| Ictaluridae (North American freshwater catfishes) |
| 6.47 cm SL (male/unsexed) |
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benthopelagic; freshwater |
| North America: USA. |
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Dorsal soft rays (total): 6-6; Anal soft rays: 15-17. Diagnosis: Distinguished from other members of the Noturus elegans species group by having: modally 16 anal rays (vs. 18 in Noturus fasciatus); modally 8 pelvic rays (vs. 9); 2-10 medium-large sized melanophores on the cheek (vs. large melanophores absent on cheek); adipose fin band extending only to base or half-way up fin (vs. extending half-way up to edge of fin in fasciatus); adipose and caudal fins distinctly joined at their juncture (vs. weakly connected in fasciatus); three evenly spaced pale and dark bands in caudal fin (vs. caudal fin bands usually two and unevenly spaced); robust body shape, with body width at pectoral fin origin 23% or more of SL and greater than anal fin base length (vs. slender body shape, with body width at pectoral fin origin 22% or less of SL and less than anal fin base length). There is an absence of shared alleles for eight allozyme loci (mAAT-A, sACOHA, GPI-B, LDH-B, sMDHP-A, Pep-b, Pep-D, and PGM-A) distinguishes crypticus and fasciatus, which also differ by 5% Cytb sequence divergence. Similarly, both share no alleles at eight allozyme loci (mAAT-A, sAATA-A, sACOH-A, FUM-A, GPI-A, GPI-b, LDH-B, sMDHP-A, and Pep-D) and are 6.3% divergent for Cytb (Ref. 56218). |
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Critically Endangered (CR); Date assessed: 02 March 2012 (B1ab(iii)+2ab(iii)) Ref. (130435)
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| harmless |
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The Chucky Madtom is known from only two streams, both of the French Broad River system of eastern Tennessee; known from a single specimen from Dunn Creek, Sevier County, and from about three stream kilometer of Little Chucky Creek from the mouth of Jackson Branch downstream to Bible Bridge road crossing, Greene County.
The Dunn Creek specimen was collected in 1940 and additional surveys have not yielded additional specimens, and the species may be extirpated from this stream. Surveys of streams with potentially suitable habitat in eastern Tennessee found the species only in a 3-km reach of Little Chucky Creek. Although the area has been intensively sampled for madtoms, by seining and snorkeling, since 1991, success has been sporadic; only 14 specimens have been collected. In May 1991, two (UT 48.724) were collected by TVA personnel at Bible Bridge road crossing; in September 1994, four specimens (3 in SIUC 52380, 1 retained by JMG for genetic analysis) at Bible Bridge Road crossing, and five specimens (1 each in SIUC 52377 and SIUC 52379, 3 for genetic analysis), at the mouth of Jackson Branch. Subsequent surveys targeting madtoms were unsuccessful, but a collection in March 2001 yielded one specimen (UAIC 12430.01). Recently, Conservation Fisheries Inc. personnel collected two specimens in May 2004 that were brought live to their aquaculture facility in Knoxville, Tennessee, with the intent of initiating a captive breeding program. The range of Noturus crypticus, like other madtoms of eastern Tennessee (e.g., N. baileyi and N. flavipinnis) likely has declined. Currently it occupies a tiny range and exists at a very low density (probably less than 100 individuals). The occupied reach of Little Chucky Creek is not pristine, but existing habitat and the fish and mussel faunas suggest the stream has not been substantially altered by anthropogenic influences. Upstream of the occupied reach was observed with greater agricultural impacts, including application of herbicides to remove riparian vegetation and bank erosion and siltation from cattle access to streams. The capacity of the system to absorb sediment without damage to the biotic community may have been reached. If the samples are indicative of population size, the species is vulnerable to a variety of anthropogenic and stochastic events (e.g., drought, disease, floods) (Ref. 56218).
Status of threat: This species should be protected as a federally endangered species. Promoting agricultural practices that minimize siltation and restoring and protecting riparian zones throughout the Little Chucky Creek watershed would preserve its habitat (Ref. 56218).
Status of threat: endangered. Criteria: 1,5 (http://fisc.er.usgs.gov/afs/) (Ref. 81264). |
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