''Zoanthus sociatus'', commonly known as the green sea mat or button polyp, is a

zoanthid Zoanthids ( order Zoantharia also called Zoanthidea or Zoanthiniaria) are an order of cnidarians commonly found in coral reefs, the deep sea and many other marine environments around the world. These animals come in a variety of different coloniz ...

usually found in shallow reef zones of tropical regions from

Caribbean The Caribbean (, ) ( es, El Caribe; french: la Caraïbe; ht, Karayib; nl, De Caraïben) is a region of the Americas that consists of the Caribbean Sea, its islands (some surrounded by the Caribbean Sea and some bordering both the Caribbean Se ...

to southeastern Brazil. ''Z. sociatus'' is currently being studied for its use against human

lymphatic Lymph (from Latin, , meaning "water") is the fluid that flows through the lymphatic system, a system composed of lymph vessels (channels) and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues to ...

parasites.

Taxonomy

''Zoanthus sociatus'' has

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, which makes it a

cnidaria Cnidaria () is a phylum under kingdom Animalia containing over 11,000 species of aquatic animals found both in freshwater and marine environments, predominantly the latter. Their distinguishing feature is cnidocytes, specialized cells that th ...

n. As it has polyp morphology, it is an

anthozoan Anthozoa is a subphylum of marine invertebrates which includes the sea anemones, stony corals and soft corals. Adult anthozoans are almost all attached to the seabed, while their larvae can disperse as part of the plankton. The basic unit of t ...

. It also has tentacles in multiples of 6, so it falls under the subclass

Hexacorallia Hexacorallia is a Class (biology), class of Anthozoa comprising approximately 4,300 species of aquatic organisms formed of polyp (zoology), polyps, generally with 6-fold symmetry. It includes all of the stony corals, most of which are Colony (b ...

. It is in the order Zoanthidea due to its lack of a calcium carbonate skeleton. Forms elaborate piecemeal mats of normally green to turquoise polyps. They are often found on reef flats exposed to high light intensity and intermittently strong currents.

Stolon In biology, stolons (from Latin '' stolō'', genitive ''stolōnis'' – "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external s ...

-connected polyps normally have 30 short tentacles, polyps are extended continuously day and night and feed predominantly on

detritus In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...

, not

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

Habitat

''Z. Sociatus'' can be found in the lower intertidal and upper subtidal zones on protected Caribbean reefs. It is a

sessile Sessility, or sessile, may refer to: * Sessility (motility), organisms which are not able to move about * Sessility (botany), flowers or leaves that grow directly from the stem or peduncle of a plant * Sessility (medicine), tumors and polyps that ...

, colonial organism. ''Z. sociatus'' grows in the reef understory and on disturbed substrate. Z. sociatus can survive desiccation (an excessive loss of moisture) and lower levels of salinity. It appears to dominate other zoanthids.

Reproduction

Reproduction in ''Z. sociatus'' is mainly asexual although sexual reproduction may happen as well. There is extratentacular

budding Budding or blastogenesis is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. For example, the small bulb-like projection coming out from the yeast cell is know ...

, which is the creation of a new polyp from an old polyp, and fission, a new fragment in formed. The size of a fragment is also controlled by the increasing rate of mortality with decreasing fragment size. A colony is generally genetically the same. Even when a colony is sexually reproductive, a large proportion of polyps remain infertile, which demonstrates the greater importance of asexual reproduction and growth. ''Z. sociatus'' colonies do not become reproductive until they reach a certain size. They use external fertilization, and are mostly hermaphroditic, although some are male or protogynous (female and then male). ''Z. sociatus'' was found to reproduce seasonally in Panama, and synchronizes the release of gametes with extremely low tides.

Diet

''Z. sociatus'' polyps obtain nearly half of their required energy from the zooxanthellae, organism that ''Z. Sociatus'' forms symbiosis with. Therefore, the rest of the energy must be obtained through feeding. Zoanthids have nematocysts on their mesenterial filaments that are used for prey capture. ''Z. sociatus'' will eat mostly anything that is the right size such as from Artemia cysts and dissolved organic matter. While zoanthids are less efficient heterotrophs, they produce more energy photosynthetically due to their lack of a calcified skeleton. The lack of a skeleton allows more light to reach the chloroplasts. To digest prey, it uses both

extracellular This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...

and intracellular methods.

References

*http://www.advancedaquarist.com/issues/feb2003/invert.htm *http://www.sealifebase.org/summary/speciessummary.php?id=44798 *http://www. Thecephalopodpage.org/MarineInvertebrateZoology/Zoanthussociatus.html *http://www.ingentaconnect.com/content/umrsmas/bullmar/1983/00000033/00000001/art00009 *http://onlinelibrary.wiley.com/doi/10.1002/bscb.19810900913/abstract Zoanthus Animals described in 1786 {{Hexacorallia-stub