Elasmobranchii (sharks and rays) >
Squaliformes (Sleeper and dogfish sharks) >
Oxynotidae (Rough sharks)
Etymology: Oxynotus: oxys (Gr.), sharp; notos (Gr.), back, referring to its keeled back (“dorso carenato”). (See ETYFish); paradoxus: Latin for strange or contrary to expectation; Frade was not sure if this shark, with its first dorsal spine directed backward instead of forward, represented a new species or an aberrant form of O. centrina. (See ETYFish).