Stomatopods have indeterminant growth. They grow at each molt their entire life. In cavity livers like Neogonodactylus, the frequency of molting and the amount of growth at each molt decreases as they get larger, but it also depends on food, reproduction, and even space.
To completely regenerate a raptorial appendage will take three molts. Usually if an animal loses both appendages, it will accelerate the molt cycle. If it has lost only one, it does not.
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