 The underside is densely carpeted by light-emitting photophores, which extend to the tip of the snout and around the eyes and nostrils, and thin to almost non-existent on the back.This species has on average only 60 vertebrae, the fewest of any shark.The diet of the spined pygmy shark consists mainly of bony fishes (including the dragonfish "Idiacanthus", the lanternfish "Diaphus", and the bristlemouth "Gonostoma") and squid (including members of the genera "Chiroteuthis" and "Histioteuthis").