Overview
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
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
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
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 fr ee-living; all the members of the Tantulocarida, Pentastomida and Branchiura are parasitic, and many of the Copepoda and Thecostraca are parasites.
related animals. It does not appear to be a monophyletic group, and no single character unites all the members.2]Description
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 leg s 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
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
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, Pentastomid a and Branchiura are parasitic, and many of the Copepoda and Thecostraca are parasites.
References
- ^ "Maxillopoda". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=621145. Retrieved October 7, 2010.
- ^ a b c Joel W. Martin & George E. Davis (2001) (PDF). An Updated Classification of the Recent Crustacea. Natural History Museum of Los Angeles County. pp. 132. http://atiniui.nhm.org/pdfs/3839/3839.pdf.
- ^ a b c "Introduction to Maxillopoda". University of California, Berkeley. http://www.ucmp.berkeley.edu/arthropoda/crustacea/maxillopoda.html. Retrieved December 31, 2009.
- ^ Phil Myers (2001). "Maxillopoda". Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/Maxillopoda.html. Retrieved December 31, 2009.
- ^ 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.
- ^ 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.
Taxonomy
The Class Maxillopoda is further organized into finer groupings including:
- Subclass (7): Branchiura · Copepoda · Halicyna · Mystacocarida · Pentastomida · Tantulocarida · Thecostraca
- Infraclass (4): Ascothoracida · Cirripedia · Neocopepoda · Progymnoplea
- Order (23): Akentrogonida · Apygophora · Arguloida · Calanoida · Cephalobaenida · Cycloidea · Cyclopoida · Dendrogastrida · Harpacticoida · Kentrogonida · Laurida · Misophrioida · Monstrilloida · Mormonilloida · Mystacocaridida · Pedunculata · Platycopioida · Poecilostomatoida · Porocephalida · Pygophora · Sessilia · Siphonostomatoida · Tantulocarida
- Species: ZipcodeZoo has pages for 3,310 species and subspecies in the Class Maxillopoda.
Orders
Akentrogonida
Apygophora
Arguloida
The family Argulidae contains the carp lice or fish lice ? a group of parasitic crustaceans of uncertain position within the Maxillopoda. Although they are thought to be forms, they have no fossil record. Argulidae is the only family in the order Arguloida (occasionally "Arguloidea"), although a second family, Dipteropeltidae, has been proposed. [more]
Calanoida
Calanoida is an order of copepods, a kind of zooplankton. They include around 40 families with about 1800 species of both marine and freshwater copepods. Calanoid copepods are dominant in the plankton in many parts of the world's oceans, making up 55%?95% of plankton samples. They are therefore important in many food webs, taking in energy from phytoplankton and algae and 'repackaging' it for consumption by higher trophic level predators. Many commercial fishes are dependent on calanoid copepods for diet in either their larval or adult forms. Baleen whales such as bowhead whales, sei whales, right whales and fin whales eat calanoid copepods. [more]
Cephalobaenida
Cycloidea
Cyclopoida
Cyclopoida is an order of small crustaceans from the subclass Copepoda. Like many other copepods, members of Cyclopoida are small, planktonic animals living both in the sea and in freshwater habitats. They are capable of rapid movement. Their larval development is metamorphic, and the embryos are carried in paired or single sacs attached to first abdominal somite. [more]
Dendrogastrida
Harpacticoida
Harpacticoida is an order of copepods, in the Subphylum Crustacea. This order comprises 463 genera and about 3,000 species. Members of it are benthic copepods found throughout the world in the marine environment (most families) and in fresh water (essentially the , Parastenocarididae and the Canthocamptidae). A few of them are planktonic or live in association with other organisms. Harpacticoida represents the second-largest meiofaunal group in marine sediment milieu, after nematodes. In Arctic and Antarctic seas, Harpacticoida are common inhabitants of sea ice. [more]
Kentrogonida
Laurida
Misophrioida
Misophrioida is an order of copepods, containing the following families: [more]
Monstrilloida
Monstrilloida is an order of copepods with a cosmopolitan distribution in the world's oceans. The order contains a single family, Monstrillidae; the family was formerly included in the order, but is now usually placed in the Cyclopoida. The taxonomy of the family is undergoing a period of revision, although some necessary changes are apparent; for instance, the genus Strilloma is now considered a taxonomic synonym of Monstrilla, the largest genus. [more]
Mormonilloida
Mystacocaridida
Mystacocarida is a subclass of crustaceans, that form part of the meiobenthos. They are less than 1 mm (0.04 in) long, and live interstitially in the intertidal zones of sandy beaches. [more]
Pedunculata
Goose barnacles (order Pedunculata), also called stalked barnacles or gooseneck barnacles, are filter-feeding crustaceans that live attached to hard surfaces of rocks and flotsam in the ocean intertidal zone. [more]
Platycopioida
Poecilostomatoida
Poecilostomatoida are an order of copepods previously included in the Cyclopoida. [more]
Porocephalida
Pygophora
Sessilia
Sessilia is an order of barnacles, comprising the barnacles without stalks, or acorn barnacles. They form a monophyletic group and are probably derived from stalked barnacles. The order is divided into three suborders. Brachylepadomorpha contains a single family, , while Verrucomorpha contains two families, Verrucidae and Neoverrucidae. The remaining twelve families are in the suborder Balanomorpha. [more]
Siphonostomatoida
Siphonostomatoida are copepods of the order of the subclass Maxillopoda, inside the subphylum Crustacea. There are 42 recognised families: [more]
Tantulocarida
At least 4 species and subspecies belong to the Order Tantulocarida.
More info about the Order Tantulocarida may be found here.
References
Sources
- The text on this page is licensed under the GNU Free Documentation License. It includes material from Wikipedia retrieved Wednesday, April 25, 2012.
- Photographs on this page are copyrighted by individual photographers, and individual copyrights apply.
- The technology underlying this page, including the controls behind Keep Exploring, is owned by the BayScience Foundation. All rights are reserved.