''Cirroteuthis muelleri'', also known as the big-finned jellyhead, was the first cirrate octopus species (and genus) to be scientifically described (in 1836). It is closely related to the genus ''Cirrothauma'' within the family

Cirroteuthidae Cirroteuthidae is a family of pelagic cirrate octopuses comprising at least five species in three genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil o ...

. The species is restricted to the

Arctic Ocean The Arctic Ocean is the smallest and shallowest of the world's five oceanic divisions. It spans an area of approximately and is the coldest of the world's oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, ...

and far North Atlantic (specimens from the southern hemisphere and Pacific have been attributed to a new species ''

Cirroteuthis kirrilyae ''Cirroteuthis muelleri'', also known as the big-finned jellyhead, was the first cirrate octopus species (and genus) to be scientifically described (in 1836). It is closely related to the genus ''Cirrothauma'' within the family Cirroteuthidae. T ...

'' Verhoeff & O'Shea, 2025).Vecchione, M. & R.E. Young 2003
''Cirroteuthis'' Eschricht, 1836
The Tree of Life Web Project.

Description

''Cirroteuthis muelleri'' can reach a maximum length of 400 mm (mantle length 170 mm). Statements that ''C. muelleri'' reaches up to 1.5 m total length are erroneous (and involve unidentified '' Cirrothauma'', then regarded as ''Cirroteuthis'' sp., being mistakenly assumed to be ''C. muelleri''). 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 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.''Cirroteuthis muelleri''
Marine Species Identification Portal. Retrieved 2011-10-03. 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. Cirroteuthis muelleri NOAA

Distribution

''Cirroteuthis muelleri'' is a deep sea species. It is found in cold seas in the

boreal Boreal, northern, of the north. Derived from the name of the god of the north wind from Ancient Greek civilisation, Boreas (god), Boreas. It may also refer to: Climatology and geography *Boreal (age), the first climatic phase of the Blytt-Sernand ...

Arctic and the far north Atlantic Ocean. Specimens of ''Cirroteuthis'' from around Australia, New Zealand, and possibly the central and northeastern Pacific have been allocated to a new species, ''

'' Verhoeff & O'Shea, 2025 (previously referred to ''Cirroteuthis'' cf. ''muelleri'').

Habitat

''Cirroteuthis muelleri'' is benthopelagic, meaning it is found swimming or drifting in the or so immediately above the

sea bed 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 usually found at depths of over . At these depths, practically no light penetrates, the temperature is about 4 °C, and observation is only possible by

submersible A submersible is an underwater vehicle which needs to be transported and supported by a larger ship, watercraft or dock, platform. This distinguishes submersibles from submarines, which are self-supporting and capable of prolonged independent ope ...

, 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 is an autonomous territory in the Danish Realm, Kingdom of Denmark. It is by far the largest geographically of three constituent parts of the kingdom; the other two are metropolitan Denmark and the Faroe Islands. Citizens of Greenlan ...

Biology

In a study of Arctic cephalopods, three specimens of ''Cirroteuthis muelleri'', all female, were caught near the ocean floor at . The eggs were found to be large and were laid on the bottom, singly. The diet of ''C. muelleri'' (from stomach contents of 18 specimens) was found to comprise small crustaceans (

Calanoida Calanoida is an order of copepods, a group of arthropods commonly found as zooplankton. The order includes around 46 families with about 1800 species of both marine and freshwater copepods between them. Description Calanoids can be distinguish ...

Mysidacea The Mysidacea is a group of shrimp-like crustaceans in the superorder Peracarida, comprising the two extant orders Mysida and Lophogastrida Lophogastrida is an Order (biology), order of malacostracan crustaceans in the superorder Peracarida, c ...

Isopoda Isopoda is an order of crustaceans. Members of this group are called isopods and include both aquatic species and terrestrial species such as woodlice. All have rigid, segmented exoskeletons, two pairs of antennae, seven pairs of jointed l ...

) and polychaetes (

Polynoidae Polynoidae is a family (biology), family of marine Polychaete worms known as "scale worms" due to the scale-like elytron (Annelida), elytra on the dorsal surface. Almost 900 species are currently recognised belonging to 9 subfamilies and 167 gen ...

), all small benthic or epibenthic prey items. The largest mysids consumed were estimated at 14.6 mm long, and the largest polychaete was estimated at 24.3 mm.

References

{{Taxonbar, from=Q18195570 Octopuses Cephalopods of Oceania Molluscs of the Pacific Ocean Molluscs of the Atlantic Ocean