''Umimayanthus parasiticus'', commonly known as the sponge zoanthid, 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 appropriate s ...

of coral in the

order Order, ORDER or Orders may refer to: * Categorization, the process in which ideas and objects are recognized, differentiated, and understood * Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...

Zoantharia 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 ...

which grows

symbiotically Symbiosis (from Ancient Greek, Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different Organism, biological organisms, be it Mutualism (biolog ...

on several species of sponge. It is found in shallow waters in the Caribbean Sea and the Gulf of Mexico.

Description

The polyps of ''Umimayanthus parasiticus'' superficially resemble rather small

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

s. They grow either singly or in small groups of two or three on the surface of certain species of sponge. The polyps are joined by a thin layer of tissue called coenenchyme and occur at densities of 3 to 10 per square centimetre (20 to 60 per square inch). The distances between the polyps widens as they spread out over the surface of the host sponge by budding. The polyp's column is encrusted with sand particles and calcareous material and is white. The oral disc is up to in diameter and there are two rings of tentacles round the edge with about 14 tentacles in each. These are brown and contain symbiotic

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 ''Sy ...

, unicellular

photosynthetic Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in c ...

algae which supply the polyp with nutrients while benefiting from its nitrogenous waste.

Distribution and habitat

''Umimayanthus parasiticus'' is found in the Caribbean Sea, the Gulf of Mexico, Florida, Bermuda and the Bahamas at depths varying from . It is common where its host sponges are found. These include '' Cliona deletrix'' and other ''

Cliona ''Cliona'' is a genus of demosponges in the family Clionaidae. It contains about eighty described species. Species Species in this genus include: * '' Cliona acephala'' Zea & López-Victoria, 2016 * '' Cliona adriatica'' Calcinai, Bavestrello, ...

spp.'', '' Gelloides ramosa'', ''

Callyspongia vaginalis ''Callyspongia'' (''Cladochalina'') ''aculeata'', commonly known as the branching vase sponge is a species of '' Porifora'', meaning sea sponge, in the family Callyspongiidae. Poriferans are typically characterized by ostia, pores that filter ou ...

'' and '' Spheciospongia spp.''.

Biology

Like other corals, the polyps of ''Umimayanthus parasiticus'' extend their tentacles to feed on

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 ...

. It is probable that the coral benefits from the flow of water into and out of the sponge which increases the number of food particles coming within its reach. The sponge is a

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

and feeds on the

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were among ...

and dissolved organic matter it removes from the water passing through its tissues. The presence of the coral obstructs the inflow of water. Some sponges produce anti-fouling compounds which they release into the surrounding water to try to prevent other organisms colonizing their surface. Nevertheless, an ongoing study of sponges colonized by zoanthid corals showed positive benefits to the sponge in growth and survival rates so the association seems to be mutualistic. The sexes are separate in ''Umimayanthus parasiticus''.

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 start developing in February and become mature when the water temperature rises to about in July. Spawning takes place precisely two nights after the full moon during the next three months, with the main spawning event taking place in September. The eggs are shed singly and contain no zooxanthellae and fertilisation occurs in 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 ...

. Little is known of the development of the larvae.

References

{{Taxonbar, from=Q3331662 Corals described in 1860 Parazoanthidae