Thecostraca

Quality 0.50 · 1 view · Updated 2 months ago

Class of crustaceans

title: "Thecostraca" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["arthropod-classes"] description: "Class of crustaceans" topic_path: "general/arthropod-classes" source: "https://en.wikipedia.org/wiki/Thecostraca" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Class of crustaceans ::

| fossil_range = | image = Seepocke fg1.jpg | image_caption = A barnacle of the family Balanidae, Mission Beach, Queensland, Australia, 2001. | taxon = Thecostraca | authority = Gruvel, 1905 | subdivision_ranks = Subclasses | subdivision = *Facetotecta

Thecostraca () is a class of marine invertebrates containing over 2,200 described species. Many species have planktonic larvae which become sessile or parasitic as adults.

The most prevalent subgroup are the barnacles (subclass Cirripedia), constituting a little over 2,100 known species.

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.

The group Ascothoracida contains about 110 species, all parasites of coelenterates and echinoderms.

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.

Classification

This 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. 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.

Class Thecostraca Gruvel, 1905

Phylogeny

The following cladogram depicts the internal relationships of the Thecostraca as of 2021. |1=Facetotecta |2={{clade |label1=Ascothoracida|1={{clade |1=Laurida |2=Dendrogastrida |label2=Cirripedia|2={{clade |1={{clade|label1=Acrothoracica|1={{clade |1=Cryptophialida |2=Lithoglyptida |2={{clade |label1=Thoracica|1={{clade |1=Iblomorpha|2=Eolepadomorpha|barbegin1=black|barend2=black |label3=Thoracicalcarea|3={{clade |1=Archaeolepadomorpha |2= |2=Rhizocephala |grouplabel1={{clade labels |width=10em; |label1="Phosphatothoracica"|top1=39%

References

References

  1. Paul Schmid-Hempel. (2011). "Evolutionary Parasitology: the Integrated Study of Infections, Immunology, Ecology, and Genetics". [[Oxford University Press]].
  2. (2008). "Induced metamorphosis in crustacean y-larvae: Towards a solution to a 100-year-old riddle". BMC Biology.
  3. (July 2014). "Atlas of Crustacean Larvae". JHU Press.
  4. Joel W. Martin & George E. Davis. (2001). "An Updated Classification of the Recent Crustacea". [[Natural History Museum of Los Angeles County]].

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

arthropod-classes