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Stephanie A. Clark

    Stephanie A. Clark

    We must begin by acknowledging Dr. Jack Burch of the Museum of Zoology, University of Michigan. The vast majority of the information contained within this workbook is directly attributed to his extraordinary contributions in malacology... more
    We must begin by acknowledging Dr. Jack Burch of the Museum of Zoology, University of Michigan. The vast majority of the information contained within this workbook is directly attributed to his extraordinary contributions in malacology spanning nearly a half century. His exceptional breadth of knowledge of mollusks has enabled him to synthesize and provide priceless volumes of not only freshwater, but terrestrial mollusks, as well. A feat few, if any malacologist could accomplish today. Dr. Burch is also very generous with his time and work. Shell images Shell images unless otherwise noted are drawn primarily from Burch’s forthcoming
    Abstract: Terrestrial gastropods are important herbivores, prey, and as decomposers in woodlands of the Midwestern USA. Vegetation structure and composition are dynamic and may influence gastropod abundance and distribution, but... more
    Abstract: Terrestrial gastropods are important herbivores, prey, and as decomposers in woodlands of the Midwestern USA. Vegetation structure and composition are dynamic and may influence gastropod abundance and distribution, but relationships among gastropod communities and environmental variables are understudied. We burned three treatment units in an oak-hickory woodland during 2004 and conducted additional burns on two of those treatment units, one in 2014 and the other in 2015. In May and August 2016, we collected leaf litter containing gastropods from transects within these three burn treatment units and used 19 environmental variables that were potentially important to gastropods. Environmental variables were associated with herbaceous and woody vegetation, ground cover, physiography, and burn history. We identified 14 species of gastropods at the study site. No significant environmental models were found for gastropod abundance, richness, effective number of species (based on Shannon entropy), or effective number of species (based on the Gini-Simpson index). Statistically significant associations among gastropods and environmental variables were seen in three species. Euchemotrema leaii was associated with areas having low coverage of shrubs and other perennials, and abundant leaf litter, whereas Neohelix alleni was positively associated with leaf litter and was abundant in areas with low total cover. Glyphyalinia indentata was associated with higher elevation transects, may be impacted by recent burning, and was found in areas with greater amounts of grasses and vines.
    The Great Artesian Basin (GAB) of Australia underlies some of the driest parts of South Australia and Queensland and feeds numerous freshwater springs. Prominent and endangered components of the GAB spring community are snails of the... more
    The Great Artesian Basin (GAB) of Australia underlies some of the driest parts of South Australia and Queensland and feeds numerous freshwater springs. Prominent and endangered components of the GAB spring community are snails of the family Hydrobiidae. This paper examines the evolutionary relationships of the entire hydrobiid fauna associated with the GAB, and includes appropriate non-GAB species to place the GAB fauna in a broader phylogenetic context. The Queensland genus Jardinella is a focus of this paper, providing a fine scale examination of relationships between spring supergroups in the northeastern regions of the GAB. Maximum parsimony and Bayesian analyses performed on 16S, CO1, and combined sequence data from 40 hydrobiid taxa found four major clades of Australian taxa. The analysis revealed that at least three separate colonization events of the GAB spring fauna have occurred. Two of these are represented by considerable radiations, (1) Jardinella to the north and east ...
    To re-evaluate the relationships of the major bivalve lineages, we amassed detailed morpho-anatomical, ultrastructural and molecular sequence data for a targeted selection of exemplar bivalves spanning the phylogenetic diversity of the... more
    To re-evaluate the relationships of the major bivalve lineages, we amassed detailed morpho-anatomical, ultrastructural and molecular sequence data for a targeted selection of exemplar bivalves spanning the phylogenetic diversity of the class. We included molecular data for 103 bivalve species (up to five markers) and also analysed a subset of taxa with four additional nuclear protein-encoding genes. Novel as well as historically employed morphological characters were explored, and we systematically disassembled widely used descriptors such as gill and stomach ‘types’. Phylogenetic analyses, conducted using parsimony direct optimisation and probabilistic methods on static alignments (maximum likelihood and Bayesian inference) of the molecular data, both alone and in combination with morphological characters, offer a robust test of bivalve relationships. A calibrated phylogeny also provided insights into the tempo of bivalve evolution. Finally, an analysis of the informativeness of mo...
    The freshwater snail genus Fluvidona (Gastropoda, Caenogastropoda, Rissooidea, Hydrobiidae) is reapprasied and described using anatomical, shell, radula and opercular characters. Five species, three of them new, are described, being... more
    The freshwater snail genus Fluvidona (Gastropoda, Caenogastropoda, Rissooidea, Hydrobiidae) is reapprasied and described using anatomical, shell, radula and opercular characters. Five species, three of them new, are described, being differentiated using anatomical, shell and opercular character states. A sixth species, similar to the Fluvidona species, is described and is tentatively assigned to the genus Austropyrgus Cotton. All six species live in northern New South Wales and southern Queensland and all are from single localities or very restricted areas. All species live in small streams, although one was found aestivating in soil in the bed of a small dry creek. The new species placed in Austropyrgus, from the Bunya Mountains, Queensland, is widely separated from putative congeners that are found in southern New South Wales and other parts of south-eastern Australia.
    We examined the patelliform snails of the subfamily Lancinae, endemic to northwestern North America, to test whether morphological variation correlated with genetic and anatomical differences. Molecular analyses using cox1, 16S,... more
    We examined the patelliform snails of the subfamily Lancinae, endemic to northwestern North America, to test whether morphological variation correlated with genetic and anatomical differences. Molecular analyses using cox1, 16S, calmodulin intron, and 28S rDNA partial sequences and anatomical data supported recognition of four species in three genera. The relationships of lancines within Lymnaeidae are not yet well-resolved. The federally endangered Banbury Springs lanx is described as a new genus and species, Idaholanx fresti, confirming its distinctiveness and narrow endemicity.
    ABSTRACT
    The taxonomy of the genus Juga (Semisulcospiridae), as in many freshwater mollusks, poses several challenges. Only a few species have been studied genetically or anatomically. We analyzed a portion of the cox1 gene for 103 specimens,... more
    The taxonomy of the genus Juga (Semisulcospiridae), as in many freshwater mollusks, poses several challenges. Only a few species have been studied genetically or anatomically. We analyzed a portion of the cox1 gene for 103 specimens, emphasizing the upper Sac-ramento e Pit system but including all recognizable named species and subspecies from across the geographic range. The rrnL gene was also sequenced for 35 specimens and showed similar patterns, but was less informative. None of the three extant subgenera appear monophyletic and additional clades of similar rank exist. Several currently recognized taxa such as Juga silicula, Juga nigrina, Juga hemphilli, Juga bulbosa, and Juga acutifilosa are polyphyletic. In contrast to previous classifications, the clades found in our study correspond closely to geography. Some geographically and genetically distinctive populations do not fit in any named species.
    Research Interests: