Cirroteuthis
Encyclopedia
Cirroteuthis muelleri is one of the largest cirrate octopus
Octopus
The octopus is a cephalopod mollusc of the order Octopoda. Octopuses have two eyes and four pairs of arms, and like other cephalopods they are bilaterally symmetric. An octopus has a hard beak, with its mouth at the center point of the arms...

es, growing to a length of 1.5 m. It is the only species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Cirroteuthis.

Description

Cirroteuthis muelleri can reach a length of 1.5 m (4.9 ft). It is off white or pale purple, with the inner side of the arms and the webs being brownish-purple.

The head has well developed eyes with lenses. The upper and lower beaks are thin and relatively weak. The body is gelatinous and fragile. The arms are nearly equal in length. A pair of translucent webs joins the dorsal and ventral sides of the arms together and the webs terminate at a nodule. The first 7 or 8 suckers are cup-shaped and raised on thick stalks, numbers 2 and 3 being the largest. There are a further 30 or so smaller suckers with delicate stalks. Between the suckers are conspicuous cirri up to 19 mm (0.748031496062992 in) long. These are elongate, fleshy tendrils set along the sides of the oral surface of the arms, the longest being in the mid-arm region. Both the suckers and the cirri do not extend as far as the tip of the arm.

The fins are elliptical when viewed from the side. They are wide, and longer than the width of the head. The aperture of the mantle is narrow and the funnel is long. It has been nicknamed "Dumbo" after the cartoon elephant of that name, because its fins resemble large ears.

Distribution

Cirroteuthis muelleri is a deep sea species. It is found in cold seas in the boreal
Boreal ecosystem
The term boreal is usually applied to ecosystems localized in subarctic and subantarctic zones, although Austral is also used for the latter....

 Arctic, the north Atlantic Ocean, the north Pacific Ocean and waters off New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...

.

Habitat

Cirroteuthis muelleri is benthopelagic, meaning that it is found swimming or drifting in the ten metres or so immediately above the sea bed. It is usually found at depths of over 2000 m (6,561.7 ft). At these depths practically no light penetrates, the temperature is about 4°C and observation is only possible by submersible
Submersible
A submersible is a small vehicle designed to operate underwater. The term submersible is often used to differentiate from other underwater vehicles known as submarines, in that a submarine is a fully autonomous craft, capable of renewing its own power and breathing air, whereas a submersible is...

 which makes these octopuses difficult to collect. Their ecology and biology are little known but they seem to be fairly common in the seas around Greenland
Greenland
Greenland is an autonomous country within the Kingdom of Denmark, located between the Arctic and Atlantic Oceans, east of the Canadian Arctic Archipelago. Though physiographically a part of the continent of North America, Greenland has been politically and culturally associated with Europe for...

.

Biology

In a study of Arctic cephalopods, three specimens of Cirroteuthis muelleri, all female, were caught near the ocean floor at 3000 –. The eggs were found to be large and were laid on the bottom, singly. The food is believed to consist mainly of small crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s.
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