{"id":{"repo_id":"uiuc","oai_identifier":"oai:www.ideals.illinois.edu:2142/32086"},"canonical_url":"https://search.dev.ndltd.org/etd/uiuc/oai:www.ideals.illinois.edu:2142/32086","repository":{"repo_id":"uiuc","name":"University of Illinois - Urbana-Champaign","base_url":"https://www.ideals.illinois.edu/oai-pmh"},"display":{"title":"Morphometrics, molecular ecology and multivariate environmental niche define the evolutionary history of the Western Rattlesnake (Crotalus viridis) complex","abstract":"Species are the currency of biodiversity and an accurate recognition of their status is a scientific necessity, particularly given the onset of the Anthropocene (the most recent biodiversity crisis). Yet, concept-based species approaches are contentious whereas those more deterministic work against the fluidity of speciation itself. This conceptual gap can be bridged through a comprehensive assessment of the nine subspecies comprising the historically enigmatic Western Rattlesnake (Crotalus viridis) complex, one that employs three disparate datasets. First, mitochondrial DNA (mtDNA) sequence data were used to derive a Bayesian phylogenetic hypothesis that revealed two well- supported lineages, each with subspecies as distinct clades. Second, morphological data relating to head shape were analyzed using Geometric Morphometric (GM) methodology to again reveal two distinct lineages, each composed of subspecies that differ significantly in shape, yet with confounding factors that obscure evolutionary relationships. Finally, GIS-based macroecological variables gathered from museum specimens again demonstrated significant subspecific niches, suggesting the potential for ecological speciation within the complex. The three datasets (molecular, morphological, and ecological) were coalesced using supertree methodology to derive a single hypothesis that supported two distinct lineages but with obscured subspecific relationships. They were also utilized in crosshair classification tests that quantified ‘historical’ and ‘recent’ non-exchangeability among lineages and subspecies (i.e., if these entities were distinct amongst themselves and worthy of taxonomic recognition). In this regard, sufficient genetic, ecological and morphological non-exchangeability exists between lineages and among subspecies to warrant species designations for six of 9 Western Rattlesnake subspecies, with the remaining three retained at subspecific status. These efforts thus represent a comprehensive and contemporary perspective of Western Rattlesnake biodiversity, and shed light on a group that has proven elusive across two centuries of scientific inquiry.","abstract_html":"Species are the currency of biodiversity and an accurate recognition of their status is a scientific necessity, particularly given the onset of the Anthropocene (the most recent biodiversity crisis). Yet, concept-based species approaches are contentious whereas those more deterministic work against the fluidity of speciation itself. This conceptual gap can be bridged through a comprehensive assessment of the nine subspecies comprising the historically enigmatic Western Rattlesnake (Crotalus viridis) complex, one that employs three disparate datasets. First, mitochondrial DNA (mtDNA) sequence data were used to derive a Bayesian phylogenetic hypothesis that revealed two well- supported lineages, each with subspecies as distinct clades. Second, morphological data relating to head shape were analyzed using Geometric Morphometric (GM) methodology to again reveal two distinct lineages, each composed of subspecies that differ significantly in shape, yet with confounding factors that obscure evolutionary relationships. Finally, GIS-based macroecological variables gathered from museum specimens again demonstrated significant subspecific niches, suggesting the potential for ecological speciation within the complex. The three datasets (molecular, morphological, and ecological) were coalesced using supertree methodology to derive a single hypothesis that supported two distinct lineages but with obscured subspecific relationships. They were also utilized in crosshair classification tests that quantified ‘historical’ and ‘recent’ non-exchangeability among lineages and subspecies (i.e., if these entities were distinct amongst themselves and worthy of taxonomic recognition). In this regard, sufficient genetic, ecological and morphological non-exchangeability exists between lineages and among subspecies to warrant species designations for six of 9 Western Rattlesnake subspecies, with the remaining three retained at subspecific status. These efforts thus represent a comprehensive and contemporary perspective of Western Rattlesnake biodiversity, and shed light on a group that has proven elusive across two centuries of scientific inquiry.","abstract_has_math":false,"creators":["Davis, Mark"],"institution":"University of Illinois at Urbana-Champaign","degree_name":"Ph.D.","degree_level":"Dissertation","degree_discipline":"Natural Res & Env Sciences","degree_department":null,"school":null,"contributors":["Douglas, Michael E.","Douglas, Marlis R","Douglas, Marlise","Paige, Ken N.","Weatherhead, Patrick J."],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2012,"date_issued":"2012-06-27T21:32:17Z","date_published":"2012-06-27T21:32:17Z","updated_at":"2026-07-22T22:25:30Z","subjects":["Western Rattlesnake, Molecular Phylogenetics","Geometric Morphometrics","Multivariate Ecological Niche","Speciation","Taxonomy"],"languages":["en"],"rights":["Copyright 2012 Mark Allen Davis"],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/2142/32086","outbound_label":"Handle","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor","label":"Contributor","values":["Douglas, Michael E.","Douglas, Marlis R","Douglas, Marlise","Paige, Ken N.","Weatherhead, Patrick J."]},{"key":"dc:creator","label":"Author","values":["Davis, Mark"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2012-06-27T21:32:17Z","2014-06-28T10:00:29Z","2012-05"]},{"key":"dc:type","label":"Dc Type","values":["text"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Natural Res & Env Sciences"]},{"key":"thesis:degree_level","label":"Degree Level","values":["Dissertation"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph.D."]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Illinois at Urbana-Champaign"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Western Rattlesnake, Molecular Phylogenetics","Geometric Morphometrics","Multivariate Ecological Niche","Speciation","Taxonomy"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]},{"key":"dc:rights","label":"Dc Rights","values":["Copyright 2012 Mark Allen Davis"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["http://hdl.handle.net/2142/32086"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Species are the currency of biodiversity and an accurate recognition of their status is a scientific necessity, particularly given the onset of the Anthropocene (the most recent biodiversity crisis). Yet, concept-based species approaches are contentious whereas those more deterministic work against the fluidity of speciation itself. This conceptual gap can be bridged through a comprehensive assessment of the nine subspecies comprising the historically enigmatic Western Rattlesnake (Crotalus viridis) complex, one that employs three disparate datasets. First, mitochondrial DNA (mtDNA) sequence data were used to derive a Bayesian phylogenetic hypothesis that revealed two well- supported lineages, each with subspecies as distinct clades. Second, morphological data relating to head shape were analyzed using Geometric Morphometric (GM) methodology to again reveal two distinct lineages, each composed of subspecies that differ significantly in shape, yet with confounding factors that obscure evolutionary relationships. Finally, GIS-based macroecological variables gathered from museum specimens again demonstrated significant subspecific niches, suggesting the potential for ecological speciation within the complex. The three datasets (molecular, morphological, and ecological) were coalesced using supertree methodology to derive a single hypothesis that supported two distinct lineages but with obscured subspecific relationships. They were also utilized in crosshair classification tests that quantified ‘historical’ and ‘recent’ non-exchangeability among lineages and subspecies (i.e., if these entities were distinct amongst themselves and worthy of taxonomic recognition). In this regard, sufficient genetic, ecological and morphological non-exchangeability exists between lineages and among subspecies to warrant species designations for six of 9 Western Rattlesnake subspecies, with the remaining three retained at subspecific status. These efforts thus represent a comprehensive and contemporary perspective of Western Rattlesnake biodiversity, and shed light on a group that has proven elusive across two centuries of scientific inquiry.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2012-04-05T17:47:28Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 Davis_Mark.docx: 14140506 bytes, checksum: cf2fce00c2773a1b27a9ddb200fde88d (MD5) Davis_Mark.pdf: 1654811 bytes, checksum: 00790dce5b8933117a238ce5301bca95 (MD5)","Made available in DSpace on 2012-06-27T21:32:17Z (GMT). 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Yet, concept-based species approaches are contentious whereas those more deterministic work against the fluidity of speciation itself. This conceptual gap can be bridged through a comprehensive assessment of the nine subspecies comprising the historically enigmatic Western Rattlesnake (Crotalus viridis) complex, one that employs three disparate datasets. First, mitochondrial DNA (mtDNA) sequence data were used to derive a Bayesian phylogenetic hypothesis that revealed two well- supported lineages, each with subspecies as distinct clades. Second, morphological data relating to head shape were analyzed using Geometric Morphometric (GM) methodology to again reveal two distinct lineages, each composed of subspecies that differ significantly in shape, yet with confounding factors that obscure evolutionary relationships. Finally, GIS-based macroecological variables gathered from museum specimens again demonstrated significant subspecific niches, suggesting the potential for ecological speciation within the complex. The three datasets (molecular, morphological, and ecological) were coalesced using supertree methodology to derive a single hypothesis that supported two distinct lineages but with obscured subspecific relationships. They were also utilized in crosshair classification tests that quantified ‘historical’ and ‘recent’ non-exchangeability among lineages and subspecies (i.e., if these entities were distinct amongst themselves and worthy of taxonomic recognition). In this regard, sufficient genetic, ecological and morphological non-exchangeability exists between lineages and among subspecies to warrant species designations for six of 9 Western Rattlesnake subspecies, with the remaining three retained at subspecific status. These efforts thus represent a comprehensive and contemporary perspective of Western Rattlesnake biodiversity, and shed light on a group that has proven elusive across two centuries of scientific inquiry.","Item withdrawn by Mark Zulauf (zulauf@illinois.edu) on 2012-04-05T17:47:28Z Item was in collections: University of Illinois Theses & Dissertations (ID: 1) No. of bitstreams: 2 Davis_Mark.docx: 14140506 bytes, checksum: cf2fce00c2773a1b27a9ddb200fde88d (MD5) Davis_Mark.pdf: 1654811 bytes, checksum: 00790dce5b8933117a238ce5301bca95 (MD5)","Made available in DSpace on 2012-06-27T21:32:17Z (GMT). No. of bitstreams: 3 Davis_Mark.pdf: 1655052 bytes, checksum: 239cf95851cdab5caa2d55e666fa9a4e (MD5) license.txt: 4059 bytes, checksum: 8be409dd6e474f12b65601a1f1b02fb0 (MD5) Davis_Mark.docx: 14150324 bytes, checksum: ac046ee8d1c02420c34fce21e44928b2 (MD5)","Item marked as restricted to the 'Administrator' Group (id=1) by William Ingram (wingram2@illinois.edu) on 2012-06-27T21:32:52Z Item is restricted until 2014-06-27T21:32:23Z","Item reinstated by Sarah Shreeves (sshreeve@illinois.edu) on 2014-06-28T10:00:29Z Item was in collections: Dissertations and Theses by Prairie Research Institute Graduate Students (ID: 814) Dissertations and Theses - Natural Resources and Environmental Sciences (ID: 671) Graduate Theses and Dissertations at Illinois (ID: 204) No. of bitstreams: 3 Davis_Mark.pdf: 1655052 bytes, checksum: 239cf95851cdab5caa2d55e666fa9a4e (MD5) license.txt: 4059 bytes, checksum: 8be409dd6e474f12b65601a1f1b02fb0 (MD5) Davis_Mark.docx: 14150324 bytes, checksum: ac046ee8d1c02420c34fce21e44928b2 (MD5)","Item released from any restrictions by Sarah Shreeves (sshreeve@illinois.edu) on 2014-06-28T10:00:29Z"],"dc:identifier":["http://hdl.handle.net/2142/32086"],"dc:language":["en"],"dc:rights":["Copyright 2012 Mark Allen Davis"],"dc:subject":["Western Rattlesnake, Molecular Phylogenetics","Geometric Morphometrics","Multivariate Ecological Niche","Speciation","Taxonomy"],"dc:title":["Morphometrics, molecular ecology and multivariate environmental niche define the evolutionary history of the Western Rattlesnake (Crotalus viridis) complex"],"dc:type":["text"],"thesis:degree_discipline":["Natural Res & Env Sciences"],"thesis:degree_level":["Dissertation"],"thesis:degree_name":["Ph.D."],"thesis:institution_name":["University of Illinois at Urbana-Champaign"]},"updated_at":"2026-07-22T22:25:30Z"}