| Phallusia mammillata | |
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| Species: | P. mammillata |
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| Phallusia mammillata (Cuvier, 1815) [1] | |
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Phallusia mammillata is a solitary marine tunicate of the ascidian class found in the eastern Atlantic Ocean and the Mediterranean Sea.
Phallusia mammillata is a solitary species of ascidian and can grow to a height of about 20 cm (8 in). The tunic is a translucent, bluish-white colour and is covered with irregular rounded lobes or mounds. [2]
This tunicate is found on rocky, sandy or muddy substrates in the northeastern Atlantic Ocean, the North Sea, the English Channel and the Mediterranean Sea to depths of about 200 m (656 ft). [2]
Like all tunicates, Phallusia mammillata has a thick leathery tunic containing a cellulosic material. The tunic encloses a sac-shaped cavity with separate siphons through which water is drawn in and expelled. The animal feeds on the planktonic particles that it filters from the incoming seawater by passing it through a mucous net. [3]
P. mammillata is one of a small number of ascidians that accumulate the element vanadium in their blood cells. [4] It is unclear why the tunicate should do this, but concentrations of up to 350 mM have been found, some ten million times higher than in the surrounding seawater. The ascidian has at least ten different types of blood cell, and the vanadium-accumulating cells have been shown to be "vacuolated and granular amoebocytes, signet ring cells and type-II compartment cells". [4]
Each P. mammillata individual is a hermaphrodite. Eggs are released through the exhalent siphon and external fertilization in the water column takes place. The eggs hatch into free-swimming, tadpole-like larvae, which within a few days settle on the seabed and undergo metamorphosis into juveniles. [5]
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'.
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.
Vanabins are a specific group of vanadium-binding metalloproteins. Vanabins are found almost exclusively in the blood cells, or vanadocytes, of some tunicates, including the Ascidiacea. The vanabins extracted from tunicate vanadocytes are often called hemovanadins. These organisms are able to concentrate vanadium to a level more than, and sometimes much more than, 100 times higher than in the surrounding seawater. Vanabin proteins seem to be involved in collecting and accumulating this metal ion. At present there is no conclusive understanding of why these organisms collect vanadium.
Ciona is a genus of sea squirts in the family Cionidae.
Botrylloides leachii is a colonial tunicate of the family Styelidae. Its unique methods of propagation and regeneration make it an ideal model organism for use in biological study of development, immunology, stem cells, and regeneration.
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.
Phallusia is a genus of tunicates of the family ascidians, which includes the following species:
Phallusia nigra is a solitary marine tunicate of the ascidian class found in tropical seas around the world. It usually lives in shallow waters, attached to any hard substrate.
Ecteinascidia turbinata, the mangrove tunicate, is a sea squirt species in the genus Ecteinascidia, which was described to science in 1880 by William Abbott Herdman. The cancer drug trabectedin is isolated from E. turbinata.
Pyura chilensis, called piure in Spanish, is a tunicate of the family Pyuridae. It was described in 1782 by Juan Ignacio Molina.
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 occulta is a species of solitary tunicate in the family Molgulidae. It is native to the north eastern Atlantic Ocean, the North Sea and the Mediterranean Sea. The specific name occulta means "tailless" and refers to the tunicate's larva, which lacks the tail found in some other species in the genus Molgula.
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).
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.
Halocynthia igaboja, commonly known as the sea hedgehog, the bristly tunicate or spiny sea squirt, is a species of tunicate in the family Pyuridae. It is native to the northeastern Pacific Ocean. This species was first described in 1906 by the Japanese marine biologist Asajiro Oka, who gave it the name Cynthia ritteri. It was later transferred to the genus Halocynthia.