Tellina fabula
Encyclopedia
Tellina fabula is a species of marine bivalve
mollusc
in the family
Tellinidae
. It is found off the coasts of north west Europe 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
s, siphons, mouth and gut and is surrounded by a mantle
inside the shell.
is transparent and glossy and the shell is white with tinges of yellow or brown. There is a sculpture of fine concentric lines on both valves and some faint radial ribs on the right valve only. The inner surface of the valves is white, sometimes tinted with yellow or orange. The mantle is white with a fringe of tentacles and the gills are unequal in size.
.
Individual molluscs are either male or female and gamete
s are liberated into the water table
during spring and summer. The larva
e are free swimming and form part of the zooplankton
for from 11 to 30 days. Maturity is reached at a size of about 10 millimetres after 1 to 2 years, and the lifespan is up to 5 years.
is found over the same distribution range but the two are not usually in competition as T tenuis occurs from the middle shore level to a depth of about seven metres.
In the sandy sea bed that it favours, T. fabula is often found in association with the sea potato, Echinocardium cordatum
, and the bivalve
molluscs
Ensis ensis
and Chamelea gallina
.
Bivalvia
Bivalvia is a taxonomic class of marine and freshwater molluscs. This class includes clams, oysters, mussels, scallops, and many other families of molluscs that have two hinged shells...
mollusc
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
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...
Tellinidae
Tellinidae
Tellinidae is a family of marine bivalve molluscs of the order Veneroida. They live under soft sediments in shallow seas.-Characteristics:Tellinids have rounded or oval, elongated shells, much flattened. The two valves are connected by a large external ligament. The two separate siphons are...
. It is found off the coasts of north west Europe where it lives buried in sandy sediments.
Bivalves are molluscs with a body compressed between two usually similar shell valves
Bivalve shell
A bivalve shell is part of the body, the exoskeleton or shell, of a bivalve mollusk. In life, the shell of this class of mollusks is composed of two parts, two valves which are hinged together...
joined by an elastic ligament. There are teeth at the edge of the shell and the animal has a muscular foot, gill
Gill
A gill is a respiratory organ found in many aquatic organisms that extracts dissolved oxygen from water, afterward excreting carbon dioxide. The gills of some species such as hermit crabs have adapted to allow respiration on land provided they are kept moist...
s, siphons, mouth and gut and is surrounded by a 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...
inside the shell.
Description
The shell of Tellina fabula is brittle and flattened and grows to a length of twenty centimetres. The outline is oval but the shell is asymmetric with the hinge slightly off centre and the beaks slightly behind the midline. The anterior dorsal margin curves gently and the anterior margin is rounded. The posterior dorsal margin is straighter and the posterior margin is somewhat pointed. The periostracumPeriostracum
The periostracum is a thin organic coating or "skin" which is the outermost layer of the shell of many shelled animals, including mollusks and brachiopods. Among mollusks it is primarily seen in snails and clams, i.e. in bivalves and gastropods, but it is also found in cephalopods such as the...
is transparent and glossy and the shell is white with tinges of yellow or brown. There is a sculpture of fine concentric lines on both valves and some faint radial ribs on the right valve only. The inner surface of the valves is white, sometimes tinted with yellow or orange. The mantle is white with a fringe of tentacles and the gills are unequal in size.
Distribution
T. fabula occurs off the coasts of north west Europe and Morocco and in the Mediterranean Sea and the Black Sea. It is found from low water level to a depth of about forty metres. In a study off the Belgian coast in 2006, this species was found at a maximum density of over a thousand individuals per square metre.Biology
T. fabula burrows in clean or slightly muddy sand and has a large foot and two long siphons which it extends to the surface of the sediment. The longer one gropes around for organic debris which is drawn down to the mollusc through this siphon while water is expelled through the other. It is both a deposit and a filter feederFilter feeder
Filter feeders are 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 feeding are clams, krill, sponges, baleen whales, and many fish and some sharks. Some birds,...
.
Individual molluscs are either male or female and gamete
Gamete
A gamete is a cell that fuses with another cell during fertilization in organisms that reproduce sexually...
s are liberated into the water table
Water table
The water table is the level at which the submarine pressure is far from atmospheric pressure. It may be conveniently visualized as the 'surface' of the subsurface materials that are saturated with groundwater in a given vicinity. However, saturated conditions may extend above the water table as...
during spring and summer. The larva
Larva
A larva 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...
e are free swimming and form part of the zooplankton
Zooplankton
Zooplankton are heterotrophic plankton. Plankton are organisms drifting in oceans, seas, and bodies of fresh water. The word "zooplankton" is derived from the Greek zoon , meaning "animal", and , meaning "wanderer" or "drifter"...
for from 11 to 30 days. Maturity is reached at a size of about 10 millimetres after 1 to 2 years, and the lifespan is up to 5 years.
Ecology
The closely related species, Tellina tenuisTellina tenuis
Tellina tenuis, the thin tellin, is a species of marine bivalve mollusc in the family Tellinidae. It is found off the coasts of north west Europe and in the Mediterranean Sea where it lives buried in sandy sediments....
is found over the same distribution range but the two are not usually in competition as T tenuis occurs from the middle shore level to a depth of about seven metres.
In the sandy sea bed that it favours, T. fabula is often found in association with the sea potato, Echinocardium cordatum
Echinocardium cordatum
Echinocardium cordatum, or the sea potato, is a sea urchin in the family Loveniidae. It is found in sub-tidal regions in temperate seas around the world and lives buried in the sandy sea floor.-Description:...
, and the bivalve
Bivalvia
Bivalvia is a taxonomic class of marine and freshwater molluscs. This class includes clams, oysters, mussels, scallops, and many other families of molluscs that have two hinged shells...
molluscs
Mollusca
The Mollusca , common name molluscs or mollusksSpelled mollusks in the USA, see reasons given in Rosenberg's ; for the spelling mollusc see the reasons given by , is a large phylum of invertebrate animals. There are around 85,000 recognized extant species of molluscs. Mollusca is the largest...
Ensis ensis
Ensis ensis
Ensis ensis, or the sword razor, is a marine bivalve mollusc in the family Pharidae. It lives buried in the sand and is found off the coasts of north west Europe....
and Chamelea gallina
Chamelea gallina
Chamelea gallina is a species of small saltwater clam, a marine bivalve mollusc in the family Veneridae, the venus clams.-Taxonomy:Linnaeus originally described Venus gallina from the Mediterranean in 1758. Other zoologists may have consequently assumed that Da Costa's 1778 Pectunculus striatulus...
.