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.
Pinnotheres is a genus of crabs, including the pea crab. Many species formerly in Pinnotheres have been placed in new genera, such as Zaops ostreus, the oyster crab and Nepinnotheres novaezelandiae, the New Zealand pea crab. The species currently recognised in the genus Pinnotheres are:
Majidae is a family of crabs, comprising around 200 marine species inside 52 genera, with a carapace that is longer than it is broad, and which forms a point at the front. The legs can be very long in some species, leading to the name "spider crab". The exoskeleton is covered with bristles to which the crab attaches algae and other items to act as camouflage.
Macrophthalmus is a genus of crabs which are widespread across the Indo-Pacific. It contains the following species : Species in this genus are often referred to as sentinel crabs.
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:
Ozius is a genus of crabs in the family Menippidae, containing the following species:
Calappidae is a family of crabs containing 16 genera, of which 7 are only known as fossils:
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.
Inachidae is a family of crabs, containing 39 genera:
Pachygrapsus is a genus of small shore crabs. Recent genetic data suggest this genus to be possibly polyphyletic.
Leucosiidae is a family of crabs containing three subfamilies and a number of genera incertae sedis:
Cycloxanthops is a genus of crabs in the family Xanthidae, containing the following species:
Lachnopodus is a genus of crabs in the family Xanthidae, containing the following species:
Micropanope is a genus of crabs in the family Pseudorhombilidae, containing one exclusively fossil species and the following species:
Paraxanthias is a genus of crabs in the family Xanthidae, containing one exclusively fossil species and the following extant species:
Pilumnus is a genus of crabs, containing the following species:
Pisinae is a subfamily of crabs in the family Epialtidae, comprising the following genera:
The Panopeidae are a family containing 26 genera of morphologically similar crabs, often known as "mud crabs". Their centers of diversity are the Atlantic Ocean and eastern Pacific Ocean.
Pseudorhombilidae is a family of crabs.
