''Planctoteuthis'' is a genus of
chiroteuthid squid
A squid (: squid) is a mollusc with an elongated soft body, large eyes, eight cephalopod limb, arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida (though many other molluscs within the broader Neocoleoidea are also ...
comprising five species, occurring worldwide in lower
mesopelagic
The mesopelagic zone (Greek language, 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 ...
to
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 bathypela ...
depths in
tropical
The tropics are the regions of Earth surrounding the equator, where the sun may shine directly overhead. This contrasts with the temperate or polar regions of Earth, where the Sun can never be directly overhead. This is because of Earth's ax ...
to
temperate
In geography, the temperate climates of Earth occur in the middle latitudes (approximately 23.5° to 66.5° N/S of the Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ran ...
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 in modern humans is more signif ...
, retaining characteristics of the doratopsis developmental stage. This is marked in the retention of the
paralarva
Coleoidea
or Dibranchiata is one of the two subclasses of cephalopod molluscs containing all the various taxa popularly thought of as "soft-bodied" or "shell-less" (i.e. octopus, squid and cuttlefish). Unlike its extant sister group Nautiloidea ...
l
tentacular
In zoology, a tentacle is a flexible, mobile, and elongated organ present in some species of animals, most of them invertebrates. In animal anatomy, tentacles usually occur in one or more pairs. Anatomically, the tentacles of animals work mainl ...
club, unique among subadult chiroteuthids. Members lack both
photophores
A photophore is a specialized anatomical structure found in a variety of organisms that emits light through the process of Bioluminescence, boluminescence. This light may be produced endogenously by the organism itself (symbiotic) or generat ...
and a funnel valve. The genus was originally placed within the monotypic
family
Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
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 Pacif ...
. Eventually, ''Valbyteuthis'' was incorporated as a
junior synonym
In taxonomy, the scientific classification of living organisms, a synonym is an alternative scientific name for the accepted scientific name of a taxon. The botanical and zoological codes of nomenclature treat the concept of synonymy differently.
...
of ''Planctoteuthis'', citing previous descriptions of the paralarvae.
Species
* ''
Planctoteuthis danae''
* ''
Planctoteuthis exopthalmica''
* ''
Planctoteuthis levimana''
* ''
Planctoteuthis lippula''
* ''
Planctoteuthis oligobessa''
References
External links
Tree of Life web project: ''Planctoteuthis''
Chiroteuthidae
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