Crush Crab
Because its ancestor, primacrabbus, did not have any living predators, its claws were of no use for defensive purposes, and used only to pick up and break small pieces off of rocks to eat.
To complement this diet, primacrushus has developed large, muscular claws capable of crushing small rocks completely. These are claws are less maneuverable than those of its ancestor, but since they are only used for feeding, it was a non-issue. However, it has increased difficulty in picking up small objects with the blunt tips of its claws, often choosing to feed on rocks it can crush into its mouth instead of picking up pieces that are already small. Like its ancestor, it still feeds upon Fungradi polarus, choosing to crouch over it and consume the domes directly rather than pulling pieces off with its claws.
Due to the increased weight of its claws, primacrushus is somewhat slower than its ancestor. The larger claws contain far more muscle than those of its ancestor, and are supported by additional muscles in its arms to assist in manipulating them. This poses a slight negative when it comes to molting, as there is more mass to remove from the old shell. Even so, its survival rate is improved due its greater access to minerals resulting in sturdier, more healthily-formed shells and molts.
Reproduction, size, and means of respiration are identical to that of its ancestor, the only notable difference being their larger claws.