''Gorgonia mariae'', commonly known as the wide-mesh sea fan, is a species of

sea fan Alcyonacea, or soft corals, are an order of corals. In addition to the fleshy soft corals, the order Alcyonacea now contains all species previously known as "gorgonian corals", that produce a more or less hard skeleton, though quite different ...

, 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 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 ...

soft coral Alcyonacea, or soft corals, are an order of corals. In addition to the fleshy soft corals, the order Alcyonacea now contains all species previously known as "gorgonian corals", that produce a more or less hard skeleton, though quite different f ...

in the family

Gorgoniidae Gorgoniidae is a family of soft corals, a member of the subclass Octocorallia in the phylum Cnidaria. Nearly all the genera and species are native to the east and west coasts of America. Characteristics Originally the members of the family G ...

. It occurs in the tropical western Atlantic Ocean and the Caribbean Sea at depths down to about .

Description

''G. mariae'' is the smallest sea fan in the Caribbean, growing to a height of about . The much-branched structure is mostly two dimensional, and as it enlarges, the branches become cross-connected to form a net. The branches are only slightly compressed and the side branches are pinnately divided. The colour varies; most specimens are whitish and others are yellow, and often some violet colour is seen near the base. Two other growth forms exist in the Caribbean; one has many short, free branches on one or both faces of the net; the other, which is usually bright yellow, has the lower part of the colony anastomising and net-like, while the upper and outer parts have free branches. The supporting axial rod in the main stem and branches is formed of

gorgonin Gorgonin is a complex protein that makes up the horny skeleton of the ''holaxonia'' suborder of gorgonians. It frequently contains appreciable quantities of bromine, iodine, and tyrosine. Scientific use Research has shown that measurements of the ...

, calcified to some extent, a flexible and almost unbreakable material. This enables the gorgonian to brace itself and sway with the current so that the polyps can expand to feed.

Distribution

The species is native to the tropical western

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

and Caribbean Sea. It is found anchored to the seabed in moderately deep water, ranging in depth from about .

Biology

In ''G. mariae'', the

gamete A gamete (; , ultimately ) is a haploid cell that fuses with another haploid cell during fertilization in organisms that reproduce sexually. Gametes are an organism's reproductive cells, also referred to as sex cells. In species that produce ...

s are shed into the coelenteron or body cavity of each polyp and pass through the mouth into the open sea, where fertilisation takes place. The fertilised egg develops into a

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 ...

larva, which is

plankton Plankton are the diverse collection of organisms found in water (or air) that are unable to propel themselves against a current (or wind). The individual organisms constituting plankton are called plankters. In the ocean, they provide a crucia ...

ic. The

tentacle In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work ma ...

septa The Southeastern Pennsylvania Transportation Authority (SEPTA) is a regional public transportation authority that operates bus, rapid transit, commuter rail, light rail, and electric trolleybus services for nearly 4 million people in five c ...

, and pharynx begin to develop before the larva settles on its aboral (non-mouth) end and metamorphs into a juvenile sea fan. In 1995, a disease affected gorgonians in the Caribbean, with ''

Gorgonia flabellum ''Gorgonia flabellum'', also known as the Venus fan, Venus sea fan, West Indian sea fan, and purple gorgonian seafan, is a species of sea fan, a sessile colonial soft coral. Description The Venus sea fan is a delicate-looking colonial soft ...

'' and ''

Gorgonia ventalina ''Gorgonia ventalina'', the common sea fan and purple sea fan, is a species of sea fan, an octocoral in the family Gorgoniidae. It is found in the western Atlantic Ocean and the Caribbean Sea. Description ''G. ventalina'' is a fan-shaped col ...

'' being particularly affected. A terrestrial ''

Aspergillus ' () is a genus consisting of several hundred mold species found in various climates worldwide. ''Aspergillus'' was first catalogued in 1729 by the Italian priest and biologist Pier Antonio Micheli. Viewing the fungi under a microscope, Mic ...

'', a

pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ ...

ic fungus, was found to be responsible, and ''G. mariae'' was also susceptible. The symptoms included tissue dieback, abnormal tufts of growth, and some purpling of affected areas. The disease varied in severity from mild to severe, with full recovery taking place on some occasions and mass deaths on others. ''Aspergillosis sydowii'', a common species found in soil, had not previously been known to affect marine invertebrates.

References

{{Taxonbar, from=Q2682785 Gorgoniidae Animals described in 1961