Marine Invertebrates Codexery

Tunicate

Marine chordates with a tunic and tadpole-like larvae.

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Tunicate

Nhobgood Nick Hobgood · via Wikipedia: Tunicate · CC BY-SA 3.0

Tunicates are marine invertebrates that have a cellulosic extracellular matrix covering their bodies.[1] About 3,000 species exist in the world's oceans, living mostly in shallow water.[2] They are more closely related to vertebrates than to lancelets or other invertebrates.[3]

Scientific classification

  1. KingdomAnimalia
  2. PhylumChordata
  3. SubphylumTunicata

Named by Lamarck, 1816

Sources: Wikipedia taxobox: Tunicate (CC BY-SA 4.0)

Quick Facts

Subphylum
Tunicata
Number of species
about 3,000
Habitat
marine, mostly shallow water
Key feature
tunic (exoskeleton of proteins and carbohydrates)
Larval stage
  • mobile
  • tadpole-like
  • with chordate features

Facts from the source article.

Key facts and history

The term "tunicate" was coined in 1760 by nurseryman James Lee, meaning "coated or covered with integuments".[4] Jean-Baptiste Lamarck established the group Tunicata in 1816.[5] In 1881, Francis Maitland Balfour proposed the name "Urochorda" for the group, aiming to highlight its chordate affinities, but the earlier name "Tunicata" established by Jean-Baptiste Lamarck in 1816 takes priority.[5] The Middle Cambrian fossil Megasiphon thylakos, which is 500 million years old and exceptionally well-preserved, indicates that the fundamental body plan of tunicates was already present at that time.[6][1]

Certain tunicates are solitary, whereas others form colonies through a budding process, with each colony member called a zooid.[7] Ascidians constitute the most abundant tunicate group; among them, under 100 species occur in waters deeper than 200 meters.[2] Among chordates, only tunicates lack myomeric segmentation, although doliolids retain segmented muscle bands.[8] Tunicates are distinctive among animals because they synthesize a substantial portion of their tunic as cellulose.[9]

What the cited sources add

A 500-million-year-old fossil, Megasiphon thylakos, shows that prehistoric tunicates evolved from tadpole-like larvae to immobile, filter-feeding adults.[1] The fossil demonstrates that most contemporary tunicate body design was already set shortly after the Cambrian Explosion.[1] The Nagalwade article notes that tunicates are mostly absent from the fossil record, with only a few fossils convincingly representing the group.[1] The Daugavet paper discusses that the tunic is composed of proteins crosslinked by phenoloxidase reaction.[10][11]

The Delsuc phylogenomic study provides a framework for comparative studies of tunicates.[12]

References

  1. Nagalwade, "A 500 million-year-old fossil reveals the amazing secrets of tunicate origins", Tech Explorist, 7 July 2023. facts only, no text reused. techexplorist.com
  2. Wikipedia, "Tunicate" (CC BY-SA 4.0), which cites: Ruppert, "Invertebrate Zoology", Cengage Learning, 2004, p. 940–956 (we also read that source) en.wikipedia.org
  3. Wikipedia, "Tunicate" (CC BY-SA 4.0), which cites: "Tunicates and not cephalochordates are the closest living relatives of vertebrates", Nature, 2006, p. 965–968; "Additional molecular support for the new chordate phylogeny", Genesis, 2008, p. 592–604; "Tunicate mitogenomics and phylogenetics: peculiarities of the Herdmania momus mitochondrial genome and support for the new chordate phylogeny", BMC Genomics, 2009, p. 534 (original not read by us) en.wikipedia.org
  4. Wikipedia, "Tunicate" (CC BY-SA 4.0), which cites: "tunicate" (original not read by us) en.wikipedia.org
  5. Wikipedia, "Tunicate" (CC BY-SA 4.0), which cites: Foster, M. (ed.); Sedgwick, Adam (ed.); The Works of Francis Maitland Balfour. Vol. III. Memorial edition. Pub: Macmillan and co. 1885. May be downloaded from (original not read by us) en.wikipedia.org
  6. Wikipedia, "Tunicate" (CC BY-SA 4.0), which cites: Nagalwade, "A 500 million-year-old fossil reveals the amazing secrets of tunicate origins", Tech Explorist, 7 July 2023 (we also read that source) en.wikipedia.org
  7. Wikipedia, "Tunicate" (CC BY-SA 4.0), which cites: Alié, "The eventful history of nonembryonic development in tunicates", Journal of Experimental Zoology Part B: Molecular and Developmental Evolution, 2020-03-19, p. 250–266 (original not read by us) en.wikipedia.org
  8. Wikipedia, "Tunicate" (CC BY-SA 4.0), which cites: Onai T, "The evolutionary origin of chordate segmentation: revisiting the enterocoel theory", Theory Biosci, 2018, p. 1–16; Gee, "Before the Backbone: Views on the origin of the vertebrates", Springer Science & Business Media, 27 July 2007; Bone, "On the Structure and Innervation of the Muscle Bands of Doliolum (Tunicata: Cyclomyaria)", Proceedings of the Royal Society of London. Series B, Biological Sciences, 1974-11-05, p. 315–327 (original not read by us) en.wikipedia.org
  9. Wikipedia, "Tunicate" (CC BY-SA 4.0), which cites: "A functional cellulose synthase from ascidian epidermis", Proceedings of the National Academy of Sciences, 2004, p. 986–991; "Is there intracellular cellulose in the appendicularian tail epidermis? A tale of the adult tail of an invertebrate chordate", Communicative & Integrative Biology, 2011, p. 768–771; "Transcriptional regulation of a horizontally transferred gene from bacterium to chordate", Proceedings of the Royal Society B, 2016; "Transposon-mediated insertional mutagenesis revealed the functions of animal cellulose synthase in the as en.wikipedia.org
  10. Wikipedia, "Tunicate" (CC BY-SA 4.0), which cites: Daugavet, "New putative phenol oxidase in ascidian blood cells", Scientific Reports, 2022-08-22, p. 14326 (we also read that source) en.wikipedia.org
  11. Maria Daugavet, "New putative phenol oxidase in ascidian blood cells", Scientific Reports (2022), doi:10.1038/s41598-022-18283-9. OpenAlex metadata CC0; paper not read. doi.org
  12. Frédéric Delsuc, "A phylogenomic framework and timescale for comparative studies of tunicates", BMC Biology (2018), doi:10.1186/s12915-018-0499-2. OpenAlex metadata CC0; paper not read. doi.org

Each numbered sentence above was checked against the source it cites before publication. Sentences citing Wikipedia adapt text from the English Wikipedia article Tunicate (contributors), used under CC BY-SA 4.0; this entry is available under the same licence. Other sources were used for facts only; no text or images are copied from them.

Related entries

Named in this entry

PhylumCarbohydrate

Also in the Codexery

Tunicate · Aquatic Invertebrates

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Sources

Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.

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