Gecarcoidea is a genus of terrestrial crabs. The crabs live in forests but must come to the coast to breed. When it is dry in the summer the crabs are inactive, but when it is the wet season they are ready to migrate.
Maja is a genus of majid crabs erected by Jean-Baptiste Lamarck in 1801. It includes the following extant species:
Cancridae is a family of crabs. It comprises six extant genera, and ten exclusively fossil genera, in two subfamilies:
Xanthoidea is a superfamily of crabs, comprising seven families. Formerly, a number of other families were included in Xanthoidea, but many of these have since been removed to other superfamilies. These include Carpilioidea, Eriphioidea, Hexapodoidea, Pilumnoidea and Trapezioidea. Even in this reduced state, Xanthoidea remains one of the most species-rich superfamilies of crabs.
Discoplax is a genus of terrestrial crabs. It is very closely related to the genera Cardisoma and Tuerkayana.
Gecarcinucoidea is a superfamily of freshwater crabs. Its members have been grouped into families in various ways, with some authors recognizing families such as "Deckeniidae", "Sundathelphusidae", and "Parathelphusidae", but now only the family Gecarcinucidae is currently recognized.
Metacarcinus is a genus of crabs formerly included in the genus Cancer. It includes nine exclusively fossil species and five extant species, of which four are also known from the fossil record. A molecular study using the cytochrome oxidase I gene does not support the monophyly of this genus.
Cheiragonidae is a small family of crabs, sometimes called helmet crabs, placed in its own superfamily, Cheriagonoidea. It comprises three extant species, Erimacrus isenbeckii, Telmessus acutidens and Telmessus cheiragonus, there are no yet evidences of Cheiragonidae in the fossil record. Many of these crabs were formerly treated as members of the Atelecyclidae.
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.
Matutidae is a family of crabs, sometimes called moon crabs, adapted for swimming or digging. They differ from the swimming crabs of the family Portunidae in that all five pairs of legs are flattened, rather than just the last pair, as in Portunidae. Crabs in the Matutidae are aggressive predators.
Epialtidae is a family of crabs, containing the subfamilies:
Panopeus is a genus of crabs, containing these extant species:
Kingsleya is a genus of crabs in the family Pseudothelphusidae, containing the following species:
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.
Euryxanthops is a genus of crabs in the family Xanthidae. It was originally established in 1983 by Garth & Kim to contain three species of deep-water crabs from Japan and the Philippines - Euryxanthops dorsiconvexus, Euryxanthops flexidentatus and Euryxanthops orientalis. Since then, several more species of this genus have been identified and described, and Euryxanthops currently contains:
Micropanope is a genus of crabs in the family Pseudorhombilidae, containing one exclusively fossil species and the following species:
Neolioxantho is a genus of crabs in the family Xanthidae, containing the following species:
Xanthias is a genus of crabs in the family Xanthidae, containing two exclusively fossil species and the following extant species:
Zosimus is a genus of crabs in the family Xanthidae, containing the following species:
Conleyus defodio is a species of crab, the only species in the genus Conleyus and the family Conleyidae. It lives in rubble beds in Guam, and is named after the collector Harry T. Conley.
