Amphioctopus marginatus
| Amphioctopus marginatus | |
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Scientific classification 
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| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Mollusca |
| Class: | Cephalopoda |
| Order: | Octopoda |
| Family: | Octopodidae |
| Genus: | Amphioctopus |
| Species: | A. marginatus
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| Binomial name | |
| Amphioctopus marginatus (Taki, 1964)
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| Synonyms | |
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Amphioctopus marginatus, also known as the coconut octopus and veined octopus, is a medium-sized cephalopod belonging to the genus Amphioctopus. It is found in tropical waters of the western Pacific Ocean. It commonly preys upon shrimp, crabs, and clams, and displays unusual behavior including bipedal walking as well as tool use through gathering coconut shells and seashells and using these for shelter.
Taxonomy
[edit]Amphioctopus marginatus is a species of octopus located in the family Octopodidae, 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 due to the pale border around the eyes.[2] In 1976, Z. Dong named the species Octopus striolatus but this name was not recognized as taxonomically valid.[1][3]
Size and description
[edit]The main body of the octopus is typically between 5 centimeters (2 in) to 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).[4][5] The octopus displays a typical color pattern with dark ramified lines similar to veins, usually with a yellow siphon. The arms are usually dark in color, with contrasting white suckers. In many color displays, a lighter trapezoidal area can be seen immediately below the eye.[4]
Behavior and habits
[edit]
The species preys predominately on Calappa crabs and bivalves. Eggs are laid in clutches of 100,000 and are 3 millimetres (0.12 in) in length.[1]
Locomotion
[edit]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".[6] This involves rolling two legs to walk while the other six legs are used to mimic the appearance of a floating coconut. According to one of the researchers, Dr Crissy Hufford, octopuses are the only animals without a rigid endo- or exoskeleton who can walk bipedally.[7] 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.[8][9]
Tool use
[edit]In 2009, researchers from the Melbourne Museum in Australia observed the coconut octopus uses 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 clam-shell.[6][10] 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".[11][6][12] Octopuses will often engage in bipedal motion when carrying stacks of debris or items larger than themselves.[6] The coconut octopus has been observed using a variety of materials for shelter, including coconut shells, clamshells, and man-made litter such as bottles.[5]
Distribution
[edit]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 ICUN's Red List. While the species may be threatened by fishing, its wide distribution is seen as enough to compensate against human impacts.[1]
Habitat
[edit]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.[13]
References
[edit]- ^ a b c d e 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.
- ^ 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.
- ^ "WoRMS – World Register of Marine Species – Amphioctopus marginatus (Taki, 1964)". www.marinespecies.org. Retrieved 28 December 2023.
- ^ a b 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.
- ^ a b 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.
- ^ a b c d 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.
- ^ Montgomery, Sy. Secrets of the Octopus (2024) National Geographic ISBN 1426223722
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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.
- ^ 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. ISBN 9780940228757.
External links
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- Photos of Amphioctopus marginatus on Sealife Collection