Eumalacostraca

Taxobox
name = Eumalacostraca

---

image_width = 250px
image_caption = Blue crabs, "Callinectes sapidus"
regnum = Animalia
phylum = Arthropoda
subphylum = Crustacea
classis = Malacostraca
subclassis = Eumalacostraca
subclassis_authority = Grobben, 1892
subdivision_ranks = Superorders
subdivision =
Syncarida
Peracarida
Eucarida See text for orders.

The Eumalacostraca (Greek: "true soft shell") are a subclass of crustaceans, containing almost all living malacostracans, about 22,000 described species. (The outgroups are the Phyllocarida and possibly the Hoplocarida or mantis shrimps.)

Eumalacostracans have 19 segments (5 cephalic, 8 thoracic, 6 abdominal). 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.

Classification

Martin and Davis [cite book|author = J. W. Martin & G. E. Davis|url = http://www.nhm.org/research/publications/CrustaceaClassification.pdf |title=An Updated Classification of the Recent Crustacea|year = 2001|publisher = Natural History Museum of Los Angeles County] present the following classification of living eumalacostracans into orders, to which extinct orders have been added, indicated by †.

The group as originally described by Karl Grobben [cite journal|quotes=no |author = C. Grobben|year = 1892|title = Zur Kenntnis des Stammbaumes und des Systems der Crustaceen|journal = Sitzber. K. Akad. Wiss., Vienna, Math. Nat. Cl.|volume = 101|pages = 237–274] included the Stomatopoda (mantis shrimp), and some modern experts continue to use this definition. Here we follow Martin and Davis in excluding them; they are placed in their own subclass, Hoplocarida.

Subclass Eumalacostraca Grobben, 1892
* Superorder Syncarida Packard, 1885
** †Order Palaeocaridacea
** Order Bathynellacea Chappuis, 1915
** Order Anaspidacea Calman, 1904 (including Stygocaridacea)
* Superorder Peracarida Calman, 1904
** Order Spelaeogriphacea Gordon, 1957
** Order Thermosbaenacea Monod, 1927
** Order Lophogastrida Sars, 1870
** Order Mysida Haworth, 1825
** Order Mictacea Bowman, Garner, Hessler, Iliffe & Sanders, 1985
** Order Amphipoda Latreille, 1816
** Order Isopoda Latreille, 1817 (pillbugs, sowbugs, woodlice)
** Order Tanaidacea Dana, 1849
** Order Cumacea Krøyer, 1846
* Superorder Eucarida Calman, 1904
** Order Euphausiacea Dana, 1852
** Order Amphionidacea Williamson, 1973
** Order Decapoda Latreille, 1802 (crabs, lobsters, shrimp)

References