| Decapoda Temporal range: Devonian–Recent |
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| "Decapoda" from Ernst Haeckel's Kunstformen der Natur, 1904 | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Superorder: | Eucarida |
| Order: | Decapoda Latreille, 1802 |
| Suborders | |
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Dendrobranchiata |
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The decapods or Decapoda (literally "ten-footed") are an order of crustaceans within the class Malacostraca, including many familiar groups, such as crayfish, crabs, lobsters, prawns and shrimp. Most decapods are scavengers. It is estimated that the order contains nearly 15,000 species in around 2,700 genera, with approximately 3,300 fossil species.[1] Nearly half of these species are crabs, with the shrimp (c. 3000 species) and Anomura (including hermit crabs, porcelain crabs, squat lobsters: c. 2500 species), making up the bulk of the remainder.[1] The earliest fossil decapod is the Devonian Palaeopalaemon.[2]
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As the name Decapoda (from the Greek δέκα, deca-, "ten", and πούς / ποδός, -pod, "foot") implies, all decapods have ten legs. These are in the form of five pairs of thoracic appendages on the last five thoracic segments. The front three pairs function as mouthparts and are generally referred to as maxillipeds; the remainder are 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 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. Dendrobranchiata consists of prawns, including many species colloquially referred to as "shrimp", such as the "white shrimp", Litopenaeus setiferus. Pleocyemata includes the remaining groups, including true shrimp. Those groups which usually walk rather than swim (Pleocyemata, excluding Stenopodidea and Caridea) form a clade called Reptantia.[3]
The following classification to the level of superfamilies follows De Grave et al.[1]
Order Decapoda Latreille, 1802
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