Superregnum: Eukaryota
Cladus: Unikonta
Cladus: Opisthokonta
Cladus: Holozoa
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Cladus: Protostomia
Cladus: Spiralia
Cladus: Lophotrochozoa
Phylum: Mollusca
Classis: Cephalopoda
Subclassis: Coleoidea
Cohors: Neocoleoidea
SuperOrdo: Octopodiformes
Ordo: Octopoda
SubOrdo: Cirrina
Familia: Opisthoteuthidae
Genera: Cirroctopus - Opisthoteuthis
Name
Opisthoteuthidae Verrill, 1896
References
Verrill, A.E. 1896: The Opisthoteuthidae. A remarkable new family of deep sea Cephalopoda, with remarks on some points in molluscan morphology. American Journal of Science (series 4) 2 (11):74-80
Umbrella octopuses (family Opisthoteuthidae) are a group of pelagic octopuses. Umbrella octopuses are characterized by a web of skin between the arms, causing them to somewhat resemble an opened umbrella when the arms are spread.
Description
Opisthoteuthidae are a group of octopuses characterized by a web of skin in between their arms. They broad U-shaped shell that support muscles for a pair of small fins on the mantle, these fins are far less developed than other families in Cirrina and essentially only act as stabilizers when the animal swims (using a medusoid motion of the arms and webbing).[1] This structure makes the umbrella octopus resemble an umbrella when they spread their arms/web out. The structure of the umbrella octopus has the oral surface below the mantle of the octopuses and the web with their arms surround the bottom of the mantle.[2] Their outer skin has a very delicate consistency that results in white spots appearing on their skin when damaged.[2] Although Opisthoteuthidae are categorized as cirrates, unlike the other cirrates, they do not have an intermediate web; rather, they use the web in between their arms to mimic the intermediate web that other cirrates have.[2] Lacking an intermediate web is what causes the indentations in the outer edge of their arms that make them look like an umbrella.
Behavior
Defense mechanisms
Opisthoteuthidae lack an intermediate web but they mimic the defensive mechanism of ballooning by extending the web between their arms as much as possible and curving the outer edges of their arms inwards in order to have the edges touch the ground. They also extend their fins parallel to the floor to help keep their balance or they curve them around their mantle. Opisthoteuthidae have been observed to hold this position for five and a half minutes. Another defensive mechanism that Opisthoteuthidae have been observed using is web-inversion which is when they have their arms turned upwards and their web with the oral surface facing outwards. The oral surface can be facing the floor, or the octopuses may lie laterally so their side is in contact with the floor. It has been noted that these defensive behaviors are the positions the octopuses may go into while feeding as well, but it is possible that this could be because of the stress of being captured and placed in an aquarium to be observed.[2]
Resting behavior[2]
When resting at the floor, the octopus's behavior falls into one of two tactics: bottom-resting or flat-spreading. Bottom-resting is when the octopus is resting near the floor. It will erect its mantle, curve the outer edges of its arms inwards to have them be the only part making contact with the floor. The fins are extended out parallel to the bottom to maintain balance. When flat-spreading they spread their arms and web, so it is parallel to the bottom and they keep the edges of their arms curved inwards. Their heads will point backwards at a small angle and their fins will be used for stabilization.
Dispersion
Opisthoteuthidae are deep sea creatures that have been found in the Clipperton-Clarion Fracture Zone in the Pacific Ocean at a depth of about 4,800 m.[3] They have also been found in the South China Sea.[4] They stay within 3,000-4,000 meters below sea level and try to stay hovering over the ocean floor.
Taxonomy
Family Opisthoteuthidae has classically contained a single genus, Opisthoteuthis, which has recently been split into three genera on the basis of differences in enlarged suckers on male specimens.[5][6] Genera Grimpoteuthis, Luteuthis, and Cryptoteuthis now are included in the family Grimpoteuthidae.
Genus Opisthoteuthis Verrill, 1883[4][7]
Opisthoteuthis agassizii Verrill, 1883
Opisthoteuthis albatrossi (Sasaki, 1920)
Opisthoteuthis borealis Collins, 2005
Opisthoteuthis bruuni (Voss, 1982)
Opisthoteuthis californiana Berry, 1949
Opisthoteuthis calypso Villanueva, Collins, Sánchez & Voss, 2002 [Possibly attributable to genus Insigniteuthis[6]]
Opisthoteuthis chathamensis O'Shea, 1999
Opisthoteuthis dongshaensis C. C. Lu, 2010 [Possibly attributable to genus Insigniteuthis[6]]
Opisthoteuthis extensa Thiele, 1915
Opisthoteuthis grimaldii (Joubin, 1903)
Opisthoteuthis hardyi Villanueva, Collins, Sánchez & Voss, 2002
Opisthoteuthis kerberos Verhoeff, 2024
Opisthoteuthis massyae (Grimpe, 1920) (Synonym Opisthoteuthis vossi Sánchez & Guerra, 1989 )
Opisthoteuthis medusoides Thiele, 1915
Opisthoteuthis mero O'Shea, 1999
Opisthoteuthis philipii Oommen, 1976
Opisthoteuthis pluto Berry, 1918
Opisthoteuthis robsoni O'Shea, 1999
Genus Exsuperoteuthis Verhoeff, 2024[8]
Exsuperoteuthis depressa Ijima & Ikeda, 1895 (Synonym Opisthoteuthis japonica Taki, 1962)
Exsuperoteuthis persephone Berry, 1918
Genus Insigniteuthis Verhoeff, 2024[9]
Insigniteuthis obscura Verhoeff, 2024
References
Gibson, R; Atkinson, R; Gordon, J, eds. (2006-06-13). Oceanography and Marine Biology: An Annual Review, Volume 44. Oceanography and Marine Biology - An Annual Review. CRC Press. doi:10.1201/9781420006391. ISBN 978-0-8493-7044-1.
Villanueva, Roger (June 2000). "Observations on the behaviour of the cirrate octopod Opisthoteuthis grimaldii (Cephalopoda)". Journal of the Marine Biological Association of the United Kingdom. 80 (3): 555–556. doi:10.1017/S0025315400002307. ISSN 1469-7769. S2CID 85020724.
Vecchione, Michael (2017). "Notes on cephalopods photographed near the bottom in the Clipperton-Clarion Fracture Zone". Marine Biodiversity. 47 (2): 307–310. doi:10.1007/s12526-016-0528-8. S2CID 255576651.
Lu, Chung-Cheng. "A new species of Opisthoteuthis, O. dongshaensis sp. nov., from the South China Sea (Octopoda: Cirrata: Opisthoteuthidae)." Zoological Studies 49.3 (2010): 405 420.
"WoRMS - World Register of Marine Species - Opisthoteuthidae A. E. Verrill, 1896". www.marinespecies.org. Retrieved 2023-09-20.
Verhoeff, Tristan J (2024). "Flapjack octopods of Australia (Cephalopoda: Cirrata: Opisthoteuthidae), Part I Southern Australia". Australian Journal of Taxonomy. 68: 1–44. doi:10.54102/ajt.wij3l.
"WoRMS - World Register of Marine Species - Opisthoteuthis A. E. Verrill, 1883". www.marinespecies.org. Retrieved 2024-08-18.
"WoRMS - World Register of Marine Species - Exsuperoteuthis Verhoeff, 2024". www.marinespecies.org. Retrieved 2024-08-18.
"WoRMS - World Register of Marine Species - Insigniteuthis Verhoeff, 2024". www.marinespecies.org. Retrieved 2024-08-18.
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