The granular dogfish shark has two dorsal, or top, fins and no anal, or unpaired bottom, fin. The dorsal fins each have a large spine on the front edge. However, the rear dorsal fin and its spine are much larger relative to the front fin and spine. The large spine on the rear dorsal fin is typical of all of the sharks in this genus. The coloration is brownish-black, with no conspicuous markings on the underside or tail. The upper and lower teeth each have a single, narrow cusp, or point, as well as narrow cusplets, or small points.

Granular dogfish sharks grow only to less than 1 foot (30 centimeters) long. They have not been well studied, thus little is known about their ecology. It is presumed that their range is restricted to the western South Atlantic Ocean, off the Falkland Islands, and off Chile in the eastern South Pacific. They are deepwater sharks and are of no importance in commercial fishing. (See also Dogfish sharks.)