The Decapoda or decapods are an order of crustaceans within the class Malacostraca, and includes crabs, lobsters, crayfish, shrimp, and prawns. Most decapods are scavengers. The order is estimated to contain nearly 15,000 extant species in around 2,700 genera, with around 3,300 fossil species. Nearly half of these species are crabs, with the shrimp and Anomura including hermit crabs, porcelain crabs, squat lobsters making up the bulk of the remainder. The earliest fossils of the group date to the Devonian.
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.
Perisesarma bidens, the red claw crab, is a species of crab found in the Indo-Pacific region from Zanzibar to Japan and Fiji.
Sand bubbler crabs are crabs of the genera Scopimera and Dotilla in the family Dotillidae. They are small crabs that live on sandy beaches in the tropical Indo-Pacific. They feed by filtering sand through their mouthparts, leaving behind balls of sand that are broken up by the incoming high tide.
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.
Hexapus is a genus of crabs in the family Hexapodidae. It contains only three extant species found in the Indo-West Pacific. They inhabit the intertidal and subtidal areas of shorelines.
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.
The Dotillidae are a family of crabs with 59 species, nearly half of which are in the genus Ilyoplax. The two genera Scopimera and Dotilla are collectively the sand bubbler crabs, which leave conspicuous collections of sand pellets on sandy beaches across the tropical and subtropical Indo-Pacific.
Palapedia is a genus of crabs in the family Xanthidae, containing the following species:
Atergatis is a genus of crabs in the family Xanthidae, containing the following species:
Helice is a genus of crabs, containing four species:
Atergatis subdentatus, also known as the red reef crab, dark-finger coral crab or eyed coral crab, is a species of crab in the family Xanthidae.
Galenidae is a family of crabs, one of three in the superfamily Pilumnoidea. It contains four genera, three of which are monotypic. At present five species have been described in this family.
Euryplacidae is a family of crabs in the superfamily Goneplacoidea which contains the following genera:
Eucrate crenata, the blunt-spined euryplacid crab, is a species of Indo-Pacific crab from the family Euryplacidae. It has invaded the Mediterranean Sea from the Red Sea by Lessepsian migration through the Suez Canal.
Halimede is a genus of crabs in the family Galenidae, with species occurring in Australia, Africa, and China.
Jonas is a genus of crustaceans belonging to the family Corystidae.
Macrophthalmus japonicus, the Japanese mud crab, is a species of sentinel crab in the family Macrophthalmidae found in Asia. The taxon was described by Wilhem de Haan in 1835.
Sesarmops is a genus of crabs in the family Sesarmidae. Its members are distributed through the Indo–West-Pacific oceanic region. They live in freshwater forest streams near the coast, and in mangroves.
