A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata (/ˌtjuːnɪˈkeɪtə/TEW-nih-KAY-tə). It is part of the Chordata, a phylum which includes all animals with dorsal nerve cords and notochords (including vertebrates). 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'.[8][9] However, doliolids still display segmentation of the muscle bands.[10]
Some tunicates live as solitary individuals, but others replicate by budding and become colonies,[11] each unit being known as a zooid. They are marine filter feeders with a water-filled, sac-like body structure and two tubular openings, known as siphons, through which they draw in and expel water. During their respiration and feeding, they take in water through the incurrent (or inhalant) siphon and expel the filtered water through the excurrent (or exhalant) siphon. Adult ascidian tunicates are sessile, immobile and permanently attached to rocks or other hard surfaces on the ocean floor. Thaliaceans (pyrosomes, doliolids, and salps) and larvaceans on the other hand, swim in the pelagic zone of the sea as adults.
Various species of ascidians, the most well-known class of tunicates, are commonly known as sea squirts, sea pork, sea livers, or sea tulips.
The earliest probable species of tunicate appears in the fossil record in the early Cambrian period. Despite their simple appearance and very different adult form, their close relationship to the vertebrates is evidenced by the fact that during their mobile larval stage, they possess a notochord or stiffening rod and resemble a tadpole. Their name derives from their unique outer covering or "tunic", which is formed from proteins and carbohydrates, and acts as an exoskeleton. In some species, it is thin, translucent, and gelatinous, while in others it is thick, tough, and stiff.
^Yang, Chuan; Li, Xian-Hua; Zhu, Maoyan; Condon, Daniel J.; Chen, Junyuan (2018). "Geochronological constraint on the Cambrian Chengjiang biota, South China" (PDF). Journal of the Geological Society. 175 (4): 659–666. Bibcode:2018JGSoc.175..659Y. doi:10.1144/jgs2017-103. ISSN 0016-7649. S2CID 135091168.
^Fedonkin, M. A.; Vickers-Rich, P.; Swalla, B. J.; Trusler, P.; Hall, M. (2012). "A new metazoan from the Vendian of the White Sea, Russia, with possible affinities to the ascidians". Paleontological Journal. 46 (1): 1–11. Bibcode:2012PalJ...46....1F. doi:10.1134/S0031030112010042. S2CID 128415270.
^Martyshyn, Andrej; Uchman, Alfred (1 December 2021). "New Ediacaran fossils from the Ukraine, some with a putative tunicate relationship". PalZ. 95 (4): 623–639. Bibcode:2021PalZ...95..623M. doi:10.1007/s12542-021-00596-1. ISSN 1867-6812. S2CID 244957825.
^ abSanamyan, Karen (2013). "Tunicata". WoRMS. World Register of Marine Species. Retrieved 4 April 2013.
^Nielsen, C. (2012). "The authorship of higher chordate taxa". Zoologica Scripta. 41 (4): 435–436. doi:10.1111/j.1463-6409.2012.00536.x. S2CID 83266247.
^Giribet, Gonzalo (27 April 2018). "Phylogenomics resolves the evolutionary chronicle of our squirting closest relatives". BMC Biology. 16 (1): 49. doi:10.1186/s12915-018-0517-4. ISSN 1741-7007. PMC 5924484. PMID 29703197.
^Cite error: The named reference Tatian was invoked but never defined (see the help page).
^Onai T (2018). "The evolutionary origin of chordate segmentation: revisiting the enterocoel theory". Theory Biosci. 137 (1): 1–16. doi:10.1007/s12064-018-0260-y. PMID 29488055. S2CID 3553695.
^Gee, H. (27 July 2007). Before the Backbone: Views on the origin of the vertebrates. Springer Science & Business Media. ISBN 9780585252728 – via Google Books.
^Bone, Q., and K. P. Ryan (1974). "On the Structure and Innervation of the Muscle Bands of Doliolum (Tunicata: Cyclomyaria)". Proceedings of the Royal Society of London. Series B, Biological Sciences. 187 (1088): 315–327. Bibcode:1974RSPSB.187..315B. doi:10.1098/rspb.1974.0077. JSTOR 76405. PMID 4154453. S2CID 20806327. Retrieved 13 May 2023.{{cite journal}}: CS1 maint: multiple names: authors list (link)
^Alié, Alexandre; Hiebert, Laurel S.; Scelzo, Marta; Tiozzo, Stefano (19 March 2020). "The eventful history of nonembryonic development in tunicates". Journal of Experimental Zoology Part B: Molecular and Developmental Evolution. 336 (3): 250–266. doi:10.1002/jez.b.22940. PMID 32190983. S2CID 213181394.
A tunicate is a marine invertebrate animal, a member of the subphylum Tunicata (/ˌtjuːnɪˈkeɪtə/ TEW-nih-KAY-tə). It is part of the Chordata, a phylum which...
grape”) or salpa (plural salpae or salpas) is a barrel-shaped, planktonic tunicate in the family Salpidae. It moves by contracting, thereby pumping water...
The predatory tunicate (Megalodicopia hians), also known as the ghostfish, is a species of tunicate which lives anchored along deep-sea canyon walls and...
Bristly tunicate is a common name for several tunicates and may refer to: Boltenia villosa Halocynthia igaboja This page is an index of articles on animal...
membrane protease ATP23, which are exclusively shared by all vertebrates, tunicates and cephalochordates. These CSIs provide molecular means to reliably distinguish...
solitary, subtidal ascidian tunicate. It has a variety of common names such as the stalked sea squirt, clubbed tunicate, Asian tunicate, leathery sea squirt...
Pyura pachydermatina is a sea tulip, a solitary species of tunicate in the suborder Stolidobranchia. It is native to shallow waters around New Zealand...
intestinalis (sometimes known by the common name of vase tunicate) is an ascidian (sea squirt), a tunicate with very soft tunic. Its Latin name literally means...
ascidian tunicate. It is commonly known as the star tunicate, but it also has several other common names, including star ascidian and golden star tunicate. Colonies...
Clavelina moluccensis, common name bluebell tunicate, blue bell tunicate, or blue sea squirt is a species of tunicate (sea squirt), in the genus Clavelina (the...
Memories of a Tunicate is an album by saxophonist Peter Brötzmann and cellist and electronic musician Fred Lonberg-Holm. Featuring seven free improvisations...
Clavelina picta, common name the painted tunicate, is a species of tunicate (sea squirt), in the genus Clavelina (the "little bottles"). These animals...
Ecteinascidia turbinata, commonly known as the mangrove tunicate, is a species of sea squirt species in the family Perophoridae. It was described to science...
chain tunicate, but has also been called several other common names, including: lined colonial tunicate, orange sheath tunicate, orange tunicate, and violet...
Thetys vagina, or the twin-sailed salp, is the largest known solitary species of salp and the only valid species of the genus Thetys. First described...
the genera Allium, Hippeastrum, Narcissus, and Tulipa all have tunicate bulbs. Non-tunicate bulbs, such as Lilium and Fritillaria species, lack the protective...
sea lampreys, zebra mussels, smallmouth bass, European green crab, vase tunicate, and sea squirts. The sea lamprey began migrating to fresh water like Lake...
reproduction at low population density. Botryllus schlosseri is a colonial tunicate able to reproduce both sexually and asexually. B. schlosseri is a sequential...
chilensis, called piure in Spanish and piür or piwü in Mapudungun, is a tunicate of the family Pyuridae. It was described in 1782 by Juan Ignacio Molina...
red tunicate and Finmark's tunicate. It is native to shallow waters in the northern and northeastern Pacific Ocean. This is a solitary tunicate, which...
a species of colonial tunicate in the family Didemnidae. It is commonly called sea vomit, marine vomit, pancake batter tunicate, or carpet sea squirt...
the gold-mouth sea squirt or the ink-spot sea squirt, is a species of tunicate in the family Styelidae. Polycarpa aurata grows to a height of 5 to 15 cm...
deposits of China, and was initially compared to the tunicates. It was originally described as a tunicate, though, this identification has been questioned...
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