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''Ocythoe tuberculata'', also known as the tuberculate pelagic octopus or football octopus, is a
pelagic The pelagic zone consists of the water column of the open ocean, and can be further divided into regions by depth (as illustrated on the right). The word ''pelagic'' is derived . The pelagic zone can be thought of as an imaginary cylinder or w ...
octopus An octopus ( : octopuses or octopodes, see below for variants) is a soft-bodied, eight- limbed mollusc of the order Octopoda (, ). The order consists of some 300 species and is grouped within the class Cephalopoda with squids, cuttlefis ...
. It is the only known species in the family Ocythoidae. ''Ocythoe tuberculata'' is found in warm and temperate seas, especially in the Northern Hemisphere, such as the North
Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contine ...
off California.


Description


Morphology

''Ocythoe'' are one of the few cephalopods to have a swimbladder. In captivity, two specimens were observed controlling their buoyancy and shooting water "forwards, upwards, sideways, and backwards" from the upper channel of the mantle cavity. ''Ocythoe'' achieves this by altering the dorso-lateral corners of the mantle opening. The entire swimbladder structure rests on the "visceral mass" and connects to the mantle cavity. It is also innervated and vascular. Juvenile and adult swimbladders exhibit key differences. Juveniles tend to have thicker and "gelatinous" walls with more spherical cells. Adults on the other hand have a less gelatinous appearance and a constitutively open lumen. Dwarf males do not possess swimbladders. ''Ocythoe'' is the only cephalopod to possess a proper gas bladder, based on specimens kept in captivity, although the origins of the gas is still an area of research.


Sexual dimorphism

Female and male tuberculate pelagic octopuses have distinct morphological differences. Females exhibit a larger dorsal mantle length upon maturity around 300 millimeters, while males only reach a dorsal mantle length of around 30 millimeters. The females are around long when full-grown. The males are considerably smaller, around . Males also have a well-developed hectocotylus on the third arm. This structure contains the spermatophores and is dislodged and detached in the mantle of the female during mating and remains for an extended period of time for fertilization. Young females and mature males have been observed residing inside
salp A salp (plural salps, also known colloquially as “sea grape”) or salpa (plural salpae or salpas) is a barrel-shaped, planktic tunicate. It moves by contracting, thereby pumping water through its gelatinous body, one of the most efficient ...
s, although little is known about this relationship.


Distribution

''O. tuberculata'' have been well known for inhabiting mainly northern hemisphere waters, typically in the Mediterranean Sea, as well as the eastern and western parts of the North Atlantic. ''O. tuberculata'' has also been found in the northern Pacific waters, with very few individuals found in the southern hemisphere, either in the Indian or Pacific oceans. ''O. tuberculata'' has typically been found in warmer waters. There is some speculation that warm ocean currents moving eastward from the Indian Ocean are responsible for the small sample of specimens found in northern pacific waters, but this has yet to be confirmed or denied. ''O. tuberculata'' is a near-surface dwelling pelagic octopus, living between depths of 100 and 200 meters.


Lifespan and reproduction

Female tuberculate pelagic octopuses are known to have a high fecundity, producing nearly 100,000 eggs. One female specimen caught in May 2003 had a record-breaking 1 million eggs, the most of any Octopoda. Egg size is typically very small, measuring 1.75 mm long and 1.00 mm wide. This has been seen as a trend in other pelagic octopus species. Tuberculate pelagic octopuses is said to be viviparous, meaning their offspring develop with in the body of the parent. However, several different authors dispute exactly how and where this development occurs. The general consensus is the eggs develop in expanded oviducts. Fertilization occurs when the hectocotylus is deposited from the male in the female's mantle cavity.


Diet

The diet of ''Ocythoe'' is undocumented, however most octopuses are predatory. It is known that open ocean octopuses typically feed on prawns, fish, or other cephalopods.


Predators

There are a number of known predators that prey on Ocythoe. These are lancet fishes (''Alepisaurus borealis'' and ''A. ferox''), tunas (''Thunnus alalunga, T. thunnus, and Germon germon)'', and Risso's dolphin (''Grampus griseus''). These predators have a large vertical range, and typically prey on ''O. tuberculata'' between 100 and 200 meters.


Gallery

File:Ocythoe tuberculata (Merculiano).jpg, Male with attached
hectocotylus A hectocotylus (plural: ''hectocotyli'') is one of the arms of male cephalopod A cephalopod is any member of the molluscan class Cephalopoda ( Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusive ...
that has broken free from its sac Image:Ocythoe tuberculata viscera.jpg, Cut-away drawing of the viscera Image:Ocythoe tuberculata hectocotylus.jpg, Details of the hectocotylus File:Ocythoe tuberculata paralarva.jpg, ''O. tuberculata''
paralarva Paralarvae (singular: ''paralarva'') are young cephalopods in the planktonic stages between hatchling and subadult. This stage differs from the larval stage of animals that undergo true metamorphosis. Paralarvae have been observed only in mem ...


References


External links


Tree of Life web project: ''Ocythoe tuberculata''
{{Taxonbar, from=Q2467252 Octopuses Molluscs of the Pacific Ocean Molluscs of North America Fauna of California Cephalopods described in 1814 Taxa named by Constantine Samuel Rafinesque