These illustrations and photos of a stained specimen show the head of a barbeled dragonfish in “resting position” (mouth closed—A, B, D, G) and as it opens its mouth completely (mouth open—A, C, E, H), showing the functional head joint (D, E). In more primitive members of the family, the flexible part of the vertebral column (notochord) forms a simple, straight connection between the head and the first ossified vertebra (F).
Nalani Schnell, Muséum national d’Histoire naturelle