Faunal exchange between Asia and Australia in the Tertiary as evidenced by recent butterflies

Based on a cladistic study of the genus Taractrocera and of the Taractrocera group of genera (Lepidoptera: Hesperiidae) it is concluded that in the evolution of the genus and of the group the crossing of the water barrier between Asia and Australia in both directions played an important part. In view of the differentiation between and within the genera at least part of the crossings cannot be of recent age but must date back to the Tertiary. The evolution of Taratrocera and its allies is discussed in relation to the geological evolution of the area. It is concluded that the first dispersal event in Taractrocera, from Australia to Asia, occurred not later than 10–12 Ma. The early differentiation of the group of genera may have taken place on island arcs now embedded in the Papuan Region from where some taxa dispersed to Australia and from there to Asia, and more recently, directly to Asia.