The mining beakworm replaced the wattle beakworm. To easier break the crystals they feed on the beak of the mining beakworm has evolved to a very specialised pickaxe like weapon. By banging its head hard with the strong neck muscles it is able to easy break the crystals. This new big beak was evolved in a kind of strange way. The beakworms that was better to break the crystals got more energy, which lets it have more muscles and support a bigger beak. When these beakworms beak grew they needed more food, so the ones that was stronger and had better suited beaks were favored, and so it went on until the almost perfect shaped beak was evolved and dominated. The beak also works as self defence, and to scare away other creatures trying to feed on "their" crystals. This is needed since the mining beakworm consumes a lot of energy. It has also grown a bit bigger to balance their strength with speed so that they still can keep a resonable speed. This is also the reason their fins have evolved differently. The cartilage under the beak is to protect the brain from the hard headbanging the mining beakworm has to perform in order to get acces to food. The eye is farther away from the beak so that it wont be damaged.