Mawson's dragonfish has a slender, naked body with the only scales being in the two lateral lines, the upper lateral line is wholly made up of perforated scales. There is a flattened ridge on the operculum which divides towards the margin. They have a thin band of conicalteeth in the jaws. The dorsal fin has 61-66 soft rays while the anal fin has 36-38. In alcohol the overall colour is brown with darker saddles and bars, the median fins are darker than the pectoral and pelvic fins. This species grows to a length of standard length.
Mawson's dragonfish in the Weddell Sea are adult at and start breeding at. Spawning takes place during the autumn and early winter. They feed largely on benthic and benthopelagicorganisms such as fishes, especially rockcods in the genus Trematomus and the decapodNotocrangon antarcticus as well as mysids, gammarids and polychaetes.