page_title: Brittle star
section_title: Diversity and taxonomy
hierarchical_section_title: Brittle star / Diversity and taxonomy
caption_attribution_description: (center): Ophiothrix capillaris (Lyman) = Macrophiothrix capillaris (Lyman, 1879), adult, underside (top center): Ophiotholia supplicans (Lyman) = Ophiotholia supplicans Lyman, 1880, adult, underside (top right): Ophiocoma rosula (Link) = Ophiothrix fragilis (Abildgaard, 1789), adult, underside (top left): Astroschema brachiatum (Lyman) = Asteroschema brachiatum Lyman, 1879, adult, upperside (center left): Astroschema horridum (Lyman) = Asteroschema horridum Lyman, 1879, adult, underside (bottom center): Astroschema rubrum (Lyman) = Asteroschema rubrum Lyman, 1879, adult, underside (center right): Ophiocreas oedipus (Lyman) = Ophiocreas oedipus Lyman, 1879, adult, upperside (bottom left): Pluteus paradoxus (Johannes Müller) = Ophiura albida Forbes, 1839, young pluteus larva (bottom right): Pluteus paradoxus (Johannes Müller) = Ophiura albida Forbes, 1839, older pluteus larva
context_page_description: Brittle 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 in length on the largest specimens. They are also known as serpent stars; the New Latin class name Ophiuroidea is derived from the Ancient Greek ὄφις, meaning "serpent".
  The Ophiuroidea contain two large clades, Ophiurida and Euryalida. Over 2,000 species of brittle stars live today. More than 1200 of these species are found in deep waters, greater than 200 m deep.
context_section_description: Between 2,064 and 2,122 species of brittle stars are currently known, but the total number of modern species may be over 3,000. This makes brittle stars the most abundant group of current echinoderms (before sea stars). Around 270 genera are known, these are distributed in 16 families, which makes them at the same time a relatively poorly diversified group structurally, compared with the other echinoderms. For example, 467 species belong to the sole family of Amphiuridae (frail brittle stars which live buried in the sediment leaving only their arms in the stream to capture the plankton). There are also 344 species in the family of Ophiuridae.
  List of families according to the World Register of Marine Species, following O'Hara 2017:
  subclass Myophiuroidea Matsumoto, 1915
  infra-class Metophiurida Matsumoto, 1913
  super-order Euryophiurida O'Hara, Hugall, Thuy, Stöhr & Martynov, 2017
  order Euryalida Lamarck, 1816
  family Asteronychidae Ljungman, 1867
  family Euryalidae Gray, 1840
  family Gorgonocephalidae Ljungman, 1867
  order Ophiurida Müller & Troschel, 1840 sensu O'Hara et al., 2017
  suborder Ophiomusina O'Hara et al., 2017
  family Ophiomusaidae (O'Hara, Stöhr, Hugall, Thuy, Martynov, 2018)
  family Ophiosphalmidae (O'Hara, Stöhr, Hugall, Thuy & Martynov, 2018)
  Ophiomusina incertae sedis
  suborder Ophiurina Müller & Troschel, 1840 sensu O'Hara et al., 2017
  family Astrophiuridae Sladen, 1879
  family Ophiopyrgidae Perrier, 1893
  family Ophiuridae Müller & Troschel, 1840
  Ophiurina incertae sedis
  Ophiurida incertae sedis
  super-order Ophintegrida O'Hara, Hugall, Thuy, Stöhr & Martynov, 2017
  order Amphilepidida O'Hara, Hugall, Thuy, Stöhr & Martynov, 2017
  suborder Gnathophiurina Matsumoto, 1915 
  super-family Amphiuroidea Ljungman, 1867
  family Amphiuridae Ljungman, 1867
  family Amphilepididae Matsumoto, 1915
  super-family Ophiactoidea Ljungman, 1867
  family Ophiactidae Matsumoto, 1915
  family Ophiopholidae O'Hara, Stöhr, Hugall, Thuy & Martynov, 2018
  family Ophiothamnidae O'Hara, Stöhr, Hugall, Thuy & Martynov, 2018
  family Ophiotrichidae Ljungman, 1867
  suborder Ophionereidina O'Hara, Hugall, Thuy, Stöhr & Martynov, 2017 
  super-family Ophiolepidoidea Ljungman, 1867
  family Hemieuryalidae Verrill, 1899
  family Ophiolepididae Ljungman, 1867 (restricted)
  super-family Ophionereidoidea Ljungman, 1867
  family Amphilimnidae O'Hara, Stöhr, Hugall, Thuy & Martynov, 2018
  family Ophionereididae Ljungman, 1867
  suborder Ophiopsilina Matsumoto, 1915 
  super-family Ophiopsiloidea Matsumoto, 1915
  family Ophiopsilidae Matsumoto, 1915
  order Ophiacanthida O'Hara, Hugall, Thuy, Stöhr & Martynov, 2017
  suborder Ophiacanthina O'Hara, Hugall, Thuy, Stöhr & Martynov, 2017
  family Clarkcomidae O'Hara, Stöhr, Hugall, Thuy & Martynov, 2018
  family Ophiacanthidae Ljungman, 1867
  family Ophiobyrsidae Matsumoto, 1915
  family Ophiocamacidae (O'Hara, Stöhr, Hugall, Thuy, Martynov, 2018)
  family Ophiopteridae O'Hara, Stöhr, Hugall, Thuy & Martynov, 2018
  family Ophiotomidae Paterson, 1985
  suborder Ophiodermatina Ljungman, 1867 
  super-family Ophiocomoidea Ljungman, 1867
  family Ophiocomidae Ljungman, 1867
  super-family Ophiodermatoidea Ljungman, 1867
  family Ophiodermatidae Ljungman, 1867
  family Ophiomyxidae Ljungman, 1867
  family Ophiopezidae O'Hara, Stöhr, Hugall, Thuy & Martynov, 2018
  Ophiacanthida incertae sedis
  order Ophioleucida O'Hara, Hugall, Thuy, Stöhr & Martynov, 2017 
  family Ophiernidae O'Hara, Stöhr, Hugall, Thuy & Martynov, 2018
  family Ophioleucidae Matsumoto, 1915
  order Ophioscolecida O'Hara, Hugall, Thuy, Stöhr & Martynov, 2017 
  family Ophiohelidae Perrier, 1893
  family Ophioscolecidae Lütken, 1869
  Ophiuroidea incertae sedis
caption: Plate of brittle stars from the Kunstformen der Natur from Ernst Haeckel (1904)
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