Parent taxon: Placodermi according to G. C. Young 2010
See also Denison 1975, Denison 1978, Dineley and Metcalf 1999, Long 2011 and Sepkoski 2002
Sister taxa: Acanthothoraci, Acanthothoraciformes, Antiarchi, Arthrodira, Asiacanthus, Austroptyctodus, Bianchengichthys, Brindabellaspida, Campbellodus, Changyonophyton, Coccostei, Coelosteichthys, Cratoselachiidae, Deinodus, Entelognathus, Hybosteus, Neopetalichthys, Nessariostoma, Oestophorus, Petalichthida, Petalichthyida, Petalichthyida, Pseudopetalichthyida, Pseudopetalichthyiformes, Ptychostei, Rhenanida, Rhenaniformes, Sedowichthys, Stensioelliformes, Tollichthys, Wangolepis, Yunnanacanthus
Subtaxa: Denisonodus Rhamphodopsis Tollodus
Ecology: nektonic carnivore
Distribution:
• Devonian of Belarus (3 collections), Estonia (1), Iran (1), the Russian Federation (1), South Africa (1), the United Kingdom (3), United States (1: Arizona)
Total: 11 collections each including a single occurrence