Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) (Greek: βραχύς, romanized: brachys = short, οὐρά / οura = tail), usually hidden entirely under the thorax. They live in all the world's oceans, in fresh water, and on land, are generally covered with a thick exoskeleton, and have a single pair of pincers. Many other animals with similar names - such as hermit crabs, king crabs, porcelain crabs, horseshoe crabs, stone crabs, and crab lice - are not true crabs, but many have evolved features similar to true crabs through a process known as carcinisation.
Scientific classificatione
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Decapoda
Suborder: Pleocyemata
Infraorder: Brachyura
Sections and subsections:
Dromiacea
Raninoida
Cyclodorippoida
Eubrachyura
Crabs are generally covered with a thick exoskeleton, composed primarily of highly mineralized chitin, and armed with a pair of chelae (claws). Crabs vary in size from the pea crab, a few millimeters wide, to the Japanese spider crab, with a leg span up to 4 m (13 ft).
Негізгі бет Үй жануарлары мен аңдар 80 SPECIES OF CRAB (Brachyura)
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