PORT PHILLIP BAY


Southern Sand Octopus 

Octopus kaurna Stranks, 1990

View scientific description and taxonomy

Scientific Details

Eight circumoral appendages; eight arms, ventrolateral tentacles absent. Mantle cavity with one opening to exterior. Arms with numerous suckers, without horny, toothed rims. Fins absent. Dorsal border of mantle fused with head. Moderate sized species. Arms long and fine, to seven times mantle length. Dorsal arms longest (1>2>3>4). Webs shallow, deepest around 10-20% of arm length. Web deepest on dorsal arms, shallowest between ventral arms. Suckers biserial; enlarged suckers absent. Gills with nine to 11 lamellae per demibranch. Funnel organ VV-shaped, outer limbs around 75% length of medial limbs. Funnel locking apparatus absent. Right third arm of males hectocotylized, length 55-70% of opposite arm. Ligula small and narrow, 5-8% of arm length. Calamus of moderate length, 33-48% of ligula length. Hectocotylized arm with 66-129 suckers. Eggs large, around nine to 11 mm.
Colour uniform orange-cream to maroon red. Sometimes forage while exhibiting an elongate form with pink base colour and a dark maroon stripe on each side of the body from the mantle to the arm tips, running through the eye. Skin texture generally smooth or covered with numerous tiny bumps. Larger scattered low papillae present on lateral faces of mantle. Supra-ocular papillae absent. Skin ridge around lateral margin of mantle absent.
Maximum mantle length to 85 mm, total length to around 420 mm.

Taxonomy

Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Coleoidea
Order:
Octopoda
Suborder:
Incirrata
Family:
Octopodidae
Genus:
Octopus
Species:
kaurna

General Description

Moderate-sized, elongate octopus. Body may be stretched into a long thin cylinder in some postures. Arms long and narrow reaching fine points. Colour generally pale orange to maroon red. Foraging animals may display a pale base colour with long dark red stripe down each side of the body extending along the side arms. Maximum mantle length to 9 cm, total length to around 42 cm.

Biology

This octopus emerges at night to forage over the sand for small crustaceans by probing its thin arms down burrows and holes. During the day it buries deep in the sand, forming a burrow with a chimney to the surface. It uses mucous and the arm tips to hold back the sand grains to form the chimney. It draws water in from the sand surface by pumping water in and out of its gill cavity, creating the necessary current. If a predator detects the octopus and attacks the sand, the octopus can crawl out of reach of the attacker through the sand. This octopus can bury very quickly by producing its own quicksand. It pumps fast jets of water into the sand making the sand bubble and loosen. It then dives in before the sand resettles. It is possible that females release a sexually attractive chemical as groups of males have been observed swarming over single females. Females lay large eggs that are attached singly to hard surfaces such as shells. The large young hatch and immediately head into the sand. This octopus is locally abundant and is sometimes collected by recreational fishers as bait.

Habitat

Sand substrates in coastal waters to depths of around 50 m.

Soft substrates

Distribution guide

Southern Australia.

Species Group

Octopuses and allies Octopuses

Depth

Shallow (1-30 m)
Deep ( > 30 m)

Water Column

On or near sea floor

Max Size

42 cm

Diet

Carnivore

Harmful

Potential to bite, especially if handled. Venom status unknown.

Commercial Species

No

Global Dispersal

Native to Australia

Identify

Conservation Status

  • DSE Advisory List : Not listed
  • EPBC Act 1999 : Not listed
  • IUCN Red List : Not listed

Author

article author Finn, J.K.

Dr. Julian Finn is a Senior Curator of marine invertebrates at Museum Victoria.

Author

article author Norman, M.

Dr. Mark Norman is Head of Sciences at Museum Victoria.

citation

Cite this page as:
Finn, J.K. & Norman, M., 2011, Southern Sand Octopus, Octopus kaurna, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 23 Jul 2017, http://portphillipmarinelife.net.au:8098/species/4007

Text: creative commons cc by licence