(Percidae: Etheostoma), with Descriptions of Five New Species

38 Bulletin 30 NOVEMBER 1, 2012E. jimmycarter, E. teddyroosevelt, and E. clinton. Both E.meadiae and E. jimmycarter separate completely or nearlycompletely from E. stigmaeum, E. akatulo, and E. clinton.Unlike the male analysis, females of E. clinton broadlyoverlap those of E. stigmaeum from Ouachita River, E. jimmycarterpartly overlaps E. teddyroosevelt, and E. teddyrooseveltpartly overlaps E. clinton (Fig. 23). Variables loading heavilyon sheared PC-II include first anal spine length, upperjaw length, snout length, and distance from the midlineat least interorbital width to the snout (Table 15). Thoseloading most heavily on sheared PC-III are first anal spinelength, anal fin base length, snout length, and two measuresof body depth.CONTACT ZONESBear Creek system, Alabama.—Howell (1968; 1980a)treated specimens from Little Bear Creek in the BearCreek system of Alabama (Tennessee River drainage) asintergrades or hybrids between E. jessiae and E. stigmaeum.Etheostoma stigmaeum occurs in adjacent Bear Creek,having presumably entered the system via stream capturefrom the upper Tombigbee River system (Wall, 1968;Starnes and Etnier, 1986). Howell based his assessment onthe observation that six of 12 available specimens (50%)possessed a frenum, which he considered the most distinctivecharacter separating the two taxa. However, meristic,breeding color, and allozyme data all indicate that LittleBear Creek contains “pure” E. jessiae and this “apparentzone of intergradation” (Wiley, 1981) does not involvegene flow between E. stigmaeum from Bear Creek and E.jessiae. This conclusion is discussed below.First, it has been shown above with a larger sample size(n = 49) that actually about 69% of specimens from LittleBear Creek possess a frenum. This frequency is comparableto that observed in geographically proximate populationsof E. jessiae from Shoal Creek, Paint Rock River,and Sequatchie River; however, there is no clear patternof clinal variation, as several intervening populations exhibitfrenum frequencies of 100%. Second, in comparingmeristic frequencies between Little Bear Creek specimens,E. jessiae, and 54 specimens of E. stigmaeum fromBear Creek, counts for Little Bear Creek are highly consistentwith those of E. jessiae. This is true for counts of lateralscales, unpored lateral scales, transverse scales, scalesbelow and above the lateral line, caudal peduncle scales,dorsal spines, dorsal soft rays, anal soft rays, pectoral rays,and nape squamation, distributions of which are diagnosticfor the two species (Tables 1 through 5, and Tables 7through 9). No meristic counts examined exhibit intermediacythat would support a hybridization hypothesis.Principal component analysis of 16 meristic variables inE. jessiae shows that Little Bear Creek specimens are typicalfor the species, broadly overlapping all other populationson the plot of PC- I versus PC-II (Fig. 24; Table 16).Figure 23. Plot of morphometric sheared principalcomponent two (PC-II) and sheared PC-III for femalesof nine species of Doration. Polygons bound all individualsof: 1—Etheostoma stigmaeum, Coosa River(Mobile Basin); 2—E. stigmaeum, Pearl River (centralGulf Coast); 3—E. stigmaeum, Clarks River (upperMississippi Embayment); 5—E. jessiae; 6—E. meadiae;7—E. akatulo; 8—E. obama; 9—E. gore; 10—E. jimmycarter;11—E. teddyroosevelt; 12—E. clinton.Third, breeding coloration (Fig. 3) and maximum size(56 mm SL) of Little Bear Creek males are typical of E. jessiae.Breeding coloration of E. stigmaeum males observedfrom Bear Creek is typical for that species (Fig. 3), andmaximum size is only about 42 mm SL. Finally, patterns ofallozyme variation presented in (Layman, 1994) indicatethat E. stigmaeum and E. jessiae from the Bear Creek systemare not hybridizing. At four diagnostic loci between E. stigmaeumfrom Bear Creek and E. jessiae, all Little Bear Creekspecimens (n = 10) possessed only E. jessiae alleles; no individualswere heterozygous for alleles from both species.There is no convincing evidence that E. stigmaeum andE. jessiae have hybridized in the Bear Creek system. Thespecies occur parapatrically in the system, with their distributionsseparated by a gap that Wall (1968) attributesto lack of suitable sand and gravel substrates. This studysuggests that the polymorphic condition of the frenum inpopulations of E. jessiae from Little Bear Creek and otherrivers in the southern bend of the Tennessee River representsresidual geographic variation left from the ancestorof E. jessiae, perhaps maintained by chance or local selection(Wiley, 1981). Furthermore, even if hybridization hadoccurred, it would have little bearing on decisions concerningthe species status of these taxa, since the phylogenypresented below suggests that they are not sister taxa.Clinch River system, Tennessee.—Etheostoma jessiae andE. meadiae occur parapatrically in the Clinch and Powellrivers (Fig. 7). Meristic and breeding color data indicatethat E. jessiae occurs both downstream of Norris Dam and