Diversification of low dispersal crustaceans through mountain uplift: a case study of Gammarus (Amphipoda: Gammaridae) with descriptions of four novel species

Lineages with low dispersal ability are geographically restricted. We used freshwater Gammarus to test this hypothesis. Sequences of two mitochondrial (cytochrome c oxidase subunit I and 16S) and two nuclear (28S and cytosolic heat‐shock protein) genes were obtained for seven species distributed in 28 localities along the Lüliang and Taihang mountains in China. Phylogenetic analyses showed that Gammarus species were grouped into two clades, one from the Lüliang range and the other from the Taihang range. Each clade was further divided into three or four species, showing a congruent pattern with geographical vicariance. Divergence time estimation indicated that the split between the two clades coincided with the uplift of the Taihang Mountains at the boundary of Oligocene/Miocene. Most speciation events may have been driven by massive uplifting of the Lüliang and Taihang mountains from the late Miocene to early Pliocene. Additionally, four new species are described: G ammarus incoercitus sp. nov. , G ammarus benignus sp. nov. , G ammarus monticellus sp. nov. , and G ammarus pisinnus sp. nov. The new species are compared with related species in this area and a key to these species is provided. © 2014 The Linnean Society of London