Regular issues
Special Issues

Southeastern Naturalist
    SENA Home
    Range and Scope
    Board of Editors
    Editorial Workflow
    Publication Charges

Other EH Journals
    Northeastern Naturalist
    Caribbean Naturalist
    Neotropical Naturalist
    Urban Naturalist
    Eastern Paleontologist
    Journal of the North Atlantic
    Eastern Biologist

EH Natural History Home

Novel Phylogeographic Patterns in a Lowland Fish, Etheostoma proeliare (Percidae)
Nicholas J. Lang and Anthony A. Echelle

Southeastern Naturalist, Volume 10, Issue 1 (2011): 133–144

Full-text pdf (Accessible only to subscribers.To subscribe click here.)


Site by Bennett Web & Design Co.
2011 SOUTHEASTERN NATURALIST 10(1):133–144 Novel Phylogeographic Patterns in a Lowland Fish, Etheostoma proeliare (Percidae) Nicholas J. Lang1,2,* and Anthony A. Echelle1 Abstract - Etheostoma proeliare is distributed in the Gulf Coastal Plain of southeastern North America from the Colorado River of eastern Texas through the Choctawhatchee River of eastern Alabama, north to the Fall Line, and upstream along the Arkansas River valley into eastern Oklahoma. Parsimony and Bayesian analysis of the ND2 gene from 28 populations recovered a monophyletic E. proeliare (PP:1.0) containing a basal split between a novel clade of populations in the northern apex of the Mississippi embayment, from the Black and St. Francis rivers to the west of, through the Yazoo River to the east of, the main channel of the Mississippi River, and all other populations (PB:99, PP:1.0). Southern populations are resolved into three clades: Trinity plus Neches Rivers (PB:100, PP:1.0), Sabine River east through western tributaries to the Mississippi River plus the Lake Pontchartrain drainage (PP:1.0), and eastern tributaries to the Mississippi River east through the Escambia River (PP:0.99). The eastern clade is further divided into Pearl plus Big Black rivers (PB:97, PP:1.0) and Mobile Basin plus Escambia River clades (PP:0.98). These results indicate that although the mainstem of the Mississippi River corresponds to some phylogeographic breaks in a lowland species, it is not an absolute barrier. Future studies of species in the region should further explore the placement of Lake Pontchartrain populations and the existence of divergent populations in the northern Gulf Coastal Plain. Introduction The North American temperate freshwater ichthyofauna is relatively rich compared to that of temperate Eurasia (Berra 2001). Most species are found east of the Continental Divide, where a large portion of the diversity is found in two clades, the minnows (Cyprinidae) and darters (Percidae) (Lee et al. 1980). Both clades consist of sympatrically distributed but ecologically divergent lineages (e.g., subgenera of Etheostoma in darters [Page and Swofford 1984]) that have given rise to multiple allopatric species across the region’s topographically diverse and temporally plastic drainages (e.g., members of the Notropis rubellus (Agassiz) (Rosyface Shiner) species group [Berendzen et al. 2008]). Endemism is highest within the Ozark, Ouachita, and Eastern Highlands, three disjunct regions of relatively high relief drained by tributaries to the Mississippi River. Most biogeographic studies of North American fishes have focused on species or clades found in one or more of these regions (Mayden 1988, Wiley and Mayden 1985). 1Department of Biology, Oklahoma State University, Stillwater, OK. 2Current address - Division of Fishes, Department of Zoology, Field Museum of Natural History, 1400 South Lake Shore Drive, Chicago, IL 60605-2496. *Corresponding author - oligocephalus@ 134 Southeastern Naturalist Vol. 10, No. 1 The ichthyofauna of the Mississippi River system is especially diverse because its tributaries encompass a wide variety of habitat types in which highland endemics are isolated by unsuitable lowland and/or big river habitat. Within linear freshwater systems, the presence of intervening unsuitable habitat can severely limit gene flow among populations, and processes such as long-term environmental change or drainage rearrangement may be required for the establishment of new populations (Echelle et al. 1975). In lowland areas, the relatively modest topographic relief between drainage systems, along with the presence of connecting lakes and/or deltas, may allow for greater connectivity among populations in separate drainages over time. Although many lowland freshwater fishes are widespread, biogeographic breaks do still occur (Bermingham and Avise 1986). In the lowland area of southeastern North America known as the Gulf Coastal Plain (GCP), the major biogeographic break is coincident with the channel of the Mississippi River (Robison 1986). Although some species are found on both sides of the Mississippi River, widespread clades generally contain distinct species on either side (Birdsong and Knapp 1969, Lee at al. 1980, Pramuk et al. 2007). A second biogeographic break delineates distinct faunal assemblages west of, within, and east of the Mobile Basin (Swift et al. 1986). Although populations within the GCP have been included in molecular studies on the phylogeography of both lowland (Bermingham and Avise 1986) and highland (Berendzen et al. 2003, Ray et al. 2006) fishes, no study has explored the phylogenetic structuring of a small stream species endemic to, and distributed across, the entire region. Etheostoma proeliare (Hay) (Cypress Darter), is found in lowland portions of GCP drainages from the Colorado River, TX (Auburn University Museum 26406) through the Choctawhatchee River, AL and fl(Burr 1978). Although largely restricted to the area below the Fall Line, which demarcates the border between upland regions and the GCP, the species crosses this boundary in transitional zones in southeastern Missouri and southern Illinois and along the Arkansas River valley upstream to eastern Oklahoma (Fig. 1). Cypress Darters can be found in the vegetated margins of swamps and lakes as well as near cover in slow, sand/silt-bottomed streams (Burr and Page 1978). Burr (1978) concluded, based on morphological data, that the Cypress Darter is the sister species of E. fonticola (Jordan and Gilbert) (Fountain Darter), which is endemic to springs of the Guadalupe River drainage, just west of the range of the Cypress Darter. Although Burr (1978) found variation among populations of the Cypress Darter, he considered the variation to be randomly distributed and not significant enough to warrant taxonomic recognition. The sister relationship between the Cypress Darter and the Fountain Darter was further supported by allozyme data in a study that found little divergence among Cypress Darter populations east of, but did not include any populations west of, the Mississippi River (Buth et al. 1980). Herein, we present the results of a phylogeographic study of the Cypress Darter and discuss our results in the broader context of Gulf Coastal Plain biogeography. 2011 N.J. Lang and A.A. Echelle 135 Materials and Methods Specimens were collected by seine, dipnet, and/or backpack electroshocker. Whole specimens were either frozen or preserved in 95% ethanol, or fin clips were placed in 95% ethanol and voucher specimens preserved in formalin. Specimens and tissues were accessioned into the collections at the University of Alabama and Saint Louis University, or are held at Oklahoma State University (Appendix 1). Attempts were made to collect specimens from all major drainages throughout the range, but failed in the Colorado, Choctawatchee, and Pascagoula rivers, where the Cypress Darter is known from one, two, and fewer than ten localities, respectively. Ingroup sampling includes one specimen per locality from at least one locality in all other major drainages within the range of the Cypress Darter. Because uncertainty regarding the relationships among subgenera of Etheostoma makes it Figure 1. Distribution of the Cypress Darter indicated with shading. The heavy dashed line indicates the approximate position of the Fall Line, the white lines within the northern portion of the shaded distribution indicate the approximate position of Crowley’s Ridge (after Robison 1986), and hollow symbols represent approximate Cypress Darter sampling localities. Symbols are clade-specific and the numbers correspond to populations within each clade. 136 Southeastern Naturalist Vol. 10, No. 1 difficult to choose a darter outgroup for this study, the dataset includes all ND2 sequences from Lang and Mayden (2007) (EF027169 through EF027233) plus one Fountain Darter, which occurs naturally in a single spring system. Whole DNA was extracted using either a standard phenol-chloroform method or the DNEasy Kit (QIAGEN, Valencia, CA). The complete mitochondrial ND2 gene was amplified (35 cycles of 94 °C for 40 sec, 56 °C for 60 sec, and 72 °C for 90 sec) with Taq DNA Polymerase (PROMEGA, Madison, WI) using the external primers of Lang and Mayden (2007). Amplification products were gel extracted using a Gel Extraction Kit (QIAGEN, Valencia, CA). Sequencing utilized both the external amplification primers and Cypress Darter-specific internal primers (Epro539L: 5-ACTCATCCATCGCCCACCTT-3’, Epro739H: 5’-AGACCTCCTAATGAAAGAAG- 3’) with chemistry specific to various visualization systems. Products were visualized using either the CEQ 8000 Genetic Analysis System (Department of Biology, Saint Louis University, St. Louis, MO) or an ABI 3700 (Auburn University Genomics Laboratory, Auburn, AL, Oklahoma State University Recombinant DNA Core Facility, Stillwater, OK, and Macrogen, Inc., Seoul, Korea). Sequence files were edited, contigs were assembled, and sequences were aligned by eye using Geneious Pro v. 3.5.6 (Drummond et al. 2007). Maximum Parsimony analyses were implemented in PAUP*4.0b10 (Swofford 2002), with 100 repetitions of random stepwise addition and TBR branch swapping, with Perca flavescens (Mitchill) (Yellow Perch) and Sander marinus (Cuvier) (Estuarine Perch) designated as outgroups. Support for nodes (PB: parsimony bootstrap) was estimated using 1000 “fast-stepwise” addition replicates of bootstrapping. MrModelTest 2.2.1 for Classic (Nylander 2004) was used to hypothesize the best-fit model for codon-position specific partitions of the dataset. These models were used in two independent mixed-model Bayesian analyses in MrBayes3.1 (Ronquist and Huelsenbeck 2003) that ran for 5,000,000 generations. Priors for these analyses were flat, four chains were utilized, and trees were sampled every 100 generations. Yellow Perch was designated as the outgroup for Bayesian analyses, which only allows a single outgroup. Stationarity of negative log-likelihood values was evaluated by plotting these values against generation, and all trees before the value stabilized were discarded as burn-in. Support for recovered nodes (BPP: Bayesian posterior probability) was calculated by creating a majority-rule consensus tree using all post-burn-in trees for each analysis and averaging the resulting values. Results The data matrix consists of 1047 base pairs. Sequences were generated for 29 specimens of Cypress Darter from 28 localities. The following samples are based on incomplete data: Ol-821, missing bp 1–537; Ol-832, missing bp 418–537; Ol-1043, -1044, -1045, -1046, and -1047, missing bp 1028–1047. Each sampled locality yielded a unique haplotype. There were 454 constant and 532 parsimony-informative characters, and maximum parsimony analysis yielded two most-parsimonious trees (5807 steps). MrModelTest selected the GTR+I+G model for the second and third codon 2011 N.J. Lang and A.A. Echelle 137 positions. For the first position, the GTR+I+G and SYM+I+G models were each selected by a single likelihood ratio test (LRT), but the remaining LRT and the Akaike information criterion selected the HKY+I+G model, which was used in the analyses. The burn-in period for both Bayesian analyses was designated as the first 50,000 generations, and average BPP values were calculated from those in the run-specific majority-rule consensuses of trees 52–5001. The results of the parsimony and Bayesian results were highly concordant, disagreeing only on the resolution of nodes with little support, and the amount of support for consistently recovered nodes. Relationships were identical to those in Lang and Mayden (2007) except for the addition of a strongly supported sisterspecies relationship (PB: 100, BPP: 1.0) between the Fountain Darter and the monophyletic Cypress Darter (PB: *, BPP: 1.0; not shown). Among populations of Cypress Darter, there is a basal split between those from the northern part of the range and all others (Fig. 2). This northern clade (PB: 99, Figure 2. One of two most parsimonious phylograms of the relationships among populations of Etheostoma proeliare recovered in our analysis. Numbers above nodes are parsimony bootstrap values and those below are Bayesian posterior probability values. Nodes found in both most-parsimonious trees, but not receiving bootstrap support, are indicated by an asterisk. Symbols and population numbers correspond to those in Figure 1. 138 Southeastern Naturalist Vol. 10, No. 1 BPP: 1.0, circles in Fig. 1) encompasses all sampled populations from streams north of and including the St. Francis River to the west, and the Yazoo River to the east, of the main channel of the Mississippi River, as well as the upper Black River in southeastern Missouri. Although the Black River is a tributary to the White River, the population sampled from the lower White River (Tarleton Creek) is not a member of the northern clade. The clade encompassing the remaining populations (PB: *, BPP: 1.0) comprises three well-supported clades distributed as follows: 1. east of the Mississippi River except the Lake Pontchartrain drainage (PB: *, BPP: 0.99, squares in Fig. 1); 2. the Neches and Trinity river drainages (PB: 100, BPP: 1.0, stars in Fig. 1); and 3. the Red River drainage, the Lake Pontchartain drainage, and the Sabine River drainage, exclusive of the Neches River (PB: *, BPP: 1.0, triangles in Fig. 1). The clade of populations east of the Mississippi River is divided into two well-supported clades: one comprised of populations from the Mobile Basin and Escambia River (PB: *, BPP: 0.98) and the other of populations from the Pearl and Big Black rivers (PB: 97, BPP: 1.0). Percent divergences within and among these major clades are presented in Table 1. Within the clade comprised of populations from the Lake Pontchartrain drainage and those drainages between the Neches and Mississippi rivers, there are a number of well-supported sub-clades. Single-drainage clades comprise the populations from the Lake Pontchartrain (PB:98, BPP: 1.0) and lowland Red River (PB: 100, BPP: 1.0) drainages, and the sampled population from the Sabine River was recovered in a clade with that from the neighboring Calcasieu River (PB: 92, BPP: 1.0). A population from the lower White River drainage was recovered as sister to the lowland Red River drainage clade (BPP: 1.0), and a clade uniting populations from the middle Arkansas (Canadian River) and upland Red (Yanubbe Creek) river drainages was also recovered (PB: 91, BPP: 1.0). Discussion Our well-supported phylogenetic hypothesis of relationships among regional populations of the Cypress Darter suggests several novel biogeographic patterns. The most interesting of these is the resolution of a distinct clade comprised of drainages in the northern apex of the GCP. West of the main channel of the Mississippi River, the southern limit of this northern clade (circles in Fig. 1) is found among tributaries to the Black River (White River drainage) and the St. Francis River. The sampled individual from the lowland portion of the White River drainage is in the Red River/Lake Pontchartrain clade (triangles in Fig. 1). Most Table 1. Uncorrected mean percent sequence divergences within (upper diagonal) and between (below diagonal) major clades identified among Cypress Darter populations. Symbol designations correspond to those in Figures 1 and 2. Circles Triangles Squares Stars Northern clade (circles) 1.51% Red River/Lake Pontchartrain/Sabine River clade (triangles) 5.57% 1.70% Eastern clade (squares) 5.39% 3.06% 2.38% Trinity and Neches rivers clade (stars) 5.17% 2.90% 3.03% 0.30% 2011 N.J. Lang and A.A. Echelle 139 populations recovered in the northern clade are from transitional areas between the lowland GCP and the Ozark or Eastern Highlands. Many highland species are shared between the upland portions of the St. Francis and Black (including Current and Spring rivers) river drainages, and the Cypress Darter is abundant in the Missouri portion of the Black River drainage at the transition between the GCP and the Ozark Highlands (Pflieger 1997, Robison and Buchanan 1988). It is possible that the northern clade gained access to this transitional area of the upland Black River drainage via former outlets that flowed east through the current St. Francis River drainage rather than south to the White River drainage. The route of the main channel of the Mississippi River has varied over time, and the present-day configuration of drainages in the northern GCP is likely too recent to explain the distribution of many species (Robison 1986). The presence of haplotypes from the northern clade so far downstream in the St. Francis River drainage may be due to the presence of Crowley’s Ridge, an isolated highland geological feature in the GCP that runs along the western edge of the lower St. Francis River drainage, and is drained by the sampled creek. It has long been recognized that streams draining the ridge are home to isolated populations of highland fishes such as Campostoma anomalum (Rafinesque) (Central Stoneroller), Etheostoma caeruleum Storer (Rainbow Darter), and Chrosomus erythrogaster (Rafinesque) (Southern Redbelly Dace) (Robison and Buchanan 1988), but our data indicate that the ridge may also harbor cryptic biodiversity within typically lowland species. Future work on the Cypress Darter should incorporate specimens from farther upstream in the White River drainage and from streams in the St. Francis River drainage that do not drain Crowley’s Ridge. East of the main channel of the Mississippi River, the northern clade extends as far south as the Yazoo River. Although there are no clear biogeographic breaks between the Big Black and Yazoo rivers in widespread lowland species, the Yazoo River is the southern limit of Snubnose Darters (Etheostoma, subgenus Ulocentra). Also, several species, such as Cyprinella whipplei Girard (Blacktail Shiner), Lythrurus roseipinnis (Hay) (Cherryfin Shiner), and Notropis texanus (Girard) (Weed Shiner), are common on one side of the Big Black/Yazoo divide, but rare on the other (Ross 2001). Within Noturus hildebrandi (Bailey and Taylor) (Least Madtom), the subspecies N. h. hildebrandi is restricted to streams from the Big Black River south, and N. h. lautus is found from the Hatchie River north, while populations in the Yazoo River were considered intergrades (Taylor 1969). It is possible that, as in the White River drainage, members of the northern clade are restricted to relatively upland headwater habitats, where the Cypress Darter is distinctly more abundant, in the Yazoo River and drainages in western Tennessee (Etnier and Starnes 1993, Ross 2001). Our samples came from small streams in the relative headwaters of these drainages, and future work should include samples from more lowland areas in eastern tributaries to the Mississippi River in order to more fully explore the range of the northern clade. Within the southern clade, we recovered both predicted and novel relationships. The split between the Mobile Basin and GCP drainages between the Mobile Basin and the main channel of the Mississippi River is predicted by both 140 Southeastern Naturalist Vol. 10, No. 1 the composition of the respective faunas (Swift et al. 1986) and the distribution of endemic species, such as those in the Notropis dorsalis (Agassiz) (Bigmouth Shiner) species group (Raley and Wood 2001) and the southern clade of Lythrurus (sensu Pramuk et al. 2007). The recovery of an unresolved trichotomy among the Mobile Basin drainages and the Escambia River drainage may be an artifact of our sampling, which does not include the Choctawhatchee River population. Although a phylogeographic break at the mainstem Mississippi River was predicted based on the inability of small-stream fishes to utilize its large-stream habitat (Robison 1986), the recovery of Lake Pontchartrain drainage populations with populations west of the main channel of the Mississippi River was novel. It is difficult to hypothesize a connection between the Lake Pontchartrain drainage and those of the western GCP because the basin that became Lake Pontchartrain roughly 4000 years ago has always been east of the Mississippi River delta (Frazier 1967). It is tempting to suggest that a lowland species, such as the Cypress Darter, may be able to utilize the dynamic environment of a large delta to facilitate crossing a large barrier such as the main channel of the Mississippi River. However, the current distribution of the Cypress Darter indicates that it does not inhabit such regions in either the Mississippi River or Mobile Basin deltas (Boschung and Mayden 2004, Douglas 1974). The Cypress Darter’s possible aversion to delta conditions may also explain the resolution of a clade composed of populations from the Neches and Trinity rivers to the exclusion of the Sabine River drainage. Conner and Suttkus (1986) described a fairly uniform fauna within what Knapp (1953) referred to as the Eastern Area of Texas, with no distinction between the fauna of the Neches and Sabine river drainages. It is possible that the distinct Neches/Trinity clade evolved in eastern Texas prior to integration of the Neches and Sabine rivers into a single outlet, and that uninhabitable delta habitat has kept the populations separated. Given the presence of the Fountain Darter on the western periphery of the range of the Cypress Darter, it is possible that the western edge of the GCP has long harbored significant genetic variation within the clade comprising both species, as was recently suggested for the clade comprised of Percina apristis (Hubbs and Hubbs) (Guadalupe Darter) and P. sciera (Swain) (Dusky Darter) (Robins and Page 2007). Inclusion of the recently discovered Cypress Darter population from the intervening Colorado River drainage should be a goal of future analyses. The remaining relationships among sampled populations west of the main channel of the Mississippi River are largely unresolved and will require finer scale sampling if phylogeographic structure is to be resolved within or among the Red and Arkansas river drainages. Although this analysis is based on a single mitochondrial gene, there is no evidence of hybridization, which is often readily apparent when using mitochondrial data due to the sharing of identical, or very similar, sequences among species (Ray et al. 2008), and the well-supported clades are not only significantly divergent (Table 1) but also geographically restricted. Reinterpretation of Burr’s (1978) morphological data in light of our results is difficult due to the presentation of statistical measures rather than raw data for some characters and the 2011 N.J. Lang and A.A. Echelle 141 grouping of populations from drainages containing clade boundaries (e.g., Burr [1978] grouped data from the Sabine and Neches Rivers and presented data from the Black River drainage as part of the White River). It does not appear, however, that the distributions of our novel clades conform to any of the patterns he identified. Discussion of cryptic speciation within the Cypress Darter will require finer sampling of genetic and possibly ecological data. Finally, although the novel biogeographic aspects of our results are difficult to interpret without additional data from co-distributed species, our analyses clearly indicate that significant phylogeographic structure can exist in widespread Gulf Coastal Plain fishes. Acknowledgments Specimens, field assistance, and/or locality information was provided by H. Bart, B. Fluker, A. George, D. Hendrickson, B. Kuhajda, D. Lynch, R. Mayden, D. Neely, S. Powers, J. Ray, T. Slack, and J. Switzer. Specimens were collected under the following permits from 2007 and 2008 (granted to N.J. Lang, or direct supervisor) or similar permits from previous years for which records are not available to the author: Alabama (4119), Arkansas (030720073 and 052720082), Illinois (A07.5059), Kentucky (SC0711079), Louisiana (1068), Mississippi (unique permit numbers not issued), Missouri (13497), Oklahoma (unique permit number not issued), Tennessee (1419), and Texas (SPR-0107-012). Literature Cited Berendzen, P.B., A.M. Simons, and R.M. Wood. 2003. Phylogeography of the Northern Hogsucker, Hypentelium nigricans (Teleostei: Cypriniformes): Genetic evidence for the existence of the ancient Teays River. Journal of Biogeography 30:1139–1152. Berendzen, P.B., A.M. Simons, R.M. Wood, T.E. Dowling, and C.L. Secor. 2008. Recovering cryptic diversity and ancient drainage patterns in eastern North America: Historical biogeography of the Notropis rubellus species group (Teleostei: Cypriniformes). Molecular Phylogenetics and Evolution 46:721–737. Bermingham, E., and J.C. Avise. 1986. Molecular zoogeography of freshwater fishes in the southeastern United States. Genetics 113:939–965. Berra, T.M. 2001. Freshwater Fish Distribution. University of Chicago Press, Chicago, IL. 606 pp. Birdsong, R.S., and L.W. Knapp. 1969. Etheostoma collettei, a new darter of the subgenus Oligocephalus from Louisiana and Arkansas. Tulane Studies in Zoology and Botany 15:106–112. Boschung, H.T., and R.L. Mayden. 2004. Fishes of Alabama. Smithsonian Institution, Washington, DC. 736 pp. Burr, B.M. 1978. Systematics of the percid fishes of the subgenus Microperca, genus Etheostoma. Bulletin of the Alabama Museum of Natural History 4:1–53. Burr, B.M., and L.M. Page. 1978. The life history of the Cypress Darter, Etheostoma proeliare, in Max Creek, Illinois. Illinois Natural History Survey Biological Notes 106:1–15. Buth, D.G., B.M. Burr, and J.R. Schenck. 1980. Electrophoretic evidence for relationships and differentiation among members of the percid subgenus Microperca. Biochemical Systematics and Ecology 8:297–304. Conner, J.V., and R.D. Suttkus. 1986. Zoogeography of freshwater fishes of the western Gulf Slope. Pp. 267–286, In C.H. Hocutt, and E.O. Wiley (Eds.). The Zoogeography of North American Freshwater Fishes. Wiley and Sons, New York, NY. 866 pp. 142 Southeastern Naturalist Vol. 10, No. 1 Douglas, N.H. 1974. Freshwater Fishes of Louisiana. Claitor’s Publishing Division, Baton Rouge, LA. 443 pp. Drummond, A.J., B. Ashton, M. Cheung, J. Heled, M. Kearse, R. Moir, S. Stones-Havas, T. Thierer, and A. Wilson. 2007. Geneious v3.5. Available online at http://www.geneious. com. Echelle, A.A., A.F. Echelle, M.H. Smith, and L.G. Hill. 1975. Analysis of genic continuity in a headwater fish, Etheostoma radiosum (Percidae). Copeia 1975:197–204. Etnier, D.A., and W.C. Starnes. 1993. The Fishes of Tennessee. University of Tennessee Press, Knoxville, TN. 681 pp. Frazier, D.E. 1967. Recent deltaic deposits of the Mississippi River: Their development and chronology. Gulf Coast Association of Geological Societies Transactions 27:287–315. Knapp., F.T. 1953. Fishes Found in the Freshwaters of Texas. Ragland Studio and Litho Printing Co., Brunswick, GA. Lang, N.J., and R.L. Mayden. 2007. Systematics of the subgenus Oligocephalus (Teleostei: Percidae: Etheostoma) with complete subgeneric sampling of the genus Etheostoma. Molecular Phylogenetics and Evolution 43:605–615. Lee, D.S., C.R. Gilbert, C.H. Hocutt, R.E. Jenkins, D.E. McAllister, and J.R. Stauffer Jr. (Eds.). 1980. Atlas of North American Freshwater Fishes. North Carolina State Museum of Natural History, Raleigh, NC. 867 pp. Leviton, A.E., R.H. Gibbs, E. Heal, and C.E. Dawson. 1985. Standards in herpetology and ichthyology. 1. Standard symbolic codes for institutional resource collections in herpetology and ichthyology. Copeia 1985:802–832. Mayden, R.L. 1988. Vicariance biogeography, parsimony, and evolution in North American freshwater fishes. Systematic Zoology 37:329–355. Nylander, J.A.A. 2004. MrModeltest v2. Program distributed by the author. Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden. Page, L.M., and D.L. Swofford. 1984. Morphological correlates to ecological specialization in darters. Environmental Biology of Fishes 11:139–159. Pflieger, W.L. 1997. The Fishes of Missouri, Revised Edition. Missouri Department of Conservation, Jefferson City, MO. 372 pp. Pramuk, J.B., M.J. Grose, A.L. Clarke, E. Greenbaum, E. Bonaccorso, J.M. Guayasamin, A.H. Smith-Pardo, B.W. Benz, B.R. Harris, E. Siegfreid, Y.R. Reid, N. Holcroft- Benson, and E.O. Wiley. 2007. Phylogeny of finescale shiners of the genus Lythrurus (Cypriniformes: Cyprinidae) inferred from four mitochondrial genes. Molecular Phylogenetics and Evolution 42:287–297. Raley, M.E., and R.M. Wood. 2001. Molecular systematics of members of the Notropis dorsalis species group (Actinopterygii: Cyprinidae). Copeia 2001:638–645. Ray, J.M, R.M. Wood, and A.M. Simons. 2006. Phylogeography and post-glacial colonization patterns of the Rainbow Darter, Etheostoma caeruleum (Teleostei: Percidae). Journal of Biogeography 33:1550–1558. Ray, J.M., N.J. Lang, R.M. Wood, and R.L. Mayden. 2008. History repeated: Recent and historical mitochondrial introgression between the Current Darter Etheostoma uniporum and Rainbow Darter Etheostoma caeruleum (Teleostei: Percidae). Journal of Fish Biology 72:418–434. Robins, R.H., and L.M. Page. 2007. Taxonomic status of the Guadalupe Darter, Percina apristis (Teleostei: Percidae). Zootaxa 1618:51–60. Robison, H.W. 1986. Zoogeographic implications of the Mississippi River basin. Pp. 267–286, In C.H. Hocutt, and E.O. Wiley (Eds.). The Zoogeography of North American Freshwater Fishes. Wiley and Sons, New York, NY. 866 pp. 2011 N.J. Lang and A.A. Echelle 143 Robison, H.W., and T.M. Buchanan. 1988. Fishes of Arkansas. University of Arkansas Press, Fayetteville, AR. 536 pp. Ronquist, F., and J.P. Huelsenbeck. 2003. MrBayes 3: Bayesian phylogenetic inference under mixed models. Bioinformatics 19:1572–1574. Ross, S.T. 2001. The Inland Fishes of Mississippi. Mississippi Department of Wildlife, Fisheries, and Parks, Jackson, MS. 624 pp. Swift, C.C., C.R. Gilbert, S.A. Bortone, G.H Burgess, and R.W. Yerger. 1986. Zoogeography of the freshwater fishes of the southeastern United States: Savannah River to Lake Pontchartrain. Pp. 213–266, In C.H. Hocutt and E.O. Wiley (Eds.). The Zoogeography of North American Freshwater Fishes. Wiley and Sons, New York, NY. 866 pp. Swofford, D.L. 2002. PAUP*. Phylogenetic Analysis Using Parsimony (* and other Methods) 4.0. Sinauer Associates, Sunderland, MA. Taylor, W.R. 1969. A revision of the catfish genus Noturus Rafinesque, with an analysis of higher groups in the Ictaluridae. US National Museum Bulletin 282:1–315. Wiley, E.O., and R.L. Mayden. 1985. Species and speciation in phylogenetic systematics, with examples from the North American fish fauna. Annals of the Missouri Botanical Garden 72:596–635. 144 Southeastern Naturalist Vol. 10, No. 1 Appendix 1: Material Examined. Institutional abbreviations follow Leviton et al. (1985), except STL, which indicates the Ichthyological Tissue Collection of Saint Louis University, Each record indicates State: Catalog Number (individual DNA extraction identification number, GenBank accession number), Locality (Drainage), County. Etheostoma fonticola Texas: STL 949.01 (Ol-0114, HM595746), San Marcos River, Hays. Etheostoma proeliare Alabama: UAIC 12411.08 (Ol-0832, HM593884), Limestone Creek (Alabama River), Monroe; UAIC 13418.08 (Ol-0885, HM593889), Conecuh River, Escambia; UAIC 15590.01 (Ol-1165, HM593872), Wards Mill Creek (Tombigbee River), Tuscaloosa. Arkansas: STL 413.01 (Ol-0826, HM593880), Bridge Creek (Arkansas River), Faulkner; STL 427.08 (Ol-0830, HM593883), Tarleton Creek (White River), Arkansas; STL 428.01 (Ol-0827, HM593881), Tuni Creek (St. Francis River), St. Francis. Illinois: UAIC 13100.12 (Ol-0890, HM593891), Max Creek (Ohio River), Johnson. Kentucky: OSUS 27599 (Ol-0873, HM593887), Richland Creek (Cumberland River), Livingston. Louisiana: STL 94.05 (Ol-0076, EF027214), Natalbany River (Lake Pontchartrain), Tangipahoa; STL 326.07 (Ol-0822, HM593876), unnamed creek (Calcasieu River), Vernon; STL 331.03 (Ol-0821, HM593875), Clark Creek (Ouachita River), Ouachita; STL 669.09 (Ol-0825, HM593879), unnamed creek (Red River), Rapides; UAIC 15185.01 (Ol-1043, HM593896), Little Natalbany River (Lake Pontchartrain), St. Helena; UAIC 15191.01 (Ol-1044, HM593897), Old River (Sabine River), Beauregard. Mississippi: OSUS 27600 (Ol-914, HM593893), unnamed stream (Yazoo River), Lafayette; OSUS 27601 (Ol-915, HM593894), Besa Chitto Creek (Pearl River), Choctaw; OSUS 27602 (Ol-916, HM593895), Bala Chitto Creek (Lake Pontchartrain), Pike; STL 870.10 (Ol- 0820, HM593874), Poplar Creek (Big Black River), Choctaw. Missouri: STL 380.04 (Ol-0889, HM593890), unnamed ditch (Black River), Butler; STL 663.04 (Ol-0828, HM593882), Ditch Number 10 (Mississippi River), New Madrid. Oklahoma: STL 277.02 (Ol-0834, HM593885), Yanubbee Creek (Red River), McCurtain; STL 288.04 (Ol-0824, HM593878), tributary to Gaines Creek (Canadian River), Latimer. Tennessee: OSUS 27597 (Ol-0877, HM593888), Cash Creek (Hatchie River), Hardeman; OSUS 27598 (Ol-0893, HM593892), Big Sandy River (Tennessee River), Henderson; UAIC 15216.02 (Ol-1047, HM593900), Kings Branch (Tennessee River), Hardin. Texas: STL 323.03 (Ol-0823, 593877; -0844, HM593886), Little Cypress Bayou (Red River), Upshur; UAIC 15195.06 (Ol-1045, HM593898), Hickory Creek (Neches River), Polk; UAIC 15196.02 (Ol-1046, HM593899), Bluff Creek (Trinity River), Polk.