The razor shell, ''Ensis magnus'', also called razor clam, razor fish or spoot (colloquially), is a

bivalve Bivalvia () or bivalves, in previous centuries referred to as the Lamellibranchiata and Pelecypoda, is a class (biology), class of aquatic animal, aquatic molluscs (marine and freshwater) that have laterally compressed soft bodies enclosed b ...

of the family

Pharidae Pharidae is a Taxonomy (biology), taxonomic family (biology), family of saltwater clams, marine (ocean), marine bivalve molluscs in the order Adapedonta. This family of clams is related to the Solenidae, razor shells, a family which is considered ...

. It is found on sandy beaches in Canada and northern

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

(north of 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 ...

). In some locations, the

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often con ...

"razor shell" is also used to refer to members of the family Solenidae, including species of the genera ''

Ensis ''Ensis'' is a genus of medium-sized edible saltwater clams, littoral bivalve molluscs in the family Pharidae. ''Ensis'', or razor clams, are known in much of Scotland as spoots, for the spouts of water they eject while burrowing into the san ...

'' and '' Solen'', by some taxonomic classifications which include the family Pharidae within the family Solenidae. It prefers coarser sand than its relatives '' E. ensis'' and '' E. siliqua''.

Description

It is known for its elongated, rectangular shape, which presents a similarity to the

straight razor A straight razor is a razor with a blade that can fold into its handle. They are also called open razors and cut-throat razors. The predecessors of the modern straight razors include bronze razors, with cutting edges and fixed handles, produced ...

, hence its name. The razor shell has been known to reach in length. The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage The fus ...

margin is straight while the

ventral Standard anatomical terms of location are used to describe unambiguously the anatomy of humans and other animals. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...

margin is curved. It can easily be confused with the slightly shorter and more curved ''E. ensis'' (in which both front and back are curved in parallel). Razor shells have a fragile shell, with open ends. The shell is smooth on the outside and whitish in color, with vertical and horizontal reddish-brown or purplish-brown markings separated by a diagonal line. 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 an ...

is olive-green. The inner surface is white with a purple tinge and the

foot The foot (: feet) is an anatomical structure found in many vertebrates. It is the terminal portion of a limb which bears weight and allows locomotion. In many animals with feet, the foot is an organ at the terminal part of the leg made up o ...

is creamy white with brown lines.

Right and left valve of the same specimen: File:Ensis magnus 01.jpg, Right valve File:Ensis magnus 02.jpg, Left valve

Habits

The razor shell lives under the sand, using its powerful foot to dig to a safe depth. Its digging activity comprises six stages, repeated cyclically. A digging cycle involves integration of the muscular foot (which takes up a large part of the body) with the opening and closing of the valve and one end. The foot is inflated

hydraulic Hydraulics () is a technology and applied science using engineering, chemistry, and other sciences involving the mechanical properties and use of liquids. At a very basic level, hydraulics is the liquid counterpart of pneumatics, which concer ...

ally, extending down into the sand and anchoring the animal. Deflation of the foot then draws the shell down. The razor shell also squirts water down into the sand, removing loose sand from its path. The foot is thought to exert a pressure of about . Its presence is revealed by a keyhole-shaped hole in the sand, made by its siphons during suspension feeding for

plankton Plankton are the diverse collection of organisms that drift in Hydrosphere, water (or atmosphere, air) but are unable to actively propel themselves against ocean current, currents (or wind). The individual organisms constituting plankton are ca ...

. Razor clams can grow up to eight inches long, but are typically only four to six inches. Razor clams are filter feeders, meaning they strain food particles from the water around them. They primarily eat microscopic

algae Algae ( , ; : alga ) is an informal term for any organisms of a large and diverse group of photosynthesis, photosynthetic organisms that are not plants, and includes species from multiple distinct clades. Such organisms range from unicellular ...

, but can also consume small

crustaceans Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of Arthropod, arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquat ...

and other organic matter.

Reproduction

In the razor shell sexual development is highly synchronous. During the summer, they are in the sexual rest stage, and

gametogenesis Gametogenesis is a biological process by which diploid or haploid precursor cells undergo cell division and differentiation to form mature haploid gametes. Depending on the biological life cycle of the organism, gametogenesis occurs by meiotic d ...

begins at the start of autumn. In winter and spring consecutive spawns take place, interrupted by gonadal restoration periods.

Vulnerability

Stired-fried Razor Clams with Black Beans and Pepper

Many intertidal populations of razor shell have declined as a result of

overfishing Overfishing is the removal of a species of fish (i.e. fishing) from a body of water at a rate greater than that the species can replenish its population naturally (i.e. the overexploitation of the fishery's existing Fish stocks, fish stock), resu ...

; the species is in decline in many areas. Razor shells are very sensitive to minor perturbations in, for instance,

salinity Salinity () is the saltiness or amount of salt (chemistry), salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensio ...

and

temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...

. They will emerge from their burrows if salt or

brine Brine (or briny water) is a high-concentration solution of salt (typically sodium chloride or calcium chloride) in water. In diverse contexts, ''brine'' may refer to the salt solutions ranging from about 3.5% (a typical concentration of seawat ...

is poured in.

Disease

Razor shells have been found to be vulnerable to

germinoma A germinoma is a type of germ-cell tumor, which is not differentiated upon examination. It may be benign or malignant. Cause Germinomas are thought to originate from an error of development, when certain primordial germ cells fail to migrate pr ...

, a variety of

tumour A neoplasm () is a type of abnormal and excessive growth of tissue (biology), tissue. The process that occurs to form or produce a neoplasm is called neoplasia. The growth of a neoplasm is uncoordinated with that of the normal surrounding tiss ...

References

External links

Razor shells in Norway

Effect of dredging on razor shell populations
{{Taxonbar, from1=Q3802489, from2=Q2248806 Pharidae Marine molluscs of Europe Marine molluscs of North America Molluscs of the Atlantic Ocean Molluscs described in 1865