Planctoteuthis is a genus of chiroteuthid

Chiroteuthidae

Chiroteuthids are deep-sea squid of the family Chiroteuthidae. They are 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 Pacific, and Indo-Pacific...

 squid

Squid

Squid are cephalopods of the order Teuthida, which comprises around 300 species. Like all other cephalopods, squid have a distinct head, bilateral symmetry, a mantle, and arms. Squid, like cuttlefish, have eight arms arranged in pairs and two, usually longer, tentacles...

 comprising five species, occurring worldwide in lower mesopelagic

Mesopelagic

The mesopelagic is that part of the pelagic zone that extends from a depth of 200 to 1000 metres below the ocean surface. It lies between the photic epipelagic above and the aphotic bathypelagic below, where there is no light at all...

 to bathypelagic depths in tropical to temperate

Temperate

In geography, temperate or tepid latitudes of the globe lie between the tropics and the polar circles. The changes in these regions between summer and winter are generally relatively moderate, rather than extreme hot or cold...

 waters. It has been suggested that members of Planctoteuthis are neotenic, retaining characteristics of the doratopsis developmental stage. This is marked in the retention of the paralarva

Paralarva

Paralarvae is the term used to describe the young planktonic stages of cephalopods, between hatchling and subadult. It is used to differentiate it from the term 'larva' used in animals which undergo true metamorphosis. They have been observed only on members of the orders Octopoda and Teuthida.The...

l tentacular

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...

 club, unique among subadult chiroteuthids. Members lack both photophores and a funnel valve. The genus was originally placed within the monotypic 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...

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

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, lidded photophores present at the end of the tentacular club...

led to its inclusion in the family Chiroteuthidae

Chiroteuthidae

Chiroteuthids are deep-sea squid of the family Chiroteuthidae. They are 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 Pacific, and Indo-Pacific...

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

Species

• Planctoteuthis danae
  Planctoteuthis danae
  Planctoteuthis danae is a species of chiroteuthid squid. It is distinguished from further members of Planctoteuthis by a fin length greater than half of the mantle. During the paralarval stage, the species occurs in depths of 200–300 m, progressing to 200–800 m at 10-15mm ML; larger specimens have...
  
  
• Planctoteuthis exopthalmica
• Planctoteuthis levimana
• Planctoteuthis lippula
• Planctoteuthis oligobessa

External links

• Tree of Life web project: Planctoteuthis