title: Autoecological approaches to resolve subjective taxonomic divisions within arcellacea.
abstract: Arcellacea (testate lobose amoebae) are important lacustrine environmental indicators that have been used in paleoclimatic reconstructions, assessing the effectiveness of mine tailings pond reclamation projects and for studying the effects of land use change in rural, industrial and urban settings. Recognition of ecophenotypically significant infra-specific 'strains' within arcellacean assemblages has the potential to enhance the utility of the group in characterizing contemporary and paleoenvironments. We present a novel approach which employs statistical tools to investigate the environmental and taxonomic significance of proposed strains. We test this approach on two identified strains: Difflugia protaeiformis Lamarck strain 'acuminata' (DPA), characterized by fine grained agglutination, and Difflugia protaeiformis Lamarck strain 'claviformis' (DPC), characterized by coarse grained agglutination. Redundancy analysis indicated that both organisms are associated with similar environmental variables. No relationship was observed between substrate particle size and abundance of DPC, indicating that DPC has a size preference for xenosomes during test construction. Thus DPC should not be designated as a distinct strain but rather form a species complex with DPA. This study elucidates the need to justify the designation of strains based on their autecology in addition to morphological stability.
authors.affiliation: Department of Earth Sciences and Ottawa-Carleton Geoscience Centre, Carleton University, Ottawa K1S 5B6, Ontario, Canada. Electronic address: andrewmacumber@cmail.carleton.ca.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Macumber
authors.affiliation: Department of Earth Sciences and Ottawa-Carleton Geoscience Centre, Carleton University, Ottawa K1S 5B6, Ontario, Canada.
authors.forename: R Timothy
authors.initials: RT
authors.lastname: Patterson
authors.affiliation: School of Geography, Archaeology and Palaeoecology, Queen's University, Belfast BT7 1NN, United Kingdom.
authors.forename: Helen M
authors.initials: HM
authors.lastname: Roe
authors.affiliation: School of Geography and Earth Sciences, McMaster University, Hamilton L8S 4K1, Ontario, Canada.
authors.forename: Eduard G
authors.initials: EG
authors.lastname: Reinhardt
authors.affiliation: Department of Earth Sciences and Ottawa-Carleton Geoscience Centre, Carleton University, Ottawa K1S 5B6, Ontario, Canada.
authors.forename: Lisa A
authors.initials: LA
authors.lastname: Neville
authors.affiliation: School of Geography, University of Leeds, Leeds BT7 1NN, United Kingdom.
authors.forename: Graeme T
authors.initials: GT
authors.lastname: Swindles
mesh_terms: D000656:Amoeba / Q000145:classification* / Q000235:genetics / Q000648:ultrastructure; D044822:Biodiversity; D002170:Canada; D016000:Cluster Analysis; D017753:Ecosystem; D004784:Environmental Monitoring; D010802:Phylogeny
keywords: Arcellacea; ecophenotype; multivariate analysis; strain; testate amoebae; thecamoebian.