Eumalacostraca

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Eumalacostraca
Blue crab on market in Piraeus - Callinectes sapidus Rathbun 20020819-317.jpg
Atlantic blue crabs, Callinectes sapidus
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Subclass: Eumalacostraca
Grobben, 1892
Superorders

Eumalacostraca is a subclass of crustaceans, containing almost all living malacostracans, or about 40,000 described species.[1] The remaining subclasses are the Phyllocarida and possibly the Hoplocarida.[2] Eumalacostracans have 19 segments (5 cephalic, 8 thoracic and 6 abdominal). This arrangement is known as the "caridoid facies", a term coined by William Thomas Calman in 1909. The thoracic limbs are jointed and used for swimming or walking. The common ancestor is thought to have had a carapace, and most living species possess one, but it has been lost in some subgroups.

Caridoid facies[edit]

Calman identified the following features as distinguishing eumalacostracan crustaceans:[3]

"Carapace enveloping the thoracic region; movably stalked eyes; biramous first antenna; scale-like exopod on the second antenna; natatory exopods on the thoracic limbs; elongate, ventrally flexible abdomen; tail fan formed by the lamellar rami of the uropods on either side of the telson."

Classification[edit]

Martin and Davis present the following classification of living eumalacostracans into orders, to which extinct orders have been added, indicated by †.[2]

The group as originally described by Karl Grobben[4] included the Stomatopoda (mantis shrimp), and some modern experts continue to use this definition. This article follows Martin and Davis in excluding them; they are placed in their own subclass, Hoplocarida.

Subclass Eumalacostraca Grobben, 1892

References[edit]

  1. ^ Gary C. B. Poore (2002). "Introduction". Crustacea: Malacostraca. Zoological catalogue of Australia. 19.2A. CSIRO Publishing. pp. 1–7. ISBN 978-0-643-06901-5. 
  2. ^ a b J. W. Martin & G. E. Davis (2001). An Updated Classification of the Recent Crustacea (PDF). Natural History Museum of Los Angeles County. pp. 132 pp. 
  3. ^ Hessler, Robert R. (1983). "A defense of the caridoid facies; wherein the early evolution of the eumalacostraca is discussed". In Schram, Frederick R. Crustacean Phylogeny. Rotterdam: A.A. Balkema. ISBN 90-6191-231-8. 
  4. ^ C. Grobben (1892). "Zur Kenntnis des Stammbaumes und des Systems der Crustaceen". Sitzungsberichte der Kaiserlichen Akademie der Wissenschaften, Vienna. Mathematisch-naturwissenschaftliche Classe 101: 237–274.