The family Cranchiidae comprises the approximately 60 species of glass squid, also known as cockatoo squid, cranchiid, cranch squid, or bathyscaphoid squid. Cranchiid squid occur in surface and midwater depths of open oceans around the world. They range in mantle length from 10 cm (3.9 in) to over 3 m (9.8 ft), in the case of the colossal squid. The common name, glass squid, derives from the transparent nature of most species. Cranchiid squid spend much of their lives in partially sunlit shallow waters, where their transparency provides camouflage. They are characterised by a swollen body and short arms, which bear two rows of suckers or hooks. The third arm pair is often enlarged. Many species are bioluminescent organisms and possess light organs on the undersides of their eyes, used to cancel their shadows. Eye morphology varies widely, ranging from large and circular to telescopic and stalked. A large, fluid-filled chamber containing ammonia solution is used to aid buoyancy. This buoyancy system is unique to the family and is the source of their common name "bathyscaphoid squid", after their resemblance to a bathyscaphe. Often the only organ that is visible through the transparent tissues is a cigar-shaped digestive gland, which is the cephalopod equivalent of a mammalian liver. This is usually held in a vertical position to reduce its silhouette and a light organ is sometimes present on the lower tip to further minimise its appearance in the water.
Bigfin squids are a group of rarely seen cephalopods with a distinctive morphology. They are placed in the genus Magnapinna and family Magnapinnidae. Although the family is known only from larval, paralarval, and juvenile specimens, some authorities believe adult specimens have also been seen. Several videos have been taken of animals nicknamed the "long-arm squid", which appear to have a similar morphology. Since none of the seemingly adult specimens have ever been captured or sampled, it remains uncertain if they are of the same genus or only distant relatives.
Brachioteuthidae is a family of squid containing two genera and around six species.
Decapodiformes is a superorder of Cephalopoda, which includes all species with ten limbs; the name derives from the Greek word meaning ten feet. The ten limbs are divided into eight short arms and two long tentacles. It is hypothesized that the ancestral coleoid 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.
Euprymna tasmanica, also known as the southern dumpling squid or southern bobtail squid, is a bobtail squid that lives in the shallow temperate coastal waters of southern Australia's continental shelf. It lives for between 5 and 8 months and the adults can grow up to 6 or 7 cm long with a mantle length of 3 to 4 cm. They are found in seagrass beds or areas with soft silty or muddy bottoms from Brisbane on the east coast to Shark Bay on the west, as well as around Tasmania. Southern dumpling squid are nocturnal and during the day hide in sand or mud covered in a mucus-lined coat of sediment. If disturbed acid glans can quickly remove this coat as an additional decoy to ink squirting.
The European squid or common squid is a large squid belonging to the family Loliginidae. It occurs abundantly in coastal waters from the North Sea to at least the west coast of Africa. This species lives from sea level to depths of 500 m (1,600 ft). Its mantle is up to 40 cm (16 in) long. The species is extensively exploited by commercial fisheries.
Megalocranchia fisheri is a species of glass squid. Its natural range covers at least the waters off Hawaii. The species may attain a mantle length of 1.8 m (5.9 ft) and a total length of over 2.7 m (8.9 ft), making it one of the largest species of squid, together with the colossal squid, giant squid, and robust clubhook squid. It inhabits surface and mid-depth waters of open ocean. Juveniles live near the surface, while adults occupy mesopelagic depths during the day and migrate to near-surface waters at night. M. fisheri possesses two large light organs in the gill cavity. Females additionally have light organs on the ends of their third arm pair. As the animal matures, its fins become spear-like in appearance.
Galiteuthis phyllura, also known as the cockatoo squid, is a species of glass squid, possibly the largest in the genus.
Chtenopteryx sicula, also known as the comb-finned squid or toothed-fin squid, is a species of squid native to at least the Mediterranean Sea. It is characterised by several distinct morphological features: ocular photophores are present but visceral photophores are absent, arm suckers are arranged in at least 4 series distally, and club suckers are borne in more than 8 series.
All cephalopods possess flexible limbs extending from their heads and surrounding their beaks. These appendages, which function as muscular hydrostats, have been variously termed arms, legs or tentacles.
Abraliopsis is a genus of squid in the family Enoploteuthidae comprising 11 nominal species. Species are characterised by the presence of photophores on arm pair IV. Suckers are absent from this arm. The type species is Abraliopsis hoylei.
The colossal squid, sometimes called the Antarctic squid or giant cranch squid, is believed to be the largest squid species in terms of mass. It is the only known member of the genus Mesonychoteuthis. It is known from only a few specimens, and current estimates put its maximum size at 12–14 m (39–46 ft) long and weighing possibly up to 750 kilograms (1,650 lb), based on analysis of smaller and immature specimen, making it the largest-known invertebrate.
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.
Sepioteuthis lessoniana, commonly known as the bigfin reef squid or oval squid, is a commercially important species of loliginid squid. It is one of the three currently recognized species belonging to the genus Sepioteuthis. Studies in 1993, however, have indicated that bigfin reef squids may comprise a cryptic species complex. The species is likely to include several very similar and closely related species.
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.
Doryteuthis is a genus of squid from the waters of the western Atlantic and eastern Pacific off the coast of the Americas species are the common inshore squids of American waters. Some species are important quarry species for fisheries.
Loliolus is a genus of squid from the family Loliginidae from the Indo-Pacific region. The genus is divided into two subgenera Loliolus and Nipponololigo. They are small squids of less than 150mm in mantle length which have an expanded tentacular club. This club has 4 series of suckers. The sucker ringss have plate-like teeth which are square in shape all around them. The males' hectocotylus has a ventral crest which is created by the fusion of the protective membrane with the ventral series of papillae and this crest completely obscures the conical shape of the papillae. The mantle is rounded posteriorly and lacks the posterior tail-like lobe while the fins are positioned on the rear of the mantle and extend to the posterior tip of the mantle. Their eggs are small and the males' spermatophore has a short cement body. They do not possess photophores. The two subgenera are distinguished by the hectocotylus which in Loliolus encompasses the enire arm and there are no unmodified suckers while in Nipponololigo the arm is only partly hectocotylsed and has normal suckers at its base.
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.
