Using molecular tools (e.g., the NADH subunit II mitochondrial gene), this study was the first to document the Brazilian cownose ray, Rhinoptera brasiliensis, within the northwestern Atlantic (NWA), and was the first study to examine population structure in R. brasiliensis within the NWA or northern Gulf of Mexico (GMX), revealing novel insights into the population biology of the animal and extending its range by nearly 1,500 km. This study also examined the sympatrically occurring American cownose ray, R. bonasus, and found population structure between the NWA and the GMX and the NWA and the southwestern Atlantic (SWA). High levels of population structuring were detected for R. bonasus between the NWA, the GMX, and the SWA, a finding which was not supported for R. brasiliensis. Low levels of genetic diversity for both species were found within the NWA and GMX, and high levels were found in the SWA, indicating a possible genetic difference between the three regions. The demographic history of both species was investigated using neutrality tests and indicated an evolutionarily recent population expansion.
","abstract_html":"<p>Using molecular tools (e.g., the NADH subunit II mitochondrial gene), this study was the first to document the Brazilian cownose ray, <em>Rhinoptera brasiliensis</em>, within the northwestern Atlantic (NWA), and was the first study to examine population structure in <em>R. brasiliensis </em>within the NWA or northern Gulf of Mexico (GMX), revealing novel insights into the population biology of the animal and extending its range by nearly 1,500 km. This study also examined the sympatrically occurring American cownose ray, <em>R. bonasus</em>, and found population structure between the NWA and the GMX and the NWA and the southwestern Atlantic (SWA). High levels of population structuring were detected for <em>R. bonasus </em>between the NWA, the GMX, and the SWA, a finding which was not supported for <em>R. brasiliensis</em>. Low levels of genetic diversity for both species were found within the NWA and GMX, and high levels were found in the SWA, indicating a possible genetic difference between the three regions. The demographic history of both species was investigated using neutrality tests and indicated an evolutionarily recent population expansion.</p>","abstract_has_math":false,"creators":["Weber, Helen"],"institution":null,"degree_name":"Master of Science (MS)","degree_level":"Masters Thesis","degree_discipline":null,"degree_department":null,"school":null,"contributors":["Dr. Nicole Phillips","Dr. Brian Kreiser","Dr. Christian Jones"],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2022,"date_issued":"2022-07-14T07:00:00Z","date_published":"2022-07-14T07:00:00Z","updated_at":"2026-07-24T05:45:40Z","subjects":["Rhinoptera bonusas","Rhinoptera brasiliensis","mtDNA","Population structure","Biology","Genetics","Population Biology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://aquila.usm.edu/masters_theses/934","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Dr. Nicole Phillips","Dr. Brian Kreiser","Dr. Christian Jones"]},{"key":"dc:creator","label":"Author","values":["Weber, Helen"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2023-08-01T07:00:00Z"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Masters Thesis"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science (MS)"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Rhinoptera bonusas","Rhinoptera brasiliensis","mtDNA","Population structure","Biology","Genetics","Population Biology"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://aquila.usm.edu/masters_theses/934"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Using molecular tools (e.g., the NADH subunit II mitochondrial gene), this study was the first to document the Brazilian cownose ray, Rhinoptera brasiliensis, within the northwestern Atlantic (NWA), and was the first study to examine population structure in R. brasiliensis within the NWA or northern Gulf of Mexico (GMX), revealing novel insights into the population biology of the animal and extending its range by nearly 1,500 km. This study also examined the sympatrically occurring American cownose ray, R. bonasus, and found population structure between the NWA and the GMX and the NWA and the southwestern Atlantic (SWA). High levels of population structuring were detected for R. bonasus between the NWA, the GMX, and the SWA, a finding which was not supported for R. brasiliensis. Low levels of genetic diversity for both species were found within the NWA and GMX, and high levels were found in the SWA, indicating a possible genetic difference between the three regions. The demographic history of both species was investigated using neutrality tests and indicated an evolutionarily recent population expansion.
"]},{"key":"dc:title","label":"Title","values":["POPULATION GENETICS OF COWNOSE RAYS, RHINOPTERA SPP. IN THE WESTERN ATLANTIC"]}]}],"canonical_facts":{"dc:contributor":["Dr. Nicole Phillips","Dr. Brian Kreiser","Dr. Christian Jones"],"dc:creator":["Weber, Helen"],"dc:date.available":["2023-08-01T07:00:00Z"],"dc:description.abstract":["Using molecular tools (e.g., the NADH subunit II mitochondrial gene), this study was the first to document the Brazilian cownose ray, Rhinoptera brasiliensis, within the northwestern Atlantic (NWA), and was the first study to examine population structure in R. brasiliensis within the NWA or northern Gulf of Mexico (GMX), revealing novel insights into the population biology of the animal and extending its range by nearly 1,500 km. This study also examined the sympatrically occurring American cownose ray, R. bonasus, and found population structure between the NWA and the GMX and the NWA and the southwestern Atlantic (SWA). High levels of population structuring were detected for R. bonasus between the NWA, the GMX, and the SWA, a finding which was not supported for R. brasiliensis. Low levels of genetic diversity for both species were found within the NWA and GMX, and high levels were found in the SWA, indicating a possible genetic difference between the three regions. The demographic history of both species was investigated using neutrality tests and indicated an evolutionarily recent population expansion.
"],"dc:identifier":["https://aquila.usm.edu/masters_theses/934"],"dc:subject":["Rhinoptera bonusas","Rhinoptera brasiliensis","mtDNA","Population structure","Biology","Genetics","Population Biology"],"dc:title":["POPULATION GENETICS OF COWNOSE RAYS, RHINOPTERA SPP. IN THE WESTERN ATLANTIC"],"thesis:degree_level":["Masters Thesis"],"thesis:degree_name":["Master of Science (MS)"]},"updated_at":"2026-07-24T05:45:40Z"}