Thecostraca is a class of marine invertebrates containing over 2,200 described species.[1] Many species have planktonic larvae which become sessile or parasitic as adults.
| Thecostraca Temporal range:
| |
|---|---|
| |
| A barnacle of the family Balanidae, Mission Beach, Queensland, Australia, 2001. | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Superclass: | Multicrustacea |
| Class: | Thecostraca Gruvel, 1905 |
| Subclasses | |
The most prevalent subgroup are the barnacles (subclass Cirripedia), constituting a little over 2,100 known species.[1]
The subgroup Facetotecta contains a single genus, Hansenocaris, known only from the tiny planktonic nauplii called "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 larval tantulocaridans. No larval tantulocaridans are currently known.[2]
The group Ascothoracida contains about 110 species, all parasites of coelenterates and echinoderms.[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 the Ascothoracida, and the c-cyprid, or just cyprid, in the Cirripedia.[4][5]
Classification
editThis article follows Chan et al. (2021) and the World Register of Marine Species in placing Thecostraca as a class of Crustacea and in the following classification of thecostracans down to the level of orders. Previously, Thecostraca was considered a subclass of Maxillopoda.[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]
Class Thecostraca Gruvel, 1905
- Subclass Ascothoracida Lacaze-Duthiers, 1880
- Order Laurida Grygier, 1987
- Order Dendrogastrida Grygier, 1987
- Subclass Facetotecta Grygier, 1985
- Subclass Cirripedia Burmeister, 1834
- Infraclass Acrothoracica Gruvel, 1905
- Order Lithoglyptida Kolbasov, Newman & Hoeg, 2009
- Order Cryptophialida Kolbasov, Newman & Hoeg, 2009
- Infraclass Rhizocephala Müller, 1862
- Infraclass Thoracica Darwin, 1854
- Superorder Phosphatothoracica Gale, 2019 (paraphyletic)
- Order Eolepadomorpha Chan et al., 2021 †
- Order Iblomorpha Buckeridge & Newman, 2006
- Superorder Thoracicalcarea Gale, 2015
- Order Calanticomorpha Chan et al., 2021
- Order Brachylepadomorpha Withers, 1923 †
- Order Archaeolepadomorpha Chan et al., 2021 †
- Order Verrucomorpha Pilsbry, 1916
- Order Scalpellomorpha Buckeridge & Newman, 2006
- Order Pollicipedomorpha Chan et al., 2021
- Order Balanomorpha Pilsbry, 1916
- Superorder Phosphatothoracica Gale, 2019 (paraphyletic)
- Infraclass Acrothoracica Gruvel, 1905
Phylogeny
editThe following cladogram depicts the internal relationships of the Thecostraca as of 2021.[1][7]
| Thecostraca | ||
References
edit- ^ 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 b 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.
- ^ 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. PMC 2412843. 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". Retrieved 2021-08-22.
- ^ 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
edit
Data related to Thecostraca at Wikispecies
