Percina kusha, Williams & Burkhead, 2007
James D. Williams, David A. Neely, Stephen J. Walsh & Noel M. Burkhead, 2007, Three new percid fishes (Percidae: Percina) from the Mobile Basin drainage of Alabama, Georgia, and Tennessee., Zootaxa 1549, pp. 1-28 : 4-11
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|Percina kusha, Williams & Burkhead|
Percina kusha, Williams & Burkhead , new species
Holotype. UF 110303 , male, 64 mm SL, Conasauga River at the mouth of Minnewauga Creek, 9.6 air km SSW of the center of Bueton (35°00'18"N; 34°41'28"W), Polk County, Tennessee, 3 April 1996. GoogleMaps
Paratypes. Coosa River drainage -Conasauga River system
Georgia: Murray County: ANSP 187097 (1; 55 mm) Conasauga River at County Route 392 (Old Georgia Hwy 2), about 1.4 air km S of Tennessee state line (34°58'28"N; 84°38'43"W), 2 April 1994. GoogleMaps GMNH 1463 (2; 50-53 mm) same locality, 9 July 1980. GoogleMaps UF 110286 (1; 58 mm) same locality, 3 April 1996. GoogleMaps UF 165704 (6; 38-60 mm) same locality, 28 April 1994. GoogleMaps USNM 389726 (6; 38-60 mm) (out of NMB 1432) same locality, 28 April 1994. GoogleMaps GMNH 1394F (1; 48 mm) Conasauga River at Gregorys Mill (34°57'10"N; 84°47'12"W), 4 November 1981. GoogleMaps UF 110260 (2; 44-59 mm) Holly Creek at County Route 301, about 5.9 air km ESE of the center of Eton (34°48'55"N; 84°41'45"W), 2 April 1996. GoogleMaps
Tennessee: Bradley County: INHS 76807 (1; 45 mm) Conasauga River at Tennessee Hwy 74 (Georgia Hwy 225), 4.8 km W of Conasauga (34°59'26"N; 84°46'32"W), 10 June 1970. GoogleMaps TU 58937 (2; 42-46 mm) same locality, 17 October 1969. GoogleMaps TU 58965 (3; 41-49 mm) same locality, 19 October 1969. GoogleMaps TU 65939 (7; 44-49 mm) same locality, 29 June 1970. GoogleMaps UAIC 8769.04 (1; 62 mm) same locality, 13 June 1977. GoogleMaps UF 42736 (1; 57 mm) same locality, 14 June 1985. GoogleMaps UF 42757 (2; 45-61 mm) same locality, 9 June 1985. GoogleMaps UT 91.1524 (1; 53 mm) Conasauga River below Tennessee Hwy 74 , 27 October 1977. Polk County: NCSM 44984 (3; 30-60 mm) Confluence of Jacks and Conasauga rivers, just N of the Georgia border (34°59'24"N; 84°38'10"W), 17 November 1967. GoogleMaps UAIC 6768.07 (1; 40 mm) Ball Play Creek, about 1.8 air km NE of Conasauga community , 12 March 1983. NCSM 44983 (1; 54 mm) Minnewauga Creek at mouth (35°00'15"N; 84°41'26"W), 11 April 1989. GoogleMaps UF 165703 (8; 44-63 mm) (out of UF 110303) same locality, 3 April 1996. GoogleMaps UF 165734 (4; 43-52 mm) same locality, 20 January 2003. GoogleMaps UT 91.4274 (5; 42-58 mm) Minnewauga Creek and tributary, 0.3 km above mouth and Conasauga River , 2 March 1992.
Additional material (nontypes).
Coosa River drainage -Conasauga River system
Georgia: Murray County: AUM 10570 (1) Conasauga River at County Route 392 (Old Georgia Hwy 2), about 1.4 air km S of Tennessee state line (34°58'28"N; 84°38'43"W), 25 June 1975. GoogleMaps UT 91.1690 (2) same locality, 1 October 1978. GoogleMaps UT 91.149 (1) Conasauga River, about 1.6 km above junction with Jack’s River , 4 August 1966. Murray/Whitfield counties: GMNH 1394E (2) Conasauga River, below Gregory’s Mill , 10 October 1981. UT 91.1647 (3) Conasauga River, about 4 river km N of Beaver Lake Bridge (Old Georgia Hwy 2), Murray/Whitfield county line , 29 August 1978.
Tennessee: Bradley County: AUM 11720 (2) Conasauga River at Tennessee Hwy 74 (Georgia Hwy 225), 4.8 km W of Conasauga (34°59'26"N; 84°46'32"W), 19 July 1975. GoogleMaps GMNH 1582 (2) same locality, 5 February 1982. GoogleMaps UF 22590 (1) same locality, 25 June 1976. GoogleMaps UF 26460 (4) same locality, 9 July 1977. GoogleMaps UT 91.160 (1) Conasauga River, second riffle below Tennessee Hwy 74 bridge , 22 October 1969. UT 91.351 (2) same locality, 29 November 1969. UF 43969 (1) Conasauga River from Tennessee Hwy 74 bridge to 0.8 km downstream , 16 May 1970. Polk County: UF 22793 (2) Conasauga River, about 0.4 km below mouth of Minnewauga Creek (35°00'18"N; 84°41'4rW), 25 June 1976. GoogleMaps UT 91.252 (1) Conasauga River at Boanerges Church Bridge (35°00'03"N; 84°45'13"W), 3- 4 November 1968. GoogleMaps UT 91.298 (2) same locality, 27- 28 March 1969. GoogleMaps UT 91.501 (11) Minnewauga Creek at mouth (35°00'15"N; 84°41'26"W), 3 March 1968. GoogleMaps UT 91.159 (1) Minnewauga Creek , 17 March 1965.
Coosa River drainage -Etowah River system
Georgia: Dawson County: GMNH 74 (1) Etowah River , 8 July 1948. GMNH 2059 (1) Amicalola Creek at County Route 25, about 14.5 air km NNW of Dawsonville (34°29'59"N; 84°14'51"W), 8 May 1990. GoogleMaps UF 165649 (4) same locality, 2 May 1990. GoogleMaps UF 165647 (1) same locality, 3 April 1994. GoogleMaps UAIC 10471.09 (1) same locality, 20 July 1992. GoogleMaps NMB 1446 (1) Little Amicalola Creek at County Route 25 (34°30'04"N; 84°14'04"W), 17 June 1994. GoogleMaps UF 165646 (1) Cochran Creek at County Route 45, about 2.1 km W of junction with State Route 342 , 3 April 1994. UF 90079 (3) Amicalola Creek, off County Route 28, 2.2 air km SW of junction of County Route 28 and State Route 136, at Fausett Lake (34°31'42"N; 84°16'48"W), 19 November 1991. GoogleMaps Lumpkin County: GMNH 2052 (1) Etowah River at Georgia Hwy 52 (34°32'05"N; 84°03'48"W), 13 May 1990. GoogleMaps UF 165648 (3) Etowah River at County Route 72 (34°33'37"N; 84°04'27"W), 28 April 1994. GoogleMaps UAIC 10621.14 (1) Etowah River, 10.6 km NW of Dahlonega, 1.6 km W of Whissenhunt Mountain on unpaved Forest Service road , 29 June 1990.
Material used in molecular analysis.
Coosa River drainage -Conasauga River system
Coosa River drainage -Etowah River system
Georgia: Dawson County: UAIC 13560.02 (2) Amicalola Creek, along Tate Hwy, 3.2 km NW of Afton (34°31'05"N 84°16'53"W), 24 March 2002, EF613217, EF613218. GoogleMaps
Diagnosis. Percina kusha is distinguished from all other described species oîPercina by a combination of the following characteristics: absence of bright colors on body and fins of adults; no orange band in spinous dorsal fin; no broad vertical bands on body extending dorsally across the back joining those of the other side; 7-11 lateral blotches connected to form a continuous dark brown to black lateral stripe with undulating margins; lateral stripe continuous with large, quadrate basicaudal blotch that extends onto base of caudal fin rays; small, dark blotch on upper and lower portion of caudal fin base, dorsal blotch typically darker; body below lateral stripe white to cream colored, without dark blotches, dusky in breeding males; suborbital bar absent or very poorly developed; lateral line complete, typically no pored scales on base of caudal fin; males with row of modified scales on midline of belly and one or two modified scales between base of pelvic fins; modified breast scale absent; nuptial tubercles absent; anal fin of breeding males not excessively elongate; males without caudal keel as a ventral extension of the caudal peduncle; snout not projecting beyond anterior margin of upper jaw; well-developed premaxillary frenum; serrae on margin of preopercle absent; branchiostegal membranes overlapping or very narrowly joined.
Percina kusha is distinguished from the other two species described herein by a combination of the following characters: dorsum above dark brown to black lateral stripe tan to light brown, uniformly pigmented, typically without dark reticulations; midline of dorsum without dark saddles or if present confined to midline of dorsum; scales present on nape, cheeks, opercles, and breast.
Description. Percina kusha is a moderately small species of Percina ; the largest specimen examined is a 65 mm SL male. Typical shape of the head and body illustrated in Figure 2a. Frequency distribution of scale, fin ray and vertebral counts given in Tables 1-8. Degree of nape squamation presented in Table 9 and the posterior extent of development of pored lateral line scales given in Table 10. Proportional measurements presented in Table 11. Body moderately elongate, slender, snout moderately long, about equal in length to the orbit, and frenum well-developed. Preopercular margin entire and branchiostegal membranes separate or very narrowly joined. Total lateral line scales 58-73, usually 65-70; transverse scale rows 14-18, usually 17 in the Conasauga River population and 15 in the Etowah River population; caudal peduncle scales 18-25, usually 22-24 in the Conasauga River population and 19-21 in the Etowah River population; dorsal spines 11-15, usually 12-14; dorsal soft rays 9-11, usually 10; anal soft rays 6-9, usually 8; pectoral rays 13-14, usually 14; vertebrae 41-43, usually 42.
Lateral line usually complete but some individuals with 1-2 unpored scales anterior to posterior edge of hypural plate or a pored scale on the caudal fin base (Table 10). Scales present on the opercles and upper three quarters of the cheek. Nape completely scaled, occasionally with some embedded scales anteriorly. Scales on the anterior portion of breast and prepectoral area usually embedded. Belly typically scaled with the exception of the area immediately posterior of the base of the pelvic fins. Males with a row of enlarged, modified ctenoid scales present on midline of belly, but usually less well-developed or absent just posterior to pelvic fin base. There are usually 1-2 modified scales present between the base of pelvic fins. Occasionally an individual will have up to four modified scales but only one or two are large and well-developed. The large, modified breast scale at the anterior junction of the pelvic girdle of some Percina is absent in P. kusha . In females the row of scales along the midline of the belly is greatly reduced or absent but there are usually one or two modified scales present between the base of the pelvic fins. Breeding tubercles are absent but some males have thickened ridges along margin of anal fin rays.
Live coloration of adult females and males is similar but females typically lack the dusky ground color present in males. Sides of the body with 8-11 elongate oval blotches which are connected forming a uniformly dark lateral stripe with undulating margins. In some individuals the dark blotches are discrete but connected by lighter brown pigment. Lateral blotches are lighter in color and less connected in juveniles. Anteriorly the lateral stripe is continuous with the postorbital and preorbital bars. Posteriorly the lateral stripe terminates on the base of the caudal fin in a somewhat quadrate-shaped blotch that is equal or slightly lighter in color to the lateral stripe. It is usually centered just below the midline of the caudal fin. The blotches on the upper and lower caudal fin base vary in size and intensity. In most individuals the upper blotch is larger and more intense. The lower blotch is often indistinct or merged with the basicaudal blotch. Above the dark, undulating lateral stripe, the dorsum is typically tan to light brown without any blotches, reticulations, bars or saddles. In some individuals thin, elongate blotches may be present along the midline of the dorsum and an adjacent scale row on each side, usually under the dorsal fins. Occasionally an individual may have a dusky, thin line, one or two scale rows wide, just above the lateral stripe. This line is often interrupted forming a series of long dashes above the lateral stripe. Intensity of the thin line of dark pigment varies but is always darker than the adjacent dorsal pigmentation but lighter than the lateral stripe. Any dark pigment present above the lateral blotches is most prevalent in juveniles. Below the lateral stripe the body is uniformly pigmented and lacks dark spots, blotches or reticulations. It is typically dusky on breeding males but always uniformly pigmented. Breast and lower side of head are white to cream colored but may be dusky in breeding males. Some individuals have a few melanophores on the anterior base of the pectoral fin. Suborbital bar is typically absent, but some breeding males have an irregular shaped cluster of melanophores on the midventral margin of the orbit.
Pigmentation of the spinous dorsal fin of males consists of a broad, dusky basal band, almost black in breeding males, an unpigmented submarginal band, and a thin, dusky marginal band. Dusky pigment in dorsal fin is usually darker posteriorly. Pigmentation of the soft dorsal and caudal fins is variable but typically there are dusky marginal and basal bands with an unpigmented band in between. The pelvic, pectoral, and anal fins are usually clear except dusky in breeding males.
Coloration of non-spawning males and females is yellowish above and below the dark bluish-black lateral stripe. Breast and belly are white to cream color. Top of head and snout variously mottled with yellowishorange color. Dorsal, pectoral, and caudal fins pale yellowish and the pelvic and anal fins colorless.
Variation in the scale counts (Tables 1-3) between the Conasauga and Etowah River populations of Percina kusha was unexpected considering the proximity of the two drainages (Fig. 3). There is almost no overlap in number of scale rows from the soft dorsal origin to the anal fin base and the caudal peduncle scale rows. There is also a modal difference in the degree of nape squamation between the two drainages (Table 9). Analysis of mitochondrial DNA revealed very little differentiation between these populations, although they were recovered as reciprocally monophyletic groups (discussed below). A higher number of lateral line scales and vertebrae were reported for P. lenticula ZBK populations in the Etowah River drainage compared to the Coosa and Cahaba River populations (Richards & Knapp 1964; Suttkus & Ramsey 1967). This variation may be the result of habitat differences between the Etowah and Conasauga River drainages. Most of the Etowah drainage is in the Piedmont physiographic province, and most of the Conasauga is in the Valley and Ridge province (Fig. 3). The presence and distribution of other endemic species in the Etowah drainage (e.g. Etheostoma etowahae ZBK , E. scotti ZBK , and Cambarus fasciatus ) suggests that the divide between the physiographic provinces has been an effective barrier to gene flow in some taxa, and may be responsible for speciation within the Piedmont portion of the Etowah River system.
Distribution. Percina kusha is restricted to the headwaters of the Coosa River in Georgia and Tennessee (Fig. 3). It occurs in the main channel of the upper reaches of the Conasauga River in Murray and Whitfield counties, Georgia, and Bradley and Polk counties, Tennessee. It is also known from short reaches of three tributaries to the Conasauga River: Holly Creek, Murray County, Georgia; and Ball Play and Minnewauga creeks, Polk County, Tennessee. In the Etowah River it occurs in the main channel in Dawson and Lumpkin counties, Georgia, and in several tributaries: Amicalola, Little Amicalola, Cochran and Shoal creeks, Dawson County, Georgia.
Ecology. Percina kusha inhabits small rivers and lower reaches of tributary creeks with good water quality. These streams are characterized by moderate gradient where the substrate consists of sand, gravel, cobble and bedrock. Percina kusha is usually found in flowing pools and backwaters adjacent to runs, where it has been observed hovering over or resting on submerged structures such woody debris, stems of Justicia americana , and large cobble. During winter we have observed P. kusha among leaf packs in pools. Frequent associates of P. kusha are Campostoma oligolepis ZBK , Cyprinella trichroistia , C. venusta ZBK , Etheostoma stigmaeum ZBK , Hypentelium etowanum , Notropis xaenocephalus ZBK , P. kathae ZBK , P. nigrofasciata and P. palmaris . Etnier & Starnes (1993) provide information on feeding and reproduction of the Conasauga River population. Johnson et al.
(2002) conducted a study of seasonal spawning habitat utilization in the Conasauga River in Murray County, Georgia, during 1999 and 2000. There is no information available on the ecology and biology of the Etowah River population of P. kusha .
Conservation status. Etnier & Starnes (1991) considered the conservation status of Percina kusha to be endangered, like two other Percina species endemic to the upper Coosa River system, P. antesella ZBK and P. jenkinsi ZBK . In a review of conservation status of fishes in Georgia, Freeman (1999) assigned a status of rare (a species in need of protection because of its scarcity) to populations in Georgia. Warren et al. (2000) and Freeman et al. (2005) both regarded P. kusha as vulnerable (any taxon that may become endangered or threatened by relatively minor disturbance to its habitat). Based on our sampling and snorkeling observations, P. kusha appears to be a species that naturally occurs in low abundance, at least when compared to sympatric congeners such as P. nigrofasciata and P. palmaris . We do not know, however, what the actual range of the species was prior to European colonization. Its association with slow-flowing habitats suggests P. kusha could have occurred throughout the Conasauga and Etowah rivers, and possibly in the geographically intermediate Coosawattee River, below the gorge now impounded by Carters Dam and Reservoir (Fig. 3). Considering its very limited distribution in portions of two small rivers and threats to its habitat from municipal and industrial development and forestry and agriculture activities we consider P. kusha to be endangered.
Etymology. The specific name, kusha, is the Choctaw Indian name for cane or canebrake and is the origin of the name of the Coosa River (Foscue 1989). The common name, Bridled Darter, is in reference to the preorbital and postorbital bars that are continuous with the lateral stripe, thus resembling an equestrian bridle and reins.
Comparison with congeners. In the headwaters of the Coosa River in northwest Georgia, populations of Percina kusha are sympatric and occasionally syntopic with eight species of Percina : P. antesella ZBK , P. aurolineata ZBK , P. jenkinsi ZBK , P. kathae ZBK , P. lenticula ZBK , P. nigrofasciata , P. palmaris and P. shumardi . The dorsum of most individuals of P. kusha are uniformly pigmented above the dark brown to black lateral band which distinguishes it from all eight species of Percina which typically have well-developed saddles that extend across the back, mid-dorsal blotches, lateral and dorsolateral bars or a dorsolateral stripe (above dark lateral stripe). Morphologically, P. kusha is easily distinguished from the logperches, P. jenkinsi ZBK and P. kathae ZBK , which have a conical snout that projects beyond the anterior margin of the upper jaw. It differs from both P. antesella ZBK and P. shumardi in having a well-developed frenum and a row of modified scales along the midline of the belly of males. Percina kusha also lacks the elongate anal fin and breeding tubercles, which are well-developed on the anal, caudal, and pelvic fins, of breeding male P. antesella ZBK and P. shumardi . Percina kusha has very narrowly joined to overlapping gill membranes which differs from the more broadly joined membranes present in P. lenticula ZBK and P. nigrofasciata . The lateral blotches of P. lenticula ZBK and P. nigrofasciata are also more vertically elongate than those of P. kusha . The remaining species, P. aurolineata ZBK , differs in having a serrate preopercle and from 1-3 pored lateral line scales on the base of the caudal fin.
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