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Percina williamsi Page & Near, 2007 Sickle darter |
| Family: | Percidae (Perches), subfamily: Etheostomatinae | |||
| Max. size: | 9.05 cm SL (female) | |||
| Environment: | benthopelagic; freshwater | |||
| Distribution: | North America: restricted to the upper Tennessee River drainage of Tennessee, Virginia and North Carolina, USA. | |||
| Diagnosis: | Dorsal spines (total): 11-16; Dorsal soft rays (total): 12-13; Anal spines: 2-2; Vertebrae: 44-45. Distinguished from all congeners, except Percina macrocephala, by having a sickle-shaped suborbital bar and a black bar subtending a medial black spot on the caudal-fin base. Differs from Percina macrocephala by having larger scales (usually 24-26 scales around the caudal peduncle vs. 27-31), 21-23 transverse scales (vs. 23-26), and 70-77 lateral scales (vs. 76-86). Has values for the combination of caudal peduncle, transverse and lateral scales and lateral scales usually 120-129 (vs. 128-141); has shorter snout on average; snout ranges from 20-28% of HL compared to 24-31 in Percina macrocephala (Ref. 75766). | |||
| Biology: | Inhabits flowing pools over rocky, sandy or silty substrates in clear creeks or small rivers (Ref. 75766). Occurs most often near woody debris, vegetation such as water willow, or large boulders (Ref. 75766). Spawning takes place in gravel shoals in later winter (Ref. 75766). | |||
| IUCN Red List Status: | Vulnerable (VU); Date assessed: 20 April 2012 (B1ab(ii,iii,iv,v)+2ab(ii,iii,iv,v)) Ref. (130435) | |||
| Threat to humans: | harmless | |||
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