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 these criteria. Like all other cephalopods, squid have a distinct head, bilateral symmetry, and a mantle. They are mainly soft-bodied, like octopuses, but have a small internal skeleton in the form of a rod-like gladius or pen, made of chitin.
Ancistrocheirus lesueurii, the sharpear enope squid, is the only species in the genus Ancistrocheirus and family Ancistrocheiridae. With a mantle length of 25 cm, this moderately sized squid may be found throughout the tropical and subtropical oceans. They tend to be found at mesopelagic depths.
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 Pacific, and Indo-Pacific. The family is represented by approximately 12 species and four subspecies in four genera, two of which are monotypic. They are sometimes known collectively as whip-lash squid, but this common name is also applied to the Mastigoteuthidae, which are sometimes treated as a subfamily (Mastigoteuthinae) of Chiroteuthidae.
The Mastigoteuthidae, also known as whip-lash squid, are a family of small deep-sea squid. Approximately 20 known species in six genera are represented, with members found in both the mesopelagic and bathypelagic zone of most oceans. Originally described by Verill in 1881, it was later lowered by Chun (1920) to a subfamily (Mastigoteuthinae) of the Chiroteuthidae. However, Roper et al. (1969) raised it back to the family level, and this has not been changed since. The taxonomy of this family is extremely unstable, and there have been at times one genus, two genera and four subgenera(Salcedo-Vargas & Okutani, 1994), two genera and several 'groups', five genera and one species with an uncertain placement, or six genera.
Vitreledonella richardi, also known as the glass octopus, is an incirrate octopus. It is in the genus Vitreledonella and of the family Amphitretidae.
Opisthoteuthis californiana, also known as the flapjack octopus or adorabilis, is a species of umbrella octopus.
Sandalops melancholicus, the sandal-eyed squid or melancholy cranch squid, is a small species of glass squid. It is known to reach a mantle length of 11 cm. It is distributed in the tropical and subtropical oceans around the world. It is the only species in the genus Sandalops but some authorities suggest that this may be a species complex rather than a monotypic genus.
Velodona togata is a species of octopus in the monotypic genus Velodona. First described by Carl Chun in 1915, with a second subspecies discovered by Guy Coburn Robson in 1924, it was named for the distinctive membranes on its arms.
Stauroteuthis syrtensis, also known as the glowing sucker octopus or bioluminescent octopus, is a species of small pelagic octopus found at great depths in the north Atlantic Ocean. It is one of a very small number of octopuses to exhibit bioluminescence.
The neon flying squid, sometimes called the red flying squid, akaika, and red squid is a species of large flying squid in the family Ommastrephidae. They are found in subtropical and temperate oceanic waters globally.
Heteroteuthis dispar, also known as the odd bobtail, is a small deep water squid found in the North Atlantic Ocean and the Mediterranean Sea.
Eledone massyae, the combed octopus, is a small benthic octopus found off the Atlantic coasts of southern South America, particularly Argentina and southern Brazil.
Eledone gaucha is a species of octopus from the southern Atlantic Ocean. It is a predator of fish, crabs, lobsters and molluscs.
Teuthowenia megalops, sometimes known as the Atlantic cranch squid, is a species of glass squid from the subarctic and temperate waters of the northern Atlantic Ocean. They are moderately sized squid with a maximum mantle length of 40 cm (16 in). Their very large eyes are the source for the specific name megalops. Like other members of the genus Teuthowenia, they are easily recognizable by the presence of three bioluminescent organs (photophores) on their eyeballs.
Japetella is a genus of pelagic octopods from the subfamily Bolitaeninae in the family Amphitretidae. It contains at least one species but another two have been questionably raised with Japetella heathi being of doubtful validity, although currently accepted and Japetella taningi being classed as a nomen dubium.
Eucleoteuthis is a monotypic genus of squid from the family Ommastrephidae; the only species is Eucleoteuthis luminosa, the striped flying squid or luminous flying squid.
Ornithoteuthis antillarum, the Atlantic bird squid, is a species of flying squid from the family Ommastrephidae which is found in the warmer waters of the Atlantic Ocean. This species is an important component of the diet of many species of fish and of cetaceans. It is taken as a bycatch in fisheries but has the potential to be commercially important if appropriate fishing methods can be developed.
Uroteuthis noctiluca, commonly known as the luminous bay squid, is a species of squid native to shallow water on the eastern coast of Australia. It uses a pair of luminous organs to camouflage itself from predators at night.
Wunderpus photogenicus, the wunderpus octopus, is a small-bodied species of octopus with distinct white and rusty brown coloration. 'Wunderpus' from German “wunder” meaning ‘marvel or wonder’.
Opisthoteuthis agassizii is a lesser-known, deep-sea octopus first described in 1883 by Addison E. Verrill.
