Encyclopedia of Life · EOL (see source)
Eumalacostraca
Sign in to saveEumalacostraca is a subclass of crustaceans, containing almost all living malacostracans, or about 40,000 described species. The remaining subclasses of crustaceans that are not in Eumalacostraca are the Phyllocarida and possibly the Hoplocarida. 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
Species
真軟甲亜綱
Subclass
- PhylumArthropoda
- ClassMalacostraca
真軟甲亜綱(Eumalacostraca)は、甲殻類の分類の1つである。現生の軟甲綱の大部分を含み、約4万種が記載されている。他の亜綱には、コノハエビ亜綱とそしておそらくトゲエビ亜綱がある。真軟甲亜綱は、19の節を持つ（頭部5節、胸部8節、腹部6節）。胸部の付属肢には関節があり、水中や陸上の移動のために用いられる。共通の祖先は、現生種の大部分がそうであるように甲羅を持っていたと考えられているが、一部のグループでは失われている。
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Encyclopedic overview
3 sectionsContents
- Caridoid facies
- Classification
- References
Eumalacostraca is a subclass of crustaceans, containing almost all living malacostracans, or about 40,000 described species. The remaining subclasses of crustaceans that are not in Eumalacostraca are the Phyllocarida and possibly the Hoplocarida. 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== Calman identified the following features as distinguishing eumalacostracan crustaceans: "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."
Excerpted from Wikipedia’s “Eumalacostraca” article, available under the CC BY-SA 4.0 licence.