Flying with the birds? Recent large‐area dispersal of four Australian Limnadopsis species (Crustacea: Branchiopoda: Spinicaudata)

Abstract

Temporary water bodies are important freshwater habitats in the arid zone of Australia. They harbor a distinct fauna and provide important feeding and breeding grounds for water birds. This paper assesses, on the basis of haplotype networks, analyses of molecular variation and relaxed molecular clock divergence time estimates, the phylogeographic history, and population structure of four common temporary water species of the Australian endemic clam shrimp taxon Limnadopsis in eastern and central Australia (an area of >1,350,000 km2). Mitochondrial cytochrome c oxidase subunit I sequences of 413 individuals and a subset of 63 nuclear internal transcribed spacer 2 sequences were analyzed. Genetic differentiation was observed between populations inhabiting southeastern and central Australia and those inhabiting the northern Lake Eyre Basin and Western Australia. However, over large parts of the study area and across river drainage systems in southeastern and central Australia (the Murray–Darling Basin, Bulloo River, and southern Lake Eyre Basin), no evidence of population subdivision was observed in any of the four Limnadopsis species. This indicates recent gene flow across an area of ∼800,000 km2. This finding contrasts with patterns observed in other Australian arid zone taxa, particularly freshwater species, whose populations are often structured according to drainage systems. The lack of genetic differentiation within the area in question may be linked to the huge number of highly nomadic water birds that potentially disperse the resting eggs of Limnadopsis among temporary water bodies. Genetically undifferentiated populations on a large geographic scale contrast starkly with findings for many other large branchiopods in other parts of the world, where pronounced genetic structure is often observed even in populations inhabiting pools separated by a few kilometers. Due to its divergent genetic lineages (up to 5.6% uncorrected p-distance) and the relaxed molecular clock divergence time estimates obtained, Limnadopsis parvispinus is assumed to have inhabited the Murray–Darling Basin continuously since the mid-Pliocene (∼4 million years ago). This means that suitable temporary water bodies would have existed in this area throughout the wet–dry cycles of the Pleistocene.

How do freshwater organisms cross the “dry ocean”? A review on passive dispersal and colonization processes with a special focus on temporary ponds

“…Actual genetic connectivity seems to be, as a rule, scarce to absent even among nearby conspecific populations (De Meester, 1996;Meglécz & Thiéry, 2005, Ketmaier et al, 2003, but see also Aguilar, 2011), or it is not possible to single out a coherent geographic pattern in the distribution of the genetic lineages (e.g. McCafferty et al, 2010), although a few exceptions are known (Schwentner et al, 2012).…”

Dancing around the pole: holarctic phylogeography of the Arctic fairy shrimp Branchinecta paludosa (Anostraca, Branchiopoda)

“…In accordance with Reniers et al (2013), model assumptions were set to constant population size with exponential prior distribution and strict molecular clock sequence divergence rates of 1.4 and 2.6% as boundary values, and inclusion of 2.0% for visualization. These boundary divergence rates were selected to represent a range previously shown to be appropriate (Schwentner et al, 2012;Reniers et al, 2013) based on previous estimates for decapod crustaceans (Knowlton et al, 1993;Knowlton & Weigt, 1998;Schubart et al, 1998). Each BEAST profile was run three independent times for 10 million generations, logging every 1,000, on the computer cluster (www.lifeportal.uio.no) at the University of Oslo.…”

Stochastic effects associated with resting egg banks lead to genetically differentiated active populations in large branchiopods from temporary water bodies

“…has little genetic variability (corresponds to Paralimnadia sp. A in Schwentner et al, 2015a), whereas Limnadopsis parvispinus (Henry, 1924) features numerous genetically well-differentiated haplotypes (Schwentner et al, 2012). L. parvispinus features two main lineages (possibly two separate species), which are genetically and geographically well separated (Schwentner et al, 2012).…”

“…A in Schwentner et al, 2015a), whereas Limnadopsis parvispinus (Henry, 1924) features numerous genetically well-differentiated haplotypes (Schwentner et al, 2012). L. parvispinus features two main lineages (possibly two separate species), which are genetically and geographically well separated (Schwentner et al, 2012). Our study is concerned only with individuals belonging to one of these lineages (termed 'Paroo' in Schwentner et al, 2012).…”

“…L. parvispinus features two main lineages (possibly two separate species), which are genetically and geographically well separated (Schwentner et al, 2012). Our study is concerned only with individuals belonging to one of these lineages (termed 'Paroo' in Schwentner et al, 2012).…”