The predatory tunicate (''Megalodicopia hians''), also known as the ghostfish,
is a species of
tunicate which lives anchored along deep-sea
canyon
A canyon (; archaic British English spelling: ''cañon''), gorge or chasm, is a deep cleft between escarpments or cliffs resulting from weathering and the erosive activity of a river over geologic time scales. Rivers have a natural tendency t ...
walls and the
seafloor. It is unique among tunicates in that, rather than being a
filter feeder
Filter feeders are aquatic animals that acquire nutrients by feeding on organic matters, food particles or smaller organisms (bacteria, microalgae and zooplanktons) suspended in water, typically by having the water pass over or through a s ...
, it has
adapted to life as an
ambush predator. Its mouth-like
siphon
A siphon (; also spelled syphon) is any of a wide variety of devices that involve the flow of liquids through tubes. In a narrower sense, the word refers particularly to a tube in an inverted "U" shape, which causes a liquid to flow upward, abo ...
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 . They mostly feed on
zooplankton and other tiny animals. Their bodies are roughly across.
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 their eggs.
Taxonomy
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.
Octacnemidae have been suspected to share
phylogenetic
In biology, phylogenetics () is the study of the evolutionary history of life using observable characteristics of organisms (or genes), which is known as phylogenetic inference. It infers the relationship among organisms based on empirical dat ...
relations with the families
Cionidae and/or
Corellidae due to the similarities in their
morphology.
Distribution
''Megalodicopia hians'' can be found sparsely to depths of about through the
Monterey Canyon system.
Their abundance tended to be the greatest in the oxygen-minimum zone, which is down.
References
External links
Predatory tunicatesMonterey Bay Aquarium
Phlebobranchia
Animals described in 1918
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