Micropterus cahabae Baker, Johnston, and Blanton, 2013

Baker, Winston H., Blanton, Rebecca E. & Johnston, Carol E., 2013, Diversity within the Redeye Bass, Micropterus coosae (Perciformes: Centrarchidae) species group, with descriptions of four new species, Zootaxa 3635 (4), pp. 379-401 : 392-393

Micropterus cahabae Baker, Johnston, and Blanton new species

Cahaba Bass

Figs. 1 & 2 D–F

Holotype. Alabama. Shelby Co., USNM 398705, 195 mm SL, Shoal Creek, Hwy 199, 11 March 2009.

Paratypes. Alabama. Bibb Co., AUM 51062 (1, 223), Six Mile Creek, St. Hwy 25, 11 May 2009; Shelby Co., AUM 51063 (1, 176), Buck Creek, Helena, 31 March 2009.

Additional Materials (nontypes).

Cahaba River Drainage

Alabama. Bibb Co., AUM 37793 (1, 158), Little Cahaba River, 19.2 km N Centerville, 21 September 2003; AUM 58730 (2, 169–172), Hill Creek at Moffat, 3 May, 2011; AUM 58731 (2, 197–219), 2 May, 2011; AUM 51109 (3, 129–223), Six Mile Creek, at St. Hwy 25, 11 May 2009. AUM 58733(1, 142), Schultz Creek at Scottsville, at CR 9, 16 June 2010; AUM 58734 (1, 236), 3 May, 2011; Jefferson Co., AUM 51108 (8, 109–210), Cahaba River, 4.8 km N Trussville, 9 March 2009; Shelby Co., AUM 51115 (1, 176), Buck Creek, St. Hwy 261, Helena, 31 March 2009; AUM 58735 (1, 244), 4 May, 2011; AUM 51110, 51111, (3, 161–200), Shoal Creek, at St. Hwy 119 Montevallo, 7 April 2009; AUM 58736 (3, 221–246), 2 May, 2011.

Diagnosis. Member of the M. coosae species group. Micropterus cahabae differs from all other species, except M. tallapoosae , by lack of red or orange pigmentation on fin rays (fin rays green or yellow-green); from M. tallapoosae and M. chattahoochae by more lateral-line scales 68–72 (in 100%; mode = 72) vs. 61–67 (in 77.2%; mode = 65, 66) and scales around caudle peduncle 30–32 (in 100%; mode = 30) vs. 26–29 (in 94.1%; mode = 28); from M. chattahoochae by narrower head (postfrontal width 11.2% SL vs. 11.8%) and from M. coosae by a wider head (11.2% vs. 11.0%); from M. chattahoochae and M. cf. coosae (Savannah River) by a smaller tongue tooth patch (less than 1.0 mm in 51.7%, absent in 34.5% of specimens vs. in 66.7% or more and absent in 9.0% or less) and from M. warriorensis by more often having a tooth patch (absent in 34.5% vs. 82.9%); further distinguished from all species by a unique pigmentation pattern along the midline of the body, having 6–12 blotches with the anterior 6–9 shorter, wider vertical bars followed posteriorly by rounded spots (Tables 2 & 9; Figs. 1 & 2 D–F ).

Description. M. cahabae is a small species of bass that attains 360 mm SL and 0.8 kg. Measurements and meristics of diagnostic characters are provided in Tables 2– 9, and general body shape and pigmentation patterns are illustrated in Figures 1 and 2 D–F .

Medium-width head, postfrontal width 10.8–11.9% (11.2%), scale width 2.5–3.0% (2.7%), tongue tooth patch size 0–2.0 mm (mode = 1.0); lateral-line scales 68–72 (72), scales above lateral line 6–8 (7), scales below lateral line 10–12 (11), scales around caudal peduncle 30–32 (30); anterior dorsal-fin spines 9, posterior dorsal-fin spines 1, anal-fin spines 3; pectoral-fin rays 14–16 (15), posterior dorsal-fin rays 11–12 (12), caudal-fin rays 17; pyloric caeca unbranched.

Body pigmentation above midline medium green often with a bronze shimmer; below midline body white, often in spawning males, with bluish tint anterior to pelvic fins; posterior to pelvic fins white with rows of blackdotted scales, and often irregular dark shaded areas. Venter uniformly white. Midline body with row of 6–12 blotches with the anterior 6–9 typically consisting of short, wide, vertical bars.

Spines of anterior dorsal fin dark green and membranes translucent medium green. Rays of posterior dorsal fin dark green; anterior five to six rays tipped in white; dark green dots present on base of membranes. Caudal-fin rays dark green with small white border at tips of superior and inferior margins; membranes translucent medium green; usually, dark green dots along membranes of anterior portion. Central portion of anal-fin rays medium green with white or silver-white at base; outer margin white; membranes light green. Pelvic-fin rays white and membranes faintly green or with white iridescence. Pectoral-fin rays medium green; membranes faintly green.

Distribution. Micropterus cahabae is endemic to the Cahaba River system in the Piedmont region of central Alabama ( Fig. 5 ).

Remarks. Micropterus cahabae is restricted to a small area of the Cahaba River.

Etymology. This species is named for the Cahaba River, to which it is endemic.

Figures

FIGURE 1. Typical pigmentation and pattern of members of the M. coosae species group: M. coosae (Coosa River), 198 mm SL, Cheaha Creek, Hwy 93, 9.6 km N Talladega, Talladega Co., AL; Micropterus cahabae (Cahaba River), 195 mm SL, Shoal Creek, Hwy 119, Shelby Co., AL; M. chattahoochae (Chattahoochee River), 158 mm SL, Centralhatchee Creek, 1.6 km W Centralhatchee, Heard Co., GA; M. tallapoosae (Tallapoosa River), 155 mm SL, Emuckfaw Creek, 4.8 km N Hwy 22, Tallapoosa Co., AL; M. warriorensis (Black Warrior River), 194 mm SL, Calvert Prong, Black Warrior River, 4.0 km N Oneonta, Blount Co., AL; M. cf. coosae (Savannah River), 164 mm SL, Hudson River, jct. Hwy 29 and Hwy 8, Madison Co., GA, 24 May 2009.

FIGURE 2. Pigmentation and pattern of M. coosae (A–C) and M. cahabae (D–F). Micropterus coosae: (A) male (185 mm SL), 7 April 2010; (B) female, (235 mm SL), 16 June 2010; (C) female (76 mm SL), 22 June 2010. Micropterus cahabae: (D) male (195 mm SL), 7 April 2010; (E), female, (142 mm SL), 16 June 2010; (F) male (134 mm SL), 22 June 2010.

FIGURE 5. Distribution of the M. coosae species group in the Mobile Bay and adjacent drainages based on specimens examined. Stars, M. warriorensis; triangles, M. cahabae; circles, M. coosae; squares, M. tallapoosae; plus symbols, M. chattahoochae. Symbols correspond to those in Figure 6.