Phylogeny and biogeography of wood-feeding cockroaches, genus Salganea Stal (Blaberidae : Panesthiinae), in Southeast Asia based on mitochondrial DNAsequences

Molecular phylogenetic relationships among 25 species of the wood-feeding c ockroach belonging to the genus Salganea Stal (Panesthiinae; Blaberidae) in Southeast Asia were analyzed based on the DNA sequence of the complete mit ochondrial cytochrome oxidase II (COH) gene. Most basal relationships among species of Salganea are poorly resolved by both neighbor-joining and nonwe ighted parsimony analyses, suggesting the possibility of a hard polytomy du e to a rapid and potentially simultaneous radiation early in the history of the genus. For more apical relationships, however, some interesting phylog enetic relationships were recognized. The monophyly of the two species grou ps, morio and foveolata, the former of which is distributed mainly in the S unda lands (containing the Malay Peninsula, Sumatra, Java, and Borneo), whe reas the latter is Sulawesi endemic, was strongly supported. Based on the i nferred phylogenetic patterns and recent palaeogeographic scenario for Sout heast Asia, it is suggested that a radiation of Salganea species occurred i n Southeast Asia presumably in the early Tertiary, and several barriers aga inst dispersal and gene flow, such as the formation of straits or high moun tains, have arisen from the middle Tertiary.