''Cirrothauma murrayi'', the blind cirrate octopus, is a presumably blind

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 ...

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 Arctic immediately below the sea ice. Like other cirrates, it has an internal shell, muscular fins for swimming, and a web connecting the arms. The species was first caught by an expedition led by Sir John Murray in 1910, and it was later named in honor of Murray. It was described by German marine biologist

Carl Chun Carl Chun or Karl Friedrich Gustav Chun (1 October 1852 – 11 April 1914) was a German marine biologist who worked as a professor at the Universities of Königsberg (1883), Breslau (1891) and Leipzig (1898). He was a pioneer of German oceanogr ...

in 1911. The diet of this species is unknown, but like other cirrate octopods, the

buccal mass The buccal mass refers to the mouthparts of a number of animal groups, such as: *Gastropods *Cephalopods, which houses the cephalopod beak All extant taxon, extant cephalopods have a two-part beak, or Rostrum (anatomy), rostrum, situated in the bu ...

, esophagus, and stomach of ''Cirrothauma murrayi'' suggest whole (but very small) organisms, especially small

crustacean Crustaceans (from Latin meaning: "those with shells" or "crusted ones") are invertebrate animals that constitute one group of arthropods that are traditionally a part of the subphylum Crustacea (), a large, diverse group of mainly aquatic arthrop ...

s, are part of its diet (it has only a vestigial trace of a radula). The enzymatic action of salivary excretions separates the crustacean's musculoskeletal attachments and allows for the tissue to be removed, leaving the exoskeleton of the crustacean undamaged. Molecular work suggests that ''Cirrothauma murrayi'' may comprise two similar species, indeed work on the species by Aldred ''et al.'' (1983) found that some specimens had sucker counts in the upper 30's per arm while others had counts around 60 per arm (despite the animals being similar in size), which may suggest two otherwise similar species.

Description

Eye structure

The eye structure is very different from other octopods (and indeed the Cephalopoda as a whole). Their eyes are small, lens-less and presumably non-functional, as the eyes also lack irises and ciliary bodies. The eyes are embedded deep in the gelatinous tissue of their head.

Suckers

''Cirrothauma murrayi'' has approximately 30 to 60 suckers per arm, the proximal 6 on each arm are sessile (without a stalk), but the remaining suckers out to the arm tips are highly modified, being minute and lacking a suction chambers, and are mounted atop elongate fleshy/gelatinous stalks.

References

Bibliography

* {{Taxonbar, from=Q2974299 Octopuses Taxa named by Carl Chun Cephalopods described in 1911