''Swiftia pallida'' is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of gorgonian-type

octocoral Octocorallia, along with Hexacorallia, is one of the two extant classes of Anthozoa. It comprises over 3,000 species of marine and brackish animals consisting of colonial polyps with 8-fold symmetry, commonly referred informally as "soft cora ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Plexauridae Plexauridae is a Family (biology), family of marine Colony (biology), colonial Octocorallia, octocorals in the phylum Cnidaria. Members of this family are found in shallow tropical and subtropical seas. Many species contain Symbiosis, symbiotic P ...

sometimes known as the northern sea fan. At one time it was considered to be a subspecies of '' Swiftia rosea''.

Description

''Swiftia pallida'' usually has a single main stem arising from a narrow base and is sparsely branched. Its normal height is about but it can grow to . The polyps are mostly arranged alternately, but somewhat irregularly, on either side of the stem and branches. Each polyp is supported by eight spindle-shaped

sclerite A sclerite (Greek language, Greek , ', meaning "hardness, hard") is a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth. Instea ...

s, spiny skeletal elements, which run from the stem or branch to the bases of the eight tentacles. In the north of its range, this species is usually white or pale grey, but in the Mediterranean it may be pink or red. This sea fan resembles pale varieties of the more common ''Swiftia rosea'' but is less bushy with fewer branches.

Distribution and habitat

''Swiftia pallida'' is native to the northeast

Atlantic Ocean The Atlantic Ocean is the second largest of the world's five borders of the oceans, oceanic divisions, with an area of about . It covers approximately 17% of Earth#Surface, Earth's surface and about 24% of its water surface area. During the ...

, 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 east by the Levant in West Asia, on the north by Anatolia in West Asia and Southern Eur ...

, the

Bay of Biscay The Bay of Biscay ( ) is a gulf of the northeast Atlantic Ocean located south of the Celtic Sea. It lies along the western coast of France from Point Penmarc'h to the Spanish border, and along the northern coast of Spain, extending westward ...

Madeira Madeira ( ; ), officially the Autonomous Region of Madeira (), is an autonomous Regions of Portugal, autonomous region of Portugal. It is an archipelago situated in the North Atlantic Ocean, in the region of Macaronesia, just under north of ...

and

Morocco Morocco, officially the Kingdom of Morocco, is a country in the Maghreb region of North Africa. It has coastlines on the Mediterranean Sea to the north and the Atlantic Ocean to the west, and has land borders with Algeria to Algeria–Morocc ...

. In the northern part of this range its depth range is between but in the southern part it occurs in very deep water, possibly as deep as . This sea fan also occurs in deep water on the continental shelf off the Atlantic coast of North America. It is found on rocks in tide-swept areas that are sheltered from excessive wave action. It often occurs in areas where a layer of sediment covers the rocks, or on large pebbles lying on a silty or broken shell seabed.

Ecology

The sea fan anemone (''

Amphianthus dohrnii ''Amphianthus dohrnii'', the sea fan anemone, is a species of sea anemone in the family Hormathiidae. It occurs in the northeastern Atlantic Ocean and Mediterranean Sea and grows on sea fans. Distribution and habitat ''Amphianthus dohrnii'' is ...

'') seems to live exclusively on sea fans. In the northern part of its range it is associated with ''Swiftia pallida'', and in the southern part with the pink sea fan ('' Eunicella verrucosa''). The rate of growth of ''Swiftia pallida'' is unknown but may be similar to that of ''Eunicella verrucosa'', about per year.

References

{{Taxonbar, from=Q3273672 Plexauridae Animals described in 1970