Population ecology, ecophysiology, phylogenetics and taxonomy of the threatened western sawshelled turtle, 'Myuchelys bellii', from the Murray-Darling Basin of Australia

Abstract

Resolving the evolutionary relationships among species remains an important focus of biodiversity conservation, and is key for assessing and reversing global trends in biodiversity decline. International and national systems of biodiversity protection rely on good taxonomic knowledge at the species level and good information about their biology and life history traits, knowledge that is often incomplete and therefore an impediment to effective conservation action. Over half of the world's turtle species are considered threatened, yet the taxonomy of many turtles species is not adequately resolved, and much work needs to be done to understand relationships between closely related taxa, and for uncovering cryptic species and genera. The 'Myuchelys' genus is a little known group of Australian freshwater turtles. The focal species, the vulnerable western sawshelled turtle 'Myuchelys bellii' located in the Murray-Darling Basin in eastern Australia, is both taxonomically confused and poorly studied. ... In summary, the molecular and morphological evidence of this research do not support the presence of a cryptic species within 'M. bellii'. Consequently, the three major populations of 'M. bellii' from the Gwydir, Namoi and Border Rivers need to be managed as a single species entity. The relatively small size and extent of each population also means that 'M. bellii' is certainly worthy of its national vulnerable status and international endangered status. Of particular concern for 'M. bellii', is the long term conservation of the isolated Queensland population. This thesis provides a clear foundation and insight into the conservation priorities for 'Myuchelys' species, and in particular, for the threatened western sawshelled turtle 'M. bellii'.