Reef Cephalopods Codexery

Blue-ringed octopus

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Blue-ringed octopus

David Breneman at English Wikipedia · via Wikipedia: Blue-ringed octopus · CC BY-SA 3.0

Blue-ringed octopuses are a genus of four highly venomous species found in tide pools and coral reefs from Japan to Australia.[1] The blue-ringed octopus is one of the most venomous marine animals, with a single individual carrying sufficient tetrodotoxin to kill more than 20 adult humans.[2][3] No antivenom exists for their bite, and the venom can cause respiratory paralysis; death can occur within minutes of exposure.[2][4]

Scientific classification

  1. OrderOctopoda
  2. FamilyOctopodidae
  3. GenusHapalochlaena

Named by Robson, 1929

Sources: Wikipedia taxobox: Blue-ringed octopus (CC BY-SA 4.0)

Quick Facts

Type species
Hapalochlaena lunulata

Facts from the source article.

Key facts and history

Four species are confirmed: greater blue-ringed octopus, southern blue-ringed octopus, blue-lined octopus, and Hapalochlaena nierstraszi.[5][6] Hapalochlaena nierstraszi was first documented from a single specimen in 1938, with a second specimen caught in 2013.[5][6] When threatened, the octopus flashes 50–60 bright iridescent blue rings within a third of a second as a warning display.[7] The blue rings are produced by multilayer iridophores that reflect blue-green light, controlled by muscles under neural control.[7]

The octopus hunts fish and crustaceans, using its beak to pierce prey and inject venom that paralyzes muscles.[8] Males mate by inserting a hectocotylus into the female's mantle cavity, and females sometimes forcibly remove over-enthusiastic males.[9] The Divers Alert Network notes that blue-ringed octopuses are not aggressive and will flee if threatened.[10][11] First aid involves pressure on the wound and artificial respiration, as victims often recover if ventilated before cyanosis develops.[12]

Tetrodotoxin, which blocks sodium channels, is the main neurotoxin in the venom; it is produced by endosymbiotic bacteria located in the octopus's posterior salivary gland.[13][4]

What the cited sources add

The Divers Alert Network states that blue-ringed octopuses have up to 24 eyes, some with corneas and retinas, enabling object avoidance.[10] A 2013 CBS News report notes that the octopus is called "hyomondako" (leopard-print octopus) in Japan and has become a popular aquarium attraction.[14] A single milligram of venom can cause respiratory failure within minutes.[14] An Ocean Conservancy article explains that the octopus uses venom primarily when hunting, pecking through prey's exoskeleton with its beak.[15]

A Fishing Chimes article records that Hapalochlaena nierstraszi specimens measured 82–165 mm and weighed 5.5–18 g.[6] At least ten species of tiny blue-ringed octopus exist, but only four have been formally named.[6]

References

  1. Wikipedia, "Blue-ringed octopus" (CC BY-SA 4.0), which cites: Craft, Lucy, "Tiny but deadly: Spike in blue-ringed octopus sightings sparks fear of invasion in Japan", CBS News, 2013-07-01 (we also read that source) en.wikipedia.org
  2. Wikipedia, "Blue-ringed octopus" (CC BY-SA 4.0), which cites: "Dangers on the Barrier Reef"; "CSL Antivenom Handbook – Jellyfish and other Marine Animals", Clinical Toxinology Resources (original not read by us) en.wikipedia.org
  3. Wikipedia, "Blue-ringed octopus" (CC BY-SA 4.0), which cites: "Ocean's Deadliest: The Deadliest Creatures – Greater Blue-Ringed Octopus", Animal Planet (original not read by us) en.wikipedia.org
  4. Wikipedia, "Blue-ringed octopus" (CC BY-SA 4.0), which cites: "Maculotoxin: a neurotoxin from the venom glands of the octopus Hapalochlaena maculosa identified as tetrodotoxin", Science, 1978, p. 188–9; "1st Occurrence of Tetrodotoxin in a Dendrobatid Frog (Colostethus inguinalis), with Further Reports for the Bufonid Genus Atelopus", Toxicon, 1994, p. 279–285 (original not read by us) en.wikipedia.org
  5. Wikipedia, "Blue-ringed octopus" (CC BY-SA 4.0), which cites: Robson, "LXXIII.— Notes on the Cephalopoda .—VIII. The genera and subgenera of Octopodinæ and Bathypolypodinæ", Annals and Magazine of Natural History, June 1929, p. 607–608; Sethi, "Blue ring Octopus, Hapalochlaena nierstraszi, from the Bay of Bengal along the Chennai Coast", Fishing Chimes, 2013, p. 82–83; Sethi, "Blue ring Octopus, Hapalochlaena nierstraszi, from the Bay of Bengal along the Chennai Coast", Fishing Chimes, 2013, p. 82–83; Allcock, "Hapalochlaena nierstraszi", 2018 (we also read that source) en.wikipedia.org
  6. Sethi, "Blue ring Octopus, Hapalochlaena nierstraszi, from the Bay of Bengal along the Chennai Coast", Fishing Chimes, 2013, p. 82–83. facts only, no text reused. eprints.cmfri.org.in
  7. Wikipedia, "Blue-ringed octopus" (CC BY-SA 4.0), which cites: Mäthger, L.M., "How does the blue-ringed octopus (Hapalochlaena lunulata) flash its blue rings?", The Journal of Experimental Biology, 2012, p. 3752–3757 (original not read by us) en.wikipedia.org
  8. Wikipedia, "Blue-ringed octopus" (CC BY-SA 4.0), which cites: Newman, "Blue-Ringed Octopus Facts, Habitat, Life Cycle, Venom, Pictures", Animal Spot, 2015-05-05 (we also read that source) en.wikipedia.org
  9. Wikipedia, "Blue-ringed octopus" (CC BY-SA 4.0), which cites: Cheng, "Sex identification and mating in the blue-ringed octopus, Hapalochlaena lunulata", Anim Behav, 2000, p. 27–33 (original not read by us) en.wikipedia.org
  10. "Blue-Ringed Octopus", Divers Alert Network. facts only, no text reused. diversalertnetwork.org
  11. Wikipedia, "Blue-ringed octopus" (CC BY-SA 4.0), which cites: "Blue-Ringed Octopus", Divers Alert Network (we also read that source) en.wikipedia.org
  12. Wikipedia, "Blue-ringed octopus" (CC BY-SA 4.0), which cites: "Blue-Ringed Octopus Bite", www.dovemed.com; "Blue-Ringed Octopus", Divers Alert Network; "Blue-Ringed Octopus", Divers Alert Network; Lippmann, John and Bugg, Stan (2004) DAN S.E. Asia-Pacific Diving First Aid Manual, J.L. Publications, Australia. (we also read that source) en.wikipedia.org
  13. Wikipedia, "Blue-ringed octopus" (CC BY-SA 4.0), which cites: Allan, "Blue ringed octopus", Australian Institute of Marine Science; Laidlaw, "Blue Ringed Octopus - Facts and Beyond", Biology Dictionary, 2 October 2020; Caldwell, Roy, "What makes blue-rings so deadly?" (original not read by us) en.wikipedia.org
  14. Craft, Lucy, "Tiny but deadly: Spike in blue-ringed octopus sightings sparks fear of invasion in Japan", CBS News, 2013-07-01. facts only, no text reused. cbsnews.com
  15. Spencer, "The Blue-Ringed Octopus: Small but Deadly", Ocean Conservancy, 13 March 2017. facts only, no text reused. oceanconservancy.org

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Blue-ringed octopus (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

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Sources

Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

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