Evolution of Stygofauna

Steve Cooper | Andy Austin | Michelle Guzik | Rachael King
Tessa Bradford | Kym Abrams

Within the arid Yilgarn Region of Western Australia there exists an extraordinary and, until recently, unknown array of subterranean aquatic (stygofauna) and terrestrial (troglofauna) animals associated with calcrete (carbonate) aquifers. We have recently shown that the calcrete aquifers are isolated systems, with extreme levels of species endemicity for aquatic beetles and crustaceans (Amphipoda, Isopoda and Bathynellacea).

The beetle fauna show a fascinating evolutionary pattern, with multiple calcretes containing 2-3 species in different size classes and cases of sympatric sister species, raising the possibility of their evolution by sympatric speciation. We are currently exploring this possibility and also studying the molecular evolution of genes involved in regressive evolution (e.g. loss of eyes) using the independently evolved subterranean beetles as a model system.

These calcrete ecosystems remain poorly understood; for example >80% of aquatic invertebrates are unidentified species and little is known about the dynamics of populations and their resilience to environmental perturbations. This limited knowledge of the fauna has become a significant issue for biodiversity conservation and the environmental review process for major resource projects, many of which rely on groundwater for their operations or carry out extensive dewatering or use calcrete as a resource. Further research on these aspects of the fauna are planned in future projects in collaboration with key researchers who are internationaly recognised for their contributions to groundwater biology.

	Modes of speciation in subterranean diving beetles from calcrete aquifers of central Western Australia		Systematics and biogeography of Australian subterranean freshwater Parabathynellidae (Crustacea: Bathynellacea)
	Diversity, evolution and population dynamics of stygofauna from the Yilgarn Region of central Western Australia		Systematics of Chiltoniidae (Amphipoda: Crustacea) in mound springs and calcrete aquifers of Western and South Australia
	Exploration of a new subterranean terrestrial ecosystem in the arid zone of Australia

Collaborators and Partners

Our researchers have strong collaborative links with Bill Humphreys (Western Australian Museum), Peter Hancock, Remko Leijs (Flinders University and South Australian Museum), Chris Watts (South Australian Museum), Stefano Taiti (Italy) and Joo-Lae Cho (South Korea).