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Cambarus

{{Short description|Genus of crayfishes}}

{{Automatic taxobox

| image=Chattooga River Crayfish (14174938652).jpg

|image_caption=Cambarus scotti

| taxon = Cambarus

| authority = Erichson, 1846

| type_species = Cambarus bartonii

| type_species_authority = Fabricius, 1798{{cite journal |title=A Checklist of the North and Middle American Crayfishes (Decapoda: Astacidae and Cambaridae) |author=Horton H. Hobbs Jr. |year=1974 |journal=Smithsonian Contributions to Zoology |volume=166 |issue=166 |pages=1–161 |doi=10.5479/si.00810282.166|author-link=Horton H. Hobbs Jr.}}

}}

Cambarus is a large and diverse genus of crayfish from the United States and Canada. The adults range in size from about {{convert|5|cm|abbr=on}} up to approximately {{convert|15|cm|abbr=on}}.

Description

The genus Cambarus is the second largest freshwater crayfish genus inhabiting the Northern Hemisphere, with only sixty fewer species than the genus Procambarus. Though Cambarus are varied across species, the two terminal elements that make up the male form I gonopod form ninety degree angles with the central appendage, allowing for their identification. Unlike the genus Procambarus whose first pleopod tends to have three processes at the tip, Cambarus has only one or two.{{Cite book|title=Biology and Ecology of Crayfish|last=Longshaw|first=Matt|publisher=CRC Press|year=2016|isbn=9781498767323|location=New York|pages=17–18}} Cambarus reach {{convert|17–26|mm|abbr=on}} carapace lengths in their first year, while average adult carapace length ranges from {{convert|55–62|mm|abbr=on}}. The name Cambarus comes from an alteration of Latin cammarus, meaning "lobster".{{citation needed|date=October 2023}}

As a genus containing nearly 100 species, Cambarus's coloration is variable. Cambarus bartonii is dark brown, while species like Cambarus pauleyi range from subtle to vibrant blues and reds. Other species are light green or grayish in color.

Biogeography

Most species of Cambarus are restricted to the United States and Canada. They are distributed along the eastern coast, extending from New Brunswick to northern Florida. However, the genus extends as far westward as the Rocky Mountains of Wyoming and Colorado, inhabiting a variety of freshwater environments.{{Cite web|url=http://eol.org/pages/313082/details|title=Cambarus diogenes|last=Cordeiro|first=J.|date=2014|website=Encyclopedia of Life|access-date=March 29, 2018}}

= Habitat =

Cambarus occupy a range of freshwater environments including streams, rivers, lakes, and burrows. Burrowing species of the genus include Cambarus dubius. Cambarus also include many cave-dwelling species, both stygobites and stygophiles. While salinity and temperature changes minimally affect Cambarus, the genus has shown an intolerance to pollution.{{Cite journal|last=Buhay|first=J|display-authors=et al|date=February 2007|title=Molecular taxonomy in the dark: Evolutionary history, phylogeography, and diversity of cave crayfish in the subgenus Aviticambarus, genus Cambarus|journal=Molecular Phylogenetics and Evolution|volume=42|issue=2|pages=435–448|doi=10.1016/j.ympev.2006.07.014|pmid=16971141}}

Ecology

= Diet =

Like other crayfish, Cambarus are foragers. Diets are largely plant-based, though Cambarus also consume small marine organisms like molluscs, larvae, tadpoles and amphibian eggs. Cambarus consume small rodents or birds when available. In their first year, Cambarus typically consume 1-4% of their overall body-weight each day.{{Cite book|title=Biology of Freshwater Crayfish|last=Holdich|first=David M.|publisher=Blackwell Science|year=2002|isbn=978-0-632-05431-2|location=London|pages=609–613}} The genus is central to many freshwater food webs as they help maintain water quality through consumption of algae.

= Vulnerability =

One of the largest crayfish genera, Cambarus includes a sizable number of vulnerable species. Cave-dwellers like Cambarus jonesi are at risk due to their lack of genetic diversity and low population count. Other species like Cambarus veteranus are at risk due to human practices like logging and mining, which increase sediment amounts in freshwater environments. Increased sediment causes these freshwater environments to be uninhabitable, and Cambarus are forced to relocate as a result.

= Growth =

Molting occurs among Cambarus approximately 5-10 times during their first year, and 3-5 times during subsequent years. Cambarus remain relatively inactive during periods of molting, as the shedding of chitinous exoskeletons leaves them more vulnerable to predation and injury. Many species of Cambarus continue to grow well into adulthood.

= Reproduction =

Cambarus typically mate in the early spring. Both Cambarus bartonii and Cambarus robustus only mate once during their three-year life span, with females of both carrying fewer eggs than those of the genus Orconectes.

Gallery

{{Gallery

| File:Cambarus aculabrum.jpg | Cambarus aculabrum

| File:Big Sandy crayfish (16382866013).jpg | Cambarus callainus

| File:Cambarus georgiae (3086810921).jpg | Cambarus georgiae

| File:Blue Crayfish - Cambarus monongalensis (165812772).jpg | Cambarus monongalensis

| File:Blackbarred Crayfish (13990939860).jpg | Cambarus unestami

}}

Classification

The genus Cambarus contains around 100 species,{{ITIS |taxon=Cambarus |id=97337}} many of which are listed on the IUCN Red List.{{cite web |publisher=IUCN |title=Search |work=IUCN Red List |url=http://www.iucnredlist.org/apps/redlist/search |access-date=October 7, 2010}} Species in the genus were formerly divided among 12 subgenera.{{cite web |author=James W. Fetzner Jr. |date=January 14, 2008 |title=Genus Cambarus Erichson, 1846 |work=Crayfish Taxon Browser |publisher=Carnegie Museum of Natural History |access-date=March 9, 2010 |url=http://iz.carnegiemnh.org/crayfish/NewAstacidea/genus.asp?g=Cambarus |archive-url=https://web.archive.org/web/20140429050406/http://iz.carnegiemnh.org/crayfish/NewAstacidea/genus.asp?g=Cambarus |archive-date=April 29, 2014 |url-status=dead }} In a 2017 study,{{Cite journal|last1=Crandall|first1=Keith A|last2=De Grave|first2=Sammy|date=September 2017|title=An updated classification of the freshwater crayfishes (Decapoda: Astacidea) of the world, with a complete species list|url=http://academic.oup.com/jcb/article/37/5/615/4060680/An-updated-classification-of-the-freshwater|journal=Journal of Crustacean Biology|language=en|volume=37|issue=5|pages=615–653|doi=10.1093/jcbiol/rux070|issn=0278-0372|doi-access=free}} these subgenera were found to lack any phylogenetic validity and were therefore eliminated.

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References

{{Reflist|2}}

Further reading

{{Commons category}}

  • {{cite web |title=Crayfish |access-date=May 10, 2021 |url=http://www.personal.psu.edu/hw7/naturetrail/speciespages/crayfish.htm |website=The Virtual Nature Trail at Penn State New Kensington |orig-year=2006 |publisher=The Pennsylvania State University |date=2013-10-08 |first=Alicia |last=Fitzgerald}}

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Category:Cambaridae

Category:Freshwater crustaceans of North America

Category:Decapod genera

Category:Taxa named by Wilhelm Ferdinand Erichson