''Tellina tenuis'', the thin tellin, is a species of marine

bivalve Bivalvia (), in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class of marine and freshwater molluscs that have laterally compressed bodies enclosed by a shell consisting of two hinged parts. As a group, biv ...

mollusc in the

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

Tellinidae The Tellinidae are a family of marine bivalve molluscs of the order Cardiida. Commonly known as tellins or tellens, they live fairly deep in soft sediments in shallow seas and respire using long siphons that reach up to the surface of the sedime ...

. It is found off the coasts of northwest Europe and in the Mediterranean Sea, where it lives buried in sandy sediments. Bivalves are molluscs with a body compressed between two usually similar shell valves joined by an elastic ligament. There are teeth at the edge of the shell and the animal has a muscular foot,

gill A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they ar ...

s, siphons, mouth and gut and is surrounded by a mantle inside the shell.

Description

The shell of ''T. tenuis'' is brittle and flattened and grows to up to nineteen millimeters in length. The outline is oval but the valves are asymmetric with the hinge slightly off centre and the beaks slightly behind the midline. The posterior of the valves is attenuated slightly and the right valve is slightly larger than the left. An olive green ligament joins the two valves. The

periostracum The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods a ...

is glossy and the colour varies through shades of pink, yellow and brown, often in bands. There is a sculpture of fine concentric lines which is grouped into growth stages and which may be emphasized by bands of colour. The inner sides of the valves are similarly coloured but paler. The mantle is fringed with

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work main ...

s and is creamy-white.Marine Species Identification Portal
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Distribution

''Tellina tenuis'' occurs off the coasts of north west Europe and

Morocco Morocco (),, ) officially the Kingdom of Morocco, is the westernmost country in the Maghreb region of North Africa. It overlooks the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria ...

and in the

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 ...

and the

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and fr ...

. It is found from the middle shore level to a depth of about seven metres. It is widely distributed and common around the coasts of the British Isles.Marine Bivalve Shells of the British Isles
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Biology

''Tellina tenuis'' burrows in clean sand and has a large foot and two long siphons which it extends to the surface of the sediment. Water and food particles are drawn down to the mollusc through one siphon while water is expelled through the other. It is both a

deposit Deposit may refer to: *Deposit (finance) (also security deposit) *Deposit (town), New York *Deposit (village), New York *Deposit account, a bank account that allows money to be deposited and withdrawn by the account holder **Demand deposit, the fund ...

and a

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

.Barrett, J. H. and C. M. Yonge, 1958. Collins Pocket Guide to the Sea Shore. P. 161. Collins, London The mollusc usually lies on its left side when feeding. When the tide is out it descends to a depth of about ten centimetres but ascends to nearer the sediment surface when feeding. At the low tide level it may be the most abundant macro-organism in the

benthos Benthos (), also known as benthon, is the community of organisms that live on, in, or near the bottom of a sea, river, lake, or stream, also known as the benthic zone.gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...

s are liberated into the

water table The water table is the upper surface of the zone of saturation. The zone of saturation is where the pores and fractures of the ground are saturated with water. It can also be simply explained as the depth below which the ground is saturated. Th ...

during the summer. The

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. Th ...

e are free swimming and form part of the

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

for a period. The lifespan is up to 5 years.

Ecology

The closely related species, ''

Tellina fabula ''Fabulina fabula'', the bean-like tellin, is a species of marine bivalve mollusc in the family Tellinidae. It is found off the coasts of northwest Europe, where it lives buried in sandy sediments. Bivalves are molluscs with a body compressed ...

'' is found over the same distribution range but the two are not usually in competition as ''T fabula'' occurs from low water level to a depth of about forty metres. Because of its greater exposure at low tides, ''T tenuis'' is more susceptible to harm in cold winter weather.Encyclopedia of Life
/ref> Young

flatfish A flatfish is a member of the ray-finned demersal fish order Pleuronectiformes, also called the Heterosomata, sometimes classified as a suborder of Perciformes. In many species, both eyes lie on one side of the head, one or the other migratin ...

sometimes feed on the tips of the protruding siphons. The damaged siphons are able to regenerate.

References

{{Taxonbar, from=Q1884947 Tellinidae Molluscs of the Atlantic Ocean Molluscs of the Mediterranean Sea Taxa named by Emanuel Mendes da Costa Bivalves described in 1778