What Divers Should Know About Squat Lobster

Gazing into crevices or exploring open seafloor can reveal a fascinating crustacean, the squat lobster. These captivating creatures are found worldwide, inhabiting everything from shallow near-surface waters to extreme deep-sea hydrothermal vents. Some species form dense aggregations, either clustered on the sea floor or even suspended in the water column, making them conspicuous. Ranging typically from 18 to 89 millimetres (0.7 to 3.5 inches) in length, they are generally smaller than true lobsters.

Squat lobsters are readily identifiable by their dorsoventrally flattened bodies and long tails, which they keep curled beneath their cephalothorax. While resembling true lobsters, their unique flattened form and a cephalothorax longer than broad make them a morphological intermediate between a lobster and a crab. A striking feature on many species are their prominent chelipeds, or claws, which can extend to more than six times their body length. With over 900 described species across numerous genera, this diverse group is a frequent encounter in many marine environments.