Decapoda

Decapoda
Fossil range: Devonian–Recent
"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

Dendrobranchiata
Pleocyemata
See text for superfamilies.

The decapods or Decapoda (literally means "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 shrimps (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]

Contents

Anatomy

As their name implies, all decapods have ten legs; these are 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 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. Dendrobranchiata consists of prawns, including many species colloquially referred to as "shrimp", such as the Atlantic white shrimp. 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]

Whiteleg shrimp, Litopenaeus vannamei (Dendrobranchiata: Penaeoidea)
Heterocarpus ensifer (Caridea: Pandaloidea)
Austropotamobius pallipes (Astacidea: Astacoidea)
Upogebia deltaura (Gebiidea: Upogebiidae)
California spiny lobster, Panulirus interruptus (Achelata: Palinuridae)
Polycheles sculptus (Polychelida: Polychelidae)
Australian land hermit crab, Coenobita variabilis (Anomura: Paguroidea)
Blue crab, Callinectes sapidus (Brachyura: Portunoidea)

Order Decapoda Latreille, 1802

See also

References

  1. ↑ 1.0 1.1 1.2 Sammy De Grave, N. Dean Pentcheff, Shane T. Ahyong et al. (2009). "A classification of living and fossil genera of decapod crustaceans". Raffles Bulletin of Zoology Suppl. 21: 1–109. http://rmbr.nus.edu.sg/rbz/biblio/s21/s21rbz1-109.pdf. 
  2. ↑ Robert P. D. Crean (November 14, 2004). "Order Decapoda: Fossil record and evolution". University of Bristol. http://palaeo.gly.bris.ac.uk/Palaeofiles/Fossilgroups/Decapoda/Fossilrecord.html. Retrieved January 2, 2010. 
  3. ↑ G. Scholtz & S. Richter (1995). "Phylogenetic systematics of the reptantian Decapoda (Crustacea, Malacostraca)". Zoological Journal of the Linnean Society 113: 289–328. doi:10.1006/zjls.1995.0011. 

External links

Extant arthropod classes by subphylum
Kingdom Animalia · Subkingdom Eumetazoa · (unranked) Bilateria · (unranked) Protostomia · Superphylum Ecdysozoa
Chelicerata
Myriapoda
Chilopoda · Diplopoda · Pauropoda · Symphyla
Hexapoda
Insecta (Apterygota, Pterygota) · Entognatha
Crustacea
Branchiopoda · Remipedia · Cephalocarida · Maxillopoda (Cirripedia, Copepoda) · Ostracoda · Malacostraca (Decapoda, Amphipoda, Isopoda)