Seven-arm Octopus

Seven-arm Octopus
Seven-arm Octopus
Ventral view of young female (70 mm ML)
Lateral view of young male
Scientific classification
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Octopoda
Superfamily: Argonautoida
Family: Alloposidae
Verrill, 1881
Genus: Haliphron
Steenstrup, 1861
Species: H. atlanticus
Binomial name
Haliphron atlanticus
Steenstrup, 1861
  • Alloposus mollis
    Verrill, 1880
  • ?Octopus alberti
    Joubin, 1895
  • Alloposus pacificus
    Ijima & Ikeda, 1902
  • Heptapus danai
    Joubin, 1929
  • Alloposus hardyi
    Robson, 1930
  • ?Alloposina albatrossi
    Robson, 1932

The Seven-arm Octopus (Haliphron atlanticus) is the largest known species of octopus based on scientific records, with a total estimated length of 4 m and weight of 75 kg.[1][2] However, there have been claims of even larger octopuses of the species Enteroctopus dofleini.



Oral view

The Seven-arm Octopus is so named because in males the hectocotylus (a specially modified arm used in egg fertilization) is coiled in a sac beneath the right eye. Due to this species' thick gelatinous tissue, the arm is easily overlooked, giving the appearance of just seven arms. However, like other octopuses, it actually has eight.

In 2002, a single specimen of giant proportions was caught by fisheries trawling off the eastern Chatham Rise, New Zealand. This specimen, the largest of this species and of all octopuses, was the first validated record of Haliphron from the South Pacific. It had a mantle length of 0.69 m, total length of 2.90 m, and weight of 61.0 kg, although it was incomplete.

The type specimen of H. atlanticus was collected in the Atlantic Ocean at 38°N 34°W. It is deposited at the Zoologisk Museum, University of Copenhagen.[3]

The genera Alloposina Grimpe, 1922, Alloposus Verrill, 1880 and Heptapus Joubin, 1929 are junior synonyms of Haliphron.

See also


  1. ^ O'Shea, S. 2004. The giant octopus Haliphron atlanticus (Mollusca : Octopoda) in New Zealand waters. New Zealand Journal of Zoology 31(1): 7-13.
  2. ^ O'Shea, S. 2002. Haliphron atlanticus — a giant gelatinous octopus. Biodiversity Update 5: 1.
  3. ^ Current Classification of Recent Cephalopoda

Further reading

  • Bakken, T. & T. Holthe 2002. Haliphron atlanticum (Cephalopoda, Alloposidae) caught in Skorafjorden (64°N), Norway. Fauna norv. 22: 37-38.
  • Willassen, E. 1986. Haliphron atlanticus Steenstrup (Cephalopoda: Octopoda) from the coast of Norway. Sarsia 71: 35-40.

External links