Decapodiformes is a
superorder of
Cephalopoda
A cephalopod is any member of the molluscan class Cephalopoda (Greek plural , ; "head-feet") such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent hea ...
comprising all cephalopod species with ten
limbs, specifically eight short arms and two long tentacles. It is hypothesized that the ancestral
coleoid
Subclass Coleoidea,
or Dibranchiata, is the grouping of cephalopods containing all the various taxa popularly thought of as "soft-bodied" or "shell-less" (i.e., octopuses, squid and cuttlefish). Unlike its extant sister group, Nautiloidea, whose ...
had five identical pairs of limbs, and that one branch of descendants evolved a modified arm pair IV to become the Decapodiformes, while another branch of descendants evolved and then eventually lost its arm pair II, becoming the
Octopodiformes
Octopodiformes is a superorder of the subclass Coleoidea, comprising the octopuses and the vampire squid. All living members of Octopodiformes have eight arms, either lacking the two tentacles of squid (as is the case in octopuses) or modifyin ...
.
The Decapodiformes include:
*Order
Spirulida
Spirulida is an order of cephalopods comprising one extant species ('' Spirula spirula'') and several extinct taxa.
Fossil record
* Oldest representative: Carboniferous, though contested: see '' Shimanskya''
* Oldest uncontested representativ ...
: ram's horn squid
*Order
Sepiida
Cuttlefish or cuttles are marine molluscs of the order Sepiida. They belong to the class Cephalopoda which also includes squid, octopuses, and nautiluses. Cuttlefish have a unique internal shell, the cuttlebone, which is used for control of bu ...
: cuttlefish, pygmy, bobtail and bottletail squid
*Order
Myopsida
Myopsida is one of the four orders of squid. It consists of two families: the monotypic '' Australiteuthis'' and the diverse and commercially important Loliginidae (~50 species). Some taxonomists classify this taxon as a suborder of the order ...
: coastal squid
*Order
Oegopsida
Oegopsida is one of the two orders of squid in the superorder Decapodiformes, in the class Cephalopoda. Together with the Myopsina, it was formerly considered to be a suborder of the order Teuthida, in which case it was known as Oegopsina. This ...
: neritic squid
References
Further reading
*
abstract
External links
The Taxonomicon: Superorder Decapodiformes
Coleoidea
Cenozoic cephalopods
Protostome superorders
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