| This dissertation presents comprehensive systematic studies of Pristomyrmex. It consists of the following four chapters, which encompass (1) a survey of the diversity and systematics of Pristomyrmex ; (2) the phylogeny of Pristomyrmex; (3) its biogeography and evolution; and (4) the position of Pristomyrmex in the tribe Myrmecinini, as inferred from a phylogenetic analysis of the tribe.; In Chapter One, the entire Pristomyrmex fauna is fully investigated, and a key to the worldwide Pristomyrmex species is provided. Line drawings and SEM photographs are used to show the diversity and identifying characters of all Pristomyrmex species, including the worker, queen, ergatoid queen and male. Twenty-one new species are described. Eleven new species-level synonyms are proposed. Two species are newly elevated from former infraspecific status.; In Chapter Two, a phylogenetic analysis of all known 52 species suggests that the punctatus group contains the most primitive characters, and that in Pristomyrmex, (the punctatus group + the cribrarius group) represents an evolutionary lineage. The quadridens group represents a second lineage. The trispinosus group represents a third lineage. The levigatus group, together with the profundus group, constitutes a fourth lineage. The umbripennis group is the fifth lineage identified.; In Chapter Three, the historical biogeography of Pristomyrmex is explored through a phylogenetic analysis. This analysis suggests that, after originating from the Oriental region and then successfully dispersing to Africa, Mauritius, Australia and temperate Asia, Pristomyrmex achieved its present distribution. The present distributional patterns of Pristomyrmex were probably formed between 10 and 40 million years ago, or more recently. In addition, I propose that the Oriental Pristomyrmex fauna can be separated from the Australian fauna by a biogeographic boundary drawn between New Guinea and Australia. Finally, three members are proposed as endangered species.; In Chapter Four, the phylogenetic relationships of the four genera ( Acanthomyrmex, Myrmecina, Perissomyrmex, and Pristomyrmex ) of the tribe Myrmecinini are analyzed using PAUP, and the evolution of several important characters in Myrmecinini is traced using MacClade. Results suggest that Perissomyrmex originated from the ancestor of Pristomyrmex, and (Pristomyrmex + Perissomyrmex ) originated from the ancestor of Myrmecina. |
