A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata. It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords. The subphylum was at one time called Urochordata, and the term urochordates is still sometimes used for these animals. They are the only chordates that have lost their myomeric segmentation, with the possible exception of the 'seriation of the gill slits'.
Larvaceans, Class Appendicularia are solitary, free-swimming tunicates found throughout the world's oceans. Like most tunicates, larvaceans are filter feeders. Unlike most other tunicates, they live in the pelagic zone, specifically in the photic zone, or sometimes deeper. They are transparent planktonic animals, generally less than 1 cm (0.39 in) in body length, excluding the tail.
Ascidiacea, commonly known as the ascidians, tunicates, and sea squirts, is a polyphyletic class in the subphylum Tunicata of sac-like marine invertebrate filter feeders. Ascidians are characterized by a tough outer "tunic" made of a polysaccharide.
Molgula, or sea grapes, are very common, globular, individual marine tunicates roughly the size of grapes.
Corella willmeriana is a solitary tunicate in the family Corellidae. It is native to the eastern Pacific Ocean where it lives on the seabed at depths down to about 75 m (250 ft) between Alaska and California.
Didemnum molle is a species of colonial tunicate in the family Didemnidae. It is commonly known as the tall urn ascidian, the green barrel sea squirt or the green reef sea-squirt. It is native to the Red Sea and the tropical waters of the Indo-Pacific region.
Ciona savignyi is a marine animal sometimes known as the Pacific transparent sea squirt or solitary sea squirt. It is a species of tunicates in the family Cionidae. It is found in shallow waters around Japan and has spread to the west coast of North America where it is regarded as an invasive species.
Ascidia mentula is a species of solitary tunicate. It is found in the north east Atlantic Ocean, the Mediterranean Sea and Black Sea. It occurs round the coasts of Britain but is seldom seen on the east coast of England or Scotland.
Molgula oculata, commonly known as the sea grape, is a species of solitary tunicate in the family Molgulidae. It is native to the north eastern Atlantic Ocean and the North Sea. The specific name oculata means "having eyes"; the species has orifices which "seem like dark eyes within a spectacle-formed frame".
Okenia aspersa is a species of sea slug, a Dorid nudibranch, a marine gastropod mollusc in the family Goniodorididae.
Okenia leachii is a species of sea slug, a Dorid nudibranch, a marine gastropod mollusc in the family Goniodorididae.
Polycarpa fibrosa is a species of tunicate in the family Styelidae. It is brown and globular and its outer surface is covered with a mat of fibrils. It normally lies buried in soft sediment on the seabed with only its two siphons protruding. It occurs in the Arctic Ocean and northern Atlantic Ocean. P. fibrosa was first identified and described by the American malacologist William Stimpson in 1852.
Molgula citrina is a species of solitary tunicate in the family Molgulidae. It is found on both sides of the northern Atlantic Ocean and in the Arctic Ocean. In 2008 it was found in Kachemak Bay in Alaska, the first time it had been detected in the Pacific Ocean.
Polycarpa pomaria is a species of tunicate or sea squirt in the family Styelidae. It is native to the northeastern Atlantic Ocean where it lives on the seabed at depths down to about 450 metres (1,500 ft).
Phallusia mammillata is a solitary marine tunicate of the ascidian class found in the eastern Atlantic Ocean and the Mediterranean Sea.
Corella eumyota, the orange-tipped sea squirt, is a solitary tunicate in the family Corellidae. It is native to the Southern Ocean, the Antarctic, South America, southern Australia, New Zealand and South Africa, and has been introduced into European waters where it has become invasive.
Molgula occidentalis is a species of marine invertebrate of the family Molgulidae. The scientific name of the species was validated and published for the first time in 1883 by Traustedt. It is a soft-bodied, intertidal ascidian, sac-like filter feeders in the subphylum tunicate characterized by a hard outer covering known as a “tunic,” abundant in the shallow subtidal and intertidal zones of the Northern Gulf of Mexico, where they establish pseudopopulations.
Boltenia villosa is a species of tunicate, a marine invertebrate of the family Pyuridae. Common names include the spiny-headed tunicate, the hairy sea squirt, the stalked hairy sea squirt and the bristly tunicate. This species was first described in 1864 by the American marine biologist William Stimpson who gave it the name Cynthia villosa. It was later transferred to the genus Boltenia. The type locality is Puget Sound, Washington state, United States.
Cnemidocarpa finmarkiensis is a species of solitary ascidian tunicate in the family Styelidae. Common names include broad base sea squirt, orange sea squirt, red sea squirt, shiny orange sea squirt, shiny red tunicate and Finmark's tunicate. It is native to shallow waters in the northern and northeastern Pacific Ocean.
Pyura haustor is a species of sessile ascidian, or sea squirt, that lives in coastal waters in the north-eastern Pacific Ocean, attached to rocks or artificial structures. Common names for this species include the wrinkled seapump, the wrinkled sea squirt and the warty tunicate.
