Grapsoidea is a superfamily of crabs. These crabs are well known and contain many taxa which are terrestrial (land-living), semi-terrestrial (taking to the sea only for reproduction) or limnic (living in fresh water). Another well-known member with a more conventional lifestyle is the Chinese mitten crab, Eriocheir sinensis.The delimitation of the Grapsidae and Plagusiidae is in need of revision; the last at least is not monophyletic.