A squid is a mollusc with an elongated soft body, large eyes, eight arms, and two tentacles in the orders Myopsida, Oegopsida, and Bathyteuthida. 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.
A cephalopod is any member of the molluscan class Cephalopoda such as a squid, octopus, cuttlefish, or nautilus. These exclusively marine animals are characterized by bilateral body symmetry, a prominent head, and a set of arms or tentacles modified from the primitive molluscan foot. Fishers sometimes call cephalopods "inkfish", referring to their common ability to squirt ink. The study of cephalopods is a branch of malacology known as teuthology.
Bobtail squid are a group of cephalopods closely related to cuttlefish. Bobtail squid tend to have a rounder mantle than cuttlefish and have no cuttlebone. They have eight suckered arms and two tentacles and are generally quite small.
Sepiolidae is a family of bobtail squid encompassing 15 genera in three or four subfamilies. A gladius is absent in subfamily Heteroteuthidinae, and in subfamily Sepiolinae it is reduced, or absent like in genus Euprymna. A third subfamily is Rossiinae, and the genus Choneteuthis is considered to be Incertae sedis. Though 72 species have been recognized in Sepiolidae, the validity of a few of them has been questioned.
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 pharaoh cuttlefish is a large cuttlefish species, growing to 42 cm in mantle length and 5 kg in weight.
Sepietta oweniana is a common marine mollusc from the order Sepiida, the cuttlefish.
Sepia mestus, also known as the reaper cuttlefish or red cuttlefish, is a species of cuttlefish native to the southwestern Pacific Ocean, specifically Escape Reef off Queensland to Murrays Beach off Jervis Bay. Reports of this species from China and Vietnam are now known to be misidentifications. S. mestus lives at a depth of between 0 and 22 m.
Euprymna scolopes, also known as the Hawaiian bobtail squid, is a species of bobtail squid in the family Sepiolidae native to the central Pacific Ocean, where it occurs in shallow coastal waters off the Hawaiian Islands and Midway Island. The type specimen was collected off the Hawaiian Islands and is located at the National Museum of Natural History in Washington, D.C.
Idiosepius thailandicus, also known as the thai pygmy squid, is a species of bobtail squid native to the Indo-Pacific waters off Thailand. The extent of this species' distribution is still to be determined and records of Idiosepius dwarf squid away from Thailand, south to Indonesia and north to Japan, may be attributable to this species.
Sepiola atlantica, also known as the Atlantic bobtail, is a species of bobtail squid native to the northeastern Atlantic Ocean and the Mediterranean Sea.
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.
Sepioteuthis lessoniana, commonly known as the bigfin reef squid, tiger squid, glitter squid, oval squid, or northern calamari, is a 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.
Illex coindetii, commonly known as the southern shortfin squid or broadtail shortfin squid, is a species of neritic squids in the family Ommastrephidae. They are found in the Mediterranean Sea and on both sides of the north Atlantic Ocean.
Euprymna berryi, commonly called hummingbird bobtail squid or Berry's bobtail squid among various other vernacular names, is a species of mollusc cephalopod in the family Sepiolidae.
Rossia pacifica, also known as the stubby squid, is a species of bobtail squid native to the northern Pacific Ocean. It usually occurs in winter on sandy slopes away from strong currents in moderately shallow water. In summer it moves to deeper water where it breeds. The female cements the egg capsules under a stone or in some other concealed location, and both male and female die soon after breeding.
Neorossia caroli, the Carol bobtail squid, is a species of bobtail squid belonging to the family Sepiolidae.
Euprymna morsei, the Mimika bobtail squid, is a species of Indo-Pacific bobtail squid from the family Sepiolidae.
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.
Rossia is a genus of 10 species of benthic bobtail squid in the family Sepioidae found in all oceans. They live at depths greater than 50 m (164 ft) and can grow up to 9 cm in mantle length. This genus was first discovered in 1832 by Sir John Ross and his nephew James Clark Ross in the Arctic Seas, showing a resemblance to another genus under the same family, Sepiola. After returning from their expedition, Sir Richard Owen officially classified Rossia to be a new genus, naming it after Sir John and James Clark Ross.
