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Friday, May 1, 2009

Species: Haliphron Atlanticus

This is an octopus that defies the way of the 'pus. "How?" you might wonder. By only having seven arms! That's right: Haliphron Atlanticus is a seven-armed octopus.

The Seven-arm Octopus (Haliphron Atlanticus) is the largest known species of octopus based on scientific records, with a total estimated length of 4m and weight of 75 kg. However, there have been disputed claims of even larger octopuses of the species Enteroctopus Dofleini (Giant Pacific Octopus).

Appearance and Anatonmy of Haliphron Atlanticus:

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, it is easily overlooked, giving the appearance of just seven arms.

Its suckers are mostly in two series but grade to single series near mouth. This species has extensive webbing between arms as pictured below.

Habitat of Haliphron Atlanticus:

This species is widely distributed from tropical to high latitudes and occupies meso- to bathypelagic depths. It is commonly associated with slopes of land masses. The habitat of this octopos is unusual. It has been captured in bottom trawls and videotaped swimming within centimeters of the ocean floor (brooding female) suggesting a benthopelagic habitat along the slope. However, it has also been taken from the open ocean thousands of meters from the ocean floor and hundreds of miles from the nearest slope. H. atlanticus is a common food item of blue sharks off New England, USA, and sperm whales near the Azores Isl.

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 0.69m, total length of 2.90m, and weight of 61.0kg, although it was incomplete.

There is still much to be learned about this mysterious species, and so the celebration of everything octopus continues!

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