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 venomous, 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.
Portunidae is a family of crabs which contains the swimming crabs. Its members include many well-known shoreline crabs, such as the blue crab and velvet crab. Two genera in the family are contrastingly named Scylla and Charybdis; the former contains the economically important species black crab and Scylla paramamosain.
Macrophthalmus is a genus of crabs which are widespread across the Indo-Pacific. It contains the following species :
Parthenopidae is a family of crabs, placed in its own superfamily, Parthenopoidea. It comprises nearly 40 genera, divided into two subfamilies, with three genera incertae sedis:
Calappidae is a family of crabs containing 16 genera, of which 7 are only known as fossils:
The Varunidae are a family of thoracotrematan crabs. The delimitation of this family, part of the taxonomically confusing Grapsoidea, is undergoing revision. For a long time, they were placed at the rank of subfamily in the Grapsidae, but they appear to be closest to Macropthalmus and the Mictyridae, which are usually placed in the Ocypodoidea. It may thus be better to merge the latter superfamily with the Grapsoidea, retaining the latter name as it is older.
Pilumnoidea is a superfamily of crabs, whose members were previously included in the Xanthoidea. The three families are unified by the free articulation of all the segments of the male crab's abdomen and by the form of the gonopods. The earliest fossils assigned to this group are of Eocene age.
Edward John Miers FZS FLS was a British zoologist and curator of the crustacean collection at the Natural History Museum in London. He contributed to the scientific reports from the Challenger expedition of 1872–1876, and described 32 new genera and at least 260 new species and subspecies of decapod crustaceans, along with four genera and 72 new species in other orders.
Inachidae is a family of crabs, containing 39 genera:
Epialtinae is a subfamily of crabs, containing the following genera:
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.
Leucosiidae is a family of crabs containing three subfamilies and a number of genera incertae sedis:
Pilumnus is a genus of crabs, containing the following species:
Cyclograpsus is a genus of crabs, containing the following species:
Pisinae is a subfamily of crabs in the family Epialtidae, comprising the following genera:
Achaeus is a genus of crabs comprising the following species:
Hyastenus is a genus of crabs in the family Epialtidae, subfamily Pisinae, containing the following extant species:
Ebalia is a genus of crab in the family Leucosiidae.
Rochinia is a genus of crab in the family Epialtidae, containing the following species:
