''Distomus variolosus'' is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

tunicate A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata (). It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one time ca ...

or sea squirt in the

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Styelidae Styelidae is a family of ascidian tunicates.Lambert, G.; Gittenberger, A.; Sanamyan, K. (2015)Styelidae Sluiter, 1895.In: Shenkar, N.; Gittenberger, A.; Lambert, G.; Rius, M.; Moreira Da Rocha, R.; Swalla, B.J.; Turon, X. (2015) Ascidiacea World ...

. It is native to the northeastern Atlantic Ocean where it lives on the seabed,Gittenberger, A.; Sanamyan, K. (2015)
''Distomus variolosus'' Gaertner, 1774.
In: Shenkar, N.; Gittenberger, A.; Lambert, G.; Rius, M.; Moreira Da Rocha, R.; Swalla, B.J.; Turon, X. (2015) Ascidiacea World Database. Accessed through: World Register of Marine Species on 2015-12-23 typically on the stems and fronds of kelp.

Description

''Distomus variolosus'' is a

colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 a ...

sea squirt that forms leathery patches, often encircling the stems of kelp. The zooids are globose or ovoid and about high, with the two short siphons close together near the apex. It is difficult to distinguish the buccal siphon from the exhalant siphon. The zooids are separate, but linked by the base or the sides. Zooids with closed siphons have a warty appearance, giving the species its specific name. Generally red, the colonies may be spotted with yellow, brown or pink.

Distribution and habitat

''Distomus variolosus'' is found in the northeastern Atlantic Ocean.Picton, B.E. & Morrow, C.C. (2015)
''Distomus variolosus'' Gaertner in Pallas, 1774.
n/nowiki> Encyclopedia of Marine Life of Britain and Ireland. Accessed on 2015-12-23 Its range extends from the southwest of Great Britain and Ireland as far south as Portugal. It has been reported from the Mediterranean Sea but this is probably a misidentification of '' Distomus fuscus'', which is believed to be the only member of the genus to be found in the Mediterranean. It typically grows on the stems and blades of kelp, such as ''

Laminaria digitata ''Laminaria digitata'' is a large brown alga in the family Laminariaceae, also known by the common name oarweed. It is found in the sublittoral zone of the northern Atlantic Ocean. Description ''Laminaria digitata'' is a tough, leathery, dark ...

'', ''

Laminaria hyperborea ''Laminaria hyperborea'' is a species of large brown alga, a kelp in the family Laminariaceae, also known by the common names of tangle and cuvie. It is found in the sublittoral zone of the northern Atlantic Ocean. A variety, ''Laminaria hyperbo ...

'' and ''

Saccharina latissima ''Saccharina latissima'' is a brown alga (class Phaeophyceae), of the family Laminariaceae. It is known by the common names sugar kelp, sea belt, and Devil's apron, and is one of the species known to Japanese cuisine as kombu. It is found in the ...

'', at the base of hydroids, and sometimes colonises the shells of

crustacean Crustaceans (Crustacea, ) form a large, diverse arthropod taxon which includes such animals as decapods, seed shrimp, branchiopods, fish lice, krill, remipedes, isopods, barnacles, copepods, amphipods and mantis shrimp. The crustacean group ...

s such as the spider crab, ''

Maja brachydactyla ''Maja brachydactyla'' is a species of crab in the family Majidae. It was initially described as a subspecies of '' M. squinado.'' A review of the species complex published in 1998 was able to differentiate between specimens from the Mediterrane ...

''.

Biology

Sea squirts take in water through the buccal siphon and expel it through the exhalant siphon, having filtered out any edible particles. The colonies grow by budding new zooids. ''Distomus variolosus'' is a

hermaphrodite In reproductive biology, a hermaphrodite () is an organism that has both kinds of reproductive organs and can produce both gametes associated with male and female sexes. Many Taxonomy (biology), taxonomic groups of animals (mostly invertebrate ...

. Sexual reproduction takes place with sperm being liberated into the sea by a male phase zooid. When this is drawn into a female phase zooid, fertilisation takes place and the larva is brooded in the sea squirt's body cavity. When it is mature enough, it is expelled into the

water column A water column is a conceptual column of water from the surface of a sea, river or lake to the bottom sediment.Munson, B.H., Axler, R., Hagley C., Host G., Merrick G., Richards C. (2004).Glossary. ''Water on the Web''. University of Minnesota-D ...

, and after a short

plankton Plankton are the diverse collection of organisms found in Hydrosphere, water (or atmosphere, air) that are unable to propel themselves against a Ocean current, current (or wind). The individual organisms constituting plankton are called plankt ...

ic life, settles on the

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (locomotion), the surface over which an organism lo ...

to form a new colony.

References

{{Taxonbar, from=Q6459711 Stolidobranchia Fauna of the Atlantic Ocean Animals described in 1774 Taxa named by Joseph Gaertner