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.
Caridina is a genus of freshwater atyid shrimp. They are widely found in tropical or subtropical water in Asia, Oceania and Africa. They are filter-feeders and omnivorous scavengers. They range from 0.9–9.8 mm to 1.2–7.4 mm in carapace length.
The Valvifera are marine isopod crustaceans. Valviferans are distinguished, however, by the flat, valve-like uropods which hinge laterally and fold inward beneath the rear part of their bodies, covering the pleopods. Some species are omnivorous, and serve as effective scavengers in the economy of the sea.
Upogebia is a genus of mud shrimp, in the family Upogebiidae, containing the following species:
Acutigebia danai is a mud shrimp of the family Upogebiidae, endemic to the coastal waters of New Zealand and the Kermadec Islands.
Callianassidae is a family of ghost shrimp of the order Decapoda.
Callianassa is a genus of mud shrimps, in the family Callianassidae. Three of the species in this genus have been split off into a new genus, Pestarella, while others such as Callianassa filholi have been moved to Biffarius.
Pagurus is a genus of hermit crabs in the family Paguridae. Like other hermit crabs, their abdomen is not calcified and they use snail shells as protection. These marine decapod crustaceans are omnivorous, but mostly prey on small animals and scavenge carrion. Trigonocheirus and Pagurixus used to be considered subgenera of Pagurus, but the former is nowadays included in Orthopagurus, while the latter has been separated as a distinct genus.
Palaemon is a genus of caridean shrimp of the family Palaemonidae. The conventional circumscription of the genus Palaemon is probably paraphyletic. Molecular data suggest that Palaemonetes, as well as the genera Exopalaemon and Couteriella, are nested within Palaemon. Phylogenetic affinities in these groups correspond better with geographical origin than conventional genus assignments.
Thalassina is a genus of mud lobsters found in the mangrove swamps of the Indian Ocean and western Pacific Ocean. Its nocturnal burrowing is important for the recycling of nutrients in the mangrove ecosystem, although it is sometimes considered a pest of fish and prawn farms.
Axiidae is a family of thalassinidean crustaceans. It includes the following genera:
Eiconaxius is a genus of mud lobster that includes the following species:
Paguristes is a genus of hermit crab in the family Diogenidae. It includes the following species :
Galathea is one of the largest genera of squat lobsters, containing 70 currently recognised species. Most species of Galathea live in shallow waters.
Munida is the largest genus of squat lobsters in the family Munididae, with over 240 species.
Biffarius is a genus of ghost shrimp in the family Callianassidae, containing species formerly included in the genus Callianassa. Its members are small and generally live in the intertidal zone. In April 2020, a new species was described from the northeastern Brazilian coast. Biffarius was named in honour of Thomas A. Biffar, and includes the following species:
Lepidophthalmus is a genus of ghost shrimp, containing the following species:
Metapenaeopsis, the velvet shrimps, is a prawn genus in the family Penaeidae. It contains these species:
Uroptychus is a genus of squat lobsters in the family Chirostylidae found across the Indo-Pacific. The genus Uroptychus contains the following species:
Chirostyloidea is an anomuran superfamily with squat lobster-like representatives. It comprises the three families Chirostylidae, Eumunididae and Kiwaidae. Although representatives of Chirostyloidea are superficially similar to galatheoid squat lobsters, they are more closely related to Lomisoidea and Aegloidea together forming the clade Australopoda. No fossils can be confidently assigned to the Chirostyloidea, although Pristinaspina may belong either in the family Kiwaidae or Chirostylidae.
