David A. Etnier

Diversity, Distribution, and Conservation Status of the Native Freshwater Fishes of the Southern United States

Abstract The Southeastern Fishes Council Technical Advisory Committee reviewed the diversity, distribution, and status of all native freshwater and diadromous fishes across 51 major drainage units of the southern United States. The southern United States supports more native fishes than any area of comparable size on the North American continent north of Mexico, but also has a high proportion of its fishes in need of conservation action. The review included 662 native freshwater and diadromous fishes and 24 marine fishes that are significant components of freshwater ecosystems. Of this total, 560 described, freshwater fish species are documented, and 49 undescribed species are included provisionally pending formal description. Described subspecies (86) are recognized within 43 species, 6 fishes have undescribed subspecies, and 9 others are recognized as complexes of undescribed taxa. Extinct, endangered, threatened, or vulnerable status is recognized for 28% (187 taxa) of southern freshwater and diadromou...

Phylogeny and Temporal Diversification of Darters (Percidae: Etheostomatinae)

Discussions aimed at resolution of the Tree of Life are most often focused on the interrelationships of major organismal lineages. In this study, we focus on the resolution of some of the most apical branches in the Tree of Life through exploration of the phylogenetic relationships of darters, a species-rich clade of North American freshwater fishes. With a near-complete taxon sampling of close to 250 species, we aim to investigate strategies for efficient multilocus data sampling and the estimation of divergence times using relaxed-clock methods when a clade lacks a fossil record. Our phylogenetic data set comprises a single mitochondrial DNA (mtDNA) gene and two nuclear genes sampled from 245 of the 248 darter species. This dense sampling allows us to determine if a modest amount of nuclear DNA sequence data can resolve relationships among closely related animal species. Darters lack a fossil record to provide age calibration priors in relaxed-clock analyses. Therefore, we use a near-complete species-sampled phylogeny of the perciform clade Centrarchidae, which has a rich fossil record, to assess two distinct strategies of external calibration in relaxed-clock divergence time estimates of darters: using ages inferred from the fossil record and molecular evolutionary rate estimates. Comparison of Bayesian phylogenies inferred from mtDNA and nuclear genes reveals that heterospecific mtDNA is present in approximately 12.5% of all darter species. We identify three patterns of mtDNA introgression in darters: proximal mtDNA transfer, which involves the transfer of mtDNA among extant and sympatric darter species, indeterminate introgression, which involves the transfer of mtDNA from a lineage that cannot be confidently identified because the introgressed haplotypes are not clearly referable to mtDNA haplotypes in any recognized species, and deep introgression, which is characterized by species diversification within a recipient clade subsequent to the transfer of heterospecific mtDNA. The results of our analyses indicate that DNA sequences sampled from single-copy nuclear genes can provide appreciable phylogenetic resolution for closely related animal species. A well-resolved near-complete species-sampled phylogeny of darters was estimated with Bayesian methods using a concatenated mtDNA and nuclear gene data set with all identified heterospecific mtDNA haplotypes treated as missing data. The relaxed-clock analyses resulted in very similar posterior age estimates across the three sampled genes and methods of calibration and therefore offer a viable strategy for estimating divergence times for clades that lack a fossil record. In addition, an informative rank-free clade-based classification of darters that preserves the rich history of nomenclature in the group and provides formal taxonomic communication of darter clades was constructed using the mtDNA and nuclear gene phylogeny. On the whole, the appeal of mtDNA for phylogeny inference among closely related animal species is diminished by the observations of extensive mtDNA introgression and by finding appreciable phylogenetic signal in a modest sampling of nuclear genes in our phylogenetic analyses of darters.

Accelerated construction of a regional DNA-barcode reference library: caddisflies (Trichoptera) in the Great Smoky Mountains National Park

Abstract Deoxyribonucleic acid (DNA) barcoding is an effective tool for species identification and life-stage association in a wide range of animal taxa. We developed a strategy for rapid construction of a regional DNA-barcode reference library and used the caddisflies (Trichoptera) of the Great Smoky Mountains National Park (GSMNP) as a model. Nearly 1000 cytochrome c oxidase subunit I (COI) sequences, representing 209 caddisfly species previously recorded from GSMNP, were obtained from the global Trichoptera Barcode of Life campaign. Most of these sequences were collected from outside the GSMNP area. Another 645 COI sequences, representing 80 species, were obtained from specimens collected in a 3-d bioblitz (short-term, intense sampling program) in GSMNP. The joint collections provided barcode coverage for 212 species, 91% of the GSMNP fauna. Inclusion of samples from other localities greatly expedited construction of the regional DNA-barcode reference library. This strategy increased intraspecific divergence and decreased average distances to nearest neighboring species, but the DNA-barcode library was able to differentiate 93% of the GSMNP Trichoptera species examined. Global barcoding projects will aid construction of regional DNA-barcode libraries, but local surveys make crucial contributions to progress by contributing rare or endemic species and full-length barcodes generated from high-quality DNA. DNA taxonomy is not a goal of our present work, but the investigation of COI divergence patterns in caddisflies is providing new insights into broader biodiversity patterns in this group and has directed attention to various issues, ranging from the need to re-evaluate species taxonomy with integrated morphological and molecular evidence to the necessity of an appropriate interpretation of barcode analyses and its implications in understanding species diversity (in contrast to a simple claim for barcoding failure).

Conservation Genetics of the Ashy Darter, Etheostoma cinereum (Percidae: Subgenus Allohistium), in the Cumberland and Tennessee Rivers of the Southeastern United States

Abstract The Ashy Darter, Etheostoma cinereum (Percidae: subgenus Allohistium), is restricted to flowing pools of relatively silt free, medium-sized rivers in the Cumberland, Duck and Tennessee River drainages in the southeastern United States. Degradation of these habitats within these drainages has fragmented the range of E. cinereum into several disjunct populations and eliminated it from many historical localities. Phylogenetic analysis of cytochrome b sequence from individuals (n = 14) representing each of the extant populations of E. cinereum indicated genetic differentiation among populations inhabiting the Cumberland, Duck, and upper Tennessee River drainages. These analyses are concordant with previously noted patterns of morphological variation and minimally support three different management units (MU) currently recognized as E. cinereum. Efforts to conserve these distinct MUs should be considered in management attempts.

Analysis of Three Cisco Forms (Coregonus, Salmonidae) from Lake Saganaga and Adjacent Lakes Near the Minnesota/Ontario Border

Abstract Based on examination of 655 ciscoes from Lake Saganaga, a Minnesota/Ontario border lake, three forms, about 90% separable on gill raker counts, are present. Form L, with the lowest gill raker counts (26–40, mean = 31.9, n = 96) is tentatively identified as Coregonus zenithicus. Form M, with intermediate gill raker counts (36–50, mean = 43.1, n = 92) was the only cisco anticipated to occur in lakes of the region and is assumed to represent Coregonus artedi. Form H, with 45–70 gill rakers, mean = 56.1, n = 467, is the most common cisco in the lake. We argue that the appropriate name for this form is Coregonus nipigon. Additional differences among the three forms include lateral-line scale and vertebral counts, gill raker length, body shape, fin pigmentation, size at sexual maturity, and maximum size. Seagull Lake, affluent to Lake Saganaga, contained only C. artedi (n = 108). Gunflint and Magnetic Lakes, also affluents to Lake Saganaga, contained C. artedi (n = 19) and C. zenithicus (n = 29). Lake Saganagons, immediately downstream of Lake Saganaga, based on only eight available specimens, appears to contain C. nipigon (7) and C. artedi (1).

Taxonomic Status of Etheostoma denoncourti Stauffer and van Snik

Abstract The upper Tennessee River drainage populations of Etheostoma tippecanoe Jordan and Evermann were recently elevated to specific status with the description of the Golden Darter, Etheostoma denoncourti Stauffer and van Snik. In the description, the Duck River system was included as part of the range of E. denoncourti, although no specimens from that system were examined. Evaluation of the taxonomic status of the Duck River system population of E. denoncourti was conducted using meristic, morphometric, and nuptial coloration characters. The Duck River population was compared with other Tennessee River drainage populations of E. denoncourti and with Cumberland and Ohio drainage populations of E. tippecanoe. The Duck River population appears to be unique based strictly on meristics; however, it is similar to other E. denoncourti populations by nuptial coloration, presence of cheek scales behind the eye, and the complete separation of the posterior nasal openings from the interorbital canal. Etheostoma denoncourti is rediagnosed, and current status and distributional information are provided for both E. tippecanoe and E. denoncourti.

Distributional Changes of the Fishes of the Hatchie River System in Western Tennessee and Northern Mississippi

Abstract Ichthyofaunal surveys of many river systems in the southeastern USA have been completed. However, subsequent surveys of these systems have been limited to searches for species of special interest and studies of anthropogenic effects on portions of river systems. Thus, little is known about temporal variation at the system level. The Hatchie River System (HRS) in northern Mississippi and western Tennessee was intensively surveyed in 1972 and again in 2001–2003. Data from 272 collections (130 localities) were used to determine patterns of species distribution and any changes that may have occurred in the past 30 years. Dispersal from neighboring systems, introductions, ecological effects, and sampling techniques appear to have influenced the distribution and composition of the known HRS species. Of the 107 known HRS species, 15 were collected for the first time since 1975, six were only collected before 1975, and 40 changed in the collection frequency between sampling prior to 1975 and in 1975 to the present. An intensive, system-wide survey was necessary to detect the changes in distribution and increase in the number of known species from the HRS.

Reproductive Success of Natural Populations of Hybrid Sunfish in Three Minnesota Lakes

Abstract Several investigators have demonstrated the ability of certain hybrid sunfish to reproduce in controlled situations. Three lakes in northern Minnesota that contained large numbers of natural sunfish hybrids were investigated to determine the extent of reproduction of these fish in natural environments. Presence of living embryos in nests guarded by male hybrids indicated a potentially significant amount of reproduction by the hybrids. A comparison of the distribution of the ratio of pectoral fin length to jaw length for the populations involved suggested that few, if any, second generation hybrids were present in the adult population. It is suggested that reduced vigor or the inability to compete with other sunfishes prevented these fish from becoming an integral part of the total sunfish population.

NEW TRICHOPTERA RECORDS FROM ARKANSAS AND MISSOURI

Abstract Analysis of about 69,000 Trichoptera from Arkansas and Missouri resulted in identification of six species previously unknown from Arkansas (i.e., Agraylea costello, Neotrichia collata, Orthotrichia curta, Oxyethira glasa, O. pescadori, Neureclipsis piersoni) and three species previously unknown from Missouri (i.e., Cheumatopsyche mollala, Hydroptila broweri, H. poirrieri). Of those species, Agraylea costello, Hydroptila poirrieri, Orthotrichia curta, Oxyethira pescadori, and Neureclipsis piersoni represent new records for the Interior Highlands. Males possibly representing Ceraclea enodis, not previously recorded from the Interior Highlands, were found in both states. An undescribed species of Neophylax (family Uenoidae) from Saline Co., AR, is discussed. Informative distributional information is provided for an additional 61 species known from the Interior Highlands.

Assessment of the Distribution of Ripistes parasita (Annelida: Clitellata: Naididae) in the Eastern United States and Canada

Abstract The non-native oligochaete Ripistes parasita (Schmidt) (Annelida: Clitellata: Naididae) has previously been reported from the northeastern United States and Mississippi. The objective of this study was to provide information regarding the spread of the invasive oligochaete within the past 32 years. We examined benthic invertebrate data from various biomonitoring projects conducted in several eastern states. Results show a significant range extension for this species.