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James D. Williams

Publications and source records attributed to James D. Williams.

At least 19 recordsLinked to original sources
USGS2023

Glacial vicariance and secondary contact shape demographic histories in a freshwater mussel species complex

Characterizing the mechanisms influencing the distribution of genetic variation in aquatic species can be difficult due to the dynamic nature of hydrological landscapes. In North America’s Central Highlands, a complex history of glacial dynamics, long-term isolation, and secondary contact have shaped genetic variation in aquatic species. Although the effects of glacial history have been demonstrated in many taxa, responses are often lineage- or species-specific and driven by organismal ecology. In this study, we reconstruct the evolutionary history of a freshwater mussel species complex using a suite of mitochondrial and nuclear loci to resolve taxonomic and demographic uncertainties. Our findings do not support Pleurobema rubrum as a valid species, which is proposed for listing as threatened under the U.S. Endangered Species Act. We synonymize P. rubrum under Pleurobema sintoxia —a common and widespread species found throughout the Mississippi River Basin. Further investigation of patterns of genetic variation in P. sintoxia identified a complex demographic history, including ancestral vicariance and secondary contact, within the Eastern Highlands. We hypothesize these patterns were shaped by ancestral vicariance driven by the formation of Lake Green and subsequent secondary contact after the last glacial maximum. Our inference aligns with demographic histories observed in other aquatic taxa in the region and mirrors patterns of genetic variation of a freshwater fish species ( Erimystax dissimilis ) confirmed to serve as a parasitic larval host for P. sintoxia . Our findings directly link species ecology to observed patterns of genetic variation and may have significant implications for future conservation and recovery actions of freshwater mussels.

Mississippi River basin↗
USGS2023

Molecular data validate historical and contemporary distributions of Pleurobema riddellii (Bivalvia: Unionidae) and help guide conservation and recovery efforts

Accurate taxonomic and distributional information are arguably the most critical components of conservation status assessments but can be greatly affected by misidentifications. The Louisiana pigtoe Pleurobema riddellii is a freshwater mussel proposed as threatened under the US Endangered Species Act. The species belongs to the tribe Pleurobemini, which includes multiple taxa that are inherently challenging to identify without molecular data. We validated historical and recent survey records of P. riddellii using a combination of DNA sequence data and morphological characters to provide a more definitive assessment of range and spatiotemporal trends in distribution. Our comprehensive assessment identified specimens collected from the Pearl drainage as P. riddellii , extending the species’ known range into eastern Gulf of Mexico drainages. Contemporary records were unavailable from the Trinity drainage; however, we designed novel minibarcode PCR primers and used historical DNA from a specimen collected in the late 1800s to confirm the historical presence of P. riddellii at the species’ type locality in the Trinity River near Dallas, Texas, USA. Our range-wide genetic diversity assessment provides strong support for 2 main geographic groups, the Ouachita and all remaining populations, with individuals from the Pearl and Trinity drainages sharing haplotypes with conspecifics from other drainages. Available data suggest P. riddellii has been extirpated from a significant portion of the historical range, including the entire Trinity drainage. Additional surveys in Lake Pontchartrain, Trinity, and other drainages in the eastern periphery of the species’ range may provide additional clarity on the distribution and conservation status of P. riddellii .

Endangered Species Research↗
USGS2021

Gulf Coast vicariance shapes phylogeographic history of a North American freshwater mussel species complex

Aim Freshwater mussels share habitat and are parasites of freshwater fishes during the larval life stage. Therefore, models of fish biogeography may also explain the historical biogeography of freshwater mussels. We tested this assumption using predictions of three biogeographic models constructed for northern Gulf of Mexico drainages on a freshwater mussel species complex. Specifically, we tested (1) if speciation was due to vicariant events of fluctuating sea levels that separated lineages east‐west of the Mobile Basin (Central Gulf Coast speciation hypothesis), (2) if the timing of divergences occurred 8.5–3.5 MYA (Gulf Coast allopatric speciation model) and (3) if diversification in Mississippi River populations was recent and for evidence of population increase consistent with range expansion into northern deglaciated regions (Pleistocene glaciation model). Location Eastern North America. Taxon Freshwater mussels (Bivalvia: Unionidae), Lampsilis teres and L. floridensis . Methods We collected 249 specimens from 73 localities across the group's distribution. We used three molecular markers (COI, NDI & ITSI) to conduct time calibrated Bayesian phylogenetic analyses, phylogeographic analyses (AMOVA & SAMOVA) and demographic analyses including Bayesian skyline plots. Results Lampsilis teres and L. floridensis are allopatric species whose distributions meet at the eastern edge of the Mobile Basin. Speciation was estimated to occur in the late Miocene. Populations from isolated river systems surrounding the Gulf of Mexico are almost all monophyletic. Mississippi drainage samples formed a shallow clade with recent diversification and showed evidence of recent population expansion. Main conclusions The historical biogeography of the L. teres species complex is broadly consistent with tested ichthyofaunal models. The timing of speciation and intraspecific divergences correspond to low sea‐level events suggesting that Gulf Coast sea‐level fluctuations are responsible for dispersal (sea‐level recession) and subsequent cladogenesis (sea‐level inundation). Consistent with numerous other freshwater studies, we found the Mobile Basin to be a suture zone, which may be due to the narrow, offshore continental shelf.

Journal of Biogeography↗
USGS2021

Review of the invasive Asian clam Corbicula spp. (Bivalvia: Cyrenidae) distribution in North America, 1924–2019

The bivalve Corbicula is one of the most successful aquatic mollusk invaders in the world. Since being intro­duced to North America from its native range in Asia, it has dispersed widely over a large portion of the continent from southern Canada to Panama. The first evidence of its introduc­tion in the Western Hemisphere was discovered in 1924 in British Columbia, Canada. A review of distribution records from natural history museums, scientific literature, Federal and State agencies, universities, and oral and written commu­nications with scientists has shown the continued dispersal of Corbicula in North America. Since the most recent compre­hensive review of its distribution information through the mid-1980s, Corbicula has been found in an additional 2 Canadian Provinces, 10 U.S. States and Puerto Rico, 9 Mexican States, Cuba, and Panama. The known distribution in North America now includes 47 U.S. States, District of Columbia, Puerto Rico, 3 Canadian Provinces, 16 Mexican States, Cuba, and Panama. Corbicula has been found in three of the Laurentian Great Lakes (Erie, Michigan, Superior) primarily associated with industrial warmwater effluent refugia. Problems associ­ated with Corbicula populations were widely realized not long after its arrival and included negative impacts to power generation, industrial water supply operations, and agricultural water conveyance. In natural settings, impacts on native mus­sels such as altering nutrient cycling, food webs, and sediment distribution dynamics have occurred. In past decades, control of established open water populations had not been a manage­ment priority. With a relatively recent interest in eradication of small, newly established populations, several attempts were made in the United States but were unsuccessful. Recent molecular genetic analyses provide evidence of multiple species and (or) genetically and morphologically distinguish­able “forms” in North America. However, the number and identification of Corbicula species in North America remain unresolved. It appears likely that more than one species of Corbicula has been introduced into U.S. waters.

Scientific Investigations Report↗
USGS2018

Integrative taxonomy resolves taxonomic uncertainty for freshwater mussels being considered for protection under the U.S. Endangered Species Act

Objectively delimiting species boundaries remains an important challenge in systematics and becomes urgent when unresolved taxonomy complicates conservation and recovery efforts. We examined species boundaries in the imperiled freshwater mussel genus Cyclonaias (Bivalvia: Unionidae) using morphometrics, molecular phylogenetics, and multispecies coalescent models to help guide pending conservation assessments and legislative decisions. Congruence across multiple lines of evidence indicated that current taxonomy overestimates diversity in the C. pustulosa species complex. The only genetically and morphologically diagnosable species in the C. pustulosa species complex were C. pustulosa and C. succissa and we consider C. aurea , C. houstonensis, C. mortoni , and C. refulgens to be synonyms of C. pustulosa . In contrast, all three species in the C. nodulata complex ( C. necki , C. nodulata , and C. petrina ) were genetically, geographically, and morphologically diagnosable. Our findings have important conservation and management implications, as three nominal species ( C. aurea , C. houstonensis , and C. petrina ) are being considered for protection under the Endangered Species Act.

Scientific Reports↗
USGS2018

Salinity tolerance among three freshwater mussels (Bivalvia: Unionidae) from Gulf Coastal Plain drainages

An important physiological constraint influencing distributions of coastal freshwater organisms is their tolerance for saline conditions. We experimentally evaluated salinity tolerance for three freshwater mussel species (Utterbackia imbecillis, Elliptio jayensis, and Glebula rotundata). Mussels were transferred abruptly from well water to one of five treatments (0 [control], 6, 12, 18 or 24 parts per thousand [ppt]). Utterbackia imbecillis survived on average about 2 days at treatments 6 ppt, while Elliptio jayensis survived slightly longer (about 4 days). Glebula rotundata was most tolerant to salinity, surviving as well at 6 and 12 ppt as it did in the control. Additionally, G. rotundata survived at higher salinities (18 and 24 ppt) for an average of 7–8 days. To our knowledge, this is the highest salinity tolerance ever reported for a unionid. The salinity tolerance of U. imbecillis may be influenced by its inability to completely seal its valves. The variation we found in salinity tolerance of these species corresponds with their distributions in the Gulf Coastal Plain drainages: U. imbecillis and E. jayensis are primarily found in strictly freshwater habitats whereas G. rotundata inhabits lower reaches of rivers closer to the coast. Stressors such as increased frequency and intensity of storms, sea level rise, drought, low flows, fossil fuel extraction, and municipal water withdrawals, among others, may increase salinities in freshwater ecosystems, potentially stressing mussels such as U. imbecillis and E. jayensis with low salinity tolerance.

Florida Scientist↗
USGS2017

A revised list of the freshwater mussels (Mollusca: Bivalvia: Unionida) of the United States and Canada

We present a revised list of freshwater mussels (order Unionida, families Margaritiferidae and Unionidae) of the United States and Canada, incorporating changes in nomenclature and systematic taxonomy since publication of the most recent checklist in 1998. We recognize a total of 298 species in 55 genera in the families Margaritiferidae (one genus, five species) and Unionidae (54 genera, 293 species). We propose one change in the Margaritiferidae: the placement of the formerly monotypic genus Cumberlandia in the synonymy of Margaritifera. In the Unionidae, we recognize three new genera, elevate four genera from synonymy, and place three previously recognized genera in synonymy. We recognize for the first time two species (one native and one nonindigenous) in the Asian genus Sinanodonta as occurring in North America. We recognize four new species and one subspecies and elevate 21 species from synonymy. We elevate 10 subspecies to species status and no longer recognize four subspecies. We change common names for five taxa, correct spelling for eight species, and correct the date of publication of original descriptions for four species.

Freshwater Mollusk Biology and Conservation↗
USGS2016

Early life history and spatiotemporal changes in distribution of the rediscovered Suwannee moccasinshell Medionidus walkeri (Bivalvia: Unionidae)

Accurate distribution data are critical to the development of conservation and management strategies for imperiled species, particularly for narrow endemics with life history traits that make them vulnerable to extinction. Medionidus walkeri is a rare freshwater mussel endemic to the Suwannee River Basin in southeastern North America. This species was rediscovered in 2012 after a 16-year hiatus between collections and is currently proposed for listing under the Endangered Species Act. Our study fills knowledge gaps regarding changes in distribution and early life history requirements of M . walkeri . Spatiotemporal changes in M. walkeri distribution were displayed using a conservation status assessment map incorporating metadata from 98 historical (1916–1999) and 401 recent (2000–2015) site surveys from museums and field notes representing records for 312 specimens. Recent surveys detected M . walkeri only in the middle Suwannee subbasin (n = 86, 22 locations) and lower Santa Fe subbasin (n = 2, 2 locations), and it appears the species may be extirpated from 67% of historically occupied 10-digit HUCs. In our laboratory experiments, M . walkeri successfully metamorphosed on Percina nigrofasciata (56.2% ± 8.9) and Etheostoma edwini (16.1% ± 7.9) but not on Trinectes maculatus , Lepomis marginatus , Notropis texanus , Noturus leptacanthus , Etheostoma fusiforme , or Gambusia holbrooki . We characterize M . walkeri as a lure-displaying host fish specialist and a long-term brooder (bradytictic), gravid from fall to early summer of the following year. The early life history and distribution data presented here provide the baseline framework for listing decisions and future efforts to conserve and recover the species.

Endangered Species Research↗
USGS2015

Generic reclassification and species boundaries in the rediscovered freshwater mussel ‘Quadrula’ mitchelli (Simpson in Dall, 1896)

The Central Texas endemic freshwater mussel, Quadrula mitchelli (Simpson in Dall, 1896), had been presumed extinct until relict populations were recently rediscovered. To help guide ongoing and future conservation efforts focused on Q . mitchelli we set out to resolve several uncertainties regarding its evolutionary history, specifically its unknown generic position and untested species boundaries. We designed a molecular matrix consisting of two loci ( cytochrome c oxidase subunit I and internal transcribed spacer I ) and 57 terminal taxa to test the generic position of Q . mitchelli using Bayesian inference and maximum likelihood phylogenetic reconstruction. We also employed two Bayesian species validation methods to test five a priori species models (i.e. hypotheses of species delimitation). Our study is the first to test the generic position of Q. mitchelli and we found robust support for its inclusion in the genus Fusconaia. Accordingly, we introduce the binomial, Fusconaia mitchelli comb. nov., to accurately represent the systematic position of the species. We resolved F. mitchelli individuals in two well supported and divergent clades that were generally distinguished as distinct species using Bayesian species validation methods, although alternative hypotheses of species delineation were also supported. Despite strong evidence of genetic isolation within F. mitchelli , we do not advocate for species-level status of the two clades as they are allopatrically distributed and no morphological, behavioral, or ecological characters are known to distinguish them. These results are discussed in the context of the systematics, distribution, and conservation of F. mitchelli .

Conservation Genetics↗
USGS2014

Freshwater mussels of Florida

An exhaustive guide to all aspects of the freshwater mussel fauna in Florida, Freshwater Mussels of Florida covers the ecology, biology, distribution, and conservation of the many species of bivalve mollusks in the Sunshine State. In the past three decades, researchers, the public, businesses that depend on wildlife, and policy makers have given more attention to the threatened natural diversity of the Southeast, including freshwater mussels. This compendium meets the increasingly urgent need to catalog this imperiled group of aquatic organisms in the United States.

Florida↗
USGS2007

Bigheaded carps : a biological synopsis and environmental risk assessment

The book is a detailed risk assessment and biological synopsis of the bigheaded carps of the genus Hypophthalmichthys, which includes the bighead, silver, and largescale silver carps. It summarizes the scientific literature describing their biology, ecology, uses, ecological effects, and risks to the environment. Includes information on taxonomy and distinguishing characteristics, hybrids, native and introduced ranges, temperature and salinity tolerances, fecundity, sexual maturity and mating behavior, spawning, early development, feeding habits, growth rate and longevity, response to physical stimuli, associated diseases and parasites, human uses, environmental effects, potential range, population control measures. Summarizes United States federal and state regulations, and assesses the risk posed by these species in the United States.

Book↗
USGS2004

Snakeheads ( Pisces, Channidae ): A biological synopsis and risk assessment

Snakeheads (family Channidae) are airbreathing freshwater fishes containing two genera, Channa with 26 species native to Asia, Malaysia, and Indonesia; and Parachanna with 3 species native to tropical Africa. Some snakeheads are small, reaching about 17 centimeters, but most are much larger, the largest reported to be 1.8 meters in length. All are considered thrust predators with most being piscivorous as adults. A few of the smaller snakeheads and colorful juveniles of some larger ones have been available to hobbyists through the aquarium fish trade. Several species are highly valued as food fishes within parts of their native ranges, especially in Asia where they are an important part of capture fisheries and aquaculture. Because of these uses by humans, introductions far beyond native ranges have occurred. One Asian snakehead has been established in Oahu, Hawaii, since before 1900. Another species was discovered established in southeastern Florida in 2000, and a third in a pond in Maryland in 2002. Others have been captured from natural waters of the United States without evidence of reproduction and likely represent released aquarium fishes. That snakeheads at or near sexual maturity were being sold alive in ethnic food markets raised fears that they could be introduced into novel waters. These concerns led to this study on the biology of snakeheads. A risk assessment is included that examines environmental and related aspects of snakehead introductions.

Circular↗
USGS2000

Prodigious polyphyly in imperilled freshwater pearly-mussels (Bivalvia: Unionidae): a phylogenetic test of species and generic designations

Unionid bivalves or freshwater pearly-mussels (Unionoidea: Unionidae) serve as an exemplary system for examining many of the problems facing systematists and conservation biologists today. Most of the species and genera were described in the late 1800s and early 1900s, but few phylogenetic studies have been conducted to test conventional views of species and classification. Pearly-mussels of Gulf Coastal drainages of the southeastern United States from the Escambia (southern Alabama to Florida) to the Suwannee Rivers (Florida) are a unique fauna comprised of approximately 100 species, with about 30 endemic to the region. In this study, mitochondrial cytochrome c oxidase subunit I and 16S rRNA gene sequences were used to test the monophyly and to estimate evolutionary relationships of five unionid species representing three different genera. The molecular phylogenies depict all three genera as polyphyletic. The prodigious polyphyly exhibited within unionids is due to incorrect notions of homology and false assumptions about missing anatomical data. In contrast, the molecular phylogeny provides evidence to support the recognition of all five unionid species as distinct evolutionary entities. Furthermore, molecular genealogical evidence supports the elevation of Quincuncina infucata (Conrad) of the Suwannee River to species level, for which Q. kleiniana (Lea) is available.

Geological Society Special Publication↗