Speciation on the continent in the Miocene? Multiple overseas dispersal to the island? –Reexamination of diversification process of Kurixalus eiffingeri (Boettger, 1895) (Amphibia: Rhacophoridae)–

Abstract

To clarify the genetic differentiation of a small tree frog species, Kurixalus eiffingeri complex from the Yaeyama Islands and Taiwan, phylogenetic analyses were conducted using the partial mitochondrial DNA sequences. K. eiffingeri was divided into four major lineages: Ishigaki, Iriomote, Central Taiwan, and Northern Taiwan. The Ishigaki and Iriomote lineages were combined as the Ryukyu clade, which is sister to the Northern Taiwan lineage, and these together were outgrouped by the Central Taiwan lineage. The expansion of Kurixalus into Taiwan is estimated to have occurred twice, the first 4.75–6.70 million years ago by the common ancestor of the K. eiffingeri species group, and the second in the Late Pleistocene (0.33–1.11 million years ago) by the ancestor of the Kurixalus idiootocus species group. The K. eiffingeri species group diverged into Kurixalus wangi and Kurixalus berylliniris, and Central and Northern Taiwan lineages through the uplift of the mountain range of Taiwan, and then the Northern Taiwan lineage spread to the Yaeyama Islands (including Ishigaki Island, Iriomote Island and son on) during the Early Pleistocene through a land bridge. The divergence time between the Ishigaki and Iriomote lineages was much older than the age of the Last Glacial Maximum (LGM). Thus, their genetic differentiation was maintained even the two islands were connected during the LGM.