''Neanthes fucata'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of marine

polychaete Polychaeta () is a paraphyletic class of generally marine Annelid, annelid worms, common name, commonly called bristle worms or polychaetes (). Each body segment has a pair of fleshy protrusions called parapodia that bear many bristles, called c ...

worm in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Nereididae Nereididae (formerly spelled Nereidae) are a family of polychaete worms. It contains about 500 - mostly-marine - species grouped into 42 genera. They may be commonly called ragworms or clamworms. Characteristics The prostomium of Nereididae be ...

. It lives in association with a

hermit crab Hermit crabs are anomuran Decapoda, decapod crustaceans of the superfamily (taxonomy), superfamily Paguroidea that have adapted to occupy empty scavenged mollusc shells to protect their fragile exoskeletons. There are over 800 species of hermit c ...

such as ''

Pagurus bernhardus ''Pagurus bernhardus'' is the common marine hermit crab of Europe's Atlantic coasts. It is sometimes referred to as the common hermit crab or soldier crab. Its carapace reaches long, and is found in both rocky and sandy areas, from the Arctic w ...

''. It occurs in the northeastern Atlantic Ocean, the

North Sea The North Sea lies between Great Britain, Denmark, Norway, Germany, the Netherlands, Belgium, and France. A sea on the European continental shelf, it connects to the Atlantic Ocean through the English Channel in the south and the Norwegian Se ...

and 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 east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

Taxonomy

This worm was first described in 1822 by the French zoologist

Marie Jules César Savigny Marie Jules César Lelorgne de Savigny (; 5 April 1777 – 5 October 1851) was a French zoologist and naturalist who served on Emperor Napoleon's Egypt expedition in 1798. He published descriptions of numerous taxa and was among the first to propo ...

, who gave it the name ''Nereis fucata'', however it was later transferred to the genus '' Neanthes'', making it ''Neanthes fucata''.

Description

The body of this segmented worm is long, slender and tapering, with a smooth

cuticle A cuticle (), or cuticula, is any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticle" are non- homologous, differing in their origin, structu ...

. The

prostomium The prostomium (From Ancient Greek, meaning "before the mouth"; : prostomia; sometimes also called the "acron") is the Cephalization, cephalized first body segment in an annelid worm's body at the anterior end. It is in front of (but does not in ...

bears a pair of antennae, a pair of palps and two pairs of eyes. The first body segment is twice as long as the rest and bears the pharynx and four pairs of tentacular cirri. Segments two and three have uniramous parapodia (unbranched lateral lobes bearing bristles) while the remaining segments bear biramous (two-lobed) parapodia. This worm is yellowish, with longitudinal stripes in red and white. A worm of 120 segments measures about .

Distribution and habitat

This worm is native to the northwestern Atlantic Ocean, the

Kattegat The Kattegat (; ; ) is a sea area bounded by the peninsula of Jutland in the west, the Danish straits islands of Denmark and the Baltic Sea to the south and the Swedish provinces of Bohuslän, Västergötland, Halland and Scania in Swede ...

, the

English Channel The English Channel, also known as the Channel, is an arm of the Atlantic Ocean that separates Southern England from northern France. It links to the southern part of the North Sea by the Strait of Dover at its northeastern end. It is the busi ...

, the

and the

Black Sea The Black Sea is a marginal sea, marginal Mediterranean sea (oceanography), mediterranean sea lying between Europe and Asia, east of the Balkans, south of the East European Plain, west of the Caucasus, and north of Anatolia. It is bound ...

. It lives in association with a

, sharing the shell of the gastropod mollusc in which it lives, but individuals have occasionally been observed away from a

host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County * Host Island, in the Wilhelm Archipelago, Antarctica People * ...

, probably only temporarily. Over much of its range, the normal host is the common European species ''

'' which is found on the mid and lower shore and at depths down to about .

Ecology

''Neanthes fucata'' lives inside an empty gastropod mollusc shell inhabited by a hermit crab. It is able to steal scraps of food from the hermit crab by protruding its pharynx between the crab's third

maxillipeds An appendage (or outgrowth) is an external body part or natural prolongation that protrudes from an organism's body such as an arm or a leg. Protrusions from single-celled bacteria and archaea are known as cell-surface appendages or surface app ...

. It has been shown that the crab recognises its commensal worm and does not attack it. A single adult worm inhabits a single host mollusc shell occupied by a hermit crab, but occasionally a single adult and several juveniles have been found living together. The adult worms show territorial behaviour, fighting with other worms of the same species. However the worms are

gonochoristic In biology, gonochorism is a sexual system where there are two sexes and each individual organism is either male or female. The term gonochorism is usually applied in animal species, the vast majority of which are gonochoric. Gonochorism contras ...

and there must be some mechanism by which a male and female come into close proximity during the period in which they are reproductively active. Some possibilities for this to happen include the hosts being close together, temporary aggregations of individual worms during the breeding season, or by the release of

gamete A gamete ( ) is a Ploidy#Haploid and monoploid, haploid cell that fuses with another haploid cell during fertilization in organisms that Sexual reproduction, reproduce sexually. Gametes are an organism's reproductive cells, also referred to as s ...

s into the sea water.

References

{{Taxonbar, from=Q3655249 Phyllodocida Animals described in 1822 Taxa named by Marie Jules César Savigny