title: Amphibians crossing the Bering Land Bridge: evidence from holarctic treefrogs (Hyla, Hylidae, Anura).
abstract: Based on an updated, time-calibrated phylogeny and applying biogeographical model testing and diversification analysis, we re-examined systematics and biogeography of the Holarctic treefrog genus Hyla with a focus on the East Asian species. We analyzed four mitochondrial genes (12S and 16S rRNA, tRNA(Leu), ND1) and one nuclear gene (POMC) for 192 samples representing 30 species of Hyla. Based on our results we suggest that H. ussuriensis is a synonym of H. japonica. Specimens from Sakhalin and Kunashir Islands might represent a cryptic species within H. japonica. We confirm earlier hypotheses that the genus Hyla originated during the Eocene to Early Oligocene and that Eurasian species originated from two independent dispersal events from North America via the Bering Land Bridge. Middle Eocene to Oligocene dispersal gave rise to the most recent common ancestor of the West Palearctic H. arborea-group and the East Palearctic, newly defined, H. chinensis-group. The Northeast Asian H. japonica-group resulted from a second wave of colonization from the Nearctic. A trans-Atlantic dispersal route could be excluded. Dispersal of the H. arborea-group to the western Palearctic coincides with the closure of the Turgai Strait at the end of the Oligocene. Diversification of Hyla decreased at the end of the Middle Miocene, possibly coinciding with the end of the Mid Miocene Climatic Optimum and the advent of cooler and drier climates in the Northern Hemisphere.
authors.affiliation: Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China. Electronic address: lijt@cib.ac.cn.
authors.forename: Jia-Tang
authors.initials: JT
authors.lastname: Li
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China.
authors.forename: Ji-Shan
authors.initials: JS
authors.lastname: Wang
authors.affiliation: Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; College of Life Sciences, Sichuan University, Chengdu 610064, China.
authors.forename: Hui-Huang
authors.initials: HH
authors.lastname: Nian
authors.affiliation: Institute of Cytology, Russian Academy of Sciences, Tikhoretsky pr. 4, 194064 St. Petersburg, Russia.
authors.forename: Spartak N
authors.initials: SN
authors.lastname: Litvinchuk
authors.affiliation: Ministry of Education Key Laboratory for Tropical Animal and Plant Ecology, College of Life Sciences, Hainan Normal University, Haikou 571158, China.
authors.forename: Jichao
authors.initials: J
authors.lastname: Wang
authors.affiliation: Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; College of Life Sciences, Sichuan University, Chengdu 610064, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650223, China. Electronic address: raodq@mail.kiz.ac.cn.
authors.forename: Ding-Qi
authors.initials: DQ
authors.lastname: Rao
authors.affiliation: Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China; Department of Ecology and Evolution, Goethe University, 60438 Frankfurt am Main, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Klaus
mesh_terms: D000818:Animals; D001001:Anura / Q000145:classification*; D001499:Bayes Theorem; D005075:Biological Evolution; D002467:Cell Nucleus / Q000235:genetics; D050259:Genes, Mitochondrial; D008957:Models, Genetic; D009656:North America; D010802:Phylogeny; D058974:Phylogeography; D017422:Sequence Analysis, DNA
keywords: Bering Land Bridge; Biogeography; Dispersal; Mid Miocene Climatic Optimum; Molecular clock; Turgai Strait