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Cherax

{{Short description|Genus of crayfishes}}

{{Use Australian English|date=May 2021}}

{{Use dmy dates|date=May 2021}}

{{Automatic taxobox

| image = Cherax papuanus.jpg

| image_caption = Cherax papuanus

| taxon = Cherax

| authority = Erichson, 1846

| type_species = Astacus preissii

| type_species_authority = Erichson, 1846

| range_map = Cherax distribution.svg

}}

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.{{cite journal |first1=D. H. N. |last1=Munasinghe |first2=C. P. |last2=Burridge |first3=C. M. |last3=Austin |year=2004 |title=The systematics of freshwater crayfish of the genus Cherax Erichson (Decapoda: Parastacidae) in eastern Australia re-examined using nucleotide sequences from 12S rRNA and 16S rRNA genes |journal=Invertebrate Systematics |volume=18 |issue=2 |pages=215–225 |url=https://www.researchgate.net/publication/225083275 |format=PDF |doi=10.1071/IS03012 |name-list-style=amp |via=ResearchGate |url-access=registration}}

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.{{cite report |first1=Dan A. |last1=Polhemus |first2=Ronald A. |last2=Englund |first3=Gerald R. |last3=Allen |title=Freshwater Biotas of New Guinea and Nearby Islands: Analysis of Endemism |url=http://pbs.bishopmuseum.org/pdf/ci-png.pdf |publisher=Bernice Pauahi Bishop Museum, Conservation International |year=2004 |name-list-style=amp}} New Guinea is also home to the only known cave-living crayfish in the Southern Hemisphere, C. acherontis.{{cite journal |last1=Patoka |first1=Jiří |last2=Bláha |first2=Martin |last3=Kouba |first3=Antonín |title=Cherax acherontis (Decapoda: Parastacidae), the first cave crayfish from the Southern Hemisphere (Papua Province, Indonesia)|journal=Zootaxa |volume=4363 |issue=1 |pages=137–144 |doi=10.11646/zootaxa.4363.1.7 |year=2017|pmid=29245414 }}

=Introduced=

Some species are very colourful and sometimes seen in the freshwater aquarium trade.{{cite magazine |title=Mysterious beautiful blue crayfish is new species from Indonesia |magazine=New Scientist |date=2015-05-13 |access-date=2015-05-28 |url=https://www.newscientist.com/article/dn27517-mysterious-beautiful-blue-crayfish-is-new-species-from-indonesia.html#.VWecmaZ7nVA |first=Agata |last=Blaszczak-Boxe |issue=3021}}

Reproduction

{{Clarify|date=November 2021 |reason=Is this all Cherax, or just C. dispar?}}

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.{{cite web |title=Crayfish |url=https://www.dept.psu.edu/nkbiology/naturetrail/speciespages/crayfish.htm |website=www.dept.psu.edu |access-date=27 May 2022 |archive-date=18 July 2022 |archive-url=https://web.archive.org/web/20220718180424/https://www.dept.psu.edu/nkbiology/naturetrail/speciespages/crayfish.htm |url-status=dead }}

File:Yabbies in shallow water During Spring001.jpg

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.{{cite journal |last1=Aquiloni |first1=L. |last2=Gherardi |first2=F. |year=2008 |title=Mutual mate choice in crayfish: Large body size is selected by both sexes, virginity by males only |journal=Journal of Zoology |volume=274 |issue=2 |pages=171–179 |doi=10.1111/j.1469-7998.2007.00370.x |name-list-style=amp|hdl=2158/252681 |s2cid=84513148 |hdl-access=free }}

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.{{cite journal |last1=Berry |first1=Fiona C. |last2=Breithaupt |first2=Thomas |year=2010 |title=To signal or not to signal? Chemical communication by urine-borne signals mirrors sexual conflict in crayfish |journal=BMC Biology |volume=8 |issue=1 |page=25 |doi=10.1186/1741-7007-8-25 |pmid=20353555 |name-list-style=amp|pmc=2867775 |doi-access=free }} 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.{{citation needed|date=May 2021}}

Once the female allows it, the male will position itself on its back, and deposit its sperm.{{cite journal |last1=Barki |first1=Assaf |last2=Karplus |first2=Ilan |year=1999 |title=Mating Behavior and a Behavioral Assay for Female Receptivity in the Red-claw Crayfish Cherax quadricarinatus |journal=Journal of Crustacean Biology |volume=19 |issue=3 |pages=493–497 |doi=10.2307/1549258 |jstor=1549258 |name-list-style=amp|doi-access=free }} 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.{{cite journal |last1=Bywater |first1=C. L. |last2=Angilletta |first2=M. J. |last3=Wilson |first3=R. S. |year=2008 |title=Weapon Size Is a Reliable Indicator of Strength and Social Dominance in Female Slender Crayfish (Cherax dispar) |journal=Functional Ecology |volume=22 |issue=2 |pages=311–316 |name-list-style=amp |doi=10.1111/j.1365-2435.2008.01379.x|doi-access=free }}

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

File:Cherax Blue moon.jpg

The genus contains at least 60 species:{{cite web |url=http://iz.carnegiemnh.org/crayfish/NewAstacidea/genus.asp?g=Cherax |title=Genus Cherax Erichson, 1846 |work=Crayfish Taxon Browser |last=Fetzner |first=James W. Jr. |publisher=Carnegie Museum of Natural History |access-date=2015-11-24 |date=2010-01-11 |archive-url=https://web.archive.org/web/20150402203502/http://iz.carnegiemnh.org/crayfish/NewAstacidea/genus.asp?g=Cherax |archive-date=2015-04-02 |url-status=dead}}{{ITIS |id=1133542 |taxon=Cherax}}

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File:Cherax robustus.jpg

  • Cherax rotundus Clark, 1941
  • Cherax setosus (Riek, 1951)
  • Cherax snowden Lukhaup, Panteleit & Schrimpf, 2015{{cite magazine |title=New species of crayfish named after Edward Snowden |magazine=Time |date=2015-08-25 |access-date=2015-08-25 |url=https://time.com/4010078/crayfish-edward-snowden/ |first=Eliana |last=Dockterman}} syn. Cherax subterigneus{{cite journal |first1=Jiří |last1=Patoka |first2=Martin |last2=Bláha |first3=Antonín |last3=Kouba |name-list-style=amp |year=2015 |title=Cherax (Cherax) subterigneus, a new crayfish (Decapoda: Parastacidae) from West Papua, Indonesia |journal=Journal of Crustacean Biology |volume=35 |issue=6 |pages=830–838 |doi=10.1163/1937240x-00002377 |doi-access=free }}
  • 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{{Cite journal |last=Patoka |first=Jiří |last2=Akmal |first2=Surya Gentha |last3=BláHa |first3=Martin |last4=Kouba |first4=AntoníN |date=2025-01-09 |title=Cherax pulverulentus, a new freshwater crayfish (Decapoda: Parastacidae) from Southwest Papua Province, Indonesia |url=https://mapress.com/zt/article/view/zootaxa.5566.3.4 |journal=Zootaxa |volume=5566 |issue=3 |pages=522–534 |doi=10.11646/zootaxa.5566.3.4 |issn=1175-5334|url-access=subscription }}

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References

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Category:Parastacidae

Category:Decapod genera