Squat lobstersGalatheidae

Squat lobsters are small, dorsoventrally flattened crustaceans, distinctive for their lobster-like body shape and tail held curled beneath the cephalothorax. Their carapace length ranges from a few millimetres to 90 mm (3.5 inches). Most species possess stalked eyes, often fringed with fine setae resembling "eyelashes." Carapaces vary, sometimes adorned with spines or bristles, with some species displaying iridescent setae. A prominent feature is the first pair of pereiopods, which are large chelipeds often several times the body length and ending in claws. A fifth, smaller pair of pereiopods is typically tucked under the carapace, used for gill cleaning. Colouration generally adapts to their surroundings, from camouflaged browns and greys to patterns mimicking their invertebrate hosts.

These crustaceans inhabit coral reefs and rocky slopes from shallow waters down to 100 metres (330 feet). Many species adopt a cryptic lifestyle, sheltering under rocks or within crevices, while others live commensally with crinoids, anemones, sponges, or corals. Their diet primarily consists of detritus, suspended particles, and host mucus. Despite being common residents across diverse reef habitats, their small size and secretive habits mean they are often overlooked during dives.