Ivell's sea anemone (''Edwardsia ivelli'') is a possibly extinct species of

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

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Edwardsiidae. It is

endemic Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...

to a single location, Widewater Lagoon in

West Sussex West Sussex is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Surrey to the north, East Sussex to the east, the English Channel to the south, and Hampshire to the west. The largest settlement is Cr ...

, England, where it was first discovered by Richard Ivell but has not been recorded since 1973.

Taxonomy

Ivell's sea anemone was first formally described in 1975 by the marine biologist Richard L. Manuel from specimens collected at Widewater Lagoon by Professor Richard Ivell in 1973. Manuel recognised that these specimens were of a species in the genus ''

Edwardsia ''Edwardsia'' is a genus of sea anemones, the type genus, type of the family Edwardsiidae. They have eight Mesentery (zoology), mesenteries and live in tubes in the sand. The name, in Neo-Latin, commemorates the French zoologist Henri Milne-Edwa ...

'' but they did not belong to any species described from the United Kingdom, so he described the new species and named it in honour of Ivell.Manuel, R.L. (1975). A new sea anemone from a brackish lagoon in Sussex, ''Edwardsia ivelli'', sp. nov. Journal of Natural History, 9, 705-711. The genus ''Edwardsia'' was proposed in 1842 by

Jean Louis Armand de Quatrefages de Bréau Jean Louis Armand de Quatrefages de Bréau (10 February 1810 – 12 January 1892) was a French biologist. Life He was born at Berthézène, in the commune of Valleraugue (Gard), the son of a Protestant farmer. He studied science and then med ...

and is classified in the family Edwardsiidae, in the superfamily Edwardsioidea in the

suborder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between family and class. In biological classification, the order is a taxonomic rank used in the classification of organisms and recognized ...

Anenthemonae Anenthemonae is a suborder of sea anemones in the order Actiniaria. It comprises those sea anemones with atypical arrangement of mesenteries for actiniarians. Superfamilies and families in the suborder Anenthemonae include:Rodríguez, E., Barbei ...

in the

order Order, ORDER or Orders may refer to: * A socio-political or established or existing order, e.g. World order, Ancien Regime, Pax Britannica * Categorization, the process in which ideas and objects are recognized, differentiated, and understood ...

Actiniaria Sea anemones ( ) are a group of predatory marine invertebrates constituting the order Actiniaria. Because of their colourful appearance, they are named after the '' Anemone'', a terrestrial flowering plant. Sea anemones are classified in the phy ...

, the sea anemones.

Description

Ivell's sea anemone is a tiny, worm-like anemone up to long and diameter; the column is similar to other ''

'' spp. There are twelve transparent tentacles, arranged in two cycles, nine tentacles in the outer cycle and three in the inner cycle. In life the tentacles of the outer cycle are held flat on the substrate, the three of the inner cycle more or less vertical, often curled over the mouth. Each tentacle has a few transverse bars of pale cream occasionally forming complete rings.

Habitat and distribution

Ivell's sea anenome lives in long burrows in very soft mud in a saline lagoons and associated creeks. It is endemic to England known from only one site, Widewater Lagoon in West Sussex, the type locality. Searches in recent years have failed to find any specimens and the species is considered

extinct Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...

by some conservationists It was last recorded in 1983.

References

{{Taxonbar, from=Q2124204 Edwardsia Endemic fauna of England Cnidarians of the Atlantic Ocean Anthozoa of Europe Marine fauna of Europe Environment of West Sussex Animals described in 1975 1975 in England Taxonomy articles created by Polbot