Stöhr, Hugall, Thuy, Martynov, 2018) family Ophiopteridae O'Hara, Stöhr, Hugall, Thuy & Martynov, 2018 family Ophiotomidae Paterson, 1985 family Ophiojuridae O'Hara, Thuy & Hugall, 2021 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 Fossil record The first known brittle stars date from Early Ordovician. Study of past distribution and evolution of brittle stars has been hampered by the tendency of dead brittle stars to disarticulate and scatter, providing poor brittle star fossils. Until discoveries in the Agrio Formation of Neuquén Basin in the 2010s no fossil brittle star was known in the Southern Hemisphere, nor was any brittle star of Cretaceous age known. Human relations Brittle stars are not used as food, though they are not toxic, because of their strong skeleton. Even if some species have blunt spines, no brittlestar is known to be dangerous, nor venomous. There is no harm evidence towards humans, and even with their predators, brittlestars' only means of defense is escaping or discarding an arm. Aquaria Brittle stars are a moderately popular invertebrate in fishkeeping. They can easily thrive in marine tanks; in fact, the micro brittle star is a common "hitchhiker" that will propagate and become common in almost any saltwater tank, if one happens to come along on some live rock. Larger brittle stars are popular because, unlike Asteroidea, they are not generally seen as a threat to coral, and are also faster-moving and more active than their more archetypical cousins. References Andrew B. Smith, Howard B. Fell, Daniel B. Blake, Howard B. Fell, "Ophiuroidea", in AccessScience@McGraw-Hill, http://www.accessscience.com, DOI 10.1036/1097-8542.471000 David L. Pawson, Andrew C. Campbell, David L. Pawson, David L. Pawson, Raymond C. Moore, J. John Sepkoski, Jr., "Echinodermata", in AccessScience@McGraw-Hill, http://www.accessscience.com, DOI 10.1036/1097-8542.210700 "brittle star."Encyclopædia Britannica. 2008. Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 17 June 2008. Palaeos: Ophiuroidea Brittlestars on wetwebmedia.com Ophiuroidea Articles containing video clips Extant Ordovician first appearances