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dc.contributor.advisorAustin, Jeremy-
dc.contributor.authorHugall, Andrew Forrest-
dc.description.abstractCamaenid land snails are the subject of this study, the object of which is the historical biogeography of eastern Australia, with phylogenetic diversity the modus operandi. The thesis is structured around two main sources of information: the distribution data and the phylogenetic data, and makes an empirical contribution to both. Beyond this are inferences on the major evolutionary processes governing biodiversity as seen from this large – or macroecological – perspective. The first chapter introduces three themes: the mosaic of forests along eastern Australia, the camaenid snails and macroecological methods. It also introduces the distribution dataset, issues concerning analysis and provides a picture of the region and the snails’ place in this – the mise en scène. Having stated the case for the need for molecular phylogenetic data, the second chapter describes in detail the gathering and assembly of such data into a comprehensive phylogeny for the snails. In doing so it makes a substantial contribution to the higher taxonomy of the whole group, and to the methodology of supermatrix ‘tree-of-life’ phylogenetics. The results suggest that the camaenids stem from Oligo-Miocene Laurasian immigration. Relictual endemics indicate that many ancestral lineages were in place before the major decline of the mesic forest realm. Polyphyly of many genera highlight the repeated radiation of shell forms and that the higher taxonomy was unacceptable. The results provide the basis of a new generic framework. The subsequent chapters use the resources now provided to investigate historical and environmental influences on biodiversity at different phylogenetic and spatial scales: within a single species in one region; a clade (genus) spread across regions; the entire biota. Chapter 3 investigates in detail a single species in a single well studied region, the Wet Tropics rainforests. This multifaceted approach, combining spatially explicit paleoclimatological models and comparative phylogeography, provides a powerful approach to locating historical refugia, highlighting the role of landscape, ecology and history in shaping population structure and hence the foundations of allopatric speciation. The next chapter expands this to encompass the whole clade – the Sphaerospira lineage – spanning the ‘mesotherm archipelago’ of mesic forest along eastern Australia. A trans-species phylogeny is combined with bioclimatic modelling, spatial mapping of phylogenetic diversity and lineage diversification analyses to reveal the profound link between the intra-specific phylogeography and the underlying inter-specific phylogeny. The final chapter (5) represents a culmination of the ideas and data introduced in the previous sections to: i) explore methods of incorporating phylogenetic information into biogeography and macroecology; ii) provide a detailed and comprehensive biogeography of eastern Australia; iii) speculate upon major patterns and processes in biodiversity: speciation, accumulation, retention, extinction. However, it does come to some broad conclusions: that diversification proceeds from peripheral isolation, is driven by environmental gradients; that diversity is governed by environment through extinction, with ecosystem turnover due to the late Tertiary aridification.en
dc.subjectmolecular ecologyen
dc.subjectland snailen
dc.titlePhylogeny and biogeography of the camaenid land snails of eastern Australiaen
dc.contributor.schoolSchool of Biological Sciencesen
dc.provenanceThis electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at:
dc.description.dissertationThesis (Ph.D.) -- University of Adelaide, School of Biological Sciences, 2017en
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