Malacostraca

From Wacklepedia - The Free Encyclopedia

Malacostraca
Scientific classification
Kingdom: Animalia Phylum: Arthropoda Subphylum: Crustacea Class : Malacostraca
Orders
not necessarily a complete list: Leptostraca Stomatopoda Bathynellacea Thermosbaenacea Mysidacea Cumacea Amphipoda Isopoda Tanaidacea Euphausiacea Amphionidacea Decapoda Peracarida

The Malacostraca are the largest subgroup of crustaceans, and include most of the animals that non-experts recognise as crustaceans, including crabs, lobsters, shrimps, mantis shrimps and krill. They also include the huge group of amphipods, and the only substantial group of land-based crustaceans, the isopods (woodlice or sowbugs and related species).

The classification of crustaceans is currently being debated, and the Malacostraca are regarded by some authors as a class and by others as a subclass.

Their characteristics include:

• Five pairs of walking legs
• The first pair of legs are often modified to form pincers
• Cephalothorax covered by a carapace
• Abdomen behind, often used for swimming
• Appendages near the mouth; these are called maxillipeds
• Two-chambered stomach
• Centralised nervous system