Percina apristis

Robert H. Robins & Lawrence M. Page, 2007, Taxonomic status of the Guadalupe Darter, Percina apristis (Teleostei: Percidae)., Zootaxa 1618, pp. 51-60 : 59

Percina apristis (Hubbs and Hubbs)

Guadalupe Darter

Diagnosis: Percina apristis is a species of Percina (Hadropterus) with 0-6 (-χ= 0.70) preopercular serrae, and usually 68 or more pored lateral-line scales, 24 or more modified midbelly scales on the male, 23 or more transverse scales, 26 or more caudal-peduncle scales, 10 anal rays and 13-14 pectoral rays. The breeding male darkens but midlateral blotches remain apparent. Percina sciera , the closest relative of P. apristis , has more preopercular serrae (usually 7 or more), 14-15 pectoral rays, and fewer modified midbelly, transverse, caudal-peduncle scales, and anal rays, and the breeding male is dusky to black with midlateral blotches nearly obliterated.

Distribution: Percina apristis occurs in gravelly runs in the San Marcos, Comal and Guadalupe rivers of the San Antonio Bay drainage. The Guadalupe River system exhibits the highest degree of endemism on the western Gulf Slope. Other endemic fishes in the system ( Gambusia geiseri , Gambusia georgei , and Etheostoma fonticola ) are San Marcos and Comal River spring isolates and are adapted to a small and unusual portion of the river system. Percina apristis is the only endemic fish found throughout the system.