Phylogeography of the E ast A sian polymitarcyid mayfly genus E phoron ( E phemeroptera: P olymitarcyidae): a comparative analysis of molecular and ecological characteristics

In E ast A sia, the mayfly genus E phoron , a member of P olymitarcyidae, has been classified into three species: E phoron eophilum , E phoron limnobium , and E phoron shigae . Using the nuclear histone 3 and internal transcribed spacer 1 and mitochondrial 16 S r RNA and cytochrome c oxidase subunit I genes, we investigated the phylogenetic relationships of these mayflies. E phoron limnobium formed polyphyletic relationships within the clade of J apanese E . shigae and shared identical sequences with E . shigae , suggesting that E . limnobium is a synonym of E . shigae . Monophyly was supported in E . eophilum , K orean E . shigae , and E . limnobium  +  J apanese E . shigae . E phoron eophilum that co‐occurs with the other E phoron species has several peculiar traits in its adult swarming period and karyotype. This suggests that both pre‐ and post‐zygotic isolation are likely to have promoted speciation of these E phoron species. The divergence between E . eophilum and E . shigae would have occurred from the late L ate M iocene to E arly P liocene according to the B ayesian relaxed clock model calibrated using the mitochondrial substitution rate. The area currently inhabited by E . eophilum emerged above sea level some 0.1 M ya, suggesting that E . eophilum moved into this area from other areas that it occupied prior to this time. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society , 2013, 109 , 181–202.