Squat lobster

Squat lobsters are dorsoventrally flattened crustaceans with long tails held curled beneath the cephalothorax. They are found in the two superfamilies Galatheoidea and Chirostyloidea, which form part of the decapod infraorder Anomura, alongside groups including the hermit crabs and mole crabs. They are distributed worldwide in the oceans, and occur from near the surface to deep sea hydrothermal vents, with one species occupying caves above sea level. More than 900 species have been described, in around 60 genera. If one considers the members of the family Aeglidae as squat lobsters, then those numbers rise to more than 1000 species in 61 genera, and they occur at an altitude up to 3600 meters above sea level. Some species form dense aggregations, either on the sea floor or in the water column, and a small number are commercially fished.