''Biemna variantia'' is a

species In biology, a species is the basic unit of Taxonomy (biology), 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 ...

sponge Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate throug ...

in the

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

Biemnidae Biemnidae is a family of sponges belonging to the order Biemnida. Genera: * '' Biemna'' Gray, 1867 * ''Neofibularia ''Neofibularia'' is a genus of sponges belonging to the family Biemnidae. The species of this genus are found in Australia and ...

. It is native to the northwestern Atlantic Ocean, the northeastern Atlantic Ocean, the North Sea and the Mediterranean Sea. This species was first described in 1858 by the British naturalist

James Scott Bowerbank James Scott Bowerbank (14 July 1797 – 8 March 1877) was a British naturalist and palaeontologist. Biography Bowerbank was born in Bishopsgate, London, and succeeded in conjunction with his brother to his father's distillery, in which he was ...

, who gave it the name ''Halichondria variantia''. It was later moved to the genus ''

Biemna ''Biemna'' is a genus of sea sponges in the family Biemnidae. Species The following species are recognised in the genus Biemna: * ''Biemna anisotoxa'' Lévi, 1963 * ''Biemna bihamigera'' (Dendy, 1922) * ''Biemna caribea'' Pulitzer-Finali, 1986 * ...

'' and is the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen( ...

of the genus. The

type locality Type locality may refer to: * Type locality (biology) * Type locality (geology) See also * Local (disambiguation) * Locality (disambiguation) {{disambiguation ...

Tenby Tenby ( cy, Dinbych-y-pysgod, lit=fortlet of the fish) is both a walled seaside town in Pembrokeshire, Wales, on the western side of Carmarthen Bay, and a local government community. Notable features include of sandy beaches and the Pembr ...

, Wales.

Description

''Biemna variantia'' is an encrusting sponge forming small cushions seldom more than across, thick in the middle and thinner near the edge. The surface is covered with small conical peaks and has a spiky appearance due to

spicule Spicules are any of various small needle-like anatomical structures occurring in organisms Spicule may also refer to: * Spicule (sponge), small skeletal elements of sea sponges *Spicule (nematode), reproductive structures found in male nematodes ...

fibres which support the surface. The

oscula ''Oscula'' is a genus of shield bugs belonging to the family Plataspidae Plataspidae (Emendation (taxonomy), emended by some later authors as "Plataspididae", in violation of International Code of Zoological Nomenclature, ICZN Code Article 29.5 ...

are irregularly scattered across the surface. Sometimes the cushions are plate-like, cup or fan-shaped, and older individuals may have protuberances and appear lumpy or shaggy. The colour of this sponge is yellowish, beige or light brown, the texture is soft, and the tissues fragile and crumbly. It may be confused with ''

Dysidea fragilis ''Dysidea'' is a genus of sponges belonging to the family Dysideidae. The genus has cosmopolitan distribution. Species: *''Dysidea aedificanda'' *''Dysidea amblia'' *''Dysidea anceps'' *''Dysidea arenaria'' *''Dysidea avara'' *''Dysidea ...

'', but that species is whiter and lacks the megascleres and microscleres present in ''Biemna variantia''.

Distribution and habitat

''Biemna variantia'' is found in the

Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately and is known as the coldest of all the oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, ...

and northern

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth#Surface, Earth's surface and about 29% of its water surface area. It is known to separate the "Old World" of Afr ...

, from the

Gulf of Saint Lawrence , image = Baie de la Tour.jpg , alt = , caption = Gulf of St. Lawrence from Anticosti National Park, Quebec , image_bathymetry = Golfe Saint-Laurent Depths fr.svg , alt_bathymetry = Bathymetry ...

and

Greenland Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is ...

to the

Barents Sea The Barents Sea ( , also ; no, Barentshavet, ; russian: Баренцево море, Barentsevo More) is a marginal sea of the Arctic Ocean, located off the northern coasts of Norway and Russia and divided between Norwegian and Russian ter ...

and the

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

. It is also known from the

English Channel The English Channel, "The Sleeve"; nrf, la Maunche, "The Sleeve" ( Cotentinais) or (Jèrriais), ( Guernésiais), "The Channel"; br, Mor Breizh, "Sea of Brittany"; cy, Môr Udd, "Lord's Sea"; kw, Mor Bretannek, "British Sea"; nl, Het Kan ...

and as far south as Portugal, the

Canary Islands The Canary Islands (; es, Canarias, ), also known informally as the Canaries, are a Spanish autonomous community and archipelago in the Atlantic Ocean, in Macaronesia. At their closest point to the African mainland, they are west of Mo ...

and the Alboran Sea, at the western end of 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 north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ...

. It grows on vertical rock faces where there is moderate water movement, under boulders and on stones, gravel and mud, at depths varying from the

intertidal zone The intertidal zone, also known as the foreshore, is the area above water level at low tide and underwater at high tide (in other words, the area within the tidal range). This area can include several types of habitats with various species ...

to . This sponge tolerates

brackish water Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estuari ...

and is not uncommon in

estuaries An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environme ...

Ecology

Like other sponges, ''Biemna variantia'' draws in water through small pores, filters out organic particles less than 3μm in diameter, and expels the water through the oscula; its diet consists mostly of

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

, unicellular

algae Algae ( , ; : alga ) are any of a large and diverse group of photosynthetic, eukaryotic organisms. The name is an informal term for a polyphyletic grouping that includes species from multiple distinct clades. Included organisms range from ...

, and organic debris. The sponge 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 taxonomic groups of animals (mostly invertebrates) do not have ...

and can reproduce both sexually and asexually. Male and female

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...

s are produced at different times, so self-fertilisation does not occur. After fertilisation, the

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male sperm ...

s are

brooded Egg incubation is the process by which an egg, of oviparous (egg-laying) animals, develops an embryo within the egg, after the egg's formation and ovipositional release. Egg incubation is done under favorable environmental conditions, possib ...

inside the sponge, and when they reach the last embryonic stage, they pass out through the oscula 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 ...

. They drift with the

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a cr ...

, and after a few days, they settle on the seabed, attach themselves to 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 ...

and become juvenile sponges. Asexual reproduction is via

budding Budding or blastogenesis is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. For example, the small bulb-like projection coming out from the yeast cell is kno ...

, or by

fragmentation Fragmentation or fragmented may refer to: Computers * Fragmentation (computing), a phenomenon of computer storage * File system fragmentation, the tendency of a file system to lay out the contents of files non-continuously * Fragmented distributi ...

, a process that occurs when pieces of sponge become detached.

References

{{Taxonbar, from=Q2786303 Demospongiae Animals described in 1858