Cycloptychius

Cycloptychius is an extinct genus of prehistoric freshwater & marine ray-finned fish that existed throughout much of the Carboniferous period in Eurasia, and possibly into the Early Permian in South Africa. It was a member of the Rhadinichthyidae, a family of basal ray-finned fish that was formerly placed in the now-paraphyletic order Palaeonisciformes.

It contains the following species:


 * C. bidens Matveeva, 1958 - Early Carboniferous (Tournaisian) of Krasnoyarsk Krai, Russia (Os’kin Formation)
 * C. carbonarius Young, 1866 - Late Carboniferous (Moscovian) of England (North Staffordshire Coalfield)
 * C. concentricus Traquair, 1881 - Early Carboniferous (Viséan) of Scotland (Glencartholm Volcanic Beds)
 * ?C. loocki Evans, 2005 - Early Permian (Artinskian) of South Africa (Whitehill Formation)