Moore, Alexandria C.
Taxonomic and Morphological Evaluation of an Endemic Freshwater Gastropod.
Degree: MS, Ecology and Evolutionary Biology, 2013, University of Michigan
Mollusks are the second most diverse animal phylum in terms of number of described species and nonmarine mollusks are among the most imperiled groups of invertebrate taxa. In particular, freshwater and terrestrial mollusks have the highest number of documented extinctions of any major taxonomic group. Such extinctions are not without their consequences as nonmarine mollusks provide several ecosystem functions including regulation of rates of primary production, decomposition, water clarity, and nutrient cycling. Given this and the level of fluidity found within freshwater mollusk taxonomy, the proper identification of potentially endangered species is an issue of great concern.
The present study evaluates the taxonomic status of a small freshwater snail endemic to southeastern Oregon within the Owyhee River, referred to here as the Owyhee physa. Molecular, morphological, and environmental analyses were employed using specimens from both a sister species, “Physa gyrina”, and another species with similar morphology and habitat conditions as the Owyhee physa, Physa zionis. Molecular analyses also incorporated supplemental sequences from other physid species to assess the status of the Owyhee physa within the Physidae family. Genetic analyses at the cytochrome oxidase 1 and ITS-1 and ITS-2 gene regions indicate that the Owyhee physa is a phylogenetically distinct species with “Physa gyrina” as its sister species. Using theoretical morphological techniques, the shell morphology of each of the three physid species was qualitatively described. Qualitative analyses of these morphological descriptions along with the phylogenetic tree and environmental data for each species suggests that convergent evolution played an important role in influencing shell morphology within this taxonomic group. The present work has provided additional
information about the current status of Physidae species richness, but additional studies must be done to both broaden and deepen our knowledge of freshwater gastropod diversity.
Advisors/Committee Members: Duda, Thomas F. (advisor), Burch, John B. (committee member), Dick, Christopher W. (committee member), Pappas, Janice L. (committee member).
Subjects/Keywords: Mollusks, Physa, Taxonomy, Conservation, Morphology, Evolution; Science - Conservation Genetics
student at the University of Michigan) produced an unpublished doctoral… …were sequenced through the
University of Michigan DNA Sequencing Core using the original… …sequencing and supplied
to the University of Michigan sequencing facility at one-micromolar… …the Family Physidae (Basommatophora: Pulmonata). PhD
thesis, University of… …Michigan.
Wethington, C. and Guralnick, R. 2004. Are population of physids from different hot…
to Zotero / EndNote / Reference
APA (6th Edition):
Moore, A. C. (2013). Taxonomic and Morphological Evaluation of an Endemic Freshwater Gastropod. (Masters Thesis). University of Michigan. Retrieved from http://hdl.handle.net/2027.42/98979
Chicago Manual of Style (16th Edition):
Moore, Alexandria C. “Taxonomic and Morphological Evaluation of an Endemic Freshwater Gastropod.” 2013. Masters Thesis, University of Michigan. Accessed April 15, 2021.
MLA Handbook (7th Edition):
Moore, Alexandria C. “Taxonomic and Morphological Evaluation of an Endemic Freshwater Gastropod.” 2013. Web. 15 Apr 2021.
Moore AC. Taxonomic and Morphological Evaluation of an Endemic Freshwater Gastropod. [Internet] [Masters thesis]. University of Michigan; 2013. [cited 2021 Apr 15].
Available from: http://hdl.handle.net/2027.42/98979.
Council of Science Editors:
Moore AC. Taxonomic and Morphological Evaluation of an Endemic Freshwater Gastropod. [Masters Thesis]. University of Michigan; 2013. Available from: http://hdl.handle.net/2027.42/98979