''Alcyonium acaule'' or Mediterranean sea-finger 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 ...

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 Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Alcyoniidae Alcyoniidae is a family of leathery or soft corals in the phylum Cnidaria.Leathery cor ...

. It is found at moderate depths on shaded rocks in the

Mediterranean Sea The Mediterranean Sea is a sea connected to the Atlantic Ocean, surrounded by the Mediterranean Basin and almost completely enclosed by land: on the north by Western and Southern Europe and Anatolia, on the south by North Africa, and on the ea ...

and adjoining parts of the

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 ...

Description

Mediterranean sea-finger is a colonial coral forming clumps of yellow, pink, brown-red to brown orange fleshy masses of finger-like lobes. The colony can reach a height of 20 cm maximum. The body's surface is entirely covered by whitish polyps from the foot to the top of the lobes. As for all the

, it uses its

hydrostatic skeleton A hydrostatic skeleton, or hydroskeleton, is a flexible skeleton supported by fluid pressure. Hydrostatic skeletons are common among simple invertebrate organisms. While more advanced organisms can be considered hydrostatic, they are sometimes refe ...

capacity to maintain and manage its body posture.

Distribution and habitat

This

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the

however its area of distribution overflows slightly and extends along the Portuguese and Spanish Atlantic coasts. It is usually found between 12 and 135 m deep.Steven Weinberg, ''Découvrir la Méditerranée'', Nathan nature, 2007, 352 p. () ''Alcyonium acaule'' is a sciophilous animal that likes to avoid places exposed to unfiltered light and prefers shaded places such as overhangs or caves.

Ecology

In the Mediterranean Sea, ''Alcyonium acaule'' frequently forms dense agglomerations, often in association with the yellow cluster anemone (''

Parazoanthus axinellae ''Parazoanthus axinellae'', commonly known as the yellow cluster anemone, is a zoanthid coral found on the southern Atlantic coasts of Europe and in the Mediterranean Sea. Zoanthids differ from true sea anemones, in having a different internal a ...

''). Other organisms in these biodiverse habitats include suspension feeders such as sponges, cnidarians,

bryozoa Bryozoa (also known as the Polyzoa, Ectoprocta or commonly as moss animals) are a phylum of simple, aquatic invertebrate animals, nearly all living in sedentary colonies. Typically about long, they have a special feeding structure called a l ...

ns and

tunicate A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata (). It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one time ca ...

s, and the rock is encrusted with

coralline alga Coralline algae are red algae in the order Corallinales. They are characterized by a thallus that is hard because of calcareous deposits contained within the cell walls. The colors of these algae are most typically pink, or some other shade of re ...

e. There is space competition among these organisms and during a two-year research study, a number of small colonies of ''Alcyonium acaule'' disappeared, and very little growth of colonies occurred. Many colonies showed less feeding activity during the summer, with up to ninety percent becoming dormant.

References

External links

* {{Taxonbar, from=Q2108270 Alcyoniidae Animals described in 1878