Cancridae is a family of crabs. It comprises six extant genera, and eleven exclusively fossil genera, in two subfamilies:
Xanthoidea is a superfamily of crabs, comprising the three families Xanthidae, Panopeidae and Pseudorhombilidae. 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.
The thumbnail crab, Thia scutellata, is a species of crab whose carapace resembles a human thumbnail. It is found in the North Sea, north-east Atlantic and Mediterranean Sea. It is the only extant species in the genus Thia, although two fossil species are known.
Tanaocheles is a genus of crabs, the only genus in the family Tanaocheleidae. It contains two species, T. bidentata and T. stenochilus. The two species were formerly placed in different families, and they were only shown to be related, and placed in a new subfamily, in 2000.
Dairoidea is a superfamily of crabs, comprising two families which each contain a single genus: Dairidae and Dacryopilumnidae (Dacryopilumnus) .
Xantho hydrophilus, the furrowed crab or Montagu's crab, is a species of crab from the family Xanthidae. It is yellowish-brown and grows to a carapace width of 70 mm (2.8 in). It is a nocturnal Omnivore that lives in shallow marine waters from western Scotland to the Cape Verde Islands.
Paraetisus globulus is a species of crab in the family Xanthidae, the only species in the genus Paraetisus. It was described in 1933 by Charles Melbourne Ward.
Medaeus is a genus of crabs in the family Xanthidae, 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.
Danielea moelensis is a species of crab in the family Xanthidae, and the only species in the genus Danielea.
Polydectus cupulifer is a species of crab in the family Xanthidae, and the only species in the genus Polydectus. Together with the genus Lybia, it forms the subfamily Polydectinae. It is found in the Indo-Pacific, ranging from Madagascar and the Red Sea in the west to Japan, Hawaii and French Polynesia in the east. P. cupulifer is densely covered with setae (bristles), and frequently carries a sea anemone in each chela (claw).
Speocarcinus is a genus of crabs in the family Xanthidae, containing six extant species, one fossil species from the Late Miocene, one fossil species from the Eocene (Lutetian) and one fossil species from the Early Eocene (Ypresian):
Melybia thalamita is a species of crab in the family Xanthidae, the only species in the genus Melybia. It is found in the western Atlantic Ocean, from Florida and the Gulf of Mexico south to São Paulo, Brazil, at depths of 10–200 metres (33–656 ft).
Micropanope is a genus of crabs in the family Xanthidae, containing one exclusively fossil species and the following species:
Paraxanthias is a genus of crabs in the family Xanthidae, containing one exclusively fossil species and the following extant species:
Xanthias is a genus of crabs in the family Xanthidae, containing two exclusively fossil species and the following extant species:
Xanthodius is a genus of crabs in the family Xanthidae, containing one exclusively fossil species and the following extant species:
Calvactaea tumida is a species of crabs in the family Xanthidae, the only species in the genus Calvactaea.
Atergatis is a genus of crabs in the family Xanthidae, containing the following species:
Zosimus is a genus of crabs in the family Xanthidae, containing the following species:
