Genetic differentiation and phylogeographical structure of the Brachionus calyciflorus complex in eastern China

Spatio-temporal patterns and processes of genetic differentiation in passively dispersing zooplankton are drawing much attention from both ecologists and evolutionary biologists. Two opposite phylogeographical scenarios have already been demonstrated in rotifers, which consist of high levels of genetic differentiation among populations even on small geographical scales on the one hand, and the traditionally known cosmopolitanism that is associated with high levels of gene flow and long-distance dispersal via diapausing stages on the other hand. Here we analyzed the population genetic structure and the phylogeography of the Brachionus calyciflorus species complex in eastern China. By screening a total of 318 individuals from ten locations along a 2320 km gradient and analyzing samples from two growing seasons, we aimed at focusing on both small- and large-scale patterns. We identified eight cryptic species, and verified species status of two of these by sexual reproduction tests. Samples...