Trivia arctica
Encyclopedia
Trivia arctica, the northern cowrie, is a species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of small sea snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

, a marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...

 gastropod mollusc in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Triviidae
Triviidae
Triviidae is a taxonomic family of small sea snails, marine gastropod molluscs in the clade Littorinimorpha.-Taxonomy:The following subfamilies were recognized in the taxonomy of Bouchet & Rocroi in 2005:*Eratoinae Gill, 1871**tribe Eratoini Gill, 1871...

, the trivias.

This is a similar species to Trivia monacha
Trivia monacha
Trivia monacha, also known as the European cowrie or spotted cowrie, is a species of small sea snail, a marine gastropod mollusc in the family Triviidae, the trivias....

and often occurs in the same areas.

The name Trivia means "common" and the word arctica means "of the arctic".

Distribution

This species occurs from the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...

 to the Orkney islands
Orkney Islands
Orkney also known as the Orkney Islands , is an archipelago in northern Scotland, situated north of the coast of Caithness...

 north of Scotland
Scotland
Scotland is a country that is part of the United Kingdom. Occupying the northern third of the island of Great Britain, it shares a border with England to the south and is bounded by the North Sea to the east, the Atlantic Ocean to the north and west, and the North Channel and Irish Sea to the...

 and Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

. It is more common in the north.

In the British Isles the shells are known as "cowries", except in Orkney where they are called Groatie Buckies. In the Isles of Scilly
Isles of Scilly
The Isles of Scilly form an archipelago off the southwestern tip of the Cornish peninsula of Great Britain. The islands have had a unitary authority council since 1890, and are separate from the Cornwall unitary authority, but some services are combined with Cornwall and the islands are still part...

 the shell is referred to as a Guinea Money.

Habitat

This species usually lives below low tide, in other words is sublittoral, but the empty shells of this species are often washed up onto beaches. In its northern range is found at depths of 100 m and in it s outhern range at depths up to 1000 m.

Description

The shell is glossy and lemon-shaped, with 20-30 transverse ridges. The upper part of the shell is a uniform very pale brown in color; there are no pigment spots present on the shell, but sometimes there are dots on the mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...

 of the animal.

The shell length is up to a maximum of about 10 mm and a width of about 8 mm.

The mantle
Mantle (mollusc)
The mantle is a significant part of the anatomy of molluscs: it is the dorsal body wall which covers the visceral mass and usually protrudes in the form of flaps well beyond the visceral mass itself.In many, but by no means all, species of molluscs, the epidermis of the mantle secretes...

 is covered with many papillae. It has a light colour in deeper waters, but becomes darker between tide marks. The foot is light yellow or light orange. The admedian teeth of the radula
Radula
The radula is an anatomical structure that is used by molluscs for feeding, sometimes compared rather inaccurately to a tongue. It is a minutely toothed, chitinous ribbon, which is typically used for scraping or cutting food before the food enters the esophagus...

 have denticles. The penis
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...

 is flat and broad.

The larvae have a light stomach and intestine. In the veliger
Veliger
A veliger is the planktonic larva of many kinds of marine and freshwater gastropod molluscs, as well as most bivalve mollusks.- Description :...

 stage they have a four-lobed velum
Velum
Velum may refer to:* Superior medullary velum, part of the nervous system that stretches between parts of the brain* Veil , the veil-like membrane of immature mushrooms extending from the margin of the cap to the stem and torn by growth...

 with very long lobes.

Life habits

This snail lives among and feeds on compound ascidians, including Botryllus schlosseri
Botryllus schlosseri
Botryllus schlosseri, commonly known as the star ascidian or golden star tunicate, is an invasive, colonial ascidian tunicate that grows on slow-moving, submerged objects, plants, and animals in nearshore saltwater environments....

. They often occur together with Trivia monacha. The breeding season is autumn, winter and early spring.

Note on differentiating the species

Both Trivia arctica and Trivia monacha
Trivia monacha
Trivia monacha, also known as the European cowrie or spotted cowrie, is a species of small sea snail, a marine gastropod mollusc in the family Triviidae, the trivias....

were considered to be two forms of the same species until 1925, when A. J. Peile published a paper in the Proceedings of the Malacological Society differentiating the two. It is now known that the larvae of the two species are readily distinguishable.

The Linnaean
Linnaean
Linnaean can refer to:*Carolus Linnaeus*Linnaean taxonomy*Linnaean enterprise*Linnean...

 name Trivia europea, now lapsed, referred to the supposed single species. Linnaeus himself mentioned two kinds: Cypraea europea and Cypraea anglica, but these terms were intended as a geographical distinction, and are not accepted as species names today.
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