A tree of sticks: dispersal and speciation of Australian Phasmatodea

Abstract

This thesis investigates the diversity, taxonomy, and evolutionary history of Australian phasmids using an integrative taxonomic approach, combining morphological, molecular, and biogeographical analyses. Chapter 1 provides a background on Phasmatodea and establishes a foundation for understanding the thesis. Chapter 2 offers a comprehensive revision of the genus Austrocarausius revealing nine new species, increasing the number in the genus to eleven. My results suggest that the diversification of Austrocarausius occurred over the past ~25-70 Ma and was linked to rainforest fragmentation in northern Queensland. The examination of the genus Anchiale in Chapter 3 results in the description of two new species, the reinstatement of one species, and the updating of known species boundaries. Chapter 4 offers a broader study of the Australian Lonchodini tribe, including Austrocarausius, Denhama, and Hyrtacus. The results reveal significant cryptic diversity in the group and supports the reinstatement of Marcenia and two previously synonymised species. Five new Marcenia species are also described. Phylogenetic analyses using mitochondrial and nuclear genes provide insights into Lonchodini diversification, particularly in response to increasing aridification over the past ~5-15 Ma. With integrative taxonomy and evolutionary timescale estimates, this thesis refines the taxonomy of Australian phasmids and provides new insights into their diversification, dispersal, and ecological adaptation.