The predatory tunicate (''Megalodicopia hians''), also known as the ghostfish, is a species of

tunicate A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata (). It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). The subphylum was at one time ca ...

which lives anchored along deep-sea

canyon A canyon (from ; archaic British English spelling: ''cañon''), or gorge, is a deep cleft between escarpments or cliffs resulting from weathering and the erosion, erosive activity of a river over geologic time scales. Rivers have a natural tenden ...

walls and the

seafloor The seabed (also known as the seafloor, sea floor, ocean floor, and ocean bottom) is the bottom of the ocean. All floors of the ocean are known as 'seabeds'. The structure of the seabed of the global ocean is governed by plate tectonics. Most of ...

. It is unique among other tunicates in that rather than being a

filter feeder Filter feeders are a sub-group of suspension feeding animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feedin ...

, it has

adapted In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...

to life as an

ambush predator Ambush predators or sit-and-wait predators are carnivorous animals that capture or trap prey via stealth, luring or by (typically instinctive) strategies utilizing an element of surprise. Unlike pursuit predators, who chase to capture prey us ...

. Its mouth-like

siphon A siphon (from grc, σίφων, síphōn, "pipe, tube", also spelled nonetymologically 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 a ...

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 Monterey Canyon, or Monterey Submarine Canyon, is a submarine canyon in Monterey Bay, California with steep canyon walls measuring a full 1 mile in height from bottom to top, which height/depth rivals the depth of the Grand Canyon itself. It is ...

at depths of . They mostly feed on

zooplankton Zooplankton are the animal component of the planktonic community ("zoo" comes from the Greek word for ''animal''). Plankton are aquatic organisms that are unable to swim effectively against currents, and consequently drift or are carried along by ...

and tiny animals, and 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 the eggs.

Taxonomy

The predatory tunicate belongs to the family

Octacnemidae Octacnemidae is a family of tunicates belonging to the order Phlebobranchia. Genera: * '' Benthascidia'' Ritter, 1907 * '' Cibacapsa'' Monniot & Monniot, 1983 * ''Cryptia'' Monniot & Monniot, 1985 * '' Dicopia'' Sluiter, 1905 * '' Kaikoja'' Monn ...

, which is a group of

deep-sea The deep sea is broadly defined as the ocean depth where light begins to fade, at an approximate depth of 200 metres (656 feet) or the point of transition from continental shelves to continental slopes. Conditions within the deep sea are a combin ...

ascidians. Thanks to the

hypertrophied Hypertrophy is the increase in the volume of an organ or tissue due to the enlargement of its component cells. It is distinguished from hyperplasia, in which the cells remain approximately the same size but increase in number.Updated by Linda J. ...

oral siphon, two larger lips have formed to be able to catch prey. Octacnemidae have been suspected to share

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

relations with the families

Cionidae Cionidae is a family of sea squirts belonging to the suborder Phlebobranchia Phlebobranchia is a suborder of tunicate, sea squirts in the class Ascidiacea. Characteristics The group includes both colonial and solitary animals. They are di ...

and/or

Corellidae Corellidae is a family of sea squirts belonging to the suborder Phlebobranchia. Genera The World Register of Marine Species includes the following genera in this family: *'' Abyssascidia'' Herdman, 1880 *''Chelyosoma ''Chelyosoma'' is a genus ...

due to the similarities in their

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

Distribution

''Megalodicopia hians'' can be found sparsely to depths of about through the

system. Their abundance tended to be the greatest in the oxygen-minimum zone, which is down.

References

External links

Predatory tunicatesMonterey Bay Aquarium
Tunicates Animals described in 1918 {{tunicata-stub