Photos by Paul Caiger, Woods Hole Oceanographic Institution

The jaw of the loosejaw dragonfish (Photostomias goodyeari) is a marvel of the animal kingdom. It has no floor and is only attached by a hinge, a tendon, and a modified tongue bone. This series of images shows the incredible extent to which it can open it’s jaw—an indication of the size of the prey it consumes. It also has a set of headlights under it’s eyes for searching out unlucky victims in the perpetual twilight of the mesopelagic.