Start Date: Aug 15, 2007
End Date: Oct 10, 2011
Generality of Phylogenetic Approaches: Comparative phylogenetics is inherently long-term, hierarchical and complex and resides at the core of all approaches outlined in this project (9). Research is largely empirical and hypothesis driven, involving articulation, integration and analyses of comparative morphological and molecular databases. The revolution of phylogenetic systematics has transformed systematic parasitiology and its linkage to animal health, medicine and biodiversity research. Development of phylogenetically informative databases is cumulative, typically involving extensive and detailed description and revision as a first-level process to provide a comparable array of structural, meristic and other characters, and phylogenetically informative sequences from nuclear and mitochondrial loci, across both higher-level and species-level taxa. Hierarchical approaches- e.g., sequential top-down research programs, have proven to be particularly effective beginning with resolution of relationships for higher taxa that form the foundations for eventual elucidation of species-level phylogeny. Robust phylogenies for parasitic groups (the focus of Objective 1) provide the basis for analyses of cospeciation, historical biogeography and phylogeography (the focus of Objective 2) applied to elucidating patterns of host-parasite association, geographic distribution and disease. Phylogenetic studies will address crown clades of nematodes among Strongylida represented by the superfamilies Metastrongyloidea, and Trichostrongyloidea. Investigations will emphasize resolution of relationships at levels extending from putative monophyletic taxa within each major taxon to the level of species and populations as outlined in detail in subsequent sections. Systematic analyses will follow established methodology as exemplified in recent studies. Represented is an integrated program linking research (Objectives 1 & 2) and the U.S. National Parasite Collection (Objective 3). Integration is defined by the following model: (Obj. 1) Specimens with definitive identifications based on morphology from field-based research, including vouchers and type materials, are linked to frozen tissue collections and DNA products as a basis for comprehensive taxonomic revision, description (diagnostic characters), and phylogenetic analyses of specific parasite groups; (Obj. 2) Results of phylogenetic analyses are used as a foundation for historical explorations of biogeography and coevolution and definition of faunal structure over time; and (Obj. 3) Primary specimens, host information, and spatial and temporal data are archived and databased in the USNPC, with results of analyses, diagnostic capacity, images, etc., being integrated in synoptic summaries for parasite and host associations. These archives further summarize the results of phylogenetic, phylogeographic and historical studies.