Chondrichthyes - Symmoriiformes - Symmoriidae
Synonym: Stethacanthidae Lund 1974
Parent taxon: Symmoriiformes according to M. Ginter 2018
See also Coates and Sequeira 2001, Ginter et al. 2010, Goto et al. 1988, Ivanov 1999, Ivanov and Lebedev 2014, Ivanov et al. 2013, Lund 1985, Lund 1986, Nelson et al. 2016, Williams 1985 and Zangerl 1981
Sister taxa: Denaeidae, Falcatidae, Kawichthys, Kungurodus, Stemmatias
Subtaxa: Akmonistion Bethacanthus Cobelodus Danaea Gutturensis Orestiacanthus Petrodus Physonemus chesterensis Physonemus parvulus Stethacanthulus Stethacanthus Symmorium
Ecology: nektonic carnivore
Distribution:
• Miocene to Pliocene of Bolivia (1 collection)
• Miocene of Panama (2)
• Permian of Japan (1), Kazakhstan (1), the Russian Federation (6), United States (33: Nebraska, Texas)
• Carboniferous to Permian of Argentina (1)
• Carboniferous of China (1), the Russian Federation (4), the United Kingdom (3), United States (34: Arizona, Colorado, Illinois, Indiana, Iowa, Kansas, Michigan, Missouri, Montana, Nebraska, New Mexico, Ohio, Oklahoma, South Dakota)
• Devonian of the Russian Federation (6), United States (4: Ohio)
Total: 97 collections including 111 occurrences