Xanthidae is a family of crabs known as gorilla crabs, mud crabs, pebble crabs or rubble crabs. Xanthid crabs are often brightly coloured and are highly poisonous, containing toxins which are not destroyed by cooking and for which no antidote is known. The toxins are similar to the tetrodotoxin and saxitoxin produced by puffer fish, and may be produced by bacteria in the genus Vibrio living in symbiosis with the crabs, mostly V. alginolyticus and V. parahaemolyticus.
Calappa is a genus of crabs known commonly as box crabs or shame-faced crabs. The name box crab comes from their distinctly bulky carapace, and the name shame-faced is from anthropomorphising the way the crab's chelae (claws) fold up and cover its face, as if it were hiding its face in shame.
Libystes is a genus of crabs, containing six species:
Maja is a genus of majid crabs erected by Jean-Baptiste Lamarck in 1801. It includes the following extant species:
The Gecarcinucidae are a family of true freshwater crabs. They are found throughout South Asia, Southeast Asia and New Guinea, with a single genus found in Australia.
Hexapodidae is a family of crabs, the only family in the superfamily Hexapodoidea. It has traditionally been treated as a subfamily of the family Goneplacidae, and was originally described as a subfamily of Pinnotheridae. Its members can be distinguished from all other true crabs by the reduction of the thorax, such that only seven sternites are exposed, and only four pairs of pereiopods are present. Not counting the enlarged pair of claws, this leaves only six walking legs, from which the type genus Hexapus, and therefore the whole family, takes its name. Some anomuran "crabs", such as porcelain crabs and king crabs also have only four visible pairs of legs. With the exception of Stevea williamsi, from Mexico, all the extant members are found either in the Indo-Pacific oceans, or around the coast of Africa.
Actumnus is a genus of crabs in the family Pilumnidae. Alongside the 28 extant species, it has a fossil record extending back into the Miocene.
Achaeopsis spinulosa, the hotlips spider crab, is a species of crab in the family Inachidae, found only around the South African coast. It is the only species in the genus Achaeopsis.
Acanthonyx dentatus, the toothed decorator crab, is a species of crab in the family Inachidae.
Lybia edmondsoni is a species of small crab in the family Xanthidae and is endemic to the Hawaiian Islands. Like other members of the genus Lybia, it is commonly known as the pom-pom crab or boxer crab because of its habit of carrying a sea anemone around in each of its claws, these resembling pom-poms or boxing gloves. Its Hawaiian name is kūmimi pua, meaning "inedible flower crab". In ancient times, this animal was used by men claiming to be sorcerers.
Leucosiidae is a family of crabs containing three subfamilies and a number of genera incertae sedis:
Epiactaea is a genus of crabs in the family Xanthidae, containing the following species:
Liomera is a genus of crabs in the family Xanthidae, containing the following species:
Odhneria is a genus of crabs in the family Xanthidae, containing the following species:
Pseudactaea is a genus of crabs in the family Xanthidae, containing the following species:
Actiomera is a genus of crabs in the family Xanthidae, containing the following species:
Polydectus cupulifer is a species of crab in the family Xanthidae, and the only species in the genus Polydectus. Together with the genus Lybia, it forms the subfamily Polydectinae. It is found in the Indo-Pacific, ranging from Madagascar and the Red Sea in the west to Japan, Hawaii and French Polynesia in the east. P. cupulifer is densely covered with setae (bristles), and frequently carries a sea anemone in each chela (claw).
Demania is a genus of crabs in the family Xanthidae, containing the following species:
Triactis is a genus of sea anemone in the family Aliciidae. It is monotypic, having only one species – Triactis producta. This species is found in shallow waters in the Indo-Pacific where it lives on the seabed, rocks and corals. It derives much of its energy needs from the symbiotic algae it contains. It also forms a mutualistic relationship with small Lybia crabs.
Lybia tessellata is a species of small crab in the family Xanthidae. It is found in shallow parts of the tropical Indo-Pacific Ocean. Like other members of the genus Lybia, it is commonly known as the pom-pom crab or boxer crab because of its habit of carrying a sea anemone around in each of its claws, these resembling pom-poms or boxing gloves.
