''Planctoteuthis'' is a genus of chiroteuthid

squid True squid are molluscs with an elongated soft body, large eyes, eight arms, and two tentacles in the superorder Decapodiformes, though many other molluscs within the broader Neocoleoidea are also called squid despite not strictly fitting ...

comprising five species, occurring worldwide in lower

mesopelagic The mesopelagic zone (Greek μέσον, middle), also known as the middle pelagic or twilight zone, is the part of the pelagic zone that lies between the photic epipelagic and the aphotic bathypelagic zones. It is defined by light, and begins a ...

bathypelagic The bathypelagic zone or bathyal zone (from Greek βαθύς (bathýs), deep) is the part of the open ocean that extends from a depth of below the ocean surface. It lies between the mesopelagic above, and the abyssopelagic below. The bathypelag ...

depths in

tropical The tropics are the regions of Earth surrounding the Equator. They are defined in latitude by the Tropic of Cancer in the Northern Hemisphere at N and the Tropic of Capricorn in the Southern Hemisphere at S. The tropics are also referred to ...

temperate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

waters. It has been suggested that members of ''Planctoteuthis'' are

neotenic Neoteny (), also called juvenilization,Montagu, A. (1989). Growing Young. Bergin & Garvey: CT. is the delaying or slowing of the physiological, or somatic, development of an organism, typically an animal. Neoteny is found in modern humans compare ...

, retaining characteristics of the doratopsis developmental stage. This is marked in the retention of the paralarval tentacular club, unique among subadult chiroteuthids. Members lack both

photophores A photophore is a glandular organ that 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, h ...

and a funnel valve. The genus was originally placed within the monotypic

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Valbyteuthidae, under the name ''Valbyteuthis''. Similarities between the paralavae of ''Valbyteuthis'' and ''

Chiroteuthis ''Chiroteuthis'' is a genus of chiroteuthid squid, comprising two subgenera. The hectocotylus is absent from all members of the genus; instead, a penis extending from the mantle opening is utilised. The genus is characterised by enlarged, lidde ...

'' led to its inclusion in the family

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 Paci ...

. Eventually, ''Valbyteuthis'' was incorporated as a junior synonym of ''Planctoteuthis'', citing previous descriptions of the paralarvae.

Species

* '' Planctoteuthis danae'' * '' Planctoteuthis exopthalmica'' * '' Planctoteuthis levimana'' * '' Planctoteuthis lippula'' * ''

Planctoteuthis oligobessa ''Planctoteuthis'' is a genus of chiroteuthid squid comprising five species, occurring worldwide in lower mesopelagic to bathypelagic depths in tropical to temperate waters. It has been suggested that members of ''Planctoteuthis'' are neotenic, ...

References

External links

Tree of Life web project: ''Planctoteuthis''
Squid {{squid-stub