''Parazoanthus swiftii'', commonly known as the golden 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 Sponges, the members of the phylum Porifera (; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through t ...

. It is found in shallow waters in the Caribbean Sea and western Atlantic Ocean.

Description

The golden zoanthid is a

colonial Colonial or The Colonial may refer to: * Colonial, of, relating to, or characteristic of a colony or colony (biology) Architecture * American colonial architecture * French Colonial * Spanish Colonial architecture Automobiles * Colonial (1920 au ...

coral that grows in small irregular groups and linear rows that wind over the surface of its

host A host is a person responsible for guests at an event or for providing hospitality during it. Host may also refer to: Places * Host, Pennsylvania, a village in Berks County People *Jim Host (born 1937), American businessman * Michel Host ...

sponge. It does not have a calcareous skeleton but the polyps are connected by a membranous basal connection. The polyps look like 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 and are orange or bright yellow and about in diameter. They have a slender column and up to twenty six long, thin, pale yellow tentacles. As much as half the surface of the sponge may be covered by the coral, which may consist of up to 200 polyps.

Distribution and habitat

The golden zoanthid is common in the Caribbean Sea and round the Bahamas. It is also known from Jamaica, Puerto Rico and the Virgin Islands. It is mostly found at depths between but occasionally occurs in shallower water. It is always found colonising a sponge, often the brown tube sponge (''

Agelas conifera ''Agelas conifera'', also known as the brown tube sponge, is a species of sponge. Its color is brown, tan, or greyish brown with a lighter interior. It is common in the Caribbean and Bahamas, and occasional in Florida. ''Agelas conifera'' contain ...

''), the green finger sponge (''

Iotrochota birotulata ''Iotrochota birotulata'', commonly known as the green finger sponge, is a species of sea sponge in the family Iotrochotidae. It is found in shallow waters in the Caribbean Sea. Description The green finger sponge usually has upright or spraw ...

'') or the pink or brown ''

Topsentia ophiraphidites ''Topsentia'' is a genus of sponges belonging to the family Halichondriidae. The genus has cosmopolitan distribution In biogeography, cosmopolitan distribution is the term for the range of a taxon that extends across all or most of the worl ...

''. It usually occurs in sandy or silty locations.

Biology

The golden zoanthid often contrasts vividly in colour with its host sponge, which would be expected to advertise its presence to potential sponge

predators 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 the ...

. It contains

toxic Toxicity is the degree to which a chemical substance or a particular mixture of substances can damage an organism. Toxicity can refer to the effect on a whole organism, such as an animal, bacterium, or plant, as well as the effect on a subst ...

substances that may deter fish such as the rock beauty (''Holacanthus tricolor'') from eating the host sponge. The golden zoanthid may also benefit from living on a sponge in that 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 actively draws in a current of water through its pores. It can only cope with the most minute particles and the polyps may be able to capture the bigger food items wafted along in the current. The size of a golden zoanthid colony is increased by budding. New polyps generally grow at the ends of the rows.

References

{{Taxonbar, from=Q3327782 Corals described in 1860 Parazoanthus