Bigfin squid
Encyclopedia
The bigfin squids are a group of rarely seen cephalopod
s with a distinctive morphology. They are placed in the genus
Magnapinna and family
Magnapinnidae. The family is known only from larval, paralarval, and juvenile specimens, but some authorities believe the adult creature has been seen: several videos have been taken of animals nicknamed the "long-arm squid", which appear to have a similar morphology. Since none of the adult specimens have ever been captured or sampled, it remains uncertain if they are the same genus, or only distant relatives.
) caught off the Azores in 1907. However, due to the damaged nature of the find, very little information could be discerned and it was lumped in with the mastigoteuthids, 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
's The Open Sea (1956), where it was identified as Octopodoteuthopsis.
During the 1990s two more immature specimens were found in the Atlantic (Magnapinna sp. A
), and three more were found in the Pacific (Magnapinna pacifica
). Researchers Michael Vecchione and Richard Young were the chief investigators of the finds, and eventually linked them up to the two previous specimens, erecting the family Magnapinnidae in 1998, with Magnapinna pacifica
as the type species
. Of particular interest was the very large fin size, up to 90% of the mantle length, that was responsible for the animals' nickname.
A single specimen of a fifth species, Magnapinna sp. B
, was collected in 2004. Magnapinna sp. A was described as Magnapinna atlantica
in 2006.
Nautile
encountered a long-armed squid off the coast of northern Brazil
, 10°42.91′N 40°53.43′W, at a depth of 4735 metres (15,534.8 ft). In July 1992, the Nautile again came across these creatures, first observing one individual two times during a dive off the coast of Ghana
at 3°40′N 2°30′W and 3010 metres (9,875.3 ft) depth, and then another one off Senegal
at 2950 metres (9,678.5 ft). Both were filmed and photographed.
In November 1998, the Japanese manned submersible Shinkai 6500 filmed another long-armed squid in the Indian Ocean south of Mauritius
, at 32°45′S 57°13′E and 2340 metres (7,677.2 ft). A third video taken from the ROV
of the oil-drilling ship Millennium Explorer in January 2000, at Mississippi Canyon
in the Gulf of Mexico
(28°37′N 88°00′W) at 2195 metres (7,201.4 ft) allowed a size estimate. By comparison with the visible parts of the ROV, the squid was estimated to measure 7 meters with arms fully extended.
The ROV Atalante filmed another Indian Ocean specimen at 19°32′S 65°52′E and 2576 metres (8,451.4 ft), in the area of Rodrigues Island, in May 2000. The year 2000 was a boon year for observations of these enigmatic animals, for in October, the manned submersible Alvin
found yet another long-armed squid at 1940 metres (6,364.8 ft) in Atwater Valley, Gulf of Mexico (27°34.714′N 88°30.59′W).
These videos did not receive any media attention; in any case, most were brief and fairly blurry. However, in May 2001, some ten minutes of crisp footage of a long-armed squid were acquired by ROV Tiburon
, causing a flurry of attention when they were released. These were taken in the Pacific Ocean north of Oʻahu, Hawaiʻi (21°54′N 158°12′W), at 3380 metres (11,089.2 ft).
On November 11, 2007, a new video of a long-arm squid was filmed off Perdido, a drilling site owned by Shell Oil Company
, located 200 statute miles (320 km) off Houston, Texas
in the Gulf of Mexico
.
The specimens in the videos looked very distinct from all previously known squids. Uniquely among cephalopods, the arms and tentacles were of the same length and looked identical (like extinct belemnites). 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 stretching up to 15–20 times the mantle length. Estimates based on video evidence put the total length of the largest specimens at 8 m or more. On close ups of the body and head, it is also 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, leaving their exact identity unknown.
.)
Cephalopod
A cephalopod is any member of the molluscan class Cephalopoda . These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot...
s with a distinctive morphology. They are placed in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
Magnapinna and family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Magnapinnidae. The family is known only from larval, paralarval, and juvenile specimens, but some authorities believe the adult creature has been seen: several videos have been taken of animals nicknamed the "long-arm squid", which appear to have a similar morphology. Since none of the adult specimens have ever been captured or sampled, it remains uncertain if they are the same genus, or only distant relatives.
Physical specimens
The first record of this family comes from a specimen (Magnapinna talismaniMagnapinna 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....
) caught off the Azores in 1907. However, due to the damaged nature of the find, very little information could be discerned and it was lumped in with the mastigoteuthids, first as Chiroteuthopsis talismani and later as Mastigoteuthis talismani. In 1956 a similar squid (Magnapinna sp. C
Magnapinna sp. C
Magnapinna sp. C is an undescribed species of bigfin squid known only from a single specimen of 79 mm mantle length collected in the southern Atlantic Ocean and held in the Natural History Museum...
) was caught in the South Atlantic, but little was thought of it at the time. The specimen was illustrated in Alister Hardy
Alister Hardy
Sir Alister Clavering Hardy, FRS was an English marine biologist, expert on zooplankton and marine ecosystems...
's The Open Sea (1956), where it was identified as Octopodoteuthopsis.
During the 1990s two more immature specimens were found in the Atlantic (Magnapinna sp. A
Magnapinna atlantica
Magnapinna atlantica, previously known as "Magnapinna sp. A", is a species of bigfin squid known from only two specimens collected in the northern Atlantic Ocean...
), and three more were found in the Pacific (Magnapinna pacifica
Magnapinna pacifica
Magnapinna pacifica is a species of bigfin squid known only from three immature specimens; two caught at a depth of less than 300 m and one from a fish stomach. M. pacifica is the type species of the genus Magnapinna. It is characterised primarily by its proximal tentacles, which are wider than...
). Researchers Michael Vecchione and Richard Young were the chief investigators of the finds, and eventually linked them up to the two previous specimens, erecting the family Magnapinnidae in 1998, with Magnapinna pacifica
Magnapinna pacifica
Magnapinna pacifica is a species of bigfin squid known only from three immature specimens; two caught at a depth of less than 300 m and one from a fish stomach. M. pacifica is the type species of the genus Magnapinna. It is characterised primarily by its proximal tentacles, which are wider than...
as the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
. Of particular interest was the very large fin size, up to 90% of the mantle length, that was responsible for the animals' nickname.
A single specimen of a fifth species, Magnapinna sp. B
Magnapinna sp. B
Magnapinna sp. B is an undescribed species of bigfin squid known only from a single immature specimen collected in the northern Atlantic Ocean. It is characterised by its dark epidermal pigmentation, which is epithelial, as opposed to the chromatophoral pigmentation found in other Magnapinna...
, was collected in 2004. Magnapinna sp. A was described as Magnapinna atlantica
Magnapinna atlantica
Magnapinna atlantica, previously known as "Magnapinna sp. A", is a species of bigfin squid known from only two specimens collected in the northern Atlantic Ocean...
in 2006.
Sightings
The first visual record of the long-arm squid dates back to September 1988. The crew of the submersibleSubmersible
A submersible is a small vehicle designed to operate underwater. The term submersible is often used to differentiate from other underwater vehicles known as submarines, in that a submarine is a fully autonomous craft, capable of renewing its own power and breathing air, whereas a submersible is...
Nautile
Nautile
The Nautile is a manned 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 ....
encountered a long-armed squid off the coast of northern Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, 10°42.91′N 40°53.43′W, at a depth of 4735 metres (15,534.8 ft). In July 1992, the Nautile again came across these creatures, first observing one individual two times during a dive off the coast of Ghana
Ghana
Ghana , officially the Republic of Ghana, is a country located in West Africa. It is bordered by Côte d'Ivoire to the west, Burkina Faso to the north, Togo to the east, and the Gulf of Guinea to the south...
at 3°40′N 2°30′W and 3010 metres (9,875.3 ft) depth, and then another one off Senegal
Senegal
Senegal , officially the Republic of Senegal , is a country in western Africa. It owes its name to the Sénégal River that borders it to the east and north...
at 2950 metres (9,678.5 ft). Both were filmed and photographed.
In November 1998, the Japanese manned submersible Shinkai 6500 filmed another long-armed squid in the Indian Ocean south of Mauritius
Mauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...
, at 32°45′S 57°13′E and 2340 metres (7,677.2 ft). A third video taken from the ROV
Rov
Rov is a Talmudic concept which means the majority.It is based on the passage in Exodus 23;2: "after the majority to wrest" , which in Rabbinic interpretation means, that you shall accept things as the majority....
of the oil-drilling ship Millennium Explorer in January 2000, at Mississippi Canyon
Mississippi Canyon
The Mississippi Canyon is an undersea canyon in the Central Gulf of Mexico, south of Louisiana. According to the U.S. Geological Survey GLORIA Mapping Program, it is the dominant feature of the north-central Gulf of Mexico. According to GCAGS Transactions, it has an average width of , and a length...
in the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
(28°37′N 88°00′W) at 2195 metres (7,201.4 ft) allowed a size estimate. By comparison with the visible parts of the ROV, the squid was estimated to measure 7 meters with arms fully extended.
The ROV Atalante filmed another Indian Ocean specimen at 19°32′S 65°52′E and 2576 metres (8,451.4 ft), in the area of Rodrigues Island, in May 2000. The year 2000 was a boon year for observations of these enigmatic animals, for in October, the manned submersible Alvin
DSV Alvin
Alvin is a manned deep-ocean research submersible owned by the United States Navy and operated by the Woods Hole Oceanographic Institution in Woods Hole, Massachusetts. The vehicle was built by General Mills' Electronics Group in the same factory used to manufacture breakfast cereal-producing...
found yet another long-armed squid at 1940 metres (6,364.8 ft) in Atwater Valley, Gulf of Mexico (27°34.714′N 88°30.59′W).
R/V Western Flyer
R/V Western Flyer is a twin hulled SWATH research vessel operated by the Monterey Bay Aquarium Research Institute . Its relatively stable SWATH design permits expanded operational capability in rough sea states. It is the platform of operations for the ROV Tiburon. The vessel carries 10 crew, 5 ROV...
, causing a flurry of attention when they were released. These were taken in the Pacific Ocean north of Oʻahu, Hawaiʻi (21°54′N 158°12′W), at 3380 metres (11,089.2 ft).
On November 11, 2007, a new video of a long-arm squid was filmed off Perdido, a drilling site owned by Shell Oil Company
Shell Oil Company
Shell Oil Company is the United States-based subsidiary of Royal Dutch Shell, a multinational oil company of Anglo Dutch origins, which is amongst the largest oil companies in the world. Approximately 22,000 Shell employees are based in the U.S. The head office in the U.S. is in Houston, Texas...
, located 200 statute miles (320 km) off Houston, Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...
in the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
.
The specimens in the videos looked very distinct from all previously known squids. Uniquely among cephalopods, the arms and tentacles were of the same length and looked identical (like extinct belemnites). 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 stretching up to 15–20 times the mantle length. Estimates based on video evidence put the total length of the largest specimens at 8 m or more. On close ups of the body and head, it is also 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, leaving their exact identity unknown.
Feeding behavior
Very little is known about the feeding behavior of these squid. Scientists have speculated that bigfin squid feed by dragging their arms and tentacles along the seafloor, and grabbing edible organisms off the floor. Alternatively, they may simply use a trapping technique, waiting passively for prey to bump into their arms. (See Cephalopod intelligenceCephalopod intelligence
Cephalopod intelligence has an important comparative aspect in the understanding of intelligence because it relies on a nervous system fundamentally different from that of vertebrates...
.)
External links
- Tree of Life Web ProjectTree of Life Web ProjectThe Tree of Life Web Project is an ongoing 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....
: Magnapinna - Cephalopods in Action: Long-armed squid videos