Because of growing concern of habitat fragmentation and its adverse effects on salamander communities in Appalachian region, sympatric populations of ambystomatid salamanders A. opacum and A. maculatum were studied in Northeast Tennessee to address a number of questions: i) the extent of sexual size dimorphism (SSD) in both species, ii) what traits influence the dorsal skin pigmentation and how, iii) whether gender differences in developmental stability occur, and iv) the extent of phenotypic variation within each species. The findings of this study revealed SSD in both species of salamanders. The most parsimonious statistical model was developed that explained the influence of body mass, dorsal body area, and sex on development of dorsal white pigmentation in marbled salamanders. Data on asymmetry indicate that females are under more stress than males in marbled salamanders, while for spotted salamanders nonsignificant asymmetry is indicative of similar level of stress in both sexes. Data on coefficient of variation (CV) suggest stabilizing selection on optimal body size and mass in female marbled salamanders compared to males; however, for spotted salamanders CV indicates relatively similar selection pressure for body size and mass for both sexes.
","abstract_html":"<p>Because of growing concern of habitat fragmentation and its adverse effects on salamander communities in Appalachian region, sympatric populations of ambystomatid salamanders <em>A. opacum</em> and <em>A. maculatum</em> were studied in Northeast Tennessee to address a number of questions: i) the extent of sexual size dimorphism (SSD) in both species, ii) what traits influence the dorsal skin pigmentation and how, iii) whether gender differences in developmental stability occur, and iv) the extent of phenotypic variation within each species. The findings of this study revealed SSD in both species of salamanders. The most parsimonious statistical model was developed that explained the influence of body mass, dorsal body area, and sex on development of dorsal white pigmentation in marbled salamanders. Data on asymmetry indicate that females are under more stress than males in marbled salamanders, while for spotted salamanders nonsignificant asymmetry is indicative of similar level of stress in both sexes. Data on coefficient of variation (CV) suggest stabilizing selection on optimal body size and mass in female marbled salamanders compared to males; however, for spotted salamanders CV indicates relatively similar selection pressure for body size and mass for both sexes.</p>","abstract_has_math":false,"creators":["Pokhrel, Lok Raj"],"institution":null,"degree_name":"MS (Master of Science)","degree_level":"Thesis - unrestricted","degree_discipline":"Biology","degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2009,"date_issued":"2009-08-19T07:00:00Z","date_published":"2009-08-19T07:00:00Z","updated_at":"2026-07-24T02:20:55Z","subjects":["Ambystoma","phenotypic variation","sexual dimorphism","pigmentation","amphibian","Animal Sciences","Life Sciences","Zoology"],"languages":[],"rights":["Copyright by the authors."],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://dc.etsu.edu/etd/1784","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Pokhrel, Lok Raj"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2009-08-19T07:00:00Z"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biology"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Thesis - unrestricted"]},{"key":"thesis:degree_name","label":"Degree Name","values":["MS (Master of Science)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Ambystoma","phenotypic variation","sexual dimorphism","pigmentation","amphibian","Animal Sciences","Life Sciences","Zoology"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["Copyright by the authors."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://dc.etsu.edu/context/etd/article/3136/viewcontent/PokhrelL051909f.pdf","https://dc.etsu.edu/etd/1784"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Because of growing concern of habitat fragmentation and its adverse effects on salamander communities in Appalachian region, sympatric populations of ambystomatid salamanders A. opacum and A. maculatum were studied in Northeast Tennessee to address a number of questions: i) the extent of sexual size dimorphism (SSD) in both species, ii) what traits influence the dorsal skin pigmentation and how, iii) whether gender differences in developmental stability occur, and iv) the extent of phenotypic variation within each species. The findings of this study revealed SSD in both species of salamanders. The most parsimonious statistical model was developed that explained the influence of body mass, dorsal body area, and sex on development of dorsal white pigmentation in marbled salamanders. Data on asymmetry indicate that females are under more stress than males in marbled salamanders, while for spotted salamanders nonsignificant asymmetry is indicative of similar level of stress in both sexes. Data on coefficient of variation (CV) suggest stabilizing selection on optimal body size and mass in female marbled salamanders compared to males; however, for spotted salamanders CV indicates relatively similar selection pressure for body size and mass for both sexes.
"]},{"key":"dc:title","label":"Title","values":["Mapping the Dorsal Skin Pigmentation Patterns of Two Sympatric Populations of Ambystomatid Salamanders, Ambystoma opacum and A. maculatum from Northeast Tennessee."]}]}],"canonical_facts":{"dc:creator":["Pokhrel, Lok Raj"],"dc:date.issued":["2009-08-19T07:00:00Z"],"dc:description.abstract":["Because of growing concern of habitat fragmentation and its adverse effects on salamander communities in Appalachian region, sympatric populations of ambystomatid salamanders A. opacum and A. maculatum were studied in Northeast Tennessee to address a number of questions: i) the extent of sexual size dimorphism (SSD) in both species, ii) what traits influence the dorsal skin pigmentation and how, iii) whether gender differences in developmental stability occur, and iv) the extent of phenotypic variation within each species. The findings of this study revealed SSD in both species of salamanders. The most parsimonious statistical model was developed that explained the influence of body mass, dorsal body area, and sex on development of dorsal white pigmentation in marbled salamanders. Data on asymmetry indicate that females are under more stress than males in marbled salamanders, while for spotted salamanders nonsignificant asymmetry is indicative of similar level of stress in both sexes. Data on coefficient of variation (CV) suggest stabilizing selection on optimal body size and mass in female marbled salamanders compared to males; however, for spotted salamanders CV indicates relatively similar selection pressure for body size and mass for both sexes.
"],"dc:identifier":["https://dc.etsu.edu/context/etd/article/3136/viewcontent/PokhrelL051909f.pdf","https://dc.etsu.edu/etd/1784"],"dc:rights":["Copyright by the authors."],"dc:subject":["Ambystoma","phenotypic variation","sexual dimorphism","pigmentation","amphibian","Animal Sciences","Life Sciences","Zoology"],"dc:title":["Mapping the Dorsal Skin Pigmentation Patterns of Two Sympatric Populations of Ambystomatid Salamanders, Ambystoma opacum and A. maculatum from Northeast Tennessee."],"thesis:degree_discipline":["Biology"],"thesis:degree_level":["Thesis - unrestricted"],"thesis:degree_name":["MS (Master of Science)"]},"updated_at":"2026-07-24T02:20:55Z"}