Grapsidae
Grapsus grapsus
The square crabs ( Grapsidae ) are a family of crustaceans from the partial order of the crabs ( Brachyura ) in the order of decapods ( Decapoda ). They live semi -aquatic (half on land and half in the water) to both freshwater as well as at sea. They appear mainly in the tropics, only a few species live in temperate latitudes.
Square crabs are identified by their typical square, flattened body. The gill cavity of the square crab needs to be moisturized. Therefore, and to discontinuation of the square crab larvae have to go back into the water.
System
The square of the crab family consists of eight extant genera with 41 species:
- Geograpsus Stimpson, 1858
- Goniopsis De Haan, 1833
- Grapsus Lamarck, 1801; Eight species, inter alia, with: Sally Lightfoot Crab ( Grapsus grapsus ): The crab is native to the Galapagos Islands and the South American Pacific coast.
- Leptograpsus variegatus
- Pachygrapsus Randall, 1840: The species of this genus are found worldwide. They are also in the Mediterranean and on the islands of the eastern Atlantic Ocean on rocky coasts, fortifications and often found to harbor walls.
- Planes Bowdich, 1825