Maxillopoda

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Maxillopoda
Temporal range: Mid Cambrian–Recent
Cyclops.jpg
Cyclops (Copepoda: Cyclopoida)
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Maxillopoda
Dahl, 1956 [1]
Sub-classes

Maxillopoda is a diverse class of crustaceans including barnacles, copepods and a number of related animals. It does not appear to be a monophyletic group, and no single character unites all the members.[2]

Description[edit]

With the exception of some barnacles, maxillopodans are mostly small,[3] including the smallest known arthropod, Stygotantulus stocki.[2] They often have short bodies, with the abdomen reduced in size, and generally lacking any appendages.[3] This may have arisen through paedomorphosis.[3]

Apart from barnacles, which use their legs for filter feeding, most maxillopodans feed with their maxillae. They have a bauplan comprising 5 cephalic segments, 6 thoracic segments and 4 abdominal segments, followed by a telson.[4]

Fossil record[edit]

The fossil record of the group extends back into the Cambrian, with fossils of both barnacles[5] and tongue worms[6] known from that period.

Classification[edit]

Six subclasses are generally recognised, although many works have further included the ostracods among the Maxillopoda.[2] Of the six groups, only Mystacocarida are entirely free-living; all the members of the Tantulocarida, Pentastomida and Branchiura are parasitic, and many of the Copepoda and Thecostraca are parasites.

Subclass Members Photo
Copepoda Calanoida
Cyclopoida
Gelyelloida
Harpacticoida
Misophrioida
Monstrilloida
Mormonilloida
Platycopioida
Poecilostomatoida
Siphonostomatoida
Haeckel Copepoda Calocalanus pavo.jpg
Calocalanus pavo
(Calanoida: Calocalanidae)
Thecostraca Cirripedia (barnacles)
Facetotecta
Ascothoracida
Chthamalus stellatus.jpg
Chthamalus stellatus
(Sessilia: Chthamalidae)
Branchiura Arguloida (fish lice)
Cyclida
Argulus.jpg
Argulus on a stickleback
(Argulidae)
Pentastomida
(tongue worms)
Cephalobaenida
Porocephalida
Raillietiellida
Reighardiida
Armillifer armillatus.jpg
Armillifer armillatus
(Porocephalidae)
Mystacocarida Ctenocheilocaris
Derocheilocaris

Ctenocheilocaris
(Derocheilocarididae)
Tantulocarida Basipodellidae
Deoterthridae
Doryphallophoridae
Microdajidae

See also[edit]

References[edit]

  1. ^ "Maxillopoda". Integrated Taxonomic Information System. Retrieved October 7, 2010. 
  2. ^ a b c Joel W. Martin & George E. Davis (2001). An Updated Classification of the Recent Crustacea (PDF). Natural History Museum of Los Angeles County. p. 132. 
  3. ^ a b c "Introduction to Maxillopoda". University of California, Berkeley. Retrieved December 31, 2009. 
  4. ^ Phil Myers (2001). "Maxillopoda". Animal Diversity Web. Retrieved December 31, 2009. 
  5. ^ B. A. Foster & J. S. Buckeridge (1987). "Barnacle palaeontology". In A. J. Southward. Crustacean Issues 5: Barnacle Biology. pp. 41–63. ISBN 90-6191-628-3. 
  6. ^ Dieter Waloszek, John E. Repetski & Andreas Maas (2005). "A new Late Cambrian pentastomid and a review of the relationships of this parasitic group". Transactions of the Royal Society of Edinburgh: Earth Sciences 96: 163–176. doi:10.1017/S0263593300001280. 

External links[edit]