Porcellanidae

Porcellanidae is a family of porcelain crabs, small decapod crustaceans in the infraorder Anomura. They occur in oceans worldwide, from warm tropical regions to temperate zones, and are commonly found in shallow coastal habitats such as rocky shores, coral reefs, and sponge or coral hosts. Many species associate with sessile invertebrates, including corals, sponges, and gorgonians, while others live free-living in crevices, under stones, or on algal mats.

Morphologically, porcellanids are notable for their broad, flattened carapace and a relatively small, often hidden abdomen tucked beneath the thorax. The body surface is usually smooth or finely sculptured, and the carapace color can be translucent or cryptic, contributing to a porcelain-like appearance. They possess five pairs of walking legs, with the first pair (chelipeds) not always markedly larger than the other legs, and they have long antennae and well-developed mouthparts used for feeding on suspended particles and detritus.

Ecologically, porcelain crabs are primarily omnivorous, feeding by filter-feeding or scavenging organic matter from the surrounding water and substrate. Many species are cryptic, relying on their host organism or shelter within crevices for protection. Reproduction follows the decapod pattern, with females carrying eggs under the abdomen (pleopods) until hatching; the life cycle includes free-swimming larval stages before metamorphosis into juvenile crabs.

Taxonomically, the family includes several genera, with Porcellana and Petrolisthes among the better-known examples. Porcellanidae is distinguished from true crabs by its anomuran body plan—most notably the reduced abdomen and a lifestyle closely tied to substrates and hosts in the marine environment.