Matutidae is a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

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, sometimes called ''moon crabs'',

adapted In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the po ...

for swimming or digging. They differ from the swimming crabs of the family

Portunidae Portunidae is a family of crabs which contains the swimming crabs. Description Portunid crabs are characterised by the flattening of the fifth pair of legs into broad paddles, which are used for swimming. This ability, together with their strong ...

in that all five pairs of

legs A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element ...

are flattened, rather than just the last pair, as in Portunidae. Crabs in the Matutidae are

aggressive Aggression is overt or covert, often harmful, social interaction with the intention of inflicting damage or other harm upon another individual; although it can be channeled into creative and practical outlets for some. It may occur either reacti ...

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

Taxonomy

Traditionally, this taxon contained the single genus ''

Matuta ''Matuta'' is a genus of crabs in the family Matutidae, containing the following species:= * '' Matuta circulifera'' Miers, 1880 * '' Matuta inermis'' Brocchi, 1883 * ''Matuta planipes'' Fabricius, 1798 * '' Matuta purnama'' Lai & Galil, 200 ...

'', and was considered a subfamily of the

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 ...

. Now, the group is

ranked A ranking is a relationship between a set of items such that, for any two items, the first is either "ranked higher than", "ranked lower than" or "ranked equal to" the second. In mathematics, this is known as a weak order or total preorder of ...

as a family and six genera (four extant and two fossil) are now recognised. Although placed in the

Calappoidea Calappoidea is a superfamily of crabs comprising the two families Calappidae and Matutidae. The earliest fossils attributable to the Calappoidea date from the Aptian The Aptian is an age in the geologic timescale or a stage in the stratigraph ...

, it is not clear that Matutidae and Calappidae are closely related. *''

Ashtoret ''Ashtoret'' is a genus of crabs in the family Matutidae, containing the following species: * '' Ashtoret granulosa'' (Miers, 1877) * ''Ashtoret lunaris'' (Forskål, 1775) * '' Ashtoret maculata'' (Miers, 1877) * '' Ashtoret miersii'' (Henderson ...

'' Galil & P. F. Clark, 1994 *† '' Eomatuta'' De Angeli & Marchiori, 2009 *''

Izanami , formally known as , is the creator deity of both creation and death in Japanese mythology, as well as the Shinto mother goddess. She and her brother-husband Izanagi are the last of the seven generations of primordial deities that manifest ...

'' Galil & P. F. Clark, 1994 *''

'' Weber, 1795 *''

Mebeli ''Mebeli michaelseni'' is a species of crab in the family 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 fi ...

'' Galil & P. F. Clark, 1994 *† '' Szaboa'' Müller & Galil, 1998 Image:Ashtoret picta (photo Miguel Ramirez).jpg, ''

Ashtoret picta ''Ashtoret'' is a genus of crabs in the family Matutidae, containing the following species: * '' Ashtoret granulosa'' (Miers, 1877) * ''Ashtoret lunaris'' (Forskål, 1775) * '' Ashtoret maculata'' (Miers, 1877) * '' Ashtoret miersii'' (Henderson ...

'' Image:Specimen of Izanami curtispina.JPG, ''

Izanami curtispina , formally known as , is the creator deity of both creation and death in Japanese mythology, as well as the Shinto mother goddess. She and her brother-husband Izanagi are the last of the seven generations of primordial deities that manifest ...

'' Image:Matuta victor - National Museum of Nature and Science, Tokyo - DSC06764.JPG, ''

Matuta victor ''Matuta'' is a genus of crabs in the family Matutidae, containing the following species:= * '' Matuta circulifera'' Miers, 1880 * '' Matuta inermis'' Brocchi, 1883 * ''Matuta planipes Matuta planipes is a species of moon crab in the fami ...

'' Image:Specimen of Matuta planipes.jpg, ''

Matuta planipes Matuta planipes is a species of moon crab in the family 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 ...

Fossil record

'' Szaboa'' is known only from Hungarian

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 ...

deposits of

Middle Miocene The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0.05 Ma to 11.608 ± 0.005 Ma (million y ...

age. '' Eomatuta'' was described from the

Middle Eocene The Eocene ( ) Epoch is a geological epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period in the modern Cenozoic Era. The name ''Eocene'' comes from the Ancient Greek (''ēṓs'', "dawn ...

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...

in 2009. Fossils of ''

'' have also been found in

Miocene The Miocene ( ) is the first geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and means "less recen ...

deposits in

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

References

{{Taxonbar, from=Q2298078 Calappoidea Taxa named by Wilhem de Haan