A REVISED PHYLOGENY OF HOLARCTIC TREEFROGS (GENUS HYLA) BASED ON NUCLEAR AND MITOCHONDRIAL DNA SEQUENCES

摘要

The treefrog genus Hyla (Anura: Hylidae) consists of at least 31 species found in North America, Central America, Europe, and Asia and is the only genus of hylids that occurs outside the New World. Despite intensive work on the phylogeny of the genus in the past few years, several problems still exist regarding relationships within Hyla. These problems include the unusual placements of H. gratiosa and H. walkeri in some recent studies and the relatively limited taxon sampling of Asian species. In the present study, we revisit the phylogeny of Hyla to address some of these problems. First, we tested the unexpected placements of H. gratiosa and H. walkeri by sampling additional individuals of these species. Our results show that the unusual placements of H. gratiosa and H. walkeri in previous studies were most likely due to a mislabelled tissue sample and a misidentified specimen, respectively. Second, we included two species of Asian Hyla not included in previous phylogenies. Our study provides additional evidence for two separate colonizations of Hyla from the New World into Asia, and suggests an unusual biogeographic pattern in the Asian Hyla clades.