Calappoidea is a

superfamily SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...

crab Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...

s comprising the two families

Calappidae Calappidae is a family of crabs containing 16 genera, of which 7 are only known as fossils: *''Acanthocarpus'' Stimpson, 1871 *'' Calappa'' Weber, 1795 *† '' Calappella'' Rathbun, 1919 *† '' Calappilia'' A. Milne-Edwards, 1873 *'' Calappula ...

and

Matutidae 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 P ...

. The earliest

fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved ...

s attributable to the Calappoidea date from the

Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraphic column. It is a subdivision of the Early or Lower Cretaceous Epoch or Series and encompasses the time from 121.4 ± 1.0 Ma to 113.0 ± 1.0 Ma (million years ago), a ...

References

External links

* Crabs Aptian first appearances Taxa named by Henri Milne-Edwards Arthropod superfamilies Extant Aptian first appearances {{crab-stub