Micropterus chattahoochae 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 : 395-396

Micropterus chattahoochae Baker, Johnston, and Blanton new species

Chattahoochee Bass

Figs. 1 & 3 D–F

Holotype. Georgia. Heard Co., USNM 398703, 158 mm SL, Centralhatchee Creek, 1.6 km W Centralhatchee, 10 March 2009.

Paratypes. Georgia. Heard Co., AUM 51066 (1,191), Centralhatchee Creek, 1.6 km W Centralhatchee, 12 November 2008; AUM 51067 (1,196), Centralhatchee Creek, 1.6 km W Centralhatchee, 10 August 2009.

Additional materials (nontypes).

Chattahoochee River Drainage

Georgia. Carroll Co., (2, 180–193), Whooping Creek, Highway 5, 10 August 1998; (1, 155), 11 August 1998. Heard Co., (1, 275), Hillabahatchee Creek, 8.0 km W Franklin, 27 May 1997; (2, 187–190), 23 June 1998; (4, 166–214), 24 June 1998; (1, 179), 13 July 1998; (1, 211), 4 November 1998; AUM 51104 (1, 200), 10 March 2009; AUM 58739 (1, 170), Deer Creek, 4.8 km W Centralhatchee, 15 July 1998; (1, 101), 20 June 2010; (4, 178–181), Centralhatchee Creek, 1.6 km W Centralhatchee, 16 July 1998; (1,312), 25 July 1998; (2, 191–211), 30 July 1998; (1, 189), 24 August 1998; AUM 51089 (3, 191–219), 12 November 2008; AUM 51103, 51088 (6, 130–200), 10 March 2009; AUM 51120 (3, 131–241), 1 May 2009; (1, 211), Centralhatchee Creek, 8.0 km W Centralhatchee, 30 July 1998. White Co., AUM 58740 (1, 158), Chattahoochee River, at SR 17, 13.0 km NE Cleveland, 13 June 2010.

Diagnosis. A member of the M. coosae species group that differs from all other members by having broad margins of bright orange pigment on posterior dorsal, caudal, and anal fins (vs. red, no orange, or faint orange often limited to anterior portion of anal fin) and by a wider head (postfrontal width 11.8% SL vs. 11.3% or less); further distinguished from all members except M. tallapoosae by having larger scales (2.9% SL vs. 2.7% or less), fewer lateral-line scales 61–67 (in 76.9%; mode = 66) vs. 68–74 (in 94.7%; mode = 69 or greater), fewer scales around the caudal peduncle 26–28 (in 71.4%; mode = 28) vs. 29–32 (in 88.3%; mode = 29 or more) and fewer total lateralline scales plus scales around the caudal peduncle (89–98; mode = 91 vs. 96 or more; mode = 93 or greater); from M. tallapoosae , M. warriorensis , and M. cahabae by larger tooth patch on tongue of 1.0 mm or more in 78.2% of individuals (absent in 9.0% examined) vs. less than 1.0 mm in 51.7% or more (absent in 25% or more of individuals).

Description. M. chattahoochae is a small species of bass that attains 367 mm SL and 1.0 kg. Measurements and meristic values for diagnostic characters are provided in Tables 2–9, and general body shape and pigmentation patterns are illustrated in Figures 1 and 3 D–F .

Broad head, postfrontal width 11.5–12.2% (11.8%), scale width 2.4–3.2% (2.9%), tongue tooth patch size 0–6.0 mm (mode = 2.0); lateral-line scales 61–70 (66), scales above lateral line usually 6–9 (7), scales below lateral line 9–13 (12), scales around caudal peduncle 26–30 (28); anterior dorsal-fin spines 9, posterior dorsal-fin spines 1, anal-fin spines 3; pectoral-fin rays 14–17 (15), posterior dorsal-fin rays 11–14 (13), anal-fin rays 10–11 (10), caudal-fin rays 17; pyloric caeca unbranched.

Body pigmentation above midline medium green often with 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 black-dotted scales, and often irregular dark shaded areas. Venter uniformly white. Midline row with 9–11 blotches, anterior 4–7 vertical bars, followed by four or five spots on the caudal region. Dorso-lateral row of blotches with 9–13 irregular spots extending from area just above eye to posterior margin of posterior dorsal fin.

Anterior dorsal-fin spines dark green, often tipped with white, and membranes translucent medium green. Posterior dorsal fin green, with anterior five to seven rays bright orange on distal one-third; membranes usually with white border and dark green dots on basal half. Caudal-fin rays green with posterior one-half of superior and inferior margins orange with narrow white borders; membranes translucent green, often with dark green dots on basal portions. Anal-fin ray bases translucent green; distal one-half of anterior six rays bright orange with white margins; membranes greenish, white at bases, changing to transparent near margins; dark green dots usually present along basal half of these membranes. Pelvic-fin rays white with membranes transparent. Pectoral-fin rays yellowish-green with transparent membranes. The orange fin is not attributed to sexual dimorphism, spawning, or age because that trait was observed in males, females, and juveniles throughout the entire year.

Distribution. This species is endemic to the Chattahoochee River system on the Piedmont of west Georgia ( Fig. 5 ).

Remarks. Micropterus chattahoochae has rapidly declined due to habitat degradation. Furthermore, the species may be affected by the introduction of nonindigenous bass species into the Chattahoochee River system ( Baker et al. 2008; Baker pers. obs.).

Etymology. This species is named for the Chattahoochee 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 3. Pigmentation and pattern of M. tallapoosae (A–C) and M. chattahoochae (D–F). Micropterus tallapoosae: (A) male (138 mm SL), 2 November 2009; (B) female (155 mm SL), 2 November 2009; (C) juvenile (108 mm SL), 28 June 2010. Micropterus chattahoochae: (D) male (179 mm SL), 27 April 2010; (E) female, (158 mm SL), 15 June 2010; (F) male (101 mm SL), 20 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.