In most fish, the skull is fused to the backbone, limiting their gape. But a barbeled dragonfish can pop open its jaw like a Pez dispenser — up to 120 degrees — thanks to a soft tissue joint that connects the fish’s head and spine, researchers report February 1 in PLOS ONE.
BIG GULP This X-ray image reveals that a dragonfish has eaten a large lanternfish in a single gulp. |
Five had a flexible rod, called a notochord, covered by special connective tissue that bridged their vertebrae and skulls. When Schnell and Johnson opened the mouths of the fish, the connective tissue stretched out. The joint may provide just enough give for dragonfish to swallow whole crustaceans and lanternfish almost as long as they are.
OPEN WIDE Some species of dragonfish (Eustomias obscurus shown) open their jaws like Pez dispensers, thanks to a flexible joint at the base of their skulls. The joint may allow the fish to swallow bigger prey, which they trap with their fanglike teeth.
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