The predatory tunicate (Megalodicopia hians), also known as the ghostfish,[1] is a species of tunicate which lives anchored along deep-sea canyon walls and the seafloor. It is unique among other tunicates in that rather than being a filter feeder, it has adapted to life as an ambush predator. Its mouth-like siphon is quick to close whenever a small animal such as a crustacean or a fish drifts inside. Once the predatory tunicate catches a meal, it keeps its trap shut until the animal inside is digested. They are known to live in the Monterey Canyon at depths of 200-. They mostly feed on zooplankton and tiny animals, and their bodies are roughly 5inches across.[2]
Predatory tunicates are hermaphrodites, producing both eggs and sperm which drift into the water. If there are no other tunicates nearby, they can self-fertilize the eggs.[2]
The predatory tunicate belongs to the family Octacnemidae, which is a group of deep-sea ascidians. Thanks to the hypertrophied oral siphon, two larger lips have formed to be able to catch prey.[3]
Octacnemidae have been suspected to share phylogenetic relations with the families Cionidae and/or Corellidae due to the similarities in their morphology.[4]
Megalodicopia hians can be found sparsely to depths of about 3800m (12,500feet) through the Monterey Canyon system.[3] Their abundance tended to be the greatest in the oxygen-minimum zone, which is 400m-800mm (1,300feet-2,600feetm) down.