There are two dorsal, or top, fins with large spines in front and at their base, and no anal, or unpaired bottom, fin. The pectoral fins sweep back to a point near the body. The body color is gray to grayish-brown, and the large green eyes are characteristic of the other sharks in this genus. The upper teeth are bladelike, with a single cusp, or point. The lower teeth are low and wide, and considerably larger than the upper teeth, with cusps that lean to the side. The overlapping dermal denticles, teethlike structures located on the body and fins, are leaf-shaped, with three cusps. The characteristics of the denticles are useful in distinguishing the needle dogfish shark from close relatives it resembles.

The needle dogfish shark can grow to at least 2.7 feet (81 centimeters) in length. They have been found in the western North Pacific off the coast of Japan and in the western North Atlantic in the Gulf of Mexico. They live in deep waters, probably below 650 feet (200 meters). These sharks have not been well studied, thus little is known about their diet. They are not important in commercial fishing. (See also Dogfish sharks.)