Doctoral Thesis
Snails in salt; taxonomy, phylogeography and physiology of the Australian salt lake gastropod genus Coxiella (Tomichiidae)
Doctor of Philosophy (PhD), Murdoch University
2023
Abstract
Australian salt lakes support a diverse and mostly endemic suite of aquatic invertebrates which are poorly understood but possess novel ecological and evolutionary origins including the halophilic gastropods within Coxiella Smith, 1894 (Truncatelloidea; Tomichiidae). Coxiella is plagued with taxonomic issues that are currently hindering the capacity to understand this groups biology. This includes being unable to determine their conservation status despite Coxiella exhibiting a vulnerability to the shorter, more saline hydroperiods developing across southern-Australian salt lakes due to climate change. This thesis aimed to (I) summarise the literature on Australian salt lake invertebrates; (II) conduct a phylogenetic analysis of the Tomichiidae including a taxonomic assessment of Coxiella; (III); investigate the evolutionary history of Coxiella and (IV) experimentally test the salinity tolerances of different Coxiella species. The main findings were (1) south-western Australia is one of the most biodiverse areas of salt lake invertebrates globally; (2) insufficient taxonomic frameworks are impeding researchers ability to study salt lake invertebrates; (3) Australian Coxiella together with southern African Tomichia and South American Idiopyrgus form the Gondwana family Tomichiidae; (4) Coxiella comprises four clades that each may merit recognition as distinct genera and although the current taxonomy was largely supported, an additional six undescribed species were identified; (6); Coxiella diversification commenced in the mid to late-Miocene, followed by speciation during the late-Miocene/Pliocene, and subsequent divergence within species during the Pliocene/Pleistocene; (7) Coxiella species possess some of the highest salinity tolerances for any gastropod globally, though tolerances varied between species. This thesis has greatly improved our understanding of the diversity and biology of Coxiella and can serve as the conservation framework for this unique group of gastropods.
Details
- Title
- Snails in salt; taxonomy, phylogeography and physiology of the Australian salt lake gastropod genus Coxiella (Tomichiidae)
- Authors/Creators
- Angus D Lawrie
- Contributors
- Jennifer Chaplin (Supervisor) - Murdoch University, School of Environmental and Conservation SciencesPeter Spencer (Supervisor) - Murdoch University, Centre for Terrestrial Ecosystem Science and SustainabilityAdrian Pinder (Supervisor)
- Awarding Institution
- Murdoch University; Doctor of Philosophy (PhD)
- Identifiers
- 991005609169407891
- Murdoch Affiliation
- Centre for Sustainable Aquatic Ecosystems; School of Environmental and Conservation Sciences
- Resource Type
- Doctoral Thesis
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