Phaxas pellucidus or the transparent razor shell 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 marine 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...

 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...

 Pharidae

Pharidae

Pharidae is a family of clams related to the razor shells , a family which includes Pharidae by some authorities.-Genera:* Afrophaxas Cosel, 1993* Cultellus Schumacher, 1817* Ensiculus H...

. It is found buried in the seabed

Seabed

The seabed is the bottom of the ocean.- Ocean structure :Most of the oceans have a common structure, created by common physical phenomena, mainly from tectonic movement, and sediment from various sources...

 in coastal waters of northwest Europe, often in great numbers.

Description

P. pellucidus is a very small razor shell seldom exceeding 4 cm (2 in) in length. The colour is cream or dull white, sometimes with reddish markings. The periostracum

Periostracum

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 olive-coloured and glossy. The two elongated 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...

 are fragile and equal in size. The dorsal side of each is straight while the ventral side is slightly curved giving a pod-like appearance. The anterior end is rounded while the posterior end is slightly truncate. There are fine sculptured lines parallel to the margins, which are themselves smooth. The ligament joining the valves is external and located close to the beaks which are very close to the anterior end. Pharus legumen is a somewhat similar species but it can be distinguished by its larger size and more cylindrical outline and the differences in the hinge teeth.

Distribution

P. pellucidus occurs in the northeastern Atlantic Ocean

Atlantic Ocean

The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...

, ranging from 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...

 and the Baltic Sea

Baltic Sea

The Baltic Sea is a brackish mediterranean sea located in Northern Europe, from 53°N to 66°N latitude and from 20°E to 26°E longitude. It is bounded by the Scandinavian Peninsula, the mainland of Europe, and the Danish islands. It drains into the Kattegat by way of the Øresund, the Great Belt and...

 southwards to Spain

Spain

Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...

 and Portugal

Portugal

Portugal , officially the Portuguese Republic is a country situated in southwestern Europe on the Iberian Peninsula. Portugal is the westernmost country of Europe, and is bordered by the Atlantic Ocean to the West and South and by Spain to the North and East. The Atlantic archipelagos of the...

, including the North Sea

North Sea

In the southwest, beyond the Straits of Dover, the North Sea becomes the English Channel connecting to the Atlantic Ocean. In the east, it connects to the Baltic Sea via the Skagerrak and Kattegat, narrow straits that separate Denmark from Norway and Sweden respectively...

 and English Channel

English Channel

The English Channel , often referred to simply as the Channel, is an arm of the Atlantic Ocean that separates southern England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest to in the Strait of Dover...

. It is found around the coasts of the British Isles

British Isles

The British Isles are a group of islands off the northwest coast of continental Europe that include the islands of Great Britain and Ireland and over six thousand smaller isles. There are two sovereign states located on the islands: the United Kingdom of Great Britain and Northern Ireland and...

.

Biology

This species is often abundant in muddy sand at depths of up to 200 metres. It is a filter feeder

Filter 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,...

 and extends its siphons to the surface to circulate water through its mantle where it extract food fragments.
Studies in Liverpool Bay

Liverpool Bay

Liverpool Bay is a bay of the Irish Sea between northeast Wales, Cheshire, Lancashire and Merseyside to the east of the Irish Sea. The bay is a classic example of a region of freshwater influence...

 show that where the sea bed has been disturbed by dredging and deposition of further sediment has occurred, P. pellucidus and the polychaete

Polychaete

The Polychaeta or polychaetes are a class of annelid worms, generally marine. Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called chaetae, which are made of chitin. Indeed, polychaetes are sometimes referred to as bristle worms. More than 10,000...

 worm Lagis koreni

Lagis koreni

Lagis koreni, commonly known as the trumpet worm, is a species of marine polychaete worm found in European waters. It lives within a narrow conical tube tube made of grains of sand and shell fragments.-Taxonomy:...

often come to dominate the community

Community (ecology)

In ecology, a community is an assemblage of two or more populations of different species occupying the same geographical area. The term community has a variety of uses...

, which includes another bivalve, Abra alba

Abra alba

Abra alba or the white furrow shell is a species of bivalve mollusc in the Semelidae family. It occurs in the north eastern Atlantic Ocean and the Mediterranean Sea, where it lives on the floor in shallow areas buried in soft sediments....

. In the study, this particular community is believed to be associated with more than one biotope

Biotope

Biotope is an area of uniform environmental conditions providing a living place for a specific assemblage of plants and animals. Biotope is almost synonymous with the term habitat, but while the subject of a habitat is a species or a population, the subject of a biotope is a biological community.It...

(the habitat of a community).