''Lebrunia coralligens'', commonly known as the hidden anemone,
[ is a species of ]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 ...
Aliciidae
Aliciidae is a family of sea anemones, comprising the following genera:
* '' Alicia'' Johnson, 1861
* '' Cradactis'' McMurrich, 1893
* '' Lebrunia'' Duchassaing de Fonbressin & Michelotti, 1860
* '' Phyllodiscus'' Kwietniewski, 1897
* ''Triactis ...
. It is found in shallow water in the Bahamas, the Caribbean, and Brazil. It lives in fissures in corals and rocks.
Description
''Lebrunia coralligens'' has a broad basal disc and a smooth column, the upper part of which has several long outgrowths known as pseudotentacles as well as feeding tentacles on the oral disc.[ The pseudotentacles are photosynthetic organs; they are lobed and may branch slightly but they are much less branched than the pseudotentacles of the closely related '' Lebrunia danae''. The tips may be darker in colour than the rest of the pseudotentacles and are slightly swollen and sometimes double-lobed, and the stalks have white rings and dark lines. The pseudotentacles are armed with small vesicles containing ]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 and these are mostly concentrated near the tips. The colour of ''Lebrunia coralligens'' varies but the pseudotentacles are often the only parts visible and are usually tan or dark grey, or sometimes bluish-green. With the pseudotentacles extended, this species may measure . The upper part of the column bears spirocysts and nematocysts (armed cells).[ The spirocysts are non-venomous and are used to entangle ]prey
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill ...
, while the nematocysts inject venom into it.[
]
Distribution and habitat
''Lebrunia coralligens'' is known from the Caribbean Sea, the Bahamas and Brazil at depths down to about . It inhabits crevices in coral heads and fissures in rocks, and often the only parts of the animal that are visible are the tips of the pseudotentacles.
Biology
Sea anemones of this species have 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 ...
, photosynthetic single-celled algae residing within the tissues of the host.[ There are between twenty and thirty times more algal cells in the pseudotentacles than there are in the true tentacles. There is a daily rhythm by which the pseudotentacles spread out to expose themselves to light by day and close up at night, at which time the feeding tentacles expand. When the anemone is in a low nutritional state, the pseudotentacles expand fully during the day, but a well-fed anemone only partially expands them. The expansion of the true tentacles is a feeding response and is increased when the animal is in a high nutritional state.]planula
A planula is the free-swimming, flattened, ciliated, bilaterally symmetric larval form of various cnidarian species and also in some species of Ctenophores. Some groups of Nemerteans also produce larvae that are very similar to the planula, which ...
larvae are released from an adult, each one being approximately long and half that width, with zooxanthellae already present in their tissues. The larvae usually settle on the seabed, often in groups, within 24 hours and undergo metamorphosis
Metamorphosis is a biological process by which an animal physically develops including birth or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and differentiation. Some inse ...
into juvenile sea anemones. These have eight tentacles at first but further whorls of tentacles arise as they grow. The pseudotentacles do not emerge until about six weeks after settlement.[
]
References
{{Taxonbar, from=Q1926795
Aliciidae
Animals described in 1890