Scyllarus arctus
Encyclopedia
Scyllarus arctus is a species
of slipper lobster
which lives in the Mediterranean Sea
and eastern Atlantic Ocean
. It is uncommon in British and Irish waters, but a number of English-language
vernacular names
have been applied, including small European locust lobster, lesser slipper lobster and broad lobster.
, Madeira
and the Canary Islands
as far north as the English Channel
. The species is rare north of the Bay of Biscay
; several specimens have been seen in British
waters, but nonetheless, S. arctus is rarer in Britain than the giant squid
, Architeuthis dux. Until 1960, S. arctus was thought to be the only species of Scyllarus
in the Mediterranean Sea, but then it was realised that the lesser known Scyllarus pygmaeus
is also present throughout much of the Mediterranean Sea.
, which lives sympatrically with S. arctus, chiefly by its larger size, but also by other features such as the shape of a tubercle on the last thoracic
sternite; this is flattened in S. arctus, but conical in S. pygmaeus. S. arctus has among the smallest measured genome size
s in the Order Decapoda
, at less than a third of that seen in the related genus Scyllarides
.
, and is predated upon by a wide range of demersal fish. It lives at depths of 4–50 m on muddy or rocky substrates, and in Posidonia meadows
. It is the subject of small scale fishery
, but its scarcity and its small size make it an unattractive target.
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 slipper lobster
Slipper lobster
Slipper lobsters are a family of decapod crustaceans found in all warm oceans and seas. Despite their name, they are not true lobsters, but are more closely related to spiny lobsters and furry lobsters. Slipper lobsters are instantly recognisable by their enlarged antennae, which project forward...
which lives in the Mediterranean Sea
Mediterranean 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...
and eastern 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...
. It is uncommon in British and Irish waters, but a number of English-language
English language
English is a West Germanic language that arose in the Anglo-Saxon kingdoms of England and spread into what was to become south-east Scotland under the influence of the Anglian medieval kingdom of Northumbria...
vernacular names
Common name
A common name of a taxon or organism is a name in general use within a community; it is often contrasted with the scientific name for the same organism...
have been applied, including small European locust lobster, lesser slipper lobster and broad lobster.
Distribution
S. arctus is found throughout the Mediterranean Sea, and in eastern parts of the Atlantic Ocean, from the AzoresAzores
The Archipelago of the Azores is composed of nine volcanic islands situated in the middle of the North Atlantic Ocean, and is located about west from Lisbon and about east from the east coast of North America. The islands, and their economic exclusion zone, form the Autonomous Region of the...
, Madeira
Madeira
Madeira is a Portuguese archipelago that lies between and , just under 400 km north of Tenerife, Canary Islands, in the north Atlantic Ocean and an outermost region of the European Union...
and the Canary Islands
Canary Islands
The Canary Islands , also known as the Canaries , is a Spanish archipelago located just off the northwest coast of mainland Africa, 100 km west of the border between Morocco and the Western Sahara. The Canaries are a Spanish autonomous community and an outermost region of the European Union...
as far north as the 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...
. The species is rare north of the Bay of Biscay
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 Brest south to the Spanish border, and the northern coast of Spain west to Cape Ortegal, and is named in English after the province of Biscay, in the Spanish...
; several specimens have been seen in British
Great Britain
Great Britain or Britain is an island situated to the northwest of Continental Europe. It is the ninth largest island in the world, and the largest European island, as well as the largest of the British Isles...
waters, but nonetheless, S. arctus is rarer in Britain than the giant squid
Giant squid
The giant squid is a deep-ocean dwelling squid in the family Architeuthidae, represented by as many as eight species...
, Architeuthis dux. Until 1960, S. arctus was thought to be the only species of Scyllarus
Scyllarus
Scyllarus is a genus of slipper lobsters, containing the following species:*Scyllarus americanus *Scyllarus arctus *Scyllarus caparti Holthuis, 1952*Scyllarus chacei Holthuis, 1960...
in the Mediterranean Sea, but then it was realised that the lesser known Scyllarus pygmaeus
Scyllarus pygmaeus
Scyllarus pygmaeus is a species of slipper lobster that lives in shallow water in the Mediterranean Sea and eastern Atlantic Ocean. It grows to a length of , which is too small for it to be fished for. The juvenile form was first described in 1885, with the description of the adult following in...
is also present throughout much of the Mediterranean Sea.
Description
Scyllarus arctus may reach up to 16 centimetres (6.3 in) long, although sizes of 5 centimetre are more typical. It is reddish-brown in colour, with a dark brown spot in the centre of each abdominal somite, although this is not sharply defined. The pereiopods have a dark blue ring around each segment. It can be told apart from its close relative Scyllarus pygmaeusScyllarus pygmaeus
Scyllarus pygmaeus is a species of slipper lobster that lives in shallow water in the Mediterranean Sea and eastern Atlantic Ocean. It grows to a length of , which is too small for it to be fished for. The juvenile form was first described in 1885, with the description of the adult following in...
, which lives sympatrically with S. arctus, chiefly by its larger size, but also by other features such as the shape of a tubercle on the last thoracic
Thorax
The thorax is a division of an animal's body that lies between the head and the abdomen.-In tetrapods:...
sternite; this is flattened in S. arctus, but conical in S. pygmaeus. S. arctus has among the smallest measured genome size
Genome size
Genome size is the total amount of DNA contained within one copy of a single genome. It is typically measured in terms of mass in picograms or less frequently in Daltons or as the total number of nucleotide base pairs typically in megabases . One picogram equals 978 megabases...
s in the Order Decapoda
Decapoda
The decapods or Decapoda are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crayfish, crabs, lobsters, prawns and shrimp. Most decapods are scavengers. It is estimated that the order contains nearly 15,000 species in around 2,700 genera, with...
, at less than a third of that seen in the related genus Scyllarides
Scyllarides
Scyllarides is a genus of slipper lobsters.-Characteristics:Scyllarides is placed in the subfamily Arctidinae, which is differentiated from other subfamilies by the presence of multiarticulated exopods on all three maxillipeds, and a three-segmented palp on the mandible...
.
Ecology
S. arctus is susceptible to white spot syndromeWhite spot syndrome
White spot syndrome is a viral infection of penaeid shrimp. The disease is highly lethal and contagious, killing shrimps quickly. Outbreaks of this disease have wiped out within a few days the entire populations of many shrimp farms throughout the world.The disease is caused by a family of related...
, and is predated upon by a wide range of demersal fish. It lives at depths of 4–50 m on muddy or rocky substrates, and in Posidonia meadows
Posidonia oceanica
Posidonia oceanica is a seagrass species that is endemic to the Mediterranean Sea. It forms large underwater meadows that are an important part of the ecosystem. The fruit is free floating and known in Italy as 'the olive of the sea'...
. It is the subject of small scale fishery
Lobster fishing
Lobster fishing, sometimes called lobstering, is the commercial or recreational harvesting of marine lobsters, spiny lobsters or crayfish.-Lobster tools and technology:...
, but its scarcity and its small size make it an unattractive target.