''Cirrothauma'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of deep water

octopus An octopus (: octopuses or octopodes) 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, cuttlefish, and nautiloids. Like oth ...

es from the cirrate

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

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 of ''Cirrothauma'' are fragile, gelatinous deep-sea octopods with a large 'butterfly-shaped' shell. They are unique in the Octopoda in being blind, with eyes lacking lenses and being imbedded/covered in head tissues. The genus contains a single species ''

Cirrothauma murrayi ''Cirrothauma murrayi'', the blind cirrate octopus, is a presumably blind octopus whose eyes can likely sense light, but not form images. It has been found worldwide, usually beneath the ocean's surface, but a single specimen was collected in the ...

''.

Species and taxonomy

Two other species have formerly been included in ''Cirrothauma'', but have recently been allocated to their own genus (''

Inopinoteuthis ''Inopinoteuthis'' is a genus of deepsea octopuses from the cirrate family Cirroteuthidae Cirroteuthidae is a family of pelagic cirrate octopuses comprising at least five species in three genera Genus (; : genera ) is a taxonomic rank ab ...

''): ''

Inopinoteuthis magna ''Cirrothauma magna'', also known as the big-eye jellyhead, is a species of deep-sea cirrate octopus that has been found in the Indian, Atlantic, and Pacific oceans. It is known from four damaged specimens. The species was originally described ...

'' (Hoyle, 1885) and ''

Inopinoteuthis hoylei ''Inopinoteuthis'' is a genus of deepsea octopuses from the cirrate family Cirroteuthidae Cirroteuthidae is a family of pelagic cirrate octopuses comprising at least five species in three genera Genus (; : genera ) is a taxonomic rank ab ...

'' (Robson, 1932). Both ''Cirrothauma'' and ''Inopinoteuthis'' have butterfly-shaped shells, and much longer arms than the related ''Cirroteuthis''. Genera ''Cirrothauma'' and ''Inopinoteuthis'' can be separated given the presence of well-developed eyes on ''Inopinoteuthis'' (vs. vestigial eyes) as well as the presence of functional suckers with suction chambers on ''Inopinoteuthis'' (''Cirrothauma'' have minute vestigial suckers atop elongate fleshy stalks across the mid-distal arm regions).

Range

The single recognized species ''Cirrothauma murrayi'' has been reported from various locations across the Atlantic, Arctic, and Pacific Oceans, but seemingly not the Southern Ocean.

Species

There is a single currently recognized species within the genus ''Cirrothauma'', though a second (as yet undescribed taxon) is indicated in molecular data. *''

'' Chun, 1911

References

{{Taxonbar, from=Q18519178 Octopuses Cephalopod genera