| Trapezioidea Temporal range: | |
|---|---|
 | |
| Trapezia tigrina (Trapeziidae) | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Malacostraca |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Section: | Eubrachyura |
| Subsection: | Heterotremata |
| Superfamily: | Trapezioidea Miers, 1886 [1] |
| Families | |
See text | |
Trapezioidea is a superfamily of crabs. Its members live symbiotically with corals and have a fossil record stretching back to the Eocene. [2]
The World Register of Marine Species lists the following families: [1]
Parathranites is a genus of crabs. It contains the following species:
Majidae is a family of crabs, comprising around 200 marine species inside 52 genera, with a carapace that is longer than it is broad, and which forms a point at the front. The legs can be very long in some species, leading to the name "spider crab". The exoskeleton is covered with bristles to which the crab attaches algae and other items to act as camouflage.
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.
Trapezia is a genus of guard crabs in the family Trapeziidae. Like other members of this family, they live in association with corals, feeding on coral tissue and mucus, and defending the corals from predators, like starfish. It contains the following species:
Calappidae is a family of crabs containing 16 genera, of which 7 are only known as fossils:
The Aethridae are a family of crabs in their own superfamily, Aethroidea. It contains these genera :
Hexapodidae is a family of crabs, the only family in the superfamily Hexapodoidea. It has traditionally been treated as a subfamily of the family Goneplacidae, and was originally described as a subfamily of Pinnotheridae. Its members can be distinguished from all other true crabs by the reduction of the thorax, such that only seven sternites are exposed, and only four pairs of pereiopods are present. Not counting the enlarged pair of claws, this leaves only six walking legs, from which the type genus Hexapus, and therefore the whole family, takes its name. Some anomuran "crabs", such as porcelain crabs and king crabs also have only four visible pairs of legs. With the exception of Stevea williamsi, from Mexico, all the extant members are found either in the Indo-Pacific oceans, or around the coast of Africa.
Goneplacoidea is a superfamily of crabs containing 11 extant families, and two families known only from fossils.
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.
Pseudozioidea is a superfamily of crabs, formerly treated in the Eriphioidea, Carpilioidea, Xanthoidea, Pilumnoidea and Goneplacoidea. A number of fossils from the Eocene onwards are known from the family Pseudoziidae. Eleven genera are recognised in three families:
Palicoidea is a superfamily of crabs, comprising the two families Crossotonotidae and Palicidae. Together, they contain 13 genera, including two genera in the Palicidae known only from fossils. The two families were previously treated as two subfamilies in a Palicidae of wider circumscription.
Trapeziidae is a family of crabs, commonly known as coral crabs. All the species in the family are found in a close symbiosis with cnidarians. They are found across the Indo-Pacific, and can best be identified to the species level by the colour patterns they display. Members of the family Tetraliidae were previously included in the Trapeziidae, but the similarities between the taxa is the result of convergent evolution.
Carcinidae is a family of crabs belonging to the order Decapoda. It has four subfamilies, including Pirimelinae which was previously treated as a family.
Ashtoret is a genus of crabs in the family Matutidae, containing the following species:
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:
The Galatheoidea are a superfamily of decapod crustaceans comprising the porcelain crabs and some squat lobsters. Squat lobsters within the three families of the superfamily Chirostyloidea are not closely related to the squat lobsters within the Galatheoidea. The fossil record of the superfamily extends back to the Middle Jurassic genus Palaeomunidopsis.
Xanthodius is a genus of crabs in the family Xanthidae, containing one exclusively fossil species and the following species:
Tetraliidae is a family of crabs.
Euryplacidae is a family of crabs in the superfamily Goneplacoidea which contains the following genera:
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