Thecostraca

Thecostraca; Temporal range:Carboniferous–Recent PreꞒ Ꞓ O S D C P T J K Pg N
	Abarnacleof the familyBalanidae,Mission Beach, Queensland, Australia, 2001.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Superclass:	Multicrustacea
Class:	Thecostraca; Gruvel,1905
Subclasses
	Facetotecta; Ascothoracida; Cirripedia;

Thecostracais aclassof marineinvertebratescontaining over 2,200 described species.^[1]Many species haveplanktonic larvaewhich becomesessileorparasiticasadults.

The most prevalent subgroup are thebarnacles(subclass Cirripedia), constituting a little over 2,100 known species.^[1]

The subgroupFacetotectacontains a single genus,Hansenocaris,known only from the tiny planktonicnaupliicalled "y-larvae". These larvae have no known adult form, though it is suspected that they are parasites, and their affinity is uncertain. Some researchers believe that they may be larvaltantulocaridans.No larval tantulocaridans are currently known.^[2]

The groupAscothoracidacontains about 110 species, all parasites ofcoelenteratesandechinoderms.^[1]^[3]

The nauplius larvae (sometimes absent) can be both lecithotrophic (non-feeding) and planktotrophic (feeding), and is followed by a larval stage called the cyprid, which is always lecithotrophic. The cypridoid larvae are referred to as the y-cyprid in the Facetotecta, the a-cyprid in theAscothoracida,and the c-cyprid, or just cyprid, in the Cirripedia.^[4]^[5]

Classification

This article follows Chan et al. (2021) and the World Register of Marine Species in placing Thecostraca as a class ofCrustaceaand in the following classification of thecostracans down to the level of orders. Previously, Thecostraca was considered a subclass ofMaxillopoda.^[2]Significant changes in the organization of Cirripedia's orders, families, and genera were introduced in 2021 by Chan et al. and accepted by the World Register of Marine Species.^[1]^[6]

ClassThecostracaGruvel,1905

SubclassAscothoracidaLacaze-Duthiers, 1880
- OrderLauridaGrygier, 1987
- OrderDendrogastridaGrygier, 1987
SubclassFacetotectaGrygier, 1985
SubclassCirripediaBurmeister, 1834
- InfraclassAcrothoracicaGruvel,1905
  - OrderLithoglyptidaKolbasov, Newman & Hoeg, 2009
  - OrderCryptophialidaKolbasov, Newman & Hoeg, 2009
- InfraclassRhizocephalaMüller, 1862
- InfraclassThoracicaDarwin,1854
  - SuperorderPhosphatothoracicaGale, 2019(paraphyletic)
    - OrderEolepadomorphaChan et al., 2021†
    - OrderIblomorphaBuckeridge & Newman, 2006
  - SuperorderThoracicalcareaGale, 2015
    - OrderCalanticomorphaChan et al., 2021
    - OrderBrachylepadomorphaWithers, 1923†
    - OrderArchaeolepadomorphaChan et al., 2021†
    - OrderVerrucomorphaPilsbry, 1916
    - OrderScalpellomorphaBuckeridge & Newman, 2006
    - OrderPollicipedomorphaChan et al., 2021
    - OrderBalanomorphaPilsbry, 1916

Phylogeny

The following cladogram depicts the internal relationships of the Thecostraca as of 2021.^[1]^[7]

References

^^a ^b ^c ^d ^e Chan, Benny K. K.; Dreyer, Niklas; Gale, Andy S.; Glenner, Henrik; et al. (2021)."The evolutionary diversity of barnacles, with an updated classification of fossil and living forms".Zoological Journal of the Linnean Society.193(3): 789–846.doi:10.1093/zoolinnean/zlaa160.hdl:11250/2990967.
^^a ^bJoel W. Martin & George E. Davis (2001).An Updated Classification of the Recent Crustacea(PDF).Natural History Museum of Los Angeles County.pp. 132 pp.
^Paul Schmid-Hempel (2011)."The diversity and natural history of parasites".Evolutionary Parasitology: the Integrated Study of Infections, Immunology, Ecology, and Genetics.Oxford University Press.pp. 18–51.ISBN 978-0-19-922949-9.
^Glenner, H.; Høeg, J. T.; Grygier, M. J.; Fujita, Y. (2008)."Induced metamorphosis in crustacean y-larvae: Towards a solution to a 100-year-old riddle".BMC Biology.6:21.doi:10.1186/1741-7007-6-21.PMC2412843.PMID 18492233.
^Martin, Joel W.; Olesen, Jørgen; Høeg, Jens T. (July 2014).Atlas of Crustacean Larvae.JHU Press.ISBN 978-1-4214-1198-9.
^ "World Register of Marine Species, class Thecostraca".Retrieved2021-08-22.
^Pérez-Losada, Marcos; T. Høeg, Jens; A. Crandall, Keith (September 2021)."Deep Phylogeny and Character Evolution in Thecostraca (Crustacea: Maxillopoda)".Integrative and Comparative Biology.52(3): 430–442.doi:10.1093/icb/ics051.PMID 22532607.

External links

Data related toThecostracaat Wikispecies

[Chan2021-1] Chan, Benny K. K.; Dreyer, Niklas; Gale, Andy S.; Glenner, Henrik; et al. (2021)."The evolutionary diversity of barnacles, with an updated classification of fossil and living forms".Zoological Journal of the Linnean Society.193(3): 789–846.doi:10.1093/zoolinnean/zlaa160.hdl:11250/2990967.

[M&D-2] Joel W. Martin & George E. Davis (2001).An Updated Classification of the Recent Crustacea(PDF).Natural History Museum of Los Angeles County.pp. 132 pp.

[3] Paul Schmid-Hempel (2011)."The diversity and natural history of parasites".Evolutionary Parasitology: the Integrated Study of Infections, Immunology, Ecology, and Genetics.Oxford University Press.pp. 18–51.ISBN 978-0-19-922949-9.

[4] Glenner, H.; Høeg, J. T.; Grygier, M. J.; Fujita, Y. (2008)."Induced metamorphosis in crustacean y-larvae: Towards a solution to a 100-year-old riddle".BMC Biology.6:21.doi:10.1186/1741-7007-6-21.PMC2412843.PMID 18492233.

[5] Martin, Joel W.; Olesen, Jørgen; Høeg, Jens T. (July 2014).Atlas of Crustacean Larvae.JHU Press.ISBN 978-1-4214-1198-9.

[worms-6] "World Register of Marine Species, class Thecostraca".Retrieved2021-08-22.

[PerezLosada-7] Pérez-Losada, Marcos; T. Høeg, Jens; A. Crandall, Keith (September 2021)."Deep Phylogeny and Character Evolution in Thecostraca (Crustacea: Maxillopoda)".Integrative and Comparative Biology.52(3): 430–442.doi:10.1093/icb/ics051.PMID 22532607.

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