The saddled swellshark reaches a maximum known length of . It has a moderately stocky body and a short, variably wide, and strongly flattened head. The snout is broadly rounded, with the nostrils preceded by laterally expanded flaps of skin that do not reach the large mouth. The slit-like eyes are positioned high on the head and followed by tiny spiracles. The tooth rows number 68–82 in the upper jaw and 68–80 in the lower jaw. The very small teeth have three cusps, with the central one the longest and sometimes 1–2 additional lateral cusplets. In females the central cusp is smaller than in males. There are no furrows at the corners of the mouth, and the upper teeth are exposed when the mouth is closed. The fourth and fifth gill slits lie over the pectoral fin bases and are shorter than the first three.