[4] The specific name rubiginosum means "rusty" and refers to the overall reddish colour of this fish.

[5] As Forbes's generic name Plagiogeneion is neuter the ending of Hutton's specific name had to be altered to -um.

[10] The rubyfish is found in the southeastern Atlantic over the Vema Seamount to the west of Cape Town, and Walvis Bay in Namibia.

[8] It is a bathydemersal fish found at depths of from 50 to 600 m (160 to 1,970 ft), near sand or mud bottoms, typically in the vicinity of the edge of the continental shelf and around seamounts.

[8] Rubyfish is an important species for major fisheries in New Zealand and the South Pacific.