Pagurus prideaux
Encyclopedia
Pagurus prideaux is a species
of hermit crab
in the family
Paguridae
. It is found in shallow waters off the northwest coast of Europe and usually lives symbiotically
with the sea anemone
Adamsia palliata
.
of appropriate size and shape, and carrying it around by clasping onto an internal part of the columella of the sea snail
shell.
The carapace
of the crab is brownish-red with paler patches and rather wider than it is long. It has several tufts of short bristles and can reach a length of 14 mm (0.551181102362205 in). The right cheliped can block the entrance to the shell. It is armed with a pincer and is larger than the left one.
, the North Sea
and the northeast Atlantic Ocean
from Cape Verde
north to Norway
.
(the "cloak anemone"). The anemone grows on the underside of the shell inhabited by the hermit crab. Its base enlarges and two flaps wrap around the shell until eventually they meet at the top. Its base secretes a chitin
ous membrane that extends the gastropod shell, enlarging its capacity, and allowing the hermit crab to occupy it for a longer period. The relationship between the two is symbiotic
. The crab is less likely to be attacked by predators
because of the anemone's nematocysts
and the anemone in turn benefits from the food fragments thrown up by the crab's activities.
Another animal with which P. prideaux has a symbiotic relationship is the polychaete worm Iphitime paguri. Adult worms and the larval stages are frequently found in the apex of the gastropod shell. Intermediate sized worms are found in the gill chambers and in a groove under the carapace.
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 hermit crab
Hermit crab
Hermit crabs are decapod crustaceans of the superfamily Paguroidea. Most of the 1100 species possess an asymmetrical abdomen which is concealed in an empty gastropod shell that is carried around by the hermit crab.-Description:...
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...
Paguridae
Paguridae
Paguridae is a family of hermit crabs of the order Decapoda. It contains 542 species in over 70 genera:*Acanthopagurus de Saint Laurent, 1968*Agaricochirus McLaughlin, 1981*Alainopaguroides McLaughlin, 1997...
. It is found in shallow waters off the northwest coast of Europe and usually lives symbiotically
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...
with the sea anemone
Sea anemone
Sea anemones are a group of water-dwelling, predatory animals of the order Actiniaria; they are named after the anemone, a terrestrial flower. Sea anemones are classified in the phylum Cnidaria, class Anthozoa, subclass Zoantharia. Anthozoa often have large polyps that allow for digestion of larger...
Adamsia palliata
Adamsia palliata
Adamsia palliata is a species of sea anemone in the family Hormathiidae. It is usually found growing on a gastropod shell inhabited by the hermit crab, Pagurus prideaux...
.
Description
Like other hermit crabs, P. prideaux has an asymmetric, unarmoured abdomen and protects this by concealing it within the empty shell of a gastropodGastropoda
The Gastropoda or gastropods, more commonly known as snails and slugs, are a large taxonomic class within the phylum Mollusca. The class Gastropoda includes snails and slugs of all kinds and all sizes from microscopic to quite large...
of appropriate size and shape, and carrying it around by clasping onto an internal part of the columella of the sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
shell.
The carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
of the crab is brownish-red with paler patches and rather wider than it is long. It has several tufts of short bristles and can reach a length of 14 mm (0.551181102362205 in). The right cheliped can block the entrance to the shell. It is armed with a pincer and is larger than the left one.
Distribution and habitat
P. prideaux is found on sand, gravel and mud between the tide marks and in the shallow sublittoral. It particularly favours muddy areas with shell fragments and gravel. It occurs in the Mediterranean SeaMediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
, 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 the northeast 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...
from Cape Verde
Cape Verde
The Republic of Cape Verde is an island country, spanning an archipelago of 10 islands located in the central Atlantic Ocean, 570 kilometres off the coast of Western Africa...
north to 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...
.
Ecology
P. prideaux is nearly always found in association with the sea anemone, Adamsia palliataAdamsia palliata
Adamsia palliata is a species of sea anemone in the family Hormathiidae. It is usually found growing on a gastropod shell inhabited by the hermit crab, Pagurus prideaux...
(the "cloak anemone"). The anemone grows on the underside of the shell inhabited by the hermit crab. Its base enlarges and two flaps wrap around the shell until eventually they meet at the top. Its base secretes a chitin
Chitin
Chitin n is a long-chain polymer of a N-acetylglucosamine, a derivative of glucose, and is found in many places throughout the natural world...
ous membrane that extends the gastropod shell, enlarging its capacity, and allowing the hermit crab to occupy it for a longer period. The relationship between the two is symbiotic
Symbiosis
Symbiosis is close and often long-term interaction between different biological species. In 1877 Bennett used the word symbiosis to describe the mutualistic relationship in lichens...
. The crab is less likely to be attacked by predators
Predation
In ecology, predation describes a biological interaction where a predator feeds on its prey . Predators may or may not kill their prey prior to feeding on them, but the act of predation always results in the death of its prey and the eventual absorption of the prey's tissue through consumption...
because of the anemone's nematocysts
Cnidocyte
A cnidocyte, cnidoblast, or nematocyte is a type of venomous cell unique to the phylum Cnidaria . The cnidocyte cell provides a means for them to catch prey and defend themselves from predators. Despite being morphologically simple, lacking a skeleton and usually being sessile, cnidarians prey on...
and the anemone in turn benefits from the food fragments thrown up by the crab's activities.
Another animal with which P. prideaux has a symbiotic relationship is the polychaete worm Iphitime paguri. Adult worms and the larval stages are frequently found in the apex of the gastropod shell. Intermediate sized worms are found in the gill chambers and in a groove under the carapace.