Biogeographic history of an Australian freshwater shrimp, Paratya australiensis (Atyidae): the role life history transition in phylogeographic diversification

Abstract

The widespread distribution of the freshwater shrimp Paratya australiensis in eastern Australia suggests that populations of this species have been connected in the past. Amphidromy is ancestral in these shrimps, although many extant populations are known to be restricted to freshwater habitats. In this study, we used a fragment of the cytochrome c oxidase I mitochondrial DNA (mtDNA) gene to examine diversity within P. australiensis and to assess the relative importance of amphidromy in its evolutionary history. We hypothesized that if transitions from an amphidromous to a freshwater life history were important, then we would find a number of divergent lineages restricted to single or groups of nearby drainages. Alternatively, if amphidromy was maintained within the species historically, we expected to find lineages distributed over many drainages. We assumed that the only way for divergence to occur within amphidromous lineages was if dispersal was limited to between nearby estuaries, which, during arid periods in the earth's history, became isolated from one another. We found nine highly divergent mtDNA lineages, estimated to have diverged from one another in the late Miocene/early Pliocene, when the climate was more arid than at present. Despite this, the geographic distribution of lineages and haplotypes within lineages did not support the notion of a stepping-stone model of dispersal between estuaries. We conclude that the extensive divergence has most likely arisen through a number of independent amphidromy-freshwater life history transitions, rather than via historical isolation of amphidromy populations. We also found evidence for extensive movement between coastal and inland drainages, supporting the notion that secondary contact between lineages may have occurred as a result of drainage rearrangements. Finally, our data indicate that P. australiensis is likely a complex of cryptic species, some of which are widely distributed, and others geographically restricted.

High gene flow due to pelagic larval dispersal among South Pacific archipelagos in two amphidromous gastropods (Neritomorpha: Neritidae)

“…In these geologically older and more stable lotic environments, selection against dispersal from the natal habitat should be unopposed. Consistent with this prediction, phylogeographic studies of amphidromous Atyid shrimp (Page et al, 2005(Page et al, , 2007Cook et al, 2006) and Galaxiid fishes (Waters and Wallis, 2001) from Australia and New Zealand show evidence for multiple losses of amphidromy, with widespread basal amphidromous lineages giving rise to multiple freshwater lineages that are restricted to watersheds. Within the Neritidae, the only genus with benthic development in fresh water (Theodoxus) occurs in Eurasia (Bunje and Lindberg, 2007), further supporting the prediction that the relative stability of continental riverine habitats supports the loss of planktonic larvae.…”

Amphidromy in shrimps: a life cycle between rivers and the sea

“…A phylogenetic analysis of the genus by Page et al (2005) supports the hypothesis of amphidromy as ancestral in this group. Cook et al (2006) found that Paratya australiensis from eastern Australia, in which some populations are restricted to freshwater while others are amphidromous, is probably a complex of cryptic species. The phylogeographic analysis of these authors indicates that amphidromic populations have colo-nized various stream systems, giving rise to repeated evolution from amphidromic coastal populations to strictly freshwater populations (or cryptic species) of Paratya, presumably with some form of ALD.…”

“…Amphidromous (ELD) species generally have broader geographic ranges than non-amphidromous species in the same taxon. Gene flow among populations of the same species tends to be greater in amphidromous or presumed (small egg size) amphidromous species (Page et al, 2005(Page et al, , 2008Cook et al, 2006;Mashiko & Shy, 2008). For example, Mashiko & Shy (2008) studied four species of Macrobrachium in the western Pacific.…”

Molecular evidence for mid-Pleistocene divergence of populations of three freshwater amphipod species (Talitroidea : Chiltoniidae) on Kangaroo Island, South Australia, with a new spring-associated genus and species

“…It is possible that through one or more of these climatic oscillation events, chiltoniid amphipods were stranded in disparate remnant freshwater areas -perhaps as marine/estuarine species that adapted to freshwater environments or as freshwater or terrestrial species adapting to contraction and fragmentation of freshwater habitats. Similar Pliocene-Pleistocene divergences have been recorded for southern Australian frogs and froglets, freshwater fish species, and invertebrates such as the isopod Phreatomerus latipes (Chilton 1922) and the freshwater shrimp Paratya australiensis (Kemp 1917) (Cook et al 2006;Edwards et al 2007;Symula et al 2008;Faulks et al 2010;Guzik et al 2012).…”