''Simnia spelta'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

sea snail Sea snails are slow-moving marine (ocean), marine gastropod Mollusca, molluscs, usually with visible external shells, such as whelk or abalone. They share the Taxonomic classification, taxonomic class Gastropoda with slugs, which are distinguishe ...

, a marine

gastropod Gastropods (), commonly known as slugs and snails, belong to a large Taxonomy (biology), taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, freshwater, and fro ...

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

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

, the ovulids, which are

cowrie Cowrie or cowry () is the common name for a group of small to large sea snails in the family Cypraeidae. Cowrie shells have held cultural, economic, and ornamental significance in various cultures. The cowrie was the shell most widely used wo ...

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 ennoblement in 1761 as Carl von Linné,#Blunt, Blunt (2004), p. 171. was a Swedish biologist and physician who formalised binomial nomenclature, the modern system of naming o ...

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 b ...

. 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 of the mollusk.

Distribution

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

endemic Endemism is the state of a species being found only 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 foun ...

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 east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

and the

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

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

Bay of Biscay The Bay of Biscay ( ) is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Point Penmarc'h to the Spanish border, and along the northern coast of Spain, extending westward ...

, the

Canary Islands The Canary Islands (; ) or Canaries are an archipelago in the Atlantic Ocean and the southernmost Autonomous communities of Spain, Autonomous Community of Spain. They are located in the northwest of Africa, with the closest point to the cont ...

and

Angola Angola, officially the Republic of Angola, is a country on the west-Central Africa, central coast of Southern Africa. It is the second-largest Portuguese-speaking world, Portuguese-speaking (Lusophone) country in both total area and List of c ...

. 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 in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

on gorgonians of the genera '' Eunicella'', '' Paramuricea'' 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 ...

, 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 * Host Island, in the Wilhelm Archipelago, Antarctica People * ...

. 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 ''Eunicella singularis'', the white gorgonian, is a species of Colony (biology), colonial soft coral, a Gorgonian, sea fan in the family (biology), family Gorgoniidae. It is found in the western Mediterranean Sea, Adriatic Sea and Ionian Sea. It ...

'' 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 ep ...

s grow on the denuded branches.

References

External links

* {{Taxonbar, from=Q7518054 Ovulidae Gastropods described in 1758 Taxa named by Carl Linnaeus Fauna of the Adriatic Sea Molluscs of the Atlantic Ocean