Cambarus gentryi, the linear cobalt crayfish,[2] is a small species of burrowing crayfish. One of 115 species in the genus Cambarus,[3] it is notable for its deep blue carapace.[4] It is endemic to Tennessee in the United States.[1][2]
Taxonomy and description
Although three specimens of C. gentryi were collected and stored in the 1890s, the species was not described until 1970 by Horton Hobbs, Jr.[5] This followed its 1968 collection by Dr. Glenn Gentry, from which the species name was derived.[5]
Geographic range
The linear cobalt crayfish has been found in the Cumberland and Duck river basins in Tennessee.[4]There are 37 reported sightings of C. gentryi on the Global Biodiversity Information Facility (GBIF) between 1962-2022.[6] They are all localized to the southern part of Tennessee in the USA, North America.[6]
Physical description
Cambarus gentryi has a shell length of around 3–5 cm (1.2–2.0 in) and pincers about 2 cm (0.79 in) long.[4] Its shell is cobalt blue in colour with orange or yellow to yellowish-green markings.[4] The eyes are small and well-developed, and the areola (a structure which runs along the centre of the cephalothorax) is sublinear, or mostly uncurved.[5] Like other decapods, C. gentryi has ten pairs of legs, of which the forward-most pair are modified into robust pincers known as chela.[7]
The type specimen is stored in the Smithsonian Institution in Washington, D.C., USA under the identifier USNM 130283.[8] The allotype (female) and morphotype (male) are in the same institution under the identifiers USNM 130284 and 130285.[8]
Habitat
The linear cobalt crayfish creates burrows in damp areas along river banks.[5] Its burrows have been described in several locations across its range; although sometimes limited by soil depth, they can have multiple openings to the surface and have been found to be up to about 2.5 m (8 ft) in length and 0.91 m (3 ft) in depth.[5][8]
Development and reproduction
Adults in family Cambaridae alternate molts between reproductive (form I) and non reproductive (Form II) forms.[7] Male form I has larger claws and altered sperm transfer gonopods; in some species, the female form I has a wider abdomen.[7] On collection of C. gentryi specimens in and prior to 1970, first-form males were collected at various times of year (April, May, and November) and egg- or young-bearing females had not been collected or identified.[5]
Lifespan
The exact lifespan of C. gentryi is not known; however, other individuals in this family (Cambaridae) have been known to live 6-7 years.[7]
Ecological Interactions
C. gentryi is a known host of Uncinocythere zancla, an entocytheridosctracod.[9] This is a small crustacean which lives as an obligate ectosymbiont to other crustaceans by attaching to the carapaces.[10]
Conservation status
Cambarus gentryi is listed as least concern by the IUCN.[1]
Genomic information
Five publicly available gene fragment sequences exist for C. gentryi, available through NCBI genbank with taxonomy ID NCBI:txid318489.[11] The following gene fragments are available:[11]
Isolate JF2508 cytochrome c oxidase subunit I (COI) gene; Accession no. KX417101.1
^ abcdBiological Society of Washington; Washington, Biological Society of; Washington, Biological Society of; Washington, Biological Society of; Institution, Smithsonian; Institution, Smithsonian (1970). Proceedings of the Biological Society of Washington. Vol. 83. Washington: Biological Society of Washington.
^ abcHobbs, Horton Holcombe Jr. (1989). "An Illustrated Checklist of the American Crayfishes (Decapoda, Astacidae, Cambaridae, Parastacidae)". Smithsonian Contributions to Zoology (480): 22. doi:10.5479/si.00810282.480.