Cambarus

Cambarus is a large and diverse genus of crayfish from the United States and Canada. The adults range in size from about 5 cm up to approximately 15 cm.

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. Cambarus reach 17–26 mm carapace lengths in their first year, while average adult carapace length ranges from 55–62 mm. The name Cambarus comes from an alteration of Latin cammarus, meaning "lobster".

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.

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.

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. 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.

Classification
The genus Cambarus contains around 100 species, many of which are listed on the IUCN Red List. Species in the genus were formerly divided among 12 subgenera. In a 2017 study, these subgenera were found to lack any phylogenetic validity and were therefore eliminated.


 * Cambarus aculabrum Hobbs & Brown, 1987 Status iucn CR icon.svg – Benton County cave crayfish
 * Cambarus acuminatus Faxon, 1884 Status iucn LC icon.svg - Acuminate Crayfish
 * Cambarus adustus Thoma, Fetzner, Stocker and Loughman, 2016 Status iucn DD icon.svg - Dusky Mudbug
 * Cambarus aldermanorum J. E. Cooper and Price, 2010 Status iucn DD icon.svg
 * Cambarus andersoni Jones and Eversole, 2015 Status iucn DD icon.svg
 * Cambarus angularis Hobbs & R. W. Bouchard, 1994 Status iucn NT icon.svg
 * Cambarus appalachiensis Loughman, Welsh and Thoma, 2017 Status iucn DD icon.svg
 * Cambarus asperimanus Faxon, 1914 Status iucn LC icon.svg
 * Cambarus bartonii (Fabricius, 1798) Status iucn LC icon.svg – Appalachian Brook Crayfish
 * Cambarus batchi Schuster, 1973 Status iucn LC icon.svg – bluegrass crayfish
 * Cambarus bouchardi Hobbs, 1970 Status iucn VU icon.svg – Big South Fork crayfish
 * Cambarus brachydactylus Hobbs, 1953 Status iucn LC icon.svg
 * Cambarus brimleyorum Cooper, 2006 Status iucn DD icon.svg
 * Cambarus buntingi R. W. Bouchard, 1973 Status iucn LC icon.svg – Bunting crayfish
 * Cambarus callainus Thoma, Loughman & Fetzner, 2014 - Big Sandy crayfish
 * Cambarus carinirostris Hay, 1914 Status iucn LC icon.svg – Rock Crayfish
 * Cambarus carolinus (Erichson, 1846) Status iucn LC icon.svg
 * Cambarus catagius Hobbs & Perkins, 1967 Status iucn DD icon.svg – Greensboro Burrowing Crayfish
 * Cambarus causeyi Reimer, 1966 Status iucn LC icon.svg
 * Cambarus chasmodactylus James, 1966 Status iucn LC icon.svg – New River crayfish
 * Cambarus chaugaensis Prins & Hobbs, 1972 Status iucn LC icon.svg – Chauga crayfish
 * Cambarus clairitae Schuster and Taylor, 2016 Status iucn DD icon.svg
 * Cambarus clivosus Taylor, Soucek & Organ, 2006 Status iucn VU icon.svg
 * Cambarus conasaugaensis Hobbs & Hobbs III, 1962 Status iucn DD icon.svg
 * Cambarus coosae Hobbs, 1981 Status iucn LC icon.svg
 * Cambarus coosawattae Hobbs, 1981 Status iucn NT icon.svg – Coosawattae crayfish
 * Cambarus cracens R. W. Bouchard & Hobbs, 1976 Status iucn EN icon.svg
 * Cambarus crinipes R. W. Bouchard, 1973 Status iucn LC icon.svg
 * Cambarus cryptodytes Hobbs, 1941 Status iucn LC icon.svg – Dougherty Plain cave crayfish
 * Cambarus cumberlandensis Hobbs & R. W. Bouchard, 1973 Status iucn LC icon.svg – Cumberland crayfish
 * Cambarus cymatilis Hobbs, 1970 Status iucn EN icon.svg – Conasauga blue burrower
 * Cambarus davidi J. E. Cooper, 2000 Status iucn LC icon.svg – Carolina Ladle Crayfish
 * Cambarus deweesae R. W. Bouchard & Etnier, 1979 Status iucn LC icon.svg – valley flame crayfish
 * Cambarus distans Rhoades, 1944 Status iucn LC icon.svg – boxclaw crawfish
 * Cambarus diupalma Jones and Eversole, 2015 Status iucn DD icon.svg
 * Cambarus doughertyensis Cooper & Skelton, 2003 Status iucn DD icon.svg - Dougherty burrowing crayfish
 * Cambarus dubius Faxon, 1884 Status iucn LC icon.svg – upland burrowing crayfish
 * Cambarus ectopistes Loughman & Williams, 2021 Status iucn DD icon.svg
 * Cambarus eeseeohensis Thoma, 2005 Status iucn VU icon.svg
 * Cambarus elkensis Jezerinac & Stocker, 1993 Status iucn VU icon.svg – Elk River crayfish
 * Cambarus englishi Hobbs & Hall, 1972 Status iucn LC icon.svg
 * Cambarus extraneus Hagen, 1870 Status iucn DD icon.svg – Chickamauga crayfish
 * Cambarus fasciatus Hobbs, 1981 Status iucn DD icon.svg – Etowah crayfish
 * Cambarus friaufi Hobbs, 1953 Status iucn LC icon.svg – hairy crayfish
 * Cambarus gentryi Hobbs, 1970 Status iucn LC icon.svg
 * Cambarus georgiae Hobbs, 1981 Status iucn LC icon.svg – Little Tennessee crayfish
 * Cambarus girardianus Faxon, 1884 Status iucn LC icon.svg
 * Cambarus graysoni Faxon, 1914 Status iucn LC icon.svg – Two-spot crayfish
 * Cambarus guenteri Loughman, Henkanaththegedara, Fetzner and Thoma, 2017 Status iucn DD icon.svg
 * Cambarus halli Hobbs, 1968 Status iucn LC icon.svg
 * Cambarus hamulatus (Cope, 1881) Status iucn LC icon.svg – Prickly cave crayfish
 * Cambarus harti Hobbs, 1981 Status iucn EN icon.svg – Piedmont blue burrower
 * Cambarus hatfeildi Z. J. Loughman, 2013 Status iucn DD icon.svg
 * Cambarus hazardi Loughman, Henkanaththegedara, Fetzner and Thoma, 2017 Status iucn DD icon.svg
 * Cambarus hiwasseensis Hobbs, 1981 Status iucn LC icon.svg – Hiwassee crayfish
 * Cambarus hobbsorum J. E. Cooper, 2001 Status iucn LC icon.svg – Rocky River crayfish
 * Cambarus howardi Hobbs & Hall, 1969 Status iucn LC icon.svg – Chattahoochee crayfish
 * Cambarus hubbsi Creaser, 1931 Status iucn LC icon.svg
 * Cambarus hubrichti Hobbs, 1952 Status iucn DD icon.svg – Salem cave crayfish
 * Cambarus hystricosus Cooper & Cooper, 2003 Status iucn LC icon.svg
 * Cambarus jezerinaci Thoma, 2000 Status iucn DD icon.svg
 * Cambarus johni Cooper, 2006 Status iucn LC icon.svg
 * Cambarus jonesi Hobbs & Barr, 1960 Status iucn LC icon.svg – Alabama cave crayfish
 * Cambarus laconensis Buhay & Crandall, 2009 Status iucn CR icon.svg - Lacon Exit cave crayfish
 * Cambarus latimanus (Le Conte, 1856) Status iucn LC icon.svg
 * Cambarus lenati J. E. Cooper, 2000 Status iucn NT icon.svg – Broad River crayfish
 * Cambarus lentiginosus Jones and Eversole, 2016 Status iucn DD icon.svg
 * Cambarus longirostris Faxon, 1885 Status iucn LC icon.svg
 * Cambarus longulus Girard, 1852 Status iucn LC icon.svg
 * Cambarus loughmani Foltz II et al., 2018 - Blue Teays mudbug
 * Cambarus maculatus Hobbs & Pflieger, 1988 Status iucn LC icon.svg – freckled crayfish
 * Cambarus magerae Thoma and Fetzner, 2015 Status iucn DD icon.svg
 * Cambarus manningi Hobbs, 1981 Status iucn LC icon.svg
 * Cambarus monongalensis Ortmann, 1905 Status iucn LC icon.svg - Monongahela or blue crayfish
 * Cambarus nerterius Hobbs, 1964 Status iucn NT icon.svg – Greenbrier cave crayfish
 * Cambarus nodosus R. W. Bouchard & Hobbs, 1976 Status iucn LC icon.svg
 * Cambarus obeyensis Hobbs & Shoup, 1947 Status iucn CR icon.svg – Obey crayfish
 * Cambarus obstipus Hall, 1959 Status iucn LC icon.svg
 * Cambarus ortmanni Williamson, 1907 Status iucn LC icon.svg – Ortmann mudbug
 * Cambarus parrishi Hobbs, 1981 Status iucn DD icon.svg – Hiwassee headwater crayfish
 * Cambarus parvoculus Hobbs & Shoup, 1947 Status iucn LC icon.svg – mountain midget crayfish
 * Cambarus pauleyi Loughman, Thoma, Fetzner and Stocker, 2015 Status iucn DD icon.svg
 * Cambarus pecki (Hobbs, 1967) Status iucn EN icon.svg - phantom cave crayfish
 * Cambarus polypilosus Loughman & Williams, 2018 Status iucn DD icon.svg
 * Cambarus pristinus Hobbs, 1965 Status iucn DD icon.svg – pristine crayfish
 * Cambarus pyronotus R. W. Bouchard, 1978 Status iucn DD icon.svg – fireback crayfish
 * Cambarus reburrus Prins, 1968 Status iucn LC icon.svg – French Broad crayfish
 * Cambarus reduncus Hobbs, 1956 Status iucn LC icon.svg
 * Cambarus reflexus Hobbs, 1981 Status iucn LC icon.svg
 * Cambarus robustus Girard, 1852 Status iucn LC icon.svg – big water crayfish
 * Cambarus rusticiformis Rhoades, 1944 Status iucn LC icon.svg – Depression crayfish
 * Cambarus sciotensis Rhoades, 1944 Status iucn LC icon.svg – Teays River crayfish
 * Cambarus scotti Hobbs, 1981 Status iucn LC icon.svg – Chattooga crayfish
 * Cambarus setosus Faxon, 1889 Status iucn NT icon.svg – bristly cave crayfish
 * Cambarus smilax Loughman, Simon, and Welch, 2011 Status iucn LC icon.svg – Greenbrier crayfish
 * Cambarus speciosus Hobbs, 1981 Status iucn NT icon.svg
 * Cambarus speleocoopi Buhay & Crandall, 2009 Status iucn EN icon.svg - Sweet Home Alabama Crayfish
 * Cambarus sphenoides Hobbs, 1968 Status iucn LC icon.svg
 * Cambarus spicatus Hobbs, 1956 Status iucn DD icon.svg - Broad River spiny crayfish
 * Cambarus stockeri Thoma, 2011 Status iucn DD icon.svg
 * Cambarus striatus Hay, 1902 Status iucn LC icon.svg – Hay Crayfish
 * Cambarus strigosus Hobbs, 1981 Status iucn DD icon.svg – lean crayfish
 * Cambarus subterraneus Hobbs III, 1993 Status iucn CR icon.svg – Delaware County cave crayfish
 * Cambarus tartarus Hobbs & M. R. Cooper, 1972 Status iucn CR icon.svg – Oklahoma cave crayfish
 * Cambarus taylori Loughman, Henkanaththegedara, Fetzner and Thoma, 2017 Status iucn DD icon.svg
 * Cambarus tenebrosus Hay, 1902 Status iucn LC icon.svg – cavespring crayfish
 * Cambarus theepiensis Loughman, Foltz, Garrison and Welsh, 2013 Status iucn DD icon.svg
 * Cambarus truncatus Hobbs, 1981 Status iucn LC icon.svg – Oconee burrowing crayfish
 * Cambarus tuckasegee Cooper & Schofield, 2002 Status iucn NT icon.svg
 * Cambarus unestami Hobbs & Hall, 1969 Status iucn LC icon.svg – Blackbarred crayfish
 * Cambarus veitchorum J. E. Cooper & M. R. Cooper, 1997 Status iucn CR icon.svg – White Spring cave crayfish
 * Cambarus veteranus Faxon, 1914 Status iucn DD icon.svg – Guyandotte River crayfish
 * Cambarus williami R. W. Bouchard & J. W. Bouchard, 1995 Status iucn NT icon.svg – Brawleys Fork crayfish
 * Cambarus zophonastes Hobbs & Bedinger, 1964 Status iucn CR icon.svg – Hell Creek cave crayfish