Open ocean of tropical and subtropical waters worldwide (WA, NT, QLD, NSW).Features:
A soft jelly-like octopus that reaches a total length of around 45 cm. It lacks fins, has an elongate body and has arms longer than the body. The entire animal is transparent so that the mouth and the lobes of the brain are visible through the head. The eyes are nearly rectangular with spherical lenses set on the sides. This octopus can be distinguished from the related Telescope Octopus by the normal eyes and a single wide opening to the gill cavity. The arms have deep webs and a single row of suckers. The suckers get much larger towards the end of the arms, starting from the limit of the webs. There is no shell. Orange pigment cells (chromatophores) are scattered in the skin but can be retracted to tiny points. The skin is smooth.Ecology/Way of Life:
This jelly-like octopus lives midwater in open ocean from the surface to over 2000 m deep. Very little is known of its biology and behaviour. The transparent form is clearly an adaptation to avoid being seen by predators from below. Like the Telescope Octopus, the only large body structure that is not transparent is the liver, which is always held vertical in the live animal to minimise its silhouette. Nothing is known of the prey or feeding habits of this octopus. It is unlikely to ever touch the seafloor and it is not known how the animal remains buoyant.
Adult males have a modified third left arm tip consisting of a swollen base and a narrow finger-like projection. This special arm is likely to be used to pass sperm packets to the female. These octopuses seem to mate by the male enclosing the female within his web. Females are thought to brood their young within their arms and webs until hatching.
There is only a single species in this family.Interaction with Humans/Threats:
This octopus is very rarely encountered and as such has little interaction with humans.Further Reading:
Norman, M.D. and A. Reid. 2000. A guide to the squid, cuttlefishes and octopuses of Australasia. Gould League/CSIRO Publishing, Melbourne. 96 pp.
Norman, M.D. 2000. Cephalopods: A world guide. ConchBooks, Hackenheim, Germany.
Text & map by Mark Norman; photographs by Dick Young.Sponsorship welcomed:
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