Crabs, lobster & shrimp are Decapod crustaceans, ten-footed (five pairs of legs) scavenging marine animals which include many familiar groups, such as crabs, hermit crabs, lobsters, and shrimp. They are found everywhere when diving Koh Lanta.
Even though decapods are ten-footed animals, they can actually have as many as 38 appendages, arranged in one pair per body segment, though only 10 are considered 'legs'.
The macrurous (shrimplike) species, which can be as small as 1 cm, have elongated bodies with long abdomens, well-developed fan tails, and often long, slender legs.
The brachyurous (crablike) types, which in the case of spider crabs can have spans of almost 4 metres between their outstretched claws, have bodies that are flattened and laterally expanded, frequently with stout, short legs and reduced tail fans.