Amphioctopus marginatus

Last updated

Amphioctopus marginatus
Coconut Octopus (Amphioctopus marginatus) (6079648725).jpg
Scientific classification OOjs UI icon edit-ltr.svg
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order: Octopoda
Family: Octopodidae
Genus: Amphioctopus
Species:
A. marginatus
Binomial name
Amphioctopus marginatus
(Taki, 1964)
Synonyms
  • Octopus marginatus
    Taki, 1964
  • Octopus striolatus
    Dong, 1976

Amphioctopus marginatus, also known as the coconut octopus and veined octopus, is a medium-sized cephalopod found in the tropical waters of the western Pacific Ocean. It prefers sandy substrates with plentiful shells or litter. It commonly preys upon shrimp, crabs, and clams, and displays unusual behavior for octopuses, being one of only two species known to exhibit bipedal walking. The coconut octopus is also known for collecting and using tools; it gathers coconut shells and seashells and uses these for shelter.

Contents

Taxonomy

Amphioctopus marginatus is a species of octopus located in the family Octopodidae and genus Amphioctopus. The species was first described in 1964 by Japanese malacologist Iwao Taki as Octopus marginatus, and synonymously as Amphioctopus marginatus. Taki chose the Latin name marginatus (literally margined, from marginum) [2] due to the pale border around the eyes. [3] In 1976, Dong Zhengzhi named the species Octopus striolatus, but this name was not recognized as taxonomically valid. [1] [4]

Characteristics

The main body of the octopus is typically between 5 centimeters (2 in) and 10 centimeters (4 in) long; including the arms, it can measure up to approximately 30 centimeters (12 in) in length. The octopus can weigh up to 400 grams (14 oz). [5] [6] The octopus displays a typical color pattern with dark branching lines similar to veins. The arms are usually dark in color, with contrasting light suckers. In many color displays, a lighter triangular area can be seen immediately below the eye. [6] In 2017, the complete mitochondrial genome of A. marginatus was successfully sequenced, showing the species to be closely related to Amphioctopus aegina . [7]

Behavior and habits

The species preys predominately on crustaceans such as Calappa crabs, along with bivalves. Eggs are laid in clutches of 100,000 and are 3 millimetres (0.12 in) in length; [1] they are laid as long chains woven together. [8] The female octopus lays eggs within a shelter such as a coconut shell [8] where she will guard and tend to her eggs; like most octopuses, [9] the female coconut octopus will starve to death whilst brooding. Eggs take between 15 and 17 days to hatch and the paralarvae are planktonic. [8]

Locomotion

In March 2005, researchers at the University of California, Berkeley, published an article in Science in which A. marginatus was reported to show bipedal locomotion, or "stilt-walking". [10] This involves rolling two arms to walk while the other six arms are used to disguise itself; the researchers speculated that the disguise might be meant to mimic the appearance of a rolling coconut. [11] According to one of the researchers, Dr Crissy Huffard, octopuses are the only animals without a rigid endo- or exoskeleton who can walk bipedally. [12] This behavior was first observed off the coast of Sulawesi, Indonesia, where coconut shell litter is common. A. marginatus is one of only two octopus species known to display such behavior, the other species being Abdopus aculeatus . [13] [11] In addition to "stilt-walking", A. marginatus also exhibits crawling behaviour typically seen in octopuses. [14]

Tool use

Small (4-5 cm diameter) individual using a nutshell and clamshell as shelter Octopus shell.jpg
Small (4–5 cm diameter) individual using a nutshell and clamshell as shelter

In 2009, researchers from the Melbourne Museum in Australia observed the coconut octopus using tools for concealment and defense by gathering available debris to create a shelter. The researchers filmed the octopus collecting coconut half-shells from the sea floor that had been discarded by humans. They were then carried up to 20 meters (66 ft) and arranged around the body of the octopus to form a spherical hiding place similar to a clamshell. [10] [15] This behavior was observed in specimen in Bali and North Sulawesi, Indonesia, and is likely the first evidence of tool use in invertebrates. Other species of octopus had been observed using shells for hiding, but this was the first case in which shells were prepared and collected for later use, in what the Melbourne Museum has described as "true tool use". [16] [17] Octopuses will often engage in bipedal motion when carrying stacks of debris or items larger than themselves. [10] The coconut octopus has been observed using a variety of materials for shelter, including coconut shells, clamshells, and man-made litter such as bottles. [6]

Distribution and habitat

The coconut octopus is broadly endemic to neritic, tropical waters in the Indian Ocean, Red Sea, Northwest and Western Pacific Ocean, and Southeast Asian Sea. Amphioctopus marginatus is listed as Least Concern on the IUCN's Red List. The primary threat faced by the species is fishing. [1]

The species prefers shallow, subtidal waters along the continental shelf. The species has a maximum depth of 190 metres (620 ft), and can often be found in mud and sand substrates. [1] Large numbers of coconut octopuses can often be found in sandy areas with a higher amount of litter that can be used for shelter. [18]

References

  1. 1 2 3 4 5 Allcock, L.; Taite, M.; Allen, G. (2018). "Amphioctopus marginatus". IUCN Red List of Threatened Species . 2018: e.T163176A980445. doi: 10.2305/IUCN.UK.2018-2.RLTS.T163176A980445.en . Retrieved 7 March 2023.
  2. ↑ Oxford Latin Dictionary. London: Oxford University Press. 1968. p. 1079.
  3. ↑ Taki, Iwao (1964). "On eleven new species of the cephalopoda from Japan, including two new genera of octopodinae". Bulletin of the Faculty of Fisheries and Livestock Sciences, Hiroshima University. 5 (2): 277–343. doi:10.15027/40363 . Retrieved 8 July 2025.
  4. ↑ "WoRMS – World Register of Marine Species – Amphioctopus marginatus (Taki, 1964)". www.marinespecies.org. Retrieved 28 December 2023.
  5. ↑ Kaneko, Natsumi; Kubodera, T; Dinh, T; Chung, BD (2008). "Shallow-water Benthic Octopuses (Cephalopoda, Octopodidae) Collected from the Coastal Waters of Vietnam" (PDF). Bulletin of the National Museum of Natural Sciences. A (34): 105–122. Retrieved 24 June 2025.
  6. 1 2 3 Norman, Mark D.; Finn, Julian K.; Hochberg, Frederick G. (2016). "Family Octopodidae". In Jereb, Patrizia; Roper, Clyde F.E.; Norman, Mark D.; Finn, Julian K. (eds.). Cephalopods of the World: An Annotated and Illustrated Catalogue of Cephalopod Species Known to Date Volume 3. Octopods and Vampire Squids. FAO Species Catalogue for Fishery Purposes No. 4. Vol. 3 (Revised ed.). Rome: Food and Agriculture Organization of the United Nations. pp. 16, 75–76. ISBN   978-92-5-107989-8. ISSN   1020-8682. OCLC   71193186 – via Food and Agriculture Organization Knowledge Repository.
  7. ↑ Tang, Yan; Zheng, Xiaodong; Ma, Yuanyuan; Cheng, Rubin; Li, Qi (March 2018). "The complete mitochondrial genome of Amphioctopus marginatus (Cephalopoda: Octopodidae) and the exploration for the optimal DNA barcoding in Octopodidae". Conservation Genetics Resources. 10 (1): 115–118. Bibcode:2018ConGR..10..115T. doi:10.1007/s12686-017-0777-2.
  8. 1 2 3 Sreeja, V; Anushma, K; Biju Kumar, A (2013). "Embryonic Development of Amphioctopus marginatus (Taki) (Mollusca: Octopodidae) in Captivity" (PDF). Journal of Aquatic Biology & Fisheries. 1 (1&2): 184–189. Retrieved 21 July 2025.
  9. ↑ Wang, Z Yan; Pergrande, Melissa; Ragsdale, Clifton; Cologna, Stephanie (2022). "Steroid hormones of the octopus self-destruct system". Current Biology. 32 (11): 2572–2579. Bibcode:2022CBio...32E2572W. doi:10.1016/j.cub.2022.04.043. PMID   35561680 . Retrieved 21 July 2025.
  10. 1 2 3 Gelineau, Kristen (15 December 2009). "Aussie scientists find coconut-carrying octopus". The Associated Press. Archived from the original on 18 December 2009. Retrieved 15 December 2009.
  11. 1 2 Christine L. Huffard, Farnis Boneka, Robert J. Full: Underwater Bipedal Locomotion by Octopuses in Disguise Archived 4 March 2009 at the Wayback Machine , Science , 25 March 2005.
  12. ↑ Montgomery, Sy (2024). Secrets of the Octopus. Washington DC: National Geographic. pp. 65–71. ISBN   9781426224232.
  13. ↑ Sanders, Robert: Octopuses occasionally stroll around on two arms, UC Berkeley biologists report Archived 5 June 2011 at the Wayback Machine , University of California, Berkeley, 24 March 2005.
  14. ↑ Sreeja, V.; Bijukumar, A. (26 June 2013). "Ethological studies of the Veined Octopus Amphioctopus marginatus (Taki) (Cephalopoda: Octopodidae) in captivity, Kerala, India". Journal of Threatened Taxa. 5 (10): 4492–4497. doi:10.11609/JoTT.o3256.4492-7.
  15. ↑ Henderson, Mark (15 December 2009). "Indonesia's veined octopus 'stilt walks' to collect coconut shells". Times Online. Archived from the original on 15 August 2011.
  16. ↑ Finn, Julian K.; Tregenza, Tom; Norman, Mark D. (2009), "Defensive tool use in a coconut-carrying octopus", Curr. Biol., 19 (23): R1069 –R1070, Bibcode:2009CBio...19R1069F, doi: 10.1016/j.cub.2009.10.052 , PMID   20064403, S2CID   26835945 .
  17. ↑ Harmon, Katherine (14 December 2009). "A tool-wielding octopus? This invertebrate builds armor from coconut halves". Scientific American. Archived from the original on 17 December 2009. Retrieved 15 December 2009.
  18. ↑ Shepherd, Bart; Ross, Richard; Avila, Marisa (15 April 2014). "Collection, Transport and Husbandry of the Coconut Octopus, Amphioctopus marginatus (Taki, 1964) from the Philippines". The Coral Triangle : the 2011 Hearst Philippine Biodiversity Expedition. San Francisco: California Academy of Sciences. pp. 237–249. ISBN   9780940228757.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.