Grimpoteuthis
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Grimpoteuthis<ref name=Voss-Prcy-1990> Template:Cite journal </ref> is a genus of pelagic cirrate (finned) octopods known as the dumbo octopus.<ref name=MarineBio-558/> The name "dumbo" originates from their resemblance to the title character of Disney's 1941 film Dumbo, having two prominent ear-like fins which extend from the mantle above each eye. There are 17 species recognized in the genus. <ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The Dumbo octopus has a gelatinous body and uses fin propulsion for movement, which also helps it to conserve energy in its extreme deep-sea environment. These unique physical traits distinguish it from other octopuses, which primarily rely on jet propulsion.<ref name="Zglr-Sgrny-2021"/> Prey include crustaceans, bivalves, worms and copepods.<ref name="MarineBio-558">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> The average life span of various Grimpoteuthis species is 3 to 5 years.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref><ref>{{#invoke:citation/CS1|citation |CitationClass=web }}Template:Dead link</ref>
Range and habitatEdit
Species of Grimpoteuthis are assumed to have a worldwide distribution, living in the cold, abyssal depths ranging from Template:Convert. Specimens have been found off the coasts of Oregon, the Philippines, Martha's Vineyard, the Azores, New Zealand, Australia, California, Papua and New Guinea, and in the Gulf of Mexico.
{A fairly recent observation was on 21 June 2022 at Template:Convert by the vessel Normand Ocean, which inspects drilling platforms with underwater drones; the vessel was examining chains and risers on the Aasta Hansteen platform outside Trøndelag, Norway. Another recent observation Template:As of was on 24 May 2023 at Template:Gaps this time in Guyana by the vessel Far Samson, which also uses underwater drones.
Further to this, the most recent known recorded observation was on 5th March 2025 by the Vessel "Boka Falcon" with a Workclass Remotely Operated Vehicle working at a depth of 960m in the Gulf Of Guinea approximately 65km South West of Abidjan, Ivory Coast. Two separate sightings approximate 20 minutes apart were observed.
Dumbo octopuses are the deepest living octopuses known, with some specimens captured or observed at hadal depths. One Grimpoteuthis specimen was captured Template:Convert southeast of Grand Cayman at Template:Convert, but this depth is uncertain (as the specimen may have been captured while the net was descending to this depth).<ref>Template:Cite book</ref>
In 2020, Grimpoteuthis was spotted Template:Convert deep in the Java Trench, confirming the hadal distribution of this genus.<ref>Template:Cite journal</ref>
Species and taxonomyEdit
As noted below, many species collected on the Challenger expedition were initially classified in the genera Cirroteuthis and Stauroteuthis.<ref name=Hoyle-1886/><ref name=Hoyle-1904/> Several species formerly classified as Grimpoteuthis were later moved to genera Cirroctopus and Opisthoteuthis.<ref name=Collins-2003/> A new family, Grimpoteuthididae (alternatively spelled Grimpoteuthidae), has been proposed to accommodate Grimpoteuthis and those of genera Enigmatiteuthis, Cryptoteuthis, and Luteuthis.<ref name=OShea-1999/><ref name="Prtny-Hudlt-etal-2003">Template:Cite journal</ref><ref name=Collns-Vllnva-2006/> The persistent confusion and disparity about the taxonomy of these species has been attributed to the poor quality and limited number of specimens available for study.<ref name=Prtny-Hudlt-etal-2003/>
Species name Reference Geographic range Depth range
(meters)Taxonomic notes Grimpoteuthis abyssicola Template:Harvp<ref name="OShea-1999">Template:Cite report</ref><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref><ref name=Vrhf-OShea-2022/>
Tasman Sea (off New Zealand and southeastern Australia) Template:Gaps–Template:Gaps Known from two specimens.<ref name=Vrhf-OShea-2022/> Grimpoteuthis angularis Template:Harvp<ref name="Vrhf-OShea-2022">Template:Cite journal</ref> (off New Zealand) 628 m Known from a single specimen. Internal shell form distinct from others in genus.<ref name=Vrhf-OShea-2022/> Grimpoteuthis bathynectes Template:Harvp<ref name=Voss-Prcy-1990/><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
North Pacific (Tufts and Cascadia abyssal Plains, off Oregon) Template:Gaps Grimpoteuthis boylei Template:Harvp<ref name="Collins-2003">Template:Cite journal</ref><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
Northeast Atlantic (Porcupine and Madeira abyssal plains) Template:Gaps–Template:Gaps Grimpoteuthis challengeri Template:Harvp<ref name=Collins-2003/><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
Northeast Atlantic (Porcupine abyssal plain) Template:Gaps–Template:Gaps Grimpoteuthis discoveryi Template:Harvp<ref name=Collins-2003/><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
Northeast Atlantic Template:Gaps–Template:Gaps Grimpoteuthis feitiana Tang, Zheng & Zhang, 2025<ref>Template:Cite journal</ref> Caroline Seamount, western Pacific Ocean 1240 m Known from one specimen Grimpoteuthis greeni Template:Harvp<ref name=Vrhf-OShea-2022/> Southern Australia 480–Template:Gaps Known from three specimens.<ref name=Vrhf-OShea-2022/> Grimpoteuthis hippocrepium Template:Harvp<ref name="Hoyle-1904">Template:Cite journal</ref><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
East Pacific (off Malpelo Island) Template:Gaps Previously assigned to genus Stauroteuthis; known from a single, "sadly mutilated" individual according to Hoyle.<ref name=Hoyle-1904/> The internal shell form is similar to G. abyssicola.<ref name=Vrhf-OShea-2022/> Grimpoteuthis imperator Template:Harvp<ref name="Zglr-Sgrny-2021">Template:Cite journal</ref> Emperor Seamounts, North Pacific Template:Gaps–Template:Gaps Known from a single specimen.<ref name=Zglr-Sgrny-2021/> Grimpoteuthis innominata Template:Harvp<ref name=OShea-1999/><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
South Pacific (east of New Zealand) Template:Gaps Alternatively classified as Enigmatiteuthis<ref name=OShea-1999/> Grimpoteuthis meangensis Template:Harvp<ref name="Hoyle-1886">Template:Cite book</ref><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
West Pacific (off Meangis Islands, near Philippines) 925 m Previously assigned to genera Cirroteuthis<ref name=Hoyle-1886/> and Stauroteuthis<ref name=Hoyle-1904/> Grimpoteuthis megaptera Verrill (1885)<ref name=Hoyle-1886/><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
Northwest Atlantic (southeast of Martha's Vineyard) Template:Gaps Previously assigned to genus Cirroteuthis<ref name=Hoyle-1886/> Grimpoteuthis pacifica Template:Harvp<ref name=Hoyle-1886/><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
South Pacific (off Papua New Guinea) Template:Gaps Previously assigned to genus Cirroteuthis<ref name=Hoyle-1886/> Grimpoteuthis plena citation CitationClass=web }}</ref>
Northwest Atlantic Template:Gaps Previously assigned to genus Cirroteuthis<ref name=Hoyle-1886/> Grimpoteuthis tuftsi Template:Harvp<ref name=Voss-Prcy-1990/><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
North Pacific (Tufts and Cascadia abyssal plains off Oregon) Template:Gaps Grimpoteuthis umbellata Fischer (1883)<ref name=Hoyle-1886/><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
North Atlantic (off Morocco, Canary Islands, and the Azores) Template:Gaps Previously assigned to genus Cirroteuthis<ref name=Hoyle-1886/> Grimpoteuthis wuelkeri Template:Harvp<ref>Template:Cite journal</ref><ref>{{#invoke:citation/CS1|citation CitationClass=web }}</ref>
Northeast and northwest Atlantic Template:Gaps
Movement, characteristics, and food supplyEdit
Observations of animals in the Atlantic reveal that Grimpoteuthis often rest on the seafloor with the arms and web spread out and uses its arms to slowly crawl along the seafloor. When disturbed, the webbing and arms are contracted to propel the animal off the seafloor and using the mantle fins for rapid locomotion.<ref name="Villnva-Sgnzc-Guerra-1997">Template:Cite journal</ref>
The cushiony cartilage that can be found in the proximal position of the fin of Grimpoteuthis is responsible for acting as a support for the thick muscles that allow for rapid locomotion.
Although it has been suggested that species of Grimpoteuthis are capable of jet-propulsion (while swimming using the fins), this has since been deemed unlikely.<ref name=Villnva-Sgnzc-Guerra-1997/>
Feeding behavior has not been directly observed in Grimpoteuthis, but presumably is similar to Opisthoteuthis which can trap small prey items in the webbing (either by enclosing the prey in the arm webbing or between the webbing and the seafloor) and then use the cirri (fingerlike projections along the arms) to move food to the mouth. Known prey items (from dissected animals) include benthic polychaetes, benthopelagic copepods, amphipods and isopods.<ref name=Collns-Vllnva-2006/>
BreedingEdit
The cirrate octopuses are classified as 'continuous spawners': Females carry multiple eggs in various stages of maturation, and only lay one or two eggs at a time, with no seasonality in spawning (however, most of these aspects of reproductive biology have only been confirmed in Opisthoteuthis, not Grimpoteuthis). Mating in cirrate octopuses has never been observed, and unlike other octopuses, members of Cirrata lack a hectocotylus for the transfer of sperm packets.<ref name=Collns-Vllnva-2006/> Cirrate octopus eggs are large and have a tough casing surrounding the chorion (not found in other octopuses), and Grimpoteuthis in particular attach their eggs to deep sea corals (octocorals).<ref name="Zglr-Millr-Naglmn-2021">Template:Cite journal</ref>
Unlike other octopuses, the female cirrate octopus does not guard or incubate the eggs.<ref name="Collns-Vllnva-2006" /> Grimpoteuthis hatchlings emerge as "fully competent" juveniles with all of the sensory and motor features to survive on their own.<ref>Template:Cite journal</ref><ref name="Zglr-Millr-Naglmn-2021" />
Sexual dimorphism between males and females is less noticeable and consistent in Grimpoteuthis compared to other cirrate octopuses (such as Opisthoteuthis). In some species (e.g., G. bathynectes<ref name=Voss-Prcy-1990/> and G.. discoveryi),<ref name=Collins-2003/> the males have enlarged suckers relative to the females, but no such enlargement is found in other Grimpoteuthis species.<ref name=Collns-Vllnva-2006/>
ThreatsEdit
Species of Grimpoteuthis face few direct threats from humans largely due to living at depths of Template:Convert and below. Natural predators of cirrate octopuses include large teleost fish and sharks, and even marine mammals such as sperm whales and seals, but these are mostly predators of other cirrate genera. Grimpoteuthis has only been recorded in the stomach contents of a shark.<ref name="Collns-Vllnva-2006">Template:Cite journal</ref>
The Grimpoteuthis do not have an ink sac (as is the case with all cirrate octopuses). Furthermore, the cirrate octopuses lack innervated chromatophores and therefore are not capable of changing color<ref name=Collns-Vllnva-2006/> (despite some unreferenced statements to the contrary).<ref>Template:Cite journal</ref> How cirrate octopuses escape or avoid predators is largely unknown.