PORT PHILLIP BAY


Southern Blue-ringed Octopus 

Hapalochlaena maculosa (Hoyle, 1883)

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, biserial in arrangement, without horny, toothed rims. Fins absent. Dorsal border of mantle fused with head. Small muscular species. Arms short, to three times mantle length. Lateral and ventral arms longest (typically 4=3=2>1). Webs of moderate depth, deepest around 20-30% of arm length. Web deepest on lateral arms, shallowest between dorsal arms. Web margins extending to arm tips. Suckers biserial; enlarged suckers absent. Gills with six to seven lamellae per demibranch. Funnel organ W-shaped, outer limbs approximately 75% length of medial limbs. Funnel locking apparatus absent. Ink sac present in juveniles, reduced or absent in sub-adults and adults. Right third arm of males hectocotylized, 75-85% length of opposite arm. Ligula of moderate size, 7-13% of arm length. Calamus large, 33-62% of ligula length. Hectocotylized arm with 45-56 suckers. Eggs large, around 7-9 mm.
Colour, of dorsal and lateral surfaces, grey-green to cream with approximately 50-60 small dark spots containing small iridescent blue rings (0.5-2.0 mm in diameter). Skin has wrinkled texture containing small closely-set low papillae. Skin ridge around lateral margin of mantle absent.
Mantle length to 57 mm, total length to around 220 mm.

Taxonomy

Phylum:
Mollusca
Class:
Cephalopoda
Subclass:
Coleoidea
Order:
Octopoda
Suborder:
Incirrata
Family:
Octopodidae
Genus:
Hapalochlaena
Species:
maculosa

Other Names

  • Blue-ring Octopus
  • Lesser Blue-ringed Octopus

General Description

Small muscular, short-armed octopus. Repeated colour pattern of brilliant iridescent blue rings over the body, head, arms and webs. Body oval in shape often with an extended pointed tip at the rear. Capable of excellent camouflage, hiding the blue markings and pushing up small bumps and spikes on the head and mantle. Mantle length to 6 cm, total length to around 22 cm.

Biology

This small octopus forages mainly at night feeding largely on crustaceans, particularly crabs. As in all blue-ringed octopuses, this species has large salivary glands that produce very strong toxins. The toxins are used to quickly paralyse their prey but also act as a good defence against attackers. The brilliant blue displays warn potential predators to keep away. This species of blue-ringed octopus has lost the ability to produce ink. It is possible that the strong toxins are enough to protect this octopus. Other members of the group can still produce ink. Mating occurs by males approaching females and climbing on to their bodies. The male inserts his third right arm into the female's gill cavity and passes sperm packets into her oviducts. The female lays large eggs in strings and carries them with her in her webs. The large young hatch with full colour patterns and immediately settle to the seafloor.

Habitat

Rocky reefs, rubble areas and seagrass meadows, from the intertidal to a depth of at least 50 m.

Seagrass meadows

Reefs

Distribution guide

Southern Australia.

Species Group

Octopuses and allies › Octopuses

Depth

Shore (0-1 m)
Shallow (1-30 m)
Deep ( > 30 m)

Water Column

On or near sea floor

Max Size

22 cm

Diet

Carnivore

Harmful

Direct threat to humans. Saliva contains the potentially lethal neurotoxin tetrodotoxin.

Commercial Species

No

Global Dispersal

Native to Australia

Species Code

MoV 4191

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 Blue-ringed Octopus, Hapalochlaena maculosa, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 26 Apr 2024, http://136.154.202.208:8098/species/7833

Text: creative commons cc by licence