Molecular phylogeny and biogeography of the Korean woodroaches Cryptocercus spp.

Phylogenetic relationships and biogeography of Northeast Asian Cryptocercus were inferred based on the DNA sequences of mitochondrial COII and 16S rRNA genes and nuclear 18S rRNA gene. The results suggest that two clades exist in Korean populations. The southwestern population (Cryptocercus from Jiri-san) was more closely related to the populations from Northeast China and eastern Russia than to all the other Korean Cryptocercus. According to molecular-based estimated divergence times, the divergence event occurred between Cryptocercus in Jiri-san, Northeast China and eastern Russia and those in the remaining South Korea during the Miocene (7.5-17.4 Myr ago), and then the divergence event between Cryptocercus in Jiri-san and those in Northeast China and eastern Russia occurred 0.8-1.9 Myr ago. In the Korean Peninsula, Jiri-san is located in the most southwestern region among the high mountains surveyed. The location is the farthest from Northeast China and eastern Russia among sampling localities in South Korea. Thus, it was unexpected that the southwestern populations are more closely related to those from Northeast China and eastern Russia rather than to the other Korean Cryptocercus. Based on Korean topography and estimated divergence times, possible scenarios are proposed for the current geographical distribution of Korean Cryptocercus.