CRAYFISH (krey-fish)
From
Wikipedia
Crayfish, often referred to
as crawfish or crawdad, are freshwater crustaceans resembling
small lobsters, to which they are closely related. They are found in bodies
of fresh water that do not freeze to the bottom, and which have shelter
against predators.
Geographical distribution and classification
There are three families of crayfish,
two in the northern hemisphere and one in the southern hemisphere. The
southern-hemisphere (Gondwana-distributed) family Parastacidae lives in
South America, Madagascar and Australasia, and is distinguished by the lack
of the first pair of pleopods. Of the other two families, members of the
Astacidae live in western Eurasia and western North America and members of
the family Cambaridae live in eastern Asia and eastern North America.
The greatest diversity of crayfish species is found in south-eastern North
America, with over 250 species in nine genera, all in the family Cambaridae.
A further genus of Astacid crayfish is found in the Pacific Northwest and
the headwaters of some rivers east of the Continental Divide.
Australasia is another centre of crayfish diversity, with over 100 species
in a dozen genera. Many of the better-known Australian crayfish are of the
genus Cherax, and include the Marron (Cherax tenuimanus),
red-claw crayfish (Cherax quadricarinatus), Yabby (Cherax
destructor) and western yabby (Cherax preissii). The world's
largest crayfish, Astacopsis gouldi, which can achieve a mass in
excess of 3 kilograms, is found in the rivers of northern Tasmania.
Madagascar has a single (endemic) crayfish species, Astacopsis
madagascariensis.
Europe is home to seven species of crayfish in the genera Astacus
and Austropotamobius.
Cambaroides is native to Japan and eastern mainland Asia.
