Ceratias tentaculatus, the southern seadevil, is a species of marine ray-finned fish belonging to the family Ceratiidae, the warty seadevils. This is bathydemersal species which can be found at depths ranging from 100to. It is restricted to the Southern Hemisphere.
Ceratias tentaculatus was first formally described in 1930 as Mancalias tentaculatus by the English ichthyologist John Roxborough Norman with its type locality given as the South Atlantic Ocean at 52°25'S, 9°50'E from a depth of . The genus Ceratias is classified by the 5th edition of Fishes of the World as belonging to the family Ceratiidae in the suborder Ceratioidei of the anglerfish order Lophiiformes.[1]
Ceratias tentaculatus belongs to the genus Ceratias, this name means "horn bearer", an allusion to the esca sticking up from the snout. The specific name tentaculatus means "tentacule", i.e. a small tentacle, this is assumed to be an allusion to the two small tentacles on the escal bulb that Norman described as "small and almost transparent".[2]
Ceratias tentaculatus is sexually dimorphic and the metamorphosed females can be distinguished from the metamorphosed females of other species in the genus Ceratias by the morphology of its dark coloured esca which has two appendages at the tip of its bulb, these appandages are almost always forked or branched. The esca is on an illicium whic has a length equivalent to 19.1% to 28.5% of the standard length of the fish. The pore of the esca is located at the apex of its bulb, and is slightly elecated on a pigmented papilla in all specimens witha standard length in excess of . There are teeth on the vomer of all known specimens.[3] This species has a maximum published total length of .
Ceratias tentaculatus has a circumglobal distribution in the Southern Ocean, where most of the specimens were taken between 35° and 68° S. Smaller specimens have also been collected from Saldanha Bay on the Atlantic Coast of the Western Cape of South Africa north to Delagoa Bay in Mozambique, in the Indian Ocean. It has been collected from depths between, but it typically is found between .