Presence of acuminate scales above and below lateral line on caudal peduncle. This characteristic is shared with N. spiniferus. Other diagnostic characters include: 8-12 very regular dark bars (vs. not very regularly shaped bars in N. spiniferus), 3-5 times wider than interspaces, the middle area of the bars being often lighter brown than the margin or as light as the background, the bar then being vertically split into two thin bars; dorsal length of head 18-22% SL (vs. 21-23%); process of acuminate scales shorter than (versus as long as) rest of scale, its base width about 1/4-1/3 of scale width (versus about 1/2).