Mastigoteuthis psychrophila is a species of whip-lash squid

Whip-lash squid

The Mastigoteuthidae, also known as whip-lash squid, are a family of small deep-sea squid. Approximately 20 known species in two genera are represented, with members found in both the mesopelagic and bathypelagic zone of most oceans...

. It was first described by Kir Nazimovich Nesis in 1977, based on four individuals found in Antarctic

Antarctic

The Antarctic is the region around the Earth's South Pole, opposite the Arctic region around the North Pole. The Antarctic comprises the continent of Antarctica and the ice shelves, waters and island territories in the Southern Ocean situated south of the Antarctic Convergence...

 waters. The largest was 143 mm long. The squid's tentacle

Tentacle

A tentacle or bothrium is one of usually two or more elongated flexible organs present in animals, especially invertebrates. The term may also refer to the hairs of the leaves of some insectivorous plants. Usually, tentacles are used for feeding, feeling and grasping. Anatomically, they work like...

s are 15 mm in diameter, with 0.15 mm diameter club suckers. Integumental photophore

Photophore

A photophore is a light-emitting organ which appears as luminous spots on various marine animals, including fish and cephalopods. The organ can be simple, or as complex as the human eye; equipped with lenses, shutters, color filters and reflectors...

s are present upon the head, arm

Cephalopod arm

A cephalopod arm is distinct from a tentacle, though the terms are often used interchangeably.Generally, cephalopod arms have suckers along most of their length, as opposed to tentacles, which have suckers only near their ends. Octopuses have eight arms and no tentacles, while squid and cuttlefish...

s and fin

Fin

A fin is a surface used for stability and/or to produce lift and thrust or to steer while traveling in water, air, or other fluid media, . The first use of the word was for the limbs of fish, but has been extended to include other animal limbs and man-made devices...

s. Although uncertain, it is believed to have two series of photophores on the arms, differing from other species in the M. agassizii

Mastigoteuthis agassizii

Mastigoteuthis agassizii is a species of whip-lash squid. It is the type species of the genus.-References:*Verrill, A.E. 1881. Report on the Cephalopods, and on Some Additional Species Dredged by the U.S. Fish Commission Steamer "Fish Hawk", During the Season of 1880. Bulletin of the Museum of...

group.