Ophiocanops fugiens

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Ophiocanops fugiens
Scientific classification
Kingdom:
Animalia
Phylum:
Echinodermata
Class:
Ophiuroidea
Order:
incertae sedis
Family:
Ophiocanopidae
Genus:
Ophiocanops
Species:
O. fugiens

Koehler, 1922
Binomial name
Ophiocanops fugiens

Ophiocanops fugiens is a living species in the brittle star family Ophiocanopidae. Though once considered to be the only one living species in this brittle star family, recent research has brought to light three specimens of Ophiocanops that differ substantially from O. fugiens. [1] It has been regarded as the most primitive brittle star, close to Paleozoic forms, [2] though other authors have disagreed with the view. [3] Classification of O. fugiens is highly argued. Ophiocanops is usually placed in the order Oegophiurida (suborder Zeugophiurina) or regarded as a genus incertae sedis [4] or even given its own subclass Oegophiuridea. [5] Some recent data suggest its relationship to the extant family Ophiomyxidae (it would thus belong to the order Phrynophiurida). [6]

Contents

Characteristics

Ophiocanops fugiens displays a central, armored, disk-shape body that is clearly demarcated from the arms and is 3mm in diameter. [2] Brittle Stars, including O. fugiens, have long flexible arms that they use to propel themselves through the water by moving them in a snake-like manner- hence the other common name for Brittle Stars- "Snake Stars". [7] The arms reach lengths of 35-40mm, and are roughly 1mm across. [2] The incredibly mobile arms are supported by an internal skeleton composed of calcium carbonate plates. [7] These plates resemble vertebrae, and are appropriately named vertebral ossicles, in which these are controlled by O. fugiens muscular system. O. fugiens displays calcium carbonate plates on the body and arms, presumably for defensive measures, and the arms bear delicate spines. [7] The arms lack dorsal and ventral shields; the madreporite is on edge of central disc. The digestive glands extend into proximal portions of arms. It has no bursae for gonads and gas exchange/excretion. [8] O. fugiens demonstrates a small, triangular plated mouth, featuring a set of six conically arranged teeth. [9] O. fugiens has been reported to be a dark brown or purple in color, sometimes exhibiting spotted coloration. [9]

Ecology

Ophiocanops fugiens is a species- once thought to be extinct- found in South Asian seas, with studied specimens being found in the shores of the Philippines. [10] O. fugiens can be found in waters as shallow as the seashore floor to depths of 200 meters. [11] O. fugiens has been found to have a mutualistic symbiotic relationship with Black Corals. [12] O. fugiens feeds on potentially harmful microorganisms and micro-particles that inhabit coral reefs. Additionally, O. fugiens may scavenge benthic floors for detritus and plankton, or alternatively, can use the propellant motion of their arms to capture surrounding particles to feed on. [12] The arms serve further purpose as well. O. fugiens lacks eyes, but receives and responds to changes in light via photoreceptive tissues in their appendages. [13] There are no reports of sexual dimorphism within the species. The evolutionary development of O. fugiens has been largely classified as an enigma, and little is known regarding it. O. fugiens. It's incredibly small and compact central disc is proposed to have developed to lessen pressure of predation, as O. fugiens is capable of regenerating arms. [14] The reproductive tendencies of O. fugiens are not well known. Highly developed gonads extend into the arms, and it is presumed that female O. fugiens carry fertilized eggs in the arms, and release them through a distinguishable genital slit, also apparent on the arms. Juvenile development is lecithotrophic, meaning the larvae feed on yolk in order to develop to metamorphosis. [15] As larvae develops, the anus is lost, and intestines are not apparent.

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<span class="mw-page-title-main">Echinoderm</span> Exclusively marine phylum of animals with generally 5-point radial symmetry

An echinoderm is any member of the phylum Echinodermata. The adults are recognisable by their radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest entirely marine phylum. The first definitive echinoderms appeared near the start of the Cambrian.

<span class="mw-page-title-main">Brittle star</span> Echinoderms, closely related to starfish

Brittle stars, serpent stars, or ophiuroids are echinoderms in the class Ophiuroidea, closely related to starfish. They crawl across the sea floor using their flexible arms for locomotion. The ophiuroids generally have five long, slender, whip-like arms which may reach up to 60 cm (24 in) in length on the largest specimens.

<span class="mw-page-title-main">Phrynophiurida</span> Order of brittle stars

The Phrynophiurida are an order of brittle stars containing the basket stars.

The Oegophiurida are an order of brittle stars, class Ophiuroidea.

<span class="mw-page-title-main">Ophiurida</span> Order of echinoderms

The Ophiurida are an order of echinoderms within the class Ophiuroidea. It includes the vast majority of living brittle stars.

<span class="mw-page-title-main">Amphiuridae</span> Family of brittle stars

Amphiuridae are a large family of brittle stars of the suborder Gnathophiurina. Some species are used to study echinoderm development and bioluminescence.

<span class="mw-page-title-main">Eleutherozoa</span> Proposed group of marine invertebrates

Eleutherozoa is a proposed subphylum of echinoderms. They are mobile animals with the mouth directed towards the substrate. They usually have a madreporite, tube feet, and moveable spines of some sort, and some have Tiedemann's bodies on the ring canal. All living echinoderms except Crinozoa and Blastozoa belong here.

<span class="mw-page-title-main">Asterozoa</span> Phylum of marine invertebrates

The Asterozoa are a subphylum in the phylum Echinodermata. Characteristics include a star-shaped body and radially divergent axes of symmetry. The subphylum includes the class Asteroidea, the class Ophiuroidea, and the extinct order Somasteroidea.

<i>Amphiodia pulchella</i> Species of brittle star

Amphiodia pulchella is a species of brittle star belonging to Amphiuridae, a diverse family of the Ophiurida order.

<i>Ophiocoma scolopendrina</i> Species of brittle star

Ophiocoma scolopendrina is a species of brittle star belonging to the family Ophiocomidae. Restricted to life in the intertidal, they live in the Indo-Pacific. They can typically be found within crevices or beneath borders on intertidal reef platforms. Unlike other Ophiocoma brittle stars, they are known for their unique way of surface-film feeding, using their arms to sweep the sea surface and trap food. Regeneration of their arms are a vital component of their physiology, allowing them to efficiently surface-film feed. These stars also have the ability to reproduce throughout the year, and have been known to have symbiotic relationships with other organisms.

<span class="mw-page-title-main">Ophiothrix</span> Genus of brittle stars

Ophiothrix is a large genus of brittle stars (Ophiuroidea) found in oceans worldwide from tropics to Arctic and Antarctic regions. At present a total of 93 Ophiothrix species have been recognized. It is considered as one of the most interesting genera because of the presence of its brilliant colors and associations with coral and sponges as well. This genus has been labelled particularly difficult with respect to taxonomy, due to a high degree of variability in characters that are described is a morphological aspect.

<i>Ophiactis savignyi</i> Species of brittle star

Ophiactis savignyi is a species of brittle star in the family Ophiactidae, commonly known as Savigny's brittle star or the little brittle star. It occurs in the tropical and subtropical parts of all the world's oceans and is thought to be the brittle star with the most widespread distribution. It was first described by the German zoologists Johannes Peter Müller and Franz Hermann Troschel in 1842. The specific name honours the French zoologist Marie Jules César Savigny.

<i>Astrobrachion adhaerens</i> Species of brittle star

Astrobrachion adhaerens is a basket star in the Euryalidae family. Along with A. constrictum, it is one of only two species in the genus Astrobrachion. Both species live in association with soft corals in moderately deep water. It is endemic to the west, north and east coasts of Australia, the Kermadec Islands and Lord Howe Island.

<i>Acrocnida</i> Genus of echinoderms

Acrocnida is a genus of brittle stars in the family Amphiuridae. The genus contains three members: Acrocnida brachiata, Acrocnida semisquamata, and Acrocnida spatulispina. There has also been observed hybridization between both Acrocnida brachiata and Acrocnida spatulispina. It is a fairly common genus, usually found along the coasts of Northwestern Europe, but with some species like semisquamata appearing around West Africa. Members of this genus primarily prefer intertidal and sub-tidal habitats, and they are they are less likely to be found in intertidal areas by comparison. This genus was not officially classified until 1926, by T. Gislén. One study found that due to the increased calcification that Acrocnida brachiata causes could be a potential source of Carbon Dioxide for not only the warm, shallow environments they live in, but also for the atmosphere.

<i>Ophiohamus</i> Genus of brittle stars

Ophiohamus is a genus of brittle stars in the family Ophiacanthidae from New Caledonia. Timothy D. O'Hara and Sabine Stöhr circumscribed and named the genus in 2006; they described the type species Ophiohamus nanus in the same work. A second species, Ophiohamus georgemartini, was described by O'Hara and Caroline Harding in 2015. As of 2018, those are the only two species recognized in this genus.

<i>Ophiocomella alexandri</i> Species of brittle star

Ophiocomella alexandri, known as Alexander's spiny brittle star or banded brittle star, is a species of marine brittle star. It was first described to science by Theodore Lyman in 1860. Lyman states in his description that the animal is named for his friend, Alexander E. R. Agassiz, the son of Lyman's mentor, Louis Agassiz.

<i>Amphiodia occidentalis</i> Species of brittle star

Amphiodia occidentalis or long-armed brittle star is a species of brittle star belonging to the family Amphiuridae. It is found in the Eastern Pacific coast from Alaska to USA, often on the seafloor within intertidal and subtidal zones. Within these areas, it is often found buried a few centimeters under the sand with 2 or 3 arms extending through the surface.

Ophiomusa is a genus of echinoderms belonging to the family Ophiolepididae that includes: sea urchins, sand dollars and sea cucumbers. Ophiurida are similar to starfish; they both have a central disc and five arms sprouting from the disc. One of the main distinguishing factors of an Ophiuroid is its arms; the arms of an Ophiurida are longer, thinner, and distinctly separated in comparison to those of a sea star.

<i>Melusinaster</i> Extinct genus of basket stars

Melusinaster is a genus of basket stars from the Jurassic period described by Thuy and Stöhr in 2018. Fossil specimens from areas throughout Germany were used to describe the genus. The individuals described with small ophiuroids with arched, crescent-shaped arm plates, articulations in the spine made of muscle and nerve openings, and no tubercles or spurs on the outer surfaces of the arm plates.

<span class="mw-page-title-main">Ophiothela mirabilis</span> Species of echinoderm

Ophiothela mirabilis is a species of ophiuroid brittle stars within the family Ophiotrichidae. O. mirabilis is an epizoic species which have a non-parasitic relationship with host sponges or gorgonians. Although native to the Pacific Ocean, it has invaded the Caribbean and southwestern Atlantic since late 2000. Many of its characteristics, including reproduction and diet, allow O. mirabilis opportunities to quickly propagate and spread through habitats.

References

  1. ↑ Sthor S (2008). "Brittle stars (Echinodermata: Ophiuroidea) from La Réunion and the systematic position of Ophiocanops Koehler, 1922".
  2. 1 2 3 Mortensen T (1933). On an extraordinary ophiurid, Ophiocanops fugiens Koehler. With remarks on Astrogymnotes, Ophiopteron, and on an albino Ophiocoma. Papers from Dr. Th. Mortensen's Pacific expedition 1914-16. LX. Videnskabelige Meddelelser Fra Dansk Naturhistorisk Forening I Kobenhaven (Report). Vol. 93.
  3. ↑ Hotchkiss FH (August 1977). "Ophiuroid Ophiocanops (Echinodermata) not a living fossil". Journal of Natural History. 11 (4): 377–80. doi:10.1080/00222937700770291.
  4. ↑ The World Ophiuroidea Database - Ophiocanops Koehler, 1922
  5. ↑ Smith AB, Paterson GL, Lafay B (June 1995). "Ophiuroid phylogeny and higher taxonomy: morphological, molecular and palaeontological perspectives". Zoological Journal of the Linnean Society. 114 (2): 213–43. doi:10.1006/zjls.1995.0024.
  6. ↑ Pearse VB, Pearse JS, Hendler G, Byrne M, Mooi R, Telford M (1998). "An accessible population of Ophiocanops off NE Sulawesi, Indonesia". In Mooi R, Telford M (eds.). Echinoderms. Vol. 413. San Francisco. Balkema, Rotterdam. pp. 413–418.{{cite book}}: CS1 maint: location missing publisher (link)
  7. 1 2 3 "The Ophiuroidea". ucmp.berkeley.edu. Retrieved 2021-04-23.
  8. ↑ Brusca RC, Brusca GJ (2003). Invertebrates (2 ed.). Sinauer Associates.
  9. 1 2 Koehler R (1922). Ophiurans of the Philippine Seas and Adjacent Waters, Issue 100, Volume 5. Washington Government Printing Office.
  10. ↑ Ophiocanops (Genus)
  11. ↑ Guille A (1979). "Les Ophiurides des marges continentales de la région des Philippines-Indonésie Distribution Bathymétrique et étagement.". Echinoderms: Proceedings of the European Colloquium on Echinoderms, Brussels.
  12. 1 2 Fujita TS, et al. (2001). Terazaki MA, et al. (eds.). Biology of a rare ophiuroid Ophiocanops fugiens Koehler, 1922 (Echinodermata) associated with black corals, with notes on the specimens collected from Lembeh Strait, Bitung, Indonesia. Proceedings of the 11th JSPS Joint Seminar on Marine Science. Tokyo: Center for International Cooperation, Ocean Research Institute, University of Tokyo. pp. 326–333.
  13. ↑ Stöhr S, O'Hara TD, Thuy B (2012-03-02). "Global diversity of brittle stars (Echinodermata: Ophiuroidea)". PLOS ONE. 7 (3): e31940. Bibcode:2012PLoSO...731940S. doi: 10.1371/journal.pone.0031940 . PMC   3292557 . PMID   22396744.
  14. ↑ Stöhr S, Conand C, Boissin E (2008). "Brittle stars (Echinodermata: Ophiuroidea) from La Réunion and the systematic position of Ophiocanops Koehler, 1922". Zoological Journal of the Linnean Society. 153 (3): 545–560. doi: 10.1111/j.1096-3642.2008.00401.x . ISSN   1096-3642.
  15. ↑ Emlet RB (2006). "Direct development of the brittle star Amphiodia occidentalis (Ophiuroidea, Amphiuridae) from the northeastern Pacific Ocean". Invertebrate Biology. 125 (2): 154–171. doi:10.1111/j.1744-7410.2006.00049.x. ISSN   1744-7410.


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