Cancer is a genus of marine crabs in the family Cancridae. It includes eight extant species and three extinct species, including familiar crabs of the littoral zone, such as the European edible crab, the Jonah crab and the red rock crab. It is thought to have evolved from related genera in the Pacific Ocean in the Miocene.
The Ocypodidae are a family of semiterrestrial crabs that includes the ghost crabs and fiddler crabs. They are found on tropical and temperate shorelines around the world.
Cancridae is a family of crabs. It comprises six extant genera, and ten exclusively fossil genera, in two subfamilies:
The Grapsoidea are a superfamily of crabs; they are well known and contain many taxa which are terrestrial (land-living), semiterrestrial, or limnic. Another well-known member with a more conventional lifestyle is the Chinese mitten crab, Eriocheir sinensis.
Pseudothelphusidae is a family of freshwater crabs found chiefly in mountain streams in the Neotropics. They are believed to have originated in the Greater Antilles and then crossed to Central America via a Pliocene land bridge. Some species of this family are troglobitic.
Sesarma reticulatum, the purple marsh crab or simply marsh crab, is a crab species native to the salt marshes of the eastern United States.
The Sesarmidae are a family of crabs, previously included in the Grapsidae by many authors. Several species, namely in Geosesarma, Metopaulias, and Sesarma, are true terrestrial crabs. They do not need to return to the sea even for breeding.
Gecarcinus is the type genus of the land crab family Gecarcinidae. They are found in warmer coastal regions of the Americas, including islands in the Caribbean. Four species from oceanic islands were formerly included in Gecarcinus as the subgenus Johngarthia, but are now treated as a separate genus, Johngarthia. While all members of this genus are largely terrestrial, they have to return to the ocean to breed. They are often colourful, with reddish, orange, purple, yellowish, whitish, or blackish being the dominating hues. This has resulted in some species, notably G. quadratus and G. lateralis, gaining a level of popularity in the pet trade.
Potamon is a genus of freshwater or semiterrestrial crabs mainly found from Southern Europe through the Middle East, and as far east as north-western India. The only exception is the North African P. algeriense, which also is the only potamid of mainland Africa. Twenty species are currently recognised:. These crabs are omnivores that have a broad ecological tolerance. The adult Potaman reach up to 50 mm in size during their 10-12 year life span.
Austruca mjoebergi is a species of fiddler crab discovered by and named after the Swedish zoologist Eric Mjöberg (1882–1938), member of a Swedish scientific expedition to Australia in the early 1900s.
Austruca perplexa is a species of fiddler crab. It is found from the Ryukyu Islands, Japan to India, throughout the Malay Archipelago, along eastern Australian coasts from Queensland to New South Wales, and in various Pacific islands, including Fiji, Tonga and Vanuatu.
Karstarma is a genus of karst-dwelling crabs formerly included in Sesarmoides.
Xantho is a genus of crabs in the family Xanthidae, containing five extant species, all restricted to the north-east Atlantic Ocean and Mediterranean Sea, although Xantho granulicarpis is not universally recognised as a separate species from Xantho hydrophilus:
Cyrtocarcinus truncatus is a species of crab in the family Xanthidae that lives in the waters around Hawaii. It was described in 1906 by Mary J. Rathbun as Harrovia truncata, based on a single immature male specimen caught near Kauai. Masatsune Takeda transferred the species to his new genus Glyptocarcinus in 1979, and Peter Ng and Diana Chia erected a new genus, Cyrtocarcinus, for this species alone, in 1994.
Marratha angusta is a species of crabs in the family Xanthidae, the only species in the genus Marratha. It was originally described as Cycloxanthops angustus by Mary J. Rathbun in 1906, but was moved to a new genus in 2003; the name of the genus, Marratha, is an "arbitrary abbreviation" of Rathbun's name. It has been recorded from the Amirante Islands (Seychelles), Hawaii and the South China Sea.
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.
Geosesarma dennerle is a species of small land-living crabs found on Java, Indonesia.
Armases is a genus of true crabs in the family Sesarmidae. There are about 13 described species in Armases.
Austruca is a genus of indo-west Pacific fiddler crabs in the family Ocypodidae. There are about 13 described species in this genus.
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.
