The molecular systematics of Leiopotherapon unicolor (Günther, 1859): testing for cryptic speciation in Australia’s most widespread freshwater fish

Leiopotherapon unicolor is the most widespread freshwater fish species in Australia. A comprehensive allozyme and mitochondrial DNA 16S rRNA data set was assembled from 141 specimens of L. unicolor collected Australia-wide in order to test for cryptic speciation in this far-ranging species. Surprisingly, little genetic diversity was observed within L. unicolor and provided no evidence for the existence of cryptic species within this lineage. In contrast, a small sample set of L. aheneus used as the outgroup showed two highly divergent haplotypes strongly suggestive of cryptic speciation. L. unicolor has a number of ecological and life history attributes that may explain the lack of significant genetic divergence over substantial geographical distances. The occurrence of other widespread fish and crustacean species that also display only limited genetic diversity indicate that climate conditions more favourable to dispersal across central and northern Australia than is suggested by the extent of present-day aridity have occurred in the relatively recent geological past.

Bust of Alfred Deakin

This replica was made by Peter J. Morley from an original, by Web Gilbert, held by Melbourne Grammar School. Similar busts are held in the Library of the Parliament of Victoria, Parliament House (Canberra) and the Avenue of Prime Ministers in Ballarat. The busts were originally commissioned in 1922 by Alfred Deakins daughter, Mrs. Ivy Brookes.

Ivy Brookes presenting the Alfred Deakin papers to the National Library of Australia

Alfred Deakin's daughters seated in the foreground from left to right: Lady Vera White, Lady Stella Rivett and Ivy Brookes; Professor J. La Nauze (Deakin's biographer) is the standing gentleman, second from the left; the Hon. Robert G. Menzies is standing on the far right next to the desk