Freyellidae

Last updated

Freyellidae
Freyastera.jpg
Freyastera sp. south from Porto Rico (4500m deep)
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Echinodermata
Class: Asteroidea
Order: Brisingida
Family: Freyellidae
Downey, 1986 [1] [2]
Genera

See text

The Freyellidae are a family of deep-sea-dwelling starfish. It is one of two families in the order Brisingida. [3] The majority of species in this family are found in Antarctic waters and near Australia. Other species have been found near New Zealand and the United States. [4]

Contents

Taxonomy

The starfish Brisinga endecacnemos was discovered in deep water off Norway in 1856, followed by another abyssal species, Brisinga coronata, now Hymenodiscus coronata . A new order, Brisingida, was erected to accommodate these, consisting of a single family, Brisingidae. Since then dozens of new species have been described from deep water habitats and in 1986, the American zoologist Maureen Downey split the family on morphological and behavioural grounds, creating the new family Freyellidae. [5]

Characteristics

Members of this family have a small, Ophiurida-like disc, clearly demarcated from the arms, which number more than five. The disc is approximately circular with a rim of fused plates which gives rigidity. The madreporite is near the margin of the disc. The arms are long and tapering with the ratio of the arm length to the disc radius being greater than 6/1. There is an acute angle between the arms . After a narrow cylindrical portion, the part of the arms closest to the disc accommodates the gonadal tissues and widens out somewhat. Beyond this area, the arms taper to a long point. In all these aspects members of this family resemble members of Brisingidae, the other family in the order Brisingida. They differ from Brisingidae in having the interradial arcs curved, having smaller madreporites, having bare interadial plates on the disc, having the aboral (upper) surface of the arms continuous with the disc, and having the plates on the proximal parts of the arms abutting rather than overlapping each other. [5]

Biology

Members of Freyellidae are usually found on soft substrates at depths between 950 and 5,600 m (3,100 and 18,400 ft). This is a greater depth than Brisingidae, which occurs between 100 and 4,000 m (300 and 13,100 ft), usually on hard surfaces. Because of the way their plates abut on the proximal ends of their arms, Freyellids have not been observed to raise their arms vertically above their discs, as do Brisingidae, and some are probably not suspension feeders. Some do however raise the distal portions of their arms, the parts beyond the gonadal regions. [5]

Genera and species

The World Asteroida Database lists the following genera and species: [2]

Related Research Articles

<i>Asterias</i> Genus of starfishes

Asterias is a genus of the Asteriidae family of sea stars. It includes several of the best-known species of sea stars, including the (Atlantic) common starfish, Asterias rubens, and the northern Pacific seastar, Asterias amurensis. The genus contains a total of eight species in all. All species have five arms and are native to shallow oceanic areas of cold to temperate parts of the Holarctic. These starfish have planktonic larvae. Asterias amurensis is an invasive species in Australia and can in some years become a pest in the Japanese mariculture industry.

<span class="mw-page-title-main">Valvatida</span> Order of starfishes

The Valvatida are an order of starfish in the class Asteroidea, which contains 695 species in 172 genera in 17 families.

<span class="mw-page-title-main">Echinasteridae</span> Family of starfishes

The Echinasteridae are a family of starfish in the monotypic order Spinulosida. The family includes eight genera and about 133 species found on the seabed in various habitats around the world.

<span class="mw-page-title-main">Asterinidae</span> Family of starfishes

The Asterinidae are a large family of sea stars in the order Valvatida.

<i>Astropecten</i> Genus of starfishes

Astropecten is a genus of sea stars of the family Astropectinidae.

<span class="mw-page-title-main">Asteriidae</span> Family of starfishes

The Asteriidae are a diverse family of Asteroidea in the order Forcipulatida. It is one of three families in the order Forcipulatida.

<i>Coscinasterias</i> Genus of starfishes

Coscinasterias is a genus of sea stars of the family Asteriidae.

<span class="mw-page-title-main">Goniasteridae</span> Family of starfishes

Goniasteridae constitute the largest family of sea stars, included in the order Valvatida. They are mostly deep-dwelling species, but the family also include several colorful shallow tropical species.

<span class="mw-page-title-main">Brisingida</span> Order of starfishes

The Brisingids are deep-sea-dwelling starfish in the order Brisingida.

<i>Henricia</i> Genus of starfishes

Henricia is a large genus of slender-armed sea stars belonging to the family Echinasteridae. It contains about fifty species.

<i>Solaster</i> Genus of starfishes

Solaster is a genus of sea stars in the family Solasteridae.

<span class="mw-page-title-main">Brisingidae</span> Family of starfishes

The Brisingidae are a family of starfish found only in the deep sea. They inhabit both the Atlantic and Pacific Oceans at abyssal depths, and also occur in the Southern Ocean and around Antarctica at slightly shallower depths.

<i>Mediaster</i> Genus of starfishes

Mediaster is a genus of starfish in the family Goniasteridae. It was circumscribed in 1857 by William Stimpson for M. aequalis, the genus's type species. Its junior synonym is the genus Isaster, which was circumscribed in 1894 by Addison Emery Verrill for the species now known as M. bairdi. Verrill himself synonymized the two genus names in 1899.

<i>Pteraster</i> Genus of starfishes

Pteraster is a genus of sea stars in the family Pterasteridae.

Brisinga is a genus of starfish in the family Brisingidae. The species in this genus are primarily found in deep sea habitats.

<i>Freyella</i> Genus of starfishes

Freyella is a genus of deep-sea-dwelling starfish in the order Brisingida.

<i>Freyella elegans</i> Species of starfish

Freyella elegans is a species of deep-water starfish in the family Freyellidae in the order Brisingida, living at abyssal depths in the northwestern Atlantic Ocean.

<i>Novodinia</i> Genus of echinoderms

Novodinia is a genus of echinoderms belonging to the family Brisingidae.

Ophidiaster is a genus of echinoderms belonging to the family Ophidiasteridae.

<i>Lophaster</i>

Lophaster is a genus of starfish within the family Solasteridae.

References

  1. "Antarctic Invertebrates: Brisingida". Invertebrates.si.edu. 1 January 1970. Archived from the original on 16 July 2011. Retrieved 25 November 2013.
  2. 1 2 "The World Asteroidea Database - Freyellidae". Marinespecies.org. Retrieved 25 November 2013.
  3. "WoRMS - World Register of Marine Species - Freyellidae Downey, 1986". Marinespecies.org. Retrieved 3 December 2018.
  4. "Freyellidae". Gbif.org. Retrieved 3 December 2018.
  5. 1 2 3 Downey, M.E. (1986). "Revision of the Atlantic Brisingida (Echinodermata: Asteroidea), with description of a new genus and family" (PDF). Smithsonian Contributions to Zoology 435:43. Retrieved 23 October 2018.

Other sources