''Exaiptasia'' is a genus of

sea anemone Sea anemones are a group of predation, predatory marine invertebrates of the order (biology), order Actiniaria. Because of their colourful appearance, they are named after the ''Anemone'', a terrestrial flowering plant. Sea anemones are classifi ...

in the family

Aiptasiidae Aiptasiidae is a family of sea anemones, comprising the following genera: * ''Aiptasia'' Gosse, 1858 * '' Aiptasiogeton'' Schmidt, 1972 * '' Bartholomea'' Duchassaing de Fonbressin & Michelotti, 1864 * '' Bellactis'' * '' Exaiptasia'' Grajales & ...

, native to shallow waters in the temperate western Atlantic Ocean, the

Caribbean Sea The Caribbean Sea ( es, Mar Caribe; french: Mer des Caraïbes; ht, Lanmè Karayib; jam, Kiaribiyan Sii; nl, Caraïbische Zee; pap, Laman Karibe) is a sea of the Atlantic Ocean in the tropics of the Western Hemisphere. It is bounded by Mexico ...

and the

Gulf of Mexico The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...

. It is

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispec ...

with a single species, ''Exaiptasia diaphana,'' and commonly known as the brown anemone, glass anemone, pale anemone, or simply as Aiptasia.

Description

''Exaiptasia diaphana'' has a slender brownish or whitish translucent column up to long, girdled by two rows of slits through which acontia (threads armed with

nematocyst A cnidocyte (also known as a cnidoblast or nematocyte) is an explosive cell containing one large secretory organelle called a cnidocyst (also known as a cnida () or nematocyst) that can deliver a sting to other organisms. The presence of this ce ...

s) can protrude. The oral disc, up to wide, has a central mouth surrounded by a whorl of up to 96 variable-length tentacles; a few of these are extra long, the majority are fairly long and a few are short.

Distribution and habitat

''Exaiptasia diaphana'' is a common species of sea anemone occurring in the western Atlantic Ocean, round the coast of the United States from

Maine Maine () is a state in the New England and Northeastern regions of the United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Canadian provinces of New Brunswick and Quebec to the northeast and north ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, and throughout the

and the

. It occurs in a range of habitats including shallow areas with hard substrates and mangrove swamps.

Ecology

''Exaiptasia diaphana'' is a

zooxanthellate Zooxanthellae is a colloquial term for single-celled dinoflagellates that are able to live in symbiosis with diverse marine invertebrates including demosponges, corals, jellyfish, and nudibranchs. Most known zooxanthellae are in the genus ''Symbi ...

species and has a

symbiotic Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...

relationship with

dinoflagellate The dinoflagellates (Greek δῖνος ''dinos'' "whirling" and Latin ''flagellum'' "whip, scourge") are a monophyletic group of single-celled eukaryotes constituting the phylum Dinoflagellata and are usually considered algae. Dinoflagellates are ...

s, single celled photosynthetic organisms which are incorporated into its tissues. ''Exaiptasia diaphana'' is a fast growing species that can quickly cover underwater surfaces. It is preyed on by several nudibranchs, including ''

Berghia coerulescens ''Berghia coerulescens'' is a species of sea slug, a marine nudibranch in the family (biology), family Aeolidiidae.Gofas, S. (2010) ''Berghia coerulescens'' (Laurillard, 1830).In: Bouchet, P.; Gofas, S.; Rosenberg, G. (2010) World Marine Mollusc ...

'', ''

Berghia stephanieae ''Berghia stephanieae'' is a species of sea slug, an aeolid nudibranch. It is a marine gastropod mollusc in the family Aeolidiidae. It was previously known as ''Aeolidiella stephanieae''. Distribution The range of this species is from the most ...

'' and ''

Spurilla neapolitana ''Spurilla neapolitana'', the Neapolitan spurilla, is a species of sea slug, an aeolid nudibranch, a marine gastropod mollusk in the family Aeolidiidae. It is native to the western Atlantic Ocean, the Caribbean Sea and the Mediterranean Sea. T ...

''. The nudibranchs tend to acquire the brownish colour of the zooxanthellae found in the sea anemone's tissues; they also incorporate the anemone's nematocysts into their bodies, which may serve a defensive function.

Relationships with humans

''Exaiptasia diaphana'' is easy to keep in the laboratory and is used as a

model organism A model organism (often shortened to model) is a non-human species that is extensively studied to understand particular biological phenomena, with the expectation that discoveries made in the model organism will provide insight into the workin ...

, when it can serve as a proxy for coral which is more difficult to maintain and research. It has been used in studying the details of the evolution and function of the little-understood processes involved in endosymbiosis. It is also susceptible to certain coral diseases and has been used as a surrogate model to study coral biology. Sea anemones exhibit great powers of regeneration; lost parts swiftly regrow and ''E. diaphana'' can be vivisected in the laboratory and then returned to the aquarium where it will heal. These very characteristics of hardiness and regeneration from parts render ''A. pallida'' a pest in the marine reef aquarium. The

genome In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...

of this sea anemone has been sequenced.

References

{{Taxonbar, from1=Q2161428, from2=Q1464185 Aiptasiidae Hexacorallia genera Animals described in 1864 Monotypic cnidarian genera