Cherax Solus

''Cherax'', commonly known as yabby/yabbies in Australia, is the most widespread genus of fully aquatic crayfish in the Southern Hemisphere. Various species of cherax may be found in both still and flowing bodies of freshwater across most of Australia and New Guinea. Together with '' Euastacus'', it is also the largest crayfish genus in the Southern Hemisphere.

Habitat

Members of the cherax genus can be found in lakes, rivers, and streams across most of Australia and New Guinea.

The most common and widely distributed species in Australia is the common yabby (''C. destructor''). It is generally found in lowland rivers and streams, lakes, swamps, and impoundments at low to medium altitude, largely within the Murray–Darling Basin. Common yabbies are found in many ephemeral waterways, and can survive dry conditions for long periods of time (at least several years) by aestivating (lying dormant) in burrows sunk deep into muddy creek and swamp beds.

In New Guinea, ''Cherax'' crayfish are found widely in rivers, streams, and lakes, with a particularly high diversity in the Paniai Lakes. New Guinea is also home to the only known cave-living crayfish in the Southern Hemisphere, ''C. acherontis''.

Introduced

Some species are very colourful and sometimes seen in the freshwater aquarium trade.

Reproduction

The mating season for ''Cherax'' is during early spring. After fertilisation, eggs develop inside the mother's body for 4 to 6 weeks. After that period, the eggs transition to the outside of the mother's body and rest on the female's tail. Then the eggs continue to develop and hatch in spring.

Both sexes of ''Cherax'' are selective with copulation partners. Females tend to choose males with a larger central mass (abdomen and tail) and cheliped. Males tend to select copulation partners who have larger body sizes and are virgins. Opposed to females who were more dominant or had symmetrical chelipeds.

As part of a mating/copulation ritual, males and females fight each other. This allows the female to test the strength of the male to determine if they will produce viable offspring. During the fight, both release urine. The female's release of urine triggers a sexual response from the male. The male's release of urine is an aggressive response towards the fight with the female. When the male smells the female's urine, it will stop releasing its own, hoping the female will allow them to copulate.

Once the female allows it, the male will position itself on its back, and deposit its sperm. Unlike other crayfish species, the ''Cherax dispar'' does not use its cheliped to cage females during copulation. It is mainly used during mating when the males and females fight.

Behaviour

In instances when displaying males have chelae of a similar size, they will engage in combat and those with the greater chelae closing force will win.

Female ''C. dispar'' uses honest signalling of strength, meaning the size of their chelae is a good indication to other ''C. dispar'' about that individual's strength. Individuals possessing larger chelae engage in more agonistic encounters and are also more likely to win. In a study of female C''. dispar'' chelae strength, researchers found that chelae size also indirectly indicated the dominance of the female because of its honest indication of strength.

Species

The genus contains at least 60 species:

*'' Cherax acherontis'' Patoka, Bláha & Kouba, 2017
*'' Cherax albertisii'' Nobili, 1899
*'' Cherax albidus'' Clarke, 1936
*'' Cherax alyciae'' Lukhaup, Eprilurahman & von Rintelen, 2018
*'' Cherax aruanus'' Roux, 1911
*'' Cherax austini'' Coughran & Hobson, 2012
*'' Cherax barretti'' Clark, 1941
*'' Cherax bicarinatus'' (Gray, 1845)
*'' Cherax boesemani'' Lukhaup & Pekny, 2008
*'' Cherax boschmai'' Holthuis, 1949
*'' Cherax buitendijkae'' Holthuis, 1949
*'' Cherax cainii'' Austin, 2002
*'' Cherax cairnsensis'' Riek, 1969
*'' Cherax cartalacoolah'' Short, 1993
*'' Cherax cid'' Coughran & Furse, 2012
*'' Cherax communis'' Holthuis, 1949
*'' Cherax crassimanus'' Riek, 1967
*'' Cherax cuspidatus'' Riek, 1969
*'' Cherax davisi'' Clark, 1941
*'' Cherax depressus'' Riek, 1951
*''Cherax destructor'' Clark, 1936
*'' Cherax dispar'' Riek, 1951
*'' Cherax esculus'' Riek, 1956
*'' Cherax gherardii'' Patoka, Bláha & Kouba, 2015
*'' Cherax glaber'' Riek, 1967
*'' Cherax glabrimanus'' Riek, 1967
*'' Cherax gladstonensis'' Riek, 1969
*'' Cherax holthuisi'' Lukhaup & Pekny, 2006
*'' Cherax leckii'' Coughran, 2005
*'' Cherax longipes'' Holthuis, 1949
*'' Cherax lorentzi'' Roux, 1911
*'' Cherax minor'' Holthuis, 1996
*'' Cherax misolicus'' Holthuis, 1949
*'' Cherax monticola'' Holthuis, 1950
*'' Cherax murido'' Holthuis, 1949
*'' Cherax neocarinatus'' Riek, 1967
*'' Cherax neopunctatus'' Riek, 1969
*'' Cherax nucifraga'' Short, 1991
*'' Cherax pallidus'' Holthuis, 1949
*'' Cherax paniaicus'' Holthuis, 1949
*''Cherax papuanus'' Holthuis, 1949
*'' Cherax parvus'' Short & Davie, 1993
*'' Cherax peknyi'' Lukhaup & Herbert, 2008
*'' Cherax plebejus'' (Hess, 1865)
*'' Cherax preissii'' (Erichson, 1846) syn. ''Cherax angustus'' McCulloch, 1914
*'' Cherax pulcher'' Lukhaup, 2015
*'' Cherax punctatus'' Clark, 1936
*'' Cherax quadricarinatus'' (von Martens, 1868)
*'' Cherax quinquecarinatus'' (Gray, 1845)
*'' Cherax rhynchotus'' Riek, 1951
*'' Cherax robustus'' Riek, 1951

*'' Cherax rotundus'' Clark, 1941
*'' Cherax setosus'' (Riek, 1951)
*'' Cherax snowden'' Lukhaup, Panteleit & Schrimpf, 2015 syn. ''Cherax subterigneus''
*'' Cherax solus'' Holthuis, 1949
*'' Cherax tenuimanus'' (Smith, 1912)
*'' Cherax urospinosus'' Riek, 1969
*'' Cherax wagenknechtae'' /Lukhaup,Eprilurahman 2022
*'' Cherax wasselli'' Riek, 1969
*'' Cherax woworae'' Patoka, Akmal, Bláha & Kouba, 2023
*'' Cherax pulverulentus'' Patoka, Akmal, Bláha, & Kouba, 2025

References

{{Authority control

Parastacidae
Decapod genera