''Anemonia sulcata'', or Mediterranean snakelocks sea anemone, 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 appropriat ...

sea anemone Sea anemones are a group of predatory marine invertebrates of the order Actiniaria. Because of their colourful appearance, they are named after the '' Anemone'', a terrestrial flowering plant. Sea anemones are classified in the phylum Cnidaria, ...

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 ...

Actiniidae Actiniidae is the largest family of sea anemones, to which most common, temperate, shore species belong. Most members of this family do not participate in symbioses with fishes. Three exceptions are the bubble-tip anemone (with anemonefish and ...

from the Mediterranean Sea. Whether ''A. sulcata'' should be recognized as a

synonym A synonym is a word, morpheme, or phrase that means exactly or nearly the same as another word, morpheme, or phrase in a given language. For example, in the English language, the words ''begin'', ''start'', ''commence'', and ''initiate'' are al ...

of '' A. viridis'' remains a matter of dispute.

Description

This sea anemone has two

ecotype In evolutionary ecology, an ecotype,Greek: ''οίκος'' = home and ''τύπος'' = type, coined by Göte Turesson in 1922 sometimes called ecospecies, describes a genetically distinct geographic variety, population, or race within a species ...

s; one has a basal disk up to in diameter and has fewer than 192 tentacles (usually 142 to 148); the other has a disk up to in diameter and 192 tentacles or more, up to 348. The tentacles are long, slender and tapering, arranged in six whorls round the central mouth on the oral disk. They vary in colour but are usually some shade of green, grey or light brown. A knob on the tip of each tentacle, where the stinging cells are concentrated, may be violet.

Distribution and habitat

This sea anemone is native to 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 ...

and the eastern

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's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

as far south as

Western Sahara Western Sahara ( '; ; ) is a disputed territory on the northwest coast and in the Maghreb region of North and West Africa. About 20% of the territory is controlled by the self-proclaimed Sahrawi Arab Democratic Republic (SADR), while the ...

. It is found in 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 ...

and the sublittoral zone, on rocky ledges, in crevices and on boulders. Ecotype 1 occurs down to about while ecotype 2 occurs down to about .

Biology

''Anemonia sulcata'' 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 para ...

relationship with

zooxanthellae 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 ''S ...

, which inhabit the tissues and provide energy for the sea anemone. It is

dioecious Dioecy (; ; adj. dioecious , ) is a characteristic of a species, meaning that it has distinct individual organisms (unisexual) that produce male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproducti ...

, with individuals becoming sexually mature when they weigh about and the basal disc measures about across. There are no

gonad A gonad, sex gland, or reproductive gland is a mixed gland that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gonad, the testicle, produces sp ...

s, and the

germ cell Germ or germs may refer to: Science * Germ (microorganism), an informal word for a pathogen * Germ cell, cell that gives rise to the gametes of an organism that reproduces sexually * Germ layer, a primary layer of cells that forms during embr ...

s develop inside the

mesenteries In zoology, a mesentery is a membrane inside the body cavity of an animal. The term identifies different structures in different phyla: in vertebrates it is a double fold of the peritoneum enclosing the intestines; in other organisms it forms com ...

and break through the

epithelium Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellul ...

to enter the

body cavity A body cavity is any space or compartment, or potential space, in an animal body. Cavities accommodate organs and other structures; cavities as potential spaces contain fluid. The two largest human body cavities are the ventral body cavity, and ...

and thence move 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 ...

. At this stage, the

oocyte An oocyte (, ), oöcyte, or ovocyte is a female gametocyte or germ cell involved in reproduction. In other words, it is an immature ovum, or egg cell. An oocyte is produced in a female fetus in the ovary during female gametogenesis. The female ...

s already contain symbiotic zooxanthellae. Fertilisation takes place in the sea. Breeding seems to take place throughout the year, but peaks between March and May. The sea anemones can also reproduce asexually. This sea anemone aggressively defends its territory from other individuals which are genetically dissimilar. It extends specialised tentacles (called acrorhagi), the tips of which have a concentration of

cnidocyte 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 c ...

s (stinging cells); these sting the invader, causing tissue

necrosis Necrosis () is a form of cell injury which results in the premature death of cells in living tissue by autolysis. Necrosis is caused by factors external to the cell or tissue, such as infection, or trauma which result in the unregulated diges ...

, and making the competitor move away.

Uses

This sea anemone is popular as a

seafood Seafood is any form of sea life regarded as food by humans, prominently including fish and shellfish. Shellfish include various species of molluscs (e.g. bivalve molluscs such as clams, oysters and mussels, and cephalopods such as octopus an ...

in southern Spain, specially,

Cádiz Cádiz (, , ) is a city and port in southwestern Spain. It is the capital of the Province of Cádiz, one of eight that make up the autonomous community of Andalusia. Cádiz, one of the oldest continuously inhabited cities in Western Europe, ...

, where it is known as or ; for the fishery to be sustainable, the

Andalusia Andalusia (, ; es, Andalucía ) is the southernmost autonomous community in Peninsular Spain. It is the most populous and the second-largest autonomous community in the country. It is officially recognised as a "historical nationality". The ...

n authorities have set a minimum weight below which the sea anemones cannot be harvested. To neutralize the poison, the anemones are marinated in water with vinegar. The usual recipe is to batter them in flour and maybe egg and fry them in olive oil until they develop a crunchy cover. ''Ortiguilla'' omelets are also cooked.

Toxicity

''Anemonia sulcata'' have toxic cnidocysts organelles that are able to inject venom and cause an allergic reaction, particularly a skin reaction. Their stings are known to cause neurotoxicity and act on the sodium and potassium channels but also cause cytolysis on the cell membranes. A research conducted in rabbits’ ventricular myocytes were analyzed under exposure to these toxins to better understand their role. Specifically, toxin ll (ATX ll) derived from the ''Anemonia sulcata'' was used in rabbit's myocytes to determine whether they induced the late sodium current causing overloading of sodium ions and consequently calcium ions inside the cell via reverse Na+/Ca2+ exchanger current. Since the heart depends heavily on the balance of Na+ and Ca2+ homeostasis, any unbalance from this can result in heart arrythmias. These toxins induce augmentations in diastolic Ca2+ concentration, calcium transient amplitude, and myocyte shortening therefore increasing serious cardiac failure and cell apoptosis. In addition, the toxin AsKC11 is found in the venom of ''Anemonia sulcata''. This toxin has been shown to be an activator of G protein-coupled inwardly-rectifying potassium (GIRK) channels 1/2, involved in the regulation of cellular excitability.

References

{{Taxonbar, from=Q5293826 Actiniidae Cnidarians of the Atlantic Ocean Fauna of the Mediterranean Sea Taxa named by Thomas Pennant Animals described in 1777