Trapped in desert springs : phylogeography of Australian desert spring snails

• AimWe investigate the phylogeographical history and determine the time-scaleof population divergence of hydrobiid freshwater snails (genus Trochidrobia)inhabiting groundwater springs in the Australian desert. We test the hypothesisthat divergence between geographically distinct snail populations occurredsimultaneously due to their isolation in hydrologically discrete spring systems, i.e.‘trapped in desert springs’.LocationGroundwater springs of the Great Artesian Basin (GAB) in centralAustralia.MethodsDNA sequence data from the mitochondrial cytochrome c oxidasesubunit I gene and the nuclear 28S and internal transcribed spacer rRNA geneswere used to reconstruct phylogenetic relationships within and among threespecies of Trochidrobia (Hydrobiidae): T. punicea (13 spring groups, n = 90),T. smithi (12 spring groups, n = 62) and T. minuta (2 spring groups, n = 4). Bayesian relaxed molecular clock analyses and approximate Bayesian computation were used to date lineage divergence and distinguish betweenalternative biogeographical scenarios.ResultsThe diversification of the three Trochidrobia species probably occurredbetween 2.54 and 9.3 Ma, prior to the formation of the springs c. 1 Ma.Intraspecific divergences within the two widespread species occurred after theformation and colonization of the springs. Coalescent modelling and molecularclock analyses supported a simultaneous radiation of five allopatric intraspecificsnail lineages within T. punicea (two lineages) and T. smithi (three lineages)across the GAB springs examined.Main conclusionsThe analyses support the ‘trapped in desert springs’hypothesis for the diversification of intraspecific lineages within the species T.punicea and T. smithi. This hypothesis suggests that the formation of desertsaround Lake Eyre in the early Pleistocene led to the hydrological isolation ofspring complexes in the GAB, resulting in significant molecular divergence, butno morphological divergence, of Trochidrobia snail populations.

Ämnesord

NATURVETENSKAP  -- Biologi -- Evolutionsbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Evolutionary Biology (hsv//eng)

NATURVETENSKAP  -- Biologi -- Genetik (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Genetics (hsv//eng)

NATURVETENSKAP  -- Biologi -- Zoologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Zoology (hsv//eng)

Nyckelord

Australia

aquatic invertebrates

comparative phylogeography

desert springs

freshwater snails

Great Artesian Basin

groundwater

landscape structure

Trochidrobia

Quaternary climate

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)