Evolution and diversity of Cyphophthalmi (Arachnida, Opiliones): Systematics and biogeography in New Zealand, across Gondwana, and worldwide

The goal of this dissertation is to develop the suborder Cyphophthalmi (Arachnida, Opiliones) as a model system for exploring biogeographical patterns at all spatial scales. Cyphophthalmi, also known as "mite harvestmen," are tiny leaf-litter and cave-dwelling daddy long-legs that are found in tropical and temperate humid areas worldwide. Each species in this group has a very restricted range, with most known from only a handful of localities. In addition, Cyphophthalmi are only known from land that is continental in origin, with no specimens known from islands that were formed de novo in mid-ocean. Taken together, these distributional patterns indicate that these animals have limited dispersal capabilities, making them outstanding candidates for historical biogeographical research. Using a combination of molecular and morphological data sets, I have explored the phylogeny of this group at all spatial scales, beginning with a global study including members of five of the six families of Cyphophthalmi. The monophyly of each family except the Laurasian Sironidae is confirmed, with biogeographical patterns corresponding to ancient tectonic rifting events. In a subsequent chapter I construct a phylogeny for the Temperate Gondwanan family Pettalidae, with representatives in Chile, South Africa, Madagascar, Sri Lanka, Australia, and New Zealand, and find several stable clades corresponding to modern landmasses. In several parts of the world the described diversity of Cyphophthalmi is strikingly high, and I have explored putative radiations in New Zealand and the Balkan Peninsula using a phylogenetic approach. I also investigate the intraspecific phylogeography of a particularly widespread species in New Zealand, Aoraki denticulata. Taxonomy for this group has not received extensive attention until the past decade; in this dissertation I revise the described genera from New Zealand and Queensland (Australia) and erect a new genus of New Zealand Cyphophthalmi. Finally, I describe a new species of Rakaia from Otago, New Zealand. Cyphophthalmi are shown to be an excellent system for addressing biogeographical questions at local, regional, and global scales.