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.
Alpheus is a genus of snapping shrimp of the family Alpheidae. This genus contains in excess of 330 species, making this the most species-rich genus of shrimp. Like other snapping shrimp, the claws of Alpheus are asymmetrical, with one of the claws enlarged for making a popping noise. Some species in the genus enter into symbiotic relationships with gobiid fishes, and others associate with sea anemones.
Betaeus is a genus of shrimp in the family Alpheidae, containing the following species:
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.
Palaemonidae is a family of shrimp in the order Decapoda. Many species are carnivores that eat small invertebrates, and can be found in any aquatic habitat except the deep sea. One significant genus is Macrobrachium, which contains commercially fished species. Others inhabit coral reefs, where they associate with certain invertebrates, such as sponges, cnidarians, mollusks, and echinoderms, as cleaner shrimps, parasites, or commensals. They generally feed on detritus, though some are carnivores and hunt tiny animals.
Palaemon is a genus of caridean shrimp in the family Palaemonidae.
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.
Goneplacidae is a family of crabs of the order Decapoda and the superfamily Goneplacoidea. It includes the following genera:
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.
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.
Etisus is a genus of crabs, containing the following extant species:
Neotrypaea is a genus of ghost shrimp in the family Callianassidae, containing the following five species:
Mursia is a genus of crabs in the family Calappidae, containing the following species:
Chlorodiella is a genus of crabs in the family Xanthidae, containing the following species:
Liomera is a genus of crabs in the family Xanthidae. It contains the following extant species:
Xanthias is a genus of crabs in the family Xanthidae, containing two exclusively fossil species and the following extant species:
Pilumnus is a genus of crabs, containing the following species:
Pachycheles is a genus of porcelain crabs in the family Porcellanidae. There are more than 40 described species in Pachycheles.
