance. It feeds and lays its eggs on the gorgonian branches. Afterwards,

epibiont An epibiont (from the Ancient Greek meaning "living on top of") is an organism that lives on the surface of another living organism, called the basibiont ("living underneath"). The interaction between the two organisms is called epibiosis. An epi ...

s grow on the denuded branches.

References

External links

* {{DEFAULTSORT:Simnia Spelta Ovulidae Gastropods described in 1758 Taxa named by Carl Linnaeus Fauna of the Adriatic Sea Molluscs of the Atlantic Ocean