For other meanings of decapod, see decapod.

The decapods or Decapoda are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crabs, lobsters, prawns and shrimps, but also some families that are less well known.

Anatomy

As their name implies, all decapods have ten legs; these are the last five of the eight pairs of thoracic appendages characteristic of crustaceans. The front three pairs function as mouthparts and are generally referred to as maxillipeds, the remainder being pereiopods. In many decapods, however, one pair of legs has enlarged pincers; the claws are called chelae, so those legs may be called chelipeds. Further appendages are found on the abdomen, with each segment capable of carrying a pair of biramous pleopods, the last of which form part of the tail fan (together with the telson) and are called uropods.

Classification

Classification within the order Decapoda depends on the structure of the gills and legs, and the way in which the larvae develop, giving rise to two suborders: Dendrobranchiata and Pleocyemata. Prawns (including many species colloquially referred to as "shrimp", such as the Atlantic white shrimp) make up the Dendrobranchiata. The remaining groups, including true shrimp, are the Pleocyemata.

The following classification to the level of superfamilies follows Martin and Davis, with some changes based on more recent morphological and molecular studies.

Order Decapoda Latreille, 1802

• Suborder Dendrobranchiata Bate, 1888 — prawns
  • Superfamily Penaeoidea Rafinesque, 1815
  • Superfamily Sergestoidea Dana, 1852
• Suborder Pleocyemata Burkenroad, 1963
  • Infraorder Stenopodidea Claus, 1872
  • Infraorder Caridea Dana, 1852 — true shrimp
    • Superfamily Procaridoidea Chace & Manning, 1972
    • Superfamily Galatheacaridoidea Vereshchaka, 1997
    • Superfamily Pasiphaeoidea Dana, 1852
    • Superfamily Oplophoroidea Dana, 1852
    • Superfamily Atyoidea de Haan, 1849
    • Superfamily Bresilioidea Calman, 1896
    • Superfamily Nematocarcinoidea Smith, 1884
    • Superfamily Psalidopodoidea Wood-Mason & Alcock, 1892
    • Superfamily Stylodactyloidea Bate, 1888
    • Superfamily Campylonotoidea Sollaud, 1913
    • Superfamily Palaemonoidea Rafinesque, 1815
    • Superfamily Alpheoidea Rafinesque, 1815
    • Superfamily Processoidea Ortmann, 1890
    • Superfamily Pandaloidea Haworth, 1825
    • Superfamily Physetocaridoidea Chace, 1940
    • Superfamily Crangonoidea Haworth, 1825
  • Infraorder Eryonoidea de Haan, 1841
  • Infraorder Achelata Scholtz & Richter, 1995
  • Infraorder Astacidea Latreille, 1802 - lobsters and crayfish
    • Superfamily Enoplometopoidea de Saint Laurent, 1988
    • Superfamily Glypheoidea Winkler, 1883
    • Superfamily Nephropoidea Dana, 1852
    • Superfamily Astacoidea Latreille, 1802
    • Superfamily Parastacoidea Huxley, 1879
  • Infraorder Thalassinidea Latreille, 1831
    • Superfamily Thalassinoidea Latreille, 1831
    • Superfamily Callianassoidea Dana, 1852
    • Superfamily Axioidea Huxley, 1879
  • Infraorder Anomura MacLeay, 1838 — hermit crabs and relatives
    • Superfamily Lomisoidea Bouvier, 1895
    • Superfamily Galatheoidea Samouelle, 1819
    • Superfamily Hippoidea Latreille, 1825
    • Superfamily Paguroidea Latreille, 1802
  • Infraorder Brachyura Latreille, 1802 — crabs
    • Section Dromiacea de Haan, 1833
      • Superfamily Homolodromioidea Alcock, 1900
      • Superfamily Dromioidea de Haan, 1833
      • Superfamily Homoloidea de Haan, 1839
    • Section Eubrachyura de Saint Laurent, 1980
      • Subsection Raninoida de Haan, 1839
        • Superfamily Raninoidea de Haan, 1839
        • Superfamily Cyclodorippoidea Ortmann, 1892
      • Subsection Heterotremata Guinot, 1977
        • Superfamily Dorippoidea MacLeay, 1838
        • Superfamily Calappoidea Milne Edwards, 1837
        • Superfamily Leucosioidea Samouelle, 1819
        • Superfamily Majoidea Samouelle, 1819
        • Superfamily Hymenosomatoidea MacLeay, 1838
        • Superfamily Parthenopoidea MacLeay, 1838
        • Superfamily Retroplumoidea Gill, 1894
        • Superfamily Cancroidea Latreille, 1802
        • Superfamily Portunoidea Rafinesque, 1815
        • Superfamily Bythograeoidea Williams, 1980
        • Superfamily Xanthoidea MacLeay, 1838
        • Superfamily Bellioidea Dana, 1852
        • Superfamily Potamoidea Ortmann, 1896
        • Superfamily Pseudothelphusoidea Ortmann, 1893
        • Superfamily Gecarcinucoidea Rathbun, 1904
        • Superfamily Cryptochiroidea Paulson, 1875
      • Subsection Thoracotremata Guinot, 1977
        • Superfamily Pinnotheroidea de Haan, 1833
        • Superfamily Ocypodoidea Rafinesque, 1815
        • Superfamily Grapsoidea MacLeay, 1838

References