Systematics of the sympetrine dragonflies with emphasis on the phylogeny, taxonomy, and historical biogeography of the genus Sympetrum (Odonata: Libellulidae)

Within dragonflies and damselflies, the family Libellulidae is the largest. The systematics have never been analyzed in a phylogenetic context. Using both molecular and morphological characters, this dissertation is the first study to address the phylogenetics of the Libellulidae, the phylogenetics and historical biogeography of Sympetrum, and several species-level disputes within Sympetrum.;Phylogenetic study of the family Libellulidae revealed that many of the libellulid subfamilies (Brachydiplactinae, Leucorrhininae, Sympetrinae, Trameinae, Trithemistinae, and Urothemistinae) were paraphyletic. Wing venation characters were not useful for delineating the hierarchy of taxa within Libellulidae.;Study of the systematics of Sympetrum shows that S. navasi did not belong in the genus, but that the Hawaiian genus Nesogonia was a junior synonym of Sympetrum. Parsimony and Bayesian analyses recovered the same clades within Sympetrum, but the relationships between these groups were not strongly supported and the relationships between these clades remained unclear. Molecular dating placed the origin of Sympetrum in the Eocene. The biogeographic analyses were equivocal in placement of the origin of Sympetrum, but suggested that it likely arose in South America or eastern Asia. These analyses also showed that dispersal has played a critical role in shaping the distribution of Sympetrum.;Analysis of the species-level disputes within Sympetrum showed that S. nigrescens is a junior synonym of S. striolatum, and that S. occidentale is a junior synonym of S. semicinctum. Sympetrum signiferum is morphologically distinct from S. vicinum. Neither morphological nor molecular data were able to support or refute the status of S. janeae. The lower North American specimens of S. danae were genetically distinct from other S. danae and represent a separate species.