This species is distinguished by the following characters: no blotches on the dorsal disc surface or a pair of white or dark blotches; dark blotch and band usually absent on the ventral disc surface; predorsal caudal vertebrae 80-87 (Ref. 123274)..

Geographical variations are present in the populations of the seas of Japan and Okhotsk: number of total tail thorns, ranging from 21-33 (average and standard deviation: 27.3±2.9) (southern Sea of Japan) vs.19-29 (26.0 ± 2.3) (northern Sea of Japan), vs. 22-27 (24.3 ± 1.5) (Sea of Okhotsk) (P < 0.05) and the frequency distribution of tail thorn numbers was bimodal in the Sea of Japan [modes: 25 and 28,29 (southern); 25,26 and 28 (northern)], but unimodal in the Sea of Okhotsk (mode: 25) (Ref. 123274).