Carcinisation is a form of convergent evolution in which non-crab crustaceans evolve a crab-like body plan. The term was introduced into evolutionary biology by L. A. Borradaile, who described it as "the many attempts of Nature to evolve a crab".
Porcelain crabs are decapod crustaceans in the widespread family Porcellanidae, which superficially resemble true crabs. They have flattened bodies as an adaptation for living in rock crevices. They are delicate, readily losing limbs when attacked, and use their large claws for maintaining territories. They first appeared in the Tithonian age of the Late Jurassic epoch, 145–152 million years ago.
Petrolisthes is a genus of marine porcelain crabs, containing these extant species:
Petrolisthes elongatus, known as the New Zealand half crab, elongated porcelain crab, blue half crab, blue false crab or simply as the half crab or false crab, is a species of porcelain crab native to New Zealand.
Parapinnixa affinis, the California Bay pea crab, is a species of pinnotherid crab endemic to Southern California. It is a small crab that lives commensally in the tube of a tube-dwelling worm. It was one of the first marine crustaceans to be included on the IUCN Red List in 1996.
Pisidia is a genus of marine porcelain crabs, comprising the following species:
The Pylojacquesidae are a small family of hermit crabs, comprising only two monotypic genera. The family was erected in 2001, after two specimens at Museum für Naturkunde at the Humboldt University of Berlin were recognised as being quite distinct from other described hermit crabs. The family members differ from other hermit crabs in that their mandibles are chitinous and toothed.
The Galatheoidea are a superfamily of decapod crustaceans comprising the porcelain crabs and some squat lobsters. Squat lobsters within the three families of the superfamily Chirostyloidea are not closely related to the squat lobsters within the Galatheoidea. The fossil record of the superfamily extends back to the Middle Jurassic genus Palaeomunidopsis.
Porcellana is a genus of decapod crustaceans in the widespread family Porcellanidae, the porcelain crabs, which superficially resemble true crabs. The genus Porcellana includes the following species:
Petrolisthes eriomerus is a species of marine porcelain crab found in the eastern Pacific Ocean. It is commonly known as the flattop crab. It is a flattened, rounded animal, with a carapace up to 20 mm (0.8 in) across. It is a filter feeder, and also sweeps food from rocks.
Allopetrolisthes spinifrons is a species of porcelain crab. It displays "hypercarcinisation", whereby the resemblance to a true crab is enhanced by sexual dimorphism of the abdomen. It lives along the Pacific coast of Peru and Chile, as a symbiont of a sea anemone.
Porcellana sayana is a species of porcelain crab that lives in the western Atlantic Ocean, often as a commensal of hermit crabs. It is red with white spots, and has a characteristic bulge behind each claw.
Insulamon is genus of freshwater crabs, comprising four species:
Petrolisthes armatus, the green porcelain crab, is a species of small porcelain crab in the family Porcellanidae. It is believed to be native to Brazil but has spread to other parts of the world. Populations in the south eastern part of the United States have increased dramatically and the species is considered to be an invasive species.
Petrolisthes novaezelandiae, known as the red half crab or red false crab, is a species of porcelain crab native to New Zealand.
The Micro Mangrove Crab (Haberma tingkok) is a species of micro-mangrove crab native to Hong Kong. It was first discovered by Stefano Cannicci from the University of Hong Kong and Peter Ng from the University of Singapore in the Ting Kok Mangrove forests in the northeast of Hong Kong and listed on the World Register of Marine Species (WoRMS) in April 2017. It was the third species placed in the genus Haberma, which was described in 2002.
Pachycheles is a genus of porcelain crabs in the family Porcellanidae. There are more than 40 described species in Pachycheles.
Pagurus dalli, commonly known as the whiteknee hermit or whiteknee hermit crab, is a species of hermit crab in the family Paguridae. It is found in the northeastern Pacific Ocean at depths down to about 276 m (900 ft). It usually lives in a mutualistic symbiosis with a sponge, or sometimes a hydroid.
Petrolisthes cinctipes is a species of marine porcelain crab found in the eastern Pacific Ocean, from British Columbia to Mexico. This species was first described by John Witt Randall in 1840.
Xylopaguridae are a family of hermit crabs of the order Decapoda. It was erected in 2016 to accommodate one new genus, Prexylopagurus, and three existing genera that had previously been placed in Paguridae. They occur in the Atlantic, Indian, and Pacific Oceans.
