Micropterus henshalli Hubbs & Bailey 1940

Micropterus henshalli Hubbs & Bailey 1940 View in CoL

Alabama bass

Fig. 1

Micropterus punctulatus henshalli — Hubbs & Bailey 1940

Holotype. Tallapoosa River drainage. Alabama. Macon Co., UMMZ 118297, 113 mm SL, Uphapee Creek, 6.4 km E. Tuskegee, 27 June 1931, F. E. Guyton.

Paratypes taken with holotype. UMMZ 118297 (9), AUM 2980 (10). Additional paratypes.

Coosa River drainage

Alabama. Elmore Co., UMMZ 26269 (1) Wetumpka. Talladega Co., UMMZ 118289 (5) Talladega Creek, Coosa River, 8.0 km SW Talladega, 9 August 1936.

Georgia. Floyd Co., UMMZ 88235 (1) trib., Coosa River, E Coosa, 1 September 1929. UMMZ 88248 (3) Armuchee Creek, Oostanaula River, Armuchee, 1 September 1929. Polk Co., UMMZ 88192 (11) trib., Coosa River, 8.0 km NW Cedartown, 31 August 1929. USNM 31142 (1) Etowah River near Rome.

Tallapoosa River drainage. Alabama. Dallas Co., UMMZ 88843 (1) Alabama River, Selma, 18 September 1929. Elmore Co., UMMZ 124135 (6) Line Creek, Tallapoosa River, near Montgomery, 7 October 1938. Lowdes/Dallas Co. line, UMMZ 88838 (3) trib., Alabama River, 18 September 1929. Macon Co., UMMZ 123949 (5) Opintlocco Creek, 4.8 km SE Tuskegee, 13 September 1937. Tallapoosa Co., AUM 2966 (1) Camp Hill, 7 October 1930.

Tombigbee River drainage

Mississippi. Lee Co., UMMZ 104103 (1) Oldtown Creek, Tombigbee River drainage, 14 June 1937. Monroe Co., ISC B3­41 (6) Tombigbee River, 1.5 mi. N Amory, 16 August 1939.

Warrior River drainage

Alabama. Jefferson Co., ISC B39­86 (1) trib., 11.3 km SW Warrior, 4 September 1939.

Diagnosis. A species of Micropterus that differs from Micropterus punctulatus by a combination of the following characters: higher scale counts, including lateral line (modally 75 vs 65), scales above lateral line (modally 8 vs 7), scales below lateral line (modally 13 vs 11), scale rows around caudal peduncle (modally 29 vs 25); more rakers on first gill arch (modally 8 vs 7); smaller scale width (mean = 2.5% vs 3.2% SL); narrower skull (mean = 10.2 % vs 11.4 % SL postfrontal width and 7.0% vs 8.0 % SL interorbital width); and a smaller tooth patch (1.5% vs 1.9% SL). Lateral blotches of M. henshalli do not coalesce into a dark stripe on caudal peduncle as in M. punctulatus . Mid­lateral spots number 10–13 (96.3%) in M. henshalli vs 8–11 (84.5%) in M. punctulatus . Dorsolateral blotches do not touch first dorsal fin base as in M. punctulatus ( Fig. 1 View FIGURE 1 ). Dorsolateral blotches number 10–12 (88.5%) vs 7–10 (98.5%) in M. punctulatus .

Description. Micropterus henshalli is a large species of bass that attains weights of 4.0 kg (8 lbs., 15 oz.). Morphological and meristic measurements are given in Tables 1 View TABLE 1 –5, and general body shape is illustrated in Fig. 1 View FIGURE 1 . Lateral­line scales 68 –84 (mean 75.3); scales above lateral line 7–9 (mean 7.9); scales below lateral line 11–15 (mean 13.3); scale rows around caudal peduncle 26–32 (mean 28.6). Rakers on first gill arch 7–8 (mean 7.9). Pectoral­fin rays 14–17 (mean 15.9). Narrow head and scales. Tongue tooth patch usually present; absent in 6 of 350 specimens examined. Dorsal­fin spines 9; dorsal­fin rays 12–14, usually 13; caudal­fin rays 16–17. Pyloric caeca are unbranched.

Body color above midline is usually light to medium green with bronze or golden shimmer. Below midline body is white or has brownish­green tint along upper portion. often with continuous or occasionally interrupted rows of dark green blotches. Venter uniformly white or with scattered pale spots. Lateral stripe dark green; often darker along caudal peduncle; composed of blotches most distinguishable along caudal peduncle. Dorsal botches usually 10–12 (88.5%). Dorsolateral blotches do not extend to first spine of dorsal fin. Fins translucent green to gray.

Comparisons. Micropterus henshalli differs from M. punctulatus , with which it has been confused, by a combination of scale count differences produced by having smaller scales overall, and by several other morphological traits ( Table 1 View TABLE 1 ). Specifically, lateral­line scales 68–84, modally 75 vs 60–71, modally 65; scales above lateral line 7–9, modally 8 vs 5–7, modally 7; scales below lateral line 11–15, modally 13 vs 9–13, modally 11; scale rows around caudal peduncle 26–32, modally 29 vs 21–28, modally 25. Additionally, M. henshalli has a narrower head than M. punctulatus (postfrontal width modally 10.2 % SL vs 11.4 % SL; interorbital width modally 7.0% SL vs 8.0 % SL), as well as narrower scales (width modally 2.5% SL vs 3.2% SL). Micropterus henshalli has a higher gill­raker count than M. punctulatus (modally 8 vs 7) and has a proportionally smaller tooth patch (modally 1.5% SL vs 1.9% SL). In addition, the lateral stripe of M. henshalli remains a series of distinguishable blotches to the caudal fin base, whereas the lateral stripe of M. punctulatus coalesces into a dark stripe. Mid­lateral spots number 10–13 (96.3%) in M. henshalli vs 8–11 (84.5%) in M. punctulatus . The dorsolateral blotches of M. henshalli do not touch the first dorsal fin base (89.5%), as they do in M. punctulatus (91.4%). Dorsolateral blotches number 10–12 (88.5%) vs 7–10 (98.5%) in M. punctulatus .

Etymology. This species was named by Hubbs and Bailey (1940) for James L. Henshall, a bass angler.

Remarks. The presumed native distribution of M. henshalli is the Mobile Bay drainage ( Fig. 2 View FIGURE 2 ). This distribution agrees with a repeated pattern of endemism in the Mobile basin system, which is home to over 60 endemic fish species ( Boschung and Mayden 2004).

Records of M. henshalli and M. punctulatus support the discussion in Williams and Burgess (1999) regarding bass introductions in the Chattahoochee River system. Both species are in the Chattahoochee River, often in syntopy. We believe our meristic data suggest interbreeding of M. punctulatus with M. henshalli and perhaps with M. coosae and M. cataractae . Some individuals from the Chattahoochee River don't fit the description of either M. punctulatus or M. henshalli , based on intermediate scale counts. Genetic work in this drainage could aid in understanding this variability.

Comparisons of growth, length and weights of Alabama and Spotted Bass are confounded by the inclusion of both species in datasets as well as a lack of separation of fish by habitat. In general, bass from reservoirs are thought to grow faster than those from riverine habitat ( Boschung and Mayden 2004). The Alabama state record Alabama Bass was captured in 1978 from Lewis Smith reservoir, on the Black Warrior River, and weighed 8 lbs, 15 oz. No length was given for this specimen: (http://www.outdooralabama.com/fishing/freshwater/fish/bassblack/spotted/).Although Hubbs and Bailey (1940) originally described M. henshalli as a subspecies of M. punctulatus , they cited a paucity of specimens from southeastern drainages as a factor limiting their understanding of variation in bass species from Alabama. We found no evidence of intergradation with M. punctulatus from coastal drainages in Alabama (Table 3), as suggested by Hubbs and Bailey (1940). Furthermore, we found no differences in meristic or morphological traits of M. henshalli found above or below the Fall Line (Table 4), as discussed by Gilbert (1973).

Further evidence of the distinctiveness of M. henshalli was provided by Harbaugh (1994) and Kassler et al. (2002) via analyses of phylogenetic relationships within Micropterus . Using characters derived from morphometric analysis and combined morphometric and meristic traits, Harbaugh's analysis (1994) produced phylogenetic trees linking M. henshalli with Micropterus salmoides rather than with M. punctulatus . In the analysis of Kassler et al. (2002), M. henshalli was linked to M. coosae . Distinguishing morphological traits of southeastern species of Micropterus are summarized in Table 5. Further studies of relationships within Micropterus that combine morphological and genetic data are needed to clarify sister­group relationships of M. henshalli .