A squid is a mollusc 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.
Bathyteuthis is the singular genus of squid in the family Bathyteuthidae, encompassing three species.
Histioteuthidae is a family of Oegopsid squid. The family was previously considered to be monotypic but the World Register of Marine Species assigns two genera to this family.
The firefly squid, also commonly known as the sparkling enope squid or hotaru-ika in Japan, is a species of squid in the family Enoploteuthidae. W. scintillans is the sole species in the monotypic genus Watasenia. These tiny squid are found on the shores of Japan in springtime during spawning season, but spend most of their lives in deeper waters between 200 and 400 metres. They are bioluminescent organisms and emit blue light from photophores, which some scientists have hypothesized could be used for communication, camouflage, or attracting food, but it is still unclear in the scientific community exactly how this species uses their bioluminescence. The firefly squid is a predator and actively hunts its food, which includes copepods, small fish, and other squids. The lifespan of a firefly squid is about one year. At the end of their lives, females return close to shore to release their eggs and then die shortly thereafter. This mass migration of firefly squid to the shore is a lucrative business for Japanese fishermen, and during spawning season many go out to the bays to collect the dying squid. Many more also visit Japan during spawning season to see the bright blue light created from the firefly squid's bioluminescence light up the bay, making their spawning season not only a fishing opportunity but also a tourist attraction.
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.
Taningia danae, the Dana octopus squid, is a species of squid in the family Octopoteuthidae. It is one of the largest known squid species, reaching a mantle length of 1.7 m (5.6 ft) and total length of 2.3 m (7.5 ft). The largest known specimen, a mature female, weighed 161.4 kg (356 lb).
Loligo reynaudii, commonly known as the Cape Hope squid, is a 20–30 cm long squid belonging to the family Loliginidae. In South Africa it is known as either calamari or chokka.
Histioteuthis bonnellii, the umbrella squid, is a species of cock-eyed squid belonging to the family Histioteuthidae.
Histioteuthis reversa, commonly known as the reverse jewel squid or the elongate jewel squid, is a species of cock-eyed squid, so called because the eyes are dissimilar. It occurs at moderate depths in the Atlantic Ocean and Mediterranean Sea and is also known from the Indian Ocean.
Stigmatoteuthis arcturi, commonly known as the jewelled squid, is a species of cock-eyed squid from the family Histioteuthidae. It occurs throughout the subtropical and tropical Atlantic Ocean in the mesopelagic zone.
Counter-illumination is a method of active camouflage seen in marine animals such as firefly squid and midshipman fish, and in military prototypes, producing light to match their backgrounds in both brightness and wavelength.
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.
Cephalopods exhibit various dermal structures on their mantles and other parts. These may take the form of conspicuous warts, cushions, papillae or scales, though in many species they are microscopic tubercles. The most elaborate forms are found among the oceanic squid of the order Teuthida.
Histioteuthis heteropsis, also known as the strawberry squid, is a species of small cock-eyed squid. The scientific nomenclature of these squid stems from their set of differently sized eyes, one being small and blue and the other being large and yellow. It is thought that the large eye is used to see objects against dim light, while the smaller eye is more able to view bioluminescent light sources. The squid's vernacular name arose due to its rich red skin pigmentation and the presence of photophores along its body, making it appear like a strawberry with seeds.
Enoploteuthis leptura, the hooked enope squid, is a species of squid from the family Enoploteuthidae. It is the type species of the genus Enoploteuthis, which is in turn the type genus of the Enoploteuthidae.
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.
The little flying squid is a species of squid, one of the arrow squids of the genus Todarodes, in the subfamily Todarodinae of the flying squid family Ommastrephidae. It is a small species from the waters around northern Australia and Indonesia.
Histioteuthis meleagroteuthis is a species of small to medium squids that have a dark, wine red skin pigment. Females at maturity average at 114mm in length, while males at maturity average at 65-102mm in length. This species is characterized by tubercles, photophores, and asymmetric features. This species can be found in circumglobal, mesopelagic waters.
