Author: (Vaillant, 1888)
Polyacanthonotus challengeri (Vaillant, 1888)
Diagnosis: body compressed, elongate and tapering. Snout about twice eye diameter; preoral portion longer than eye diameter. Anterior and posterior nostrils closely set. Teeth and squamation as in P. rissoanus. Mouth large, posterior end extending to anterior edge of orbit. First spine of dorsal fin inserted posterior to insertion of pectoral fin. Dorsal fin with 32-46 isolated spines (the last double); pelvic fin with fulcral spine plus 8-10 rays; pectoral fin with fulcral spine plus 10-14 rays. Anterior gill arch with 11-21 rakers. Pyloric caeca 3, very short. Colour: as in P. rissoanus, except lateral line usually darker and more conspicuous. Size: variable regionally; to about 50 cm (gnathoproctal length to about 18 cm).
Habitat: benthopelagic at depths of 1,300-3,700 m, commonly between 2,000-3,000 m. Food: benthic invertebrates, especially amphipods, polychaetes and mysids. Reproduction: females greatly outnumber males. Mature males have the nostrils darkened.
Distribution: off Morocco, the Canaries and the Azores. Elsewhere, bitemperate in Atlantic, Pacific and Indian Oceans.