Bigfin squids are a group of rarely seen
cephalopod
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
s with a distinctive
morphology
Morphology, from the Greek and meaning "study of shape", may refer to:
Disciplines
*Morphology (archaeology), study of the shapes or forms of artifacts
*Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...
. They are placed in the
genus
Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...
''Magnapinna'' and
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
Magnapinnidae. Although the family was described only from larval,
paralarva
Coleoidea
or Dibranchiata is one of the two subclasses of cephalopod molluscs containing all the various taxa popularly thought of as "soft-bodied" or "shell-less" (i.e. octopus, squid and cuttlefish). Unlike its extant sister group Nautiloidea ...
l, and juvenile specimens, numerous video observations of much larger squid with similar morphology are assumed to be adult specimens of the same family.
The arms and tentacles of the squid are both extremely long, estimated at . These appendages are held perpendicular to the body, creating "elbows". How the squid feeds is yet to be discovered.
''Magnapinna'' is thought to be the deepest-occurring squid genus, with sightings as deep as below the surface, making it the only squid known to inhabit the
hadal zone
The hadal zone, also known as the hadopelagic zone, is the deep sea, deepest region of the ocean, lying within oceanic trenches. The hadal zone ranges from around below sea level, and exists in long, narrow, topographic V-shaped depressions.
T ...
.
Taxonomy
''Magnapinna'' is the
sister group
In phylogenetics, a sister group or sister taxon, also called an adelphotaxon, comprises the closest relative(s) of another given unit in an evolutionary tree.
Definition
The expression is most easily illustrated by a cladogram:
Taxon A and ...
to ''
Joubiniteuthis'', another little-known deep-sea squid with an unusual body plan and long arms. Both ''Magnapinna'' and ''Joubiniteuthis'' are
monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unisp ...
genera within their own families, Magnapinnidae and Joubiniteuthidae respectively. They are also closely related to the "whip-lash squid" in the families
Chiroteuthidae
The Chiroteuthidae are a family of deep-sea squid, generally small to medium in size, rather soft and gelatinous, and slow moving. They are found in most temperate and tropical oceans, but are known primarily from the North Atlantic, North Pacif ...
and
Mastigoteuthidae
The Mastigoteuthidae, also known as whip-lash squid, are a family of small deep-sea squid. Approximately 20 known species in six genera are represented, with members found in both the mesopelagic and bathypelagic zone of most oceans. Originally de ...
.''
''
Physical specimens
The first record of this family comes from a specimen (''
Magnapinna talismani
''Magnapinna talismani'' is a species of bigfin squid known only from a single damaged specimen. It is characterised by small white nodules present on the ventral surface of its fins.
It is the first described species of '' Magnapinna'', althou ...
'') caught off the
Azores
The Azores ( , , ; , ), officially the Autonomous Region of the Azores (), is one of the two autonomous regions of Portugal (along with Madeira). It is an archipelago composed of nine volcanic islands in the Macaronesia region of the North Atl ...
on 10 August 1883.
Due to the damaged nature of the find, little information could be discerned, and it was classified as a
mastigoteuthid
The Mastigoteuthidae, also known as whip-lash squid, are a family of small deep-sea squid. Approximately 20 known species in six genera are represented, with members found in both the mesopelagic and bathypelagic zone of most oceans. Originally de ...
, first as ''Chiroteuthopsis talismani''
and later as ''Mastigoteuthis talismani''. In 1956, a similar squid (
''Magnapinna'' sp. C) was caught in the South Atlantic, but little was thought of it at the time. The specimen was illustrated in
Alister Hardy
Sir Alister Clavering Hardy (10 February 1896 – 22 May 1985) was a British Marine biology, marine biologist, an expert on marine ecosystems spanning organisms from zooplankton to whales. He had the artistic skill to illustrate his books with h ...
's ''The Open Sea'' (1956), where it was identified as ''Octopodoteuthis sicula''.

During the 1980s, two additional immature specimens were found in the Atlantic (
''Magnapinna'' sp. A), and three more were found in the Pacific (''
Magnapinna pacifica''). Researchers
Michael Vecchione
Michael Vecchione is an American zoologist currently at the Smithsonian National Museum of Natural History and an Elected Fellow of the American Association for the Advancement of Science since 2001. His highest cited paper is ''Common and scien ...
and
Richard Young were the chief investigators of the finds, and eventually linked them to the two previous specimens, erecting the family Magnapinnidae in 1998, with ''
Magnapinna pacifica'' as the
type species
In International_Code_of_Zoological_Nomenclature, zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the spe ...
. Of particular interest was the very large fin size, up to 90% of the mantle length, that was responsible for the animals' common name.
A single specimen of a fifth species,
''Magnapinna'' sp. B, was collected in 2006. ''Magnapinna'' sp. A was described as ''
Magnapinna atlantica'' in 2006.
The genus was described from two juveniles and
paralarva
Coleoidea
or Dibranchiata is one of the two subclasses of cephalopod molluscs containing all the various taxa popularly thought of as "soft-bodied" or "shell-less" (i.e. octopus, squid and cuttlefish). Unlike its extant sister group Nautiloidea ...
, none of which had developed the characteristic long arm tips. However, they did all have large fins, and were therefore named "magna pinna", meaning "big fin".
Sightings
The presumed adult stage of ''Magnapinna'' is known only from video observations from submersibles and remotely-operated vehicles (ROVs); no physical specimens have yet been collected, leaving their exact identity unknown. These individuals and the collected juvenile specimens share the very large fins and the
vermiform
Vermes (" vermin/vermes") is an obsolete taxon used by Carl Linnaeus and Jean-Baptiste Lamarck for non-arthropod invertebrate animals.
Linnaeus
In Linnaeus's ''Systema Naturae'', the Vermes had the rank of class, occupying the 6th (and last) ...
arm tips with no suckers, but the iconic elongated arm tips are known only from observed individuals. Although it has not been directly confirmed whether these squid are the same as the ''Magnapinna'' known from specimens, it is largely accepted that they are members of Magnapinnidae.
Although observations had been made over a decade earlier, adult bigfin squid only became known to science in 2001, when marine biology student Heather Holston sent footage of what she described as a "21-foot-long squid" to
teuthologist
Teuthology (from Ancient Greek, Greek τεῦθος, "Common Cuttlefish, cuttlefish, European squid, squid", and -λογία, ''-logy, -logia'') is the study of Cephalopod, cephalopods, which are members of the class Cephalopod, Cephalopoda in ...
Michael Vecchione
Michael Vecchione is an American zoologist currently at the Smithsonian National Museum of Natural History and an Elected Fellow of the American Association for the Advancement of Science since 2001. His highest cited paper is ''Common and scien ...
. The footage had been recorded from an ROV in the
Gulf of Mexico
The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...
in January 2000 at the request of Holston's boyfriend Eric Leveton, who planned on showing it to her. Leveton was a structural engineer aboard the oil-drilling ship ''Millennium Explorer'', who had happened to look into the ROV operation shack when the squid was observed by operators. Although Vecchione initially surmised from Holston's description that the footage might be the first video of a live
giant squid
The giant squid (''Architeuthis dux'') is a species of deep-ocean dwelling squid
A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, ...
(''Architeuthis dux''), he realized that the video itself portrayed a completely different squid that had no known identity.
Further discussions with other cephalopod researchers found no leads on the identity of the squid, and it was thus dubbed the "mystery squid" for a portion of time. Analysis by Vecchione ''et al'' of previous footage from submersibles found other video records of bigfin squid, the earliest from 1988. Around the same time, new high-quality footage of a bigfin squid was also recorded off
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
by the
ROV Tiburon
RV ''Western Flyer'' is a twin hulled SWATH research vessel operated by the Florida Institute of Oceanography (FIO). In November 2022, the R/V Western Flyer was acquired by the Florida Institute of Oceanography and its Host Institution, the Univ ...
. In December 2001, Vecchione ''et al'' published a paper collating these observations; this was also the first paper to identify them as potential members of the Magnapinnidae, which had been named by Vecchione from the juvenile specimens a few years earlier.
Independent of Vecchione's publication, Guerra ''et al'' published a paper the following year analyzing some of the early bigfin squid footage, and also identified them as potential adult magnapinnids.
Anatomy
The specimens in the videos looked very distinct from all previously known squids. Uniquely among
cephalopod
A cephalopod is any member of the molluscan Taxonomic rank, class Cephalopoda (Greek language, Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral symm ...
s, the arms and tentacles were of the same length and looked identical (similar to extinct
belemnite
Belemnitida (or belemnites) is an extinct order (biology), order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous (And possibly the Eocene). Unlike squid, belemnites had an internal skeleton that made up the cone ...
s). The appendages were also held perpendicular to the body, creating the appearance of strange "elbows". Most remarkable was the length of the elastic tentacles, which has been estimated at up to 15–20 times the mantle length. This trait is caused by filament coiling of the tentacles, a trait that is rare among similar species.
Estimates based on video evidence put the total length of the largest specimens at or more, with some estimates up to . Viewing close-ups of the body and head, it is apparent that the fins are extremely large, being proportionately nearly as big as those of bigfin squid larvae. While they do appear similar to the larvae, no specimens or samples of the adults have been taken. While their exact identity is unknown, all of the discovered specimens can be observed to have a beige color body, translucent fins, near-white tentacles, and dark eyes.
These species of squids are mainly identifiable by their long thin arms and specific colors. The squid also have a very unique brachial crown that sets them aside from the rest of other families that are known.
Feeding behaviour
Little is known about the feeding-behaviour of these squids. Scientists have speculated that the bigfin squid feeds by dragging their arms and tentacles along the seafloor and grabbing edible organisms from the floor.
Alternatively, they may simply use a trapping technique, waiting passively for prey such as
zooplankton
Zooplankton are the heterotrophic component of the planktonic community (the " zoo-" prefix comes from ), having to consume other organisms to thrive. Plankton are aquatic organisms that are unable to swim effectively against currents. Consequent ...
to bump into their arms
(see
Cephalopod intelligence
Cephalopod intelligence is a measure of the cognitive ability of the cephalopod class of molluscs.
Intelligence is generally defined as the process of acquiring, storing, retrieving, combining, and comparing information and skills. Though these ...
). The diet of the bigfin squid is unknown. However, cephalopods are known to feed on crustaceans, jellyfish, and even other cephalopods.
Observation timeline
The first visual record of an adult bigfin squid was in September 1988. The crew of the
submersible
A submersible is an underwater vehicle which needs to be transported and supported by a larger ship, watercraft or dock, platform. This distinguishes submersibles from submarines, which are self-supporting and capable of prolonged independent ope ...
''
Nautile
''Nautile'' is a crewed submersible owned by Ifremer, the French Research Institute for Exploitation of the Sea. Commissioned in 1984, the submersible can be operated at depths of up to .
Features
''Nautile'' is capable of housing three peopl ...
'' encountered a bigfin squid off the coast of northern
Brazil
Brazil, officially the Federative Republic of Brazil, is the largest country in South America. It is the world's List of countries and dependencies by area, fifth-largest country by area and the List of countries and dependencies by population ...
, , at a depth of . In July 1992, the ''Nautile'' again encountered these creatures, observing two individuals during a dive off the coast of
Ghana
Ghana, officially the Republic of Ghana, is a country in West Africa. It is situated along the Gulf of Guinea and the Atlantic Ocean to the south, and shares borders with Côte d’Ivoire to the west, Burkina Faso to the north, and Togo to t ...
at , first at depth, and then again at . Both were filmed and photographed.
In November 1998, the Japanese crewed submersible ''
Shinkai 6500
''Shinkai 6500'' (しんかい) is a crewed research submersible that can dive up to a depth of . It was completed in 1990. The ''Shinkai 6500'' is owned and run by the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and it is la ...
'' filmed another bigfin squid in the Indian Ocean south of
Mauritius
Mauritius, officially the Republic of Mauritius, is an island country in the Indian Ocean, about off the southeastern coast of East Africa, east of Madagascar. It includes the main island (also called Mauritius), as well as Rodrigues, Ag ...
, at and .
Eric Leveton's video, which was later shared with Vecchione, was taken from the
remotely operated underwater vehicle
A remotely operated underwater vehicle (ROUV) or remotely operated vehicle (ROV) is a free-swimming submersible craft used to perform underwater observation, inspection and physical tasks such as valve operations, hydraulic functions and other g ...
(ROV) of the oil-drilling ship ''Millennium Explorer'' in January 2000, at
Mississippi Canyon
The Mississippi Canyon is an Submarine canyon, undersea canyon, part of the Mississippi Submarine Valley in the North-central Gulf of Mexico, south of Louisiana. According to the United States Geological Survey, U.S. Geological Survey GLORIA Map ...
in the
Gulf of Mexico
The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...
() at , and allowed for a size estimate. By comparison with the visible parts of the ROV, the squid was estimated to measure with arms fully extended.
The ''Nautile'' filmed another Indian Ocean specimen at and , in the area of
Rodrigues Island
Rodrigues ( ; Creole: ) is a autonomous outer island of the Republic of Mauritius in the Indian Ocean, about east of Mauritius. It is part of the Mascarene Islands, which include Mauritius and Réunion. Like Agaléga, Rodrigues is a consti ...
, in May 2000.
In October 2000, the crewed submersible ''
Alvin
''Alvin'' (DSV-2) is a crewed deep-ocean research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institution (WHOI) of Woods Hole, Massachusetts. The original vehicle was built by General Mills' Electro ...
'' found another bigfin squid at in , Gulf of Mexico ().
These videos did not receive any media attention; most were brief and fairly blurry. In May 2001, approximately ten minutes of crisp footage of a bigfin squid were acquired by
ROV ''Tiburon'', causing a flurry of attention when released. These were taken in the Pacific Ocean north of
Oʻahu
Oahu (, , sometimes written Oahu) is the third-largest and most populated island of the Hawaiian Islands and of the U.S. state of Hawaii. The state capital, Honolulu, is on Oahu's southeast coast. The island of Oahu and the uninhabited Northwe ...
,
Hawaii
Hawaii ( ; ) is an island U.S. state, state of the United States, in the Pacific Ocean about southwest of the U.S. mainland. One of the two Non-contiguous United States, non-contiguous U.S. states (along with Alaska), it is the only sta ...
(), at . This video and the pre-2001 videos (which had not previously received much scientific attention) were documented by Vecchione ''et al'' in a paper that year, and some of the earlier footage was further analyzed by Guerra ''et al'' (2002).
On 11 November 2007, a bigfin squid was filmed off
Perdido, a drilling-site owned by
Shell Oil Company
Shell USA, Inc. (formerly Shell Oil Company, Inc.) is the United States–based wholly owned subsidiary of Shell plc, a UK-based transnational corporation " oil major" which is among the largest oil companies in the world. Approximately 18,000 ...
, located off
Houston
Houston ( ) is the List of cities in Texas by population, most populous city in the U.S. state of Texas and in the Southern United States. Located in Southeast Texas near Galveston Bay and the Gulf of Mexico, it is the county seat, seat of ...
,
Texas
Texas ( , ; or ) is the most populous U.S. state, state in the South Central United States, South Central region of the United States. It borders Louisiana to the east, Arkansas to the northeast, Oklahoma to the north, New Mexico to the we ...
in the
Gulf of Mexico
The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...
. The ROV that filmed the squid had originally been sent to retrieve drilling equipment from the seabed, and encountered the squid floating near a well. After being circulated within the oil industry, the footage was shared with
''National Geographic News'' to have its identity determined, and was released to the public in 2008. This video received significant online attention in the years since its filming.

Observations of bigfin squid were made in the
Great Australian Bight
The Great Australian Bight is a large oceanic bight (geography), bight, or open bay, off the central and western portions of the southern Coast, coastline of mainland Australia.
There are two definitions for its extent—one by the Internation ...
during towed camera and remote operated vehicle surveys in 2015 and 2017 respectively.
In 2018, the first observations of a bigfin squid were made from the Southern Caribbean, off the coast of
Colombia
Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...
.
In March 2021, during the expedition to document the wreck of the
USS Johnston
Two ships have been named USS ''Johnston'' in the United States Navy
The United States Navy (USN) is the naval warfare, maritime military branch, service branch of the United States Department of Defense. It is the world's most powerful ...
, the submersible
DSV ''Limiting Factor'' recorded footage of a juvenile bigfin squid from the
Philippine Trench
The Philippine Trench (also called the Philippine Deep, Mindanao Trench, and the Mindanao Deep) is a Oceanic trench, submarine trench to the east of the Philippines. The trench is located in the Philippine sea of the western North Pacific Ocean ...
at a depth of . This is the deepest observation of any squid, and rivalled only by some unidentified
cirrate octopods from the same habitat as the deepest observation of any cephalopod. This makes ''Magnapinna'' the first squid known to inhabit the
hadal zone
The hadal zone, also known as the hadopelagic zone, is the deep sea, deepest region of the ocean, lying within oceanic trenches. The hadal zone ranges from around below sea level, and exists in long, narrow, topographic V-shaped depressions.
T ...
.
On 9 November 2021, a video of a bigfin squid was captured at a ridge feature off the
West Florida Escarpment by an ROV from the
NOAAS ''Okeanos Explorer'' as part of the Windows to the Deep 2021 expedition. The squid was found at a depth of , and its size is currently being measured using paired lasers.
ROV SuBastian of
Schmidt Ocean Institute
Schmidt Ocean Institute (SOI) is a 501(c)(3) non-profit operating foundation established in March 2009 by Eric Schmidt and Wendy Schmidt. The Institute's goal is to advance innovative oceanographic research and discovery through technological adv ...
observed a bigfin squid in close proximity to a black smoker-type
hydrothermal vent
Hydrothermal vents are fissures on the seabed from which geothermally heated water discharges. They are commonly found near volcanically active places, areas where tectonic plates are moving apart at mid-ocean ridges, ocean basins, and hot ...
on 4 April 2023, during the "In Search of Hydrothermal Lost Cities" expedition. The squid was seen at a depth of .
See also
*
*
*
References
Citations
*
External links
*
Tree of Life Web Project
The Tree of Life Web Project (ToL) is an Internet project providing information about the diversity and phylogeny of life on Earth.
This collaborative peer reviewed project began in 1995, and is written by biologists from around the world. The s ...
''Magnapinna''!-- this might be turned into a proper ref -->
* Cephalopods in Action
August 2022 Bigfin Squid sighting
{{Taxonbar, from=Q288222
Cephalopod genera
Chiroteuthoidea
Cephalopods described in 1998