# Ophiothrix

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.

## Evolution

The fossil record of brittle stars can be traced back around 500 million years to Early Ordovician period. Despite the fact there have been a considerable number of fossils reported from Paleozoic, Mesozoic and Cenozoic periods, a startlingly little amount is known about the evolutionary history of the group. Paleozoic ophiuroids bear an uncanny resemblance to the modern relatives with respect to ambulacral plate pairs which have been fused firmly into their vertebrae and ambulacral groove which their ventral arm plates cover. They also have the presence of ventrally lateral arm plates.

## Systematics and phylogeny

Ophiothrix is a large genus that is currently divided into the following three subgenera: Acanthophiothrix, Ophiothrix and Theophiothrix'. Extant species include:
| Subgenus Ophiothrix (Acanthophiothrix) Ophiothrix armata Koehler, 1905 Ophiothrix deceptor Koehler, 1922 Ophiothrix diligens Koehler, 1898 Ophiothrix exhibita Koehler, 1905 Ophiothrix lepidus de Loriol, 1893 Ophiothrix leucotrigonia H.L. Clark, 1918 Ophiothrix proteus Koehler, 1905 Ophiothrix purpurea von Martens, 1867 Ophiothrix scorpio (Müller & Troschel, 1842) Ophiothrix scotiosa Murakami, 1943 Ophiothrix signata Koehler, 1922 Ophiothrix spinosissima Koehler, 1905 Ophiothrix suensoni Lütken, 1856 Ophiothrix versatilis Koehler, 1930 Ophiothrix vetusta Koehler, 1930 Ophiothrix vexator Koehler, 1930 Ophiothrix vigelandi A.M. Clark, 1968 Ophiothrix viridialba von Martens, 1867 Subgenus Ophiothrix (Ophiothrix) Ophiothrix accedens Koehler, 1930 Ophiothrix ailsae Tommasi, 1970 Ophiothrix angulata (Say, 1825) Ophiothrix aristulata Lyman, 1879 Ophiothrix caespitosa Lyman, 1879 Ophiothrix ciliaris (Lamarck, 1816) Ophiothrix consecrata Koehler, 1930 Ophiothrix contenta Koehler, 1930 Ophiothrix crassispina Koehler, 1904 Ophiothrix deposita Koehler, 1904 Ophiothrix dyscrita Clark, 1915 Ophiothrix echinotecta Balinsky, 1957 Ophiothrix elegans Lütken, 1869 Ophiothrix exigua Lyman, 1874 | Ophiothrix foveolata Marktanner-Turneretscher, 1887 Ophiothrix infirma Koehler, 1905 Ophiothrix koreana Duncan, 1879 Ophiothrix leucospida Koehler, 1930 Ophiothrix liodisca H.L. Clark, 1915 Ophiothrix marenzelleri Koehler, 1904 Ophiothrix miles Koehler, 1905 Ophiothrix oerstedii Lütken, 1856 Ophiothrix oliveri Benham, 1910 Ophiothrix panchyendyta Clark, 1911 Ophiothrix pavida Koehler, 1922 Ophiothrix picteti de Loriol, 1893 Ophiothrix plana Lyman, 1874 Ophiothrix prostrata Koehler, 1922 Ophiothrix roseocoerulans Grube, 1868 Ophiothrix rotata von Martens, 1870 Ophiothrix rudis Lyman, 1874 Ophiothrix savignyi (Müller & Troschel, 1842) Ophiothrix spiculata Le Conte, 1851 Ophiothrix tradita Koehler, 1930 Ophiothrix tricuspida Cherbonnier & Guille, 1978 Ophiothrix trilineata Lütken, 1869 Ophiothrix trindadensis Tommasi, 1970 Ophiothrix vitrea Döderlein, 1896 Subgenus Ophiothrix (Theophrix) Ophiothrix pusilla Lyman, 1874 | Subgenus not allocated Ophiothrix amphibola H.L. Clark, 1939 Ophiothrix beata Koehler, 1907 Ophiothrix berberis Lyman, 1879 Ophiothrix brachyactis H.L. Clark, 1915 Ophiothrix cimar Hendler, 2005 Ophiothrix comata Müller & Troschel, 1842 Ophiothrix congensis Koehler, 1911 Ophiothrix convoluta Koehler, 1914 Ophiothrix cotteaui (de Loriol, 1900) Ophiothrix dedita Koehler, 1930 Ophiothrix dirrhabdota H.L. Clark, 1918 Ophiothrix eurycolpodes H.L. Clark, 1918 Ophiothrix fragilis (Abildgaard, in O.F. Müller, 1789) Ophiothrix galapagensis Lütken & Mortensen, 1899 Ophiothrix hartforti A.H. Clark, 1939 Ophiothrix innocens Koehler, 1898 Ophiothrix lineata Lyman, 1860 Ophiothrix luetkeni Wyville Thomson, 1873 Ophiothrix maculata Ljungman, 1872 Ophiothrix magnifica Lyman, 1860 Ophiothrix marginata Koehler, 1905 Ophiothrix merguiensis Duncan, 1887 Ophiothrix nociva Koehler, 1907 Ophiothrix pallida Ljungman, 1872 Ophiothrix parasita Müller & Troschel, 1844 Ophiothrix petersi Studer, 1882 Ophiothrix planulatus Stimpson, 1855 Ophiothrix platyactis H.L. Clark, 1939 Ophiothrix quinquemaculata (Delle Chiaje, 1828) Ophiothrix rathbuni Ludwig, 1882 Ophiothrix simplex Koehler, 1905 Ophiothrix stri Hendler, 2005 Ophiothrix synoecina Schoppe, 1996 Ophiothrix tenuis Koehler, 1905 Ophiothrix variegata Duncan, 1887 Ophiothrix viator Koehler, 1904 |