Bigfin squid
Bigfin squids are a group of rarely seen cephalopods with a distinctive morphology. They are placed in the genus Magnapinna and family Magnapinnidae.[2] Although the family is known only from larval, paralarval, and juvenile specimens, some authorities believe adult specimens have also 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 seemingly adult specimens has ever been captured or sampled, it remains uncertain if they are of the same genus or only relatives.
The arms and tentacles of the squid are both extremely long and believed to be 4 to 8 m (13 to 26 ft) long. These appendages are held perpendicular to the body, creating "elbows." How the squid feeds is yet to be discovered.[3]
The first record of this family comes from a specimen (Magnapinna talismani) caught off the Azores in 1907.[4] Due to the damaged nature of the find, little information could be discerned, and it was classified as a mastigoteuthid, first as Chiroteuthopsis talismani[4] 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.[5]
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 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.[6] 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.[7]
The genus was described from two juveniles and paralarva, 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".[8]
