natal lightfoot crab grapsus tenuicrustatus or maculatus, colorful crab from rocky shores, key scavenger, great climber, vital to

white tropical tide tenuicrustatus subtropical species south shores shore seychelles scavenger sandy sally rocks rock reef reddish predator pools orange ocean nocturnal natal mozambique mottled mollusks marine madagascar maculatus lightfoot intertidal indian grapsus grapsid foraging detritus crustacean crevice crepuscular crab coastal climbing camouflage burrow brown black biodiversity algae agile africa colorful rocky key great climber vital ecosystems active dawn dusk