''Anemonia sulcata'', or Mediterranean snakelocks sea anemone, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

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 ...

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

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

synonym A synonym is a word, morpheme, or phrase that means precisely 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 a ...

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

Description

This sea anemone has two

ecotype Ecotypes are organisms which belong to the same species but possess different phenotypical features as a result of environmental factors such as elevation, climate and predation. Ecotypes can be seen in wide geographical distributions and may event ...

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 east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

and the eastern

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

as far south as

Western Sahara Western Sahara is a territorial dispute, disputed territory in Maghreb, North-western Africa. It has a surface area of . Approximately 30% of the territory () is controlled by the Sahrawi Arab Democratic Republic (SADR); the remaining 70% is ...

. It is found in the

intertidal zone The intertidal zone or foreshore is the area above water level at low tide and underwater at high tide; in other words, it is the part of the littoral zone within the tidal range. This area can include several types of habitats with various ...

and the

sublittoral zone The neritic zone (or sublittoral zone) is the relatively shallow part of the ocean above the drop-off of the continental shelf, approximately in depth. From the point of view of marine biology it forms a relatively stable and well-illuminated ...

, 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 (Ancient Greek : living with, companionship < : together; and ''bíōsis'': living) is any type of a close and long-term biolo ...

relationship with

zooxanthellae Zooxanthellae (; zooxanthella) is a colloquial term for single-celled photosynthetic organisms that are able to live in symbiosis with diverse marine invertebrates including corals, jellyfish, demosponges, and nudibranchs. Most known zooxanthell ...

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

dioecious Dioecy ( ; ; adj. dioecious, ) is a characteristic of certain species that have distinct unisexual individuals, each producing either male or female gametes, either directly (in animals) or indirectly (in seed plants). Dioecious reproduction is ...

, 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 Heterocrine gland, mixed gland and sex organ that produces the gametes and sex hormones of an organism. Female reproductive cells are egg cells, and male reproductive cells are sperm. The male gon ...

s, and the

germ cell A germ cell is any cell that gives rise to the gametes of an organism that reproduces sexually. In many animals, the germ cells originate in the primitive streak and migrate via the gut of an embryo to the developing gonads. There, they unde ...

s develop inside the

mesenteries In human anatomy, the mesentery is an organ that attaches the intestines to the posterior abdominal wall, consisting of a double fold of the peritoneum. It helps (among other functions) in storing fat and allowing blood vessels, lymphatics, a ...

and break through the

epithelium Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of man ...

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, a ...

and thence move into the

water column The (oceanic) water column is a concept used in oceanography to describe the physical (temperature, salinity, light penetration) and chemical ( pH, dissolved oxygen, nutrient salts) characteristics of seawater at different depths for a defined ...

. 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 ger ...

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) is a type of cell containing a large secretory organelle called a ''cnidocyst'', that can deliver a sting to other organisms as a way to capture prey and defend against predators. A cnidocyte explosively ...

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. The term "necrosis" came about in the mid-19th century and is commonly attributed to German pathologist Rudolf Virchow, who i ...

, and making the competitor move away.

Uses

This sea anemone is popular as a

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

in southern Spain, specially,

Cádiz Cádiz ( , , ) is a city in Spain and the capital of the Province of Cádiz in the Autonomous communities of Spain, autonomous community of Andalusia. It is located in the southwest of the Iberian Peninsula off the Atlantic Ocean separated fr ...

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

Andalusia Andalusia ( , ; , ) is the southernmost autonomous communities of Spain, autonomous community in Peninsular Spain, located in the south of the Iberian Peninsula, in southwestern Europe. It is the most populous and the second-largest autonomou ...

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 Neurotoxicity is a form of toxicity in which a biological, chemical, or physical agent produces an adverse effect on the structure or function of the central and/or peripheral nervous system. It occurs when exposure to a substance – specifical ...

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 arrhythmias. 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