Three new subterranean diving beetles (Coleoptera: Dytiscidae) from the Yeelirrie groundwater calcretes, Western Australia, and their distribution between several calcrete deposits including a potential mine site

WA Museum Records and Supplements | Updated 8 years ago

ABSTRACT – Three new species of stygobitic Dytiscidae are described from groundwater calcretes in the Yilgarn region of Western Australia; Paroster angustus sp. nov., Limbodessus yeelirrieensis sp. nov. and Limbodessus odysseus sp. nov. As is the case in most Yilgarn stygobitic beetles the three species are eyeless, apterous, uniformly light testaceous and do not overlap in body length. All three species are short range endemics with their distribution restricted to a series of geologically discontinuous groundwater calcrete deposits occupying a linear extent of approximately 60 kilometres on Yeelirrie Station in the upper reaches of the Carey Palaeoriver system. The sympatric occurrence of the three species at one of the calcrete deposits is consistent with speciation, differentiation in body-size, and distribution patterns observed at numerous other calcretes in the Yilgarn region. Limbodessus odysseus has a wider distribution range than the other two species within the Yeelirrie groundwater system, possibly related to its smaller body size which may facilitate its dispersal and colonisation of interstitial or sub-karstic calcrete habitats. DNA sequencing established that the two Limbodessus species from Yeelirirrie are more closely related to species from calcretes in adjacent palaeochannels than to each other. A proposed uranium mine and associated aquifer dewatering activities would impact 42% of the core stygofauna habitat and 60% of the recorded distribution range of Paroster angustus sp. nov. and Limbodessus yeelirrieensis sp. nov. The impact of this amount of habitat removal and watertable lowering on the long term viability of the surviving populations of these two dytiscid species, and their associated stygofauna community, is unknown and cannot be predicted with any confidence.