{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/44171"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/44171","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Tertiary marine prosobranchs: larval dispersal and geographic range","abstract":"Scheltema (1971, 1978) and others have proposed that extensive larval dispersal allows marine invertebrate species to establish great geographic ranges; several studies along a single margin of an ocean basin have supported this proposal (Shuto, 1975; Hansen, 1978). This study makes use of the fossil record to examine larval dispersal patterns on a larger geographic scale: across an entire ocean basin. Sixteen genera/subgenera of marine prosobranch gastropods were selected as the data base for the study. Eight of the genera were widely distributed (have fossil representatives on both the eastern and western margins of the North Atlantic Ocean) during the Neogene, and eight genera were narrowly distributed (fossil representatives were restricted to either the eastern or the western margin of the North Atlantic) during the Neogene. The larval forms of fossil species within each genus were inferred by examination of protoconch morphologies, according to guidelines established by modern biologists (Robertson, 1974; Shuto, 1975). The two groups were compared using statistical methods to test a null hypothesis of no relationship between geographic distribution and larval form. The results of the study reject the null hypothesis, and support the conclusion that Neogene marine prosobranch genera that are widely distributed across the North Atlantic Ocean basin are much more likely to exhibit planktotrophic larval development than are prosobranch genera that are geographically limited to a single margin of the ocean basin.","abstract_html":"Scheltema (1971, 1978) and others have proposed that extensive larval dispersal allows marine invertebrate species to establish great geographic ranges; several studies along a single margin of an ocean basin have supported this proposal (Shuto, 1975; Hansen, 1978). This study makes use of the fossil record to examine larval dispersal patterns on a larger geographic scale: across an entire ocean basin. Sixteen genera/subgenera of marine prosobranch gastropods were selected as the data base for the study. Eight of the genera were widely distributed (have fossil representatives on both the eastern and western margins of the North Atlantic Ocean) during the Neogene, and eight genera were narrowly distributed (fossil representatives were restricted to either the eastern or the western margin of the North Atlantic) during the Neogene. The larval forms of fossil species within each genus were inferred by examination of protoconch morphologies, according to guidelines established by modern biologists (Robertson, 1974; Shuto, 1975). The two groups were compared using statistical methods to test a null hypothesis of no relationship between geographic distribution and larval form. The results of the study reject the null hypothesis, and support the conclusion that Neogene marine prosobranch genera that are widely distributed across the North Atlantic Ocean basin are much more likely to exhibit planktotrophic larval development than are prosobranch genera that are geographically limited to a single margin of the ocean basin.","abstract_has_math":false,"creators":["Phillips, Susan Elizabeth Penny"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Geological Sciences","degree_department":"Geological Sciences","school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":1993,"date_issued":"1993","date_published":"1993","updated_at":"2026-07-22T22:19:29Z","subjects":[],"languages":["en"],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-08042009-040456"],"render_values":[{"text":"etd-08042009-040456","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/44171","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.department","label":"Department","values":["Geological Sciences"]},{"key":"dc:creator","label":"Author","values":["Phillips, Susan Elizabeth Penny"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T21:42:15Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T21:42:15Z","2009-08-04"]},{"key":"dc:date.issued","label":"Date","values":["1993"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.dcmitype","label":"Dc Type Dcmitype","values":["Text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Geological Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-08042009-040456"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/44171"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Scheltema (1971, 1978) and others have proposed that extensive larval dispersal allows marine invertebrate species to establish great geographic ranges; several studies along a single margin of an ocean basin have supported this proposal (Shuto, 1975; Hansen, 1978). This study makes use of the fossil record to examine larval dispersal patterns on a larger geographic scale: across an entire ocean basin. Sixteen genera/subgenera of marine prosobranch gastropods were selected as the data base for the study. Eight of the genera were widely distributed (have fossil representatives on both the eastern and western margins of the North Atlantic Ocean) during the Neogene, and eight genera were narrowly distributed (fossil representatives were restricted to either the eastern or the western margin of the North Atlantic) during the Neogene. The larval forms of fossil species within each genus were inferred by examination of protoconch morphologies, according to guidelines established by modern biologists (Robertson, 1974; Shuto, 1975). The two groups were compared using statistical methods to test a null hypothesis of no relationship between geographic distribution and larval form. The results of the study reject the null hypothesis, and support the conclusion that Neogene marine prosobranch genera that are widely distributed across the North Atlantic Ocean basin are much more likely to exhibit planktotrophic larval development than are prosobranch genera that are geographically limited to a single margin of the ocean basin."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:format.medium","label":"Dc Format Medium","values":["BTD"]},{"key":"dc:format.mimetype","label":"Dc Format Mimetype","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Tertiary marine prosobranchs: larval dispersal and geographic range"]}]}],"canonical_facts":{"dc:contributor.department":["Geological Sciences"],"dc:creator":["Phillips, Susan Elizabeth Penny"],"dc:date.accessioned":["2014-03-14T21:42:15Z"],"dc:date.available":["2014-03-14T21:42:15Z","2009-08-04"],"dc:date.issued":["1993"],"dc:description.abstract":["Scheltema (1971, 1978) and others have proposed that extensive larval dispersal allows marine invertebrate species to establish great geographic ranges; several studies along a single margin of an ocean basin have supported this proposal (Shuto, 1975; Hansen, 1978). This study makes use of the fossil record to examine larval dispersal patterns on a larger geographic scale: across an entire ocean basin. Sixteen genera/subgenera of marine prosobranch gastropods were selected as the data base for the study. Eight of the genera were widely distributed (have fossil representatives on both the eastern and western margins of the North Atlantic Ocean) during the Neogene, and eight genera were narrowly distributed (fossil representatives were restricted to either the eastern or the western margin of the North Atlantic) during the Neogene. The larval forms of fossil species within each genus were inferred by examination of protoconch morphologies, according to guidelines established by modern biologists (Robertson, 1974; Shuto, 1975). The two groups were compared using statistical methods to test a null hypothesis of no relationship between geographic distribution and larval form. The results of the study reject the null hypothesis, and support the conclusion that Neogene marine prosobranch genera that are widely distributed across the North Atlantic Ocean basin are much more likely to exhibit planktotrophic larval development than are prosobranch genera that are geographically limited to a single margin of the ocean basin."],"dc:description.degree":["Master of Science"],"dc:format.medium":["BTD"],"dc:format.mimetype":["application/pdf"],"dc:identifier.other":["etd-08042009-040456"],"dc:identifier.uri":["http://hdl.handle.net/10919/44171"],"dc:language.iso":["en"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:title":["Tertiary marine prosobranchs: larval dispersal and geographic range"],"dc:type":["Thesis"],"dc:type.dcmitype":["Text"],"thesis:degree_discipline":["Geological Sciences"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:19:29Z"}