The phylogeography of Middle Eastern tree frogs in Israel

Western Palearctic treefrogs of the genus Hyla provide an example of a morphologically and ecologically cryptic group. Up to three distinct Hyla species have been proposed as resident in Israel and this number has consistently been subject to taxonomical debates. Here, we analyzed 16S rRNA and COI gene fragments of 658 individuals sampled at 47 pools in nine regions across Israel and the West Bank in order to resolve the taxonomic status of Hyla frogs. We generated both Bayesian and Maximum Likelihood phylogenies, and constructed time-calibrated trees to provide an evolutionary and historical context of sequence variations. We further applied SAMOVA as well as Monmonier's maximum-difference algorithm to study the genetic structure among populations and to identify potential zones acting as barriers to gene flow across locations. Our results revealed two distinct haplogroups for each gene fragment, with 95% CI divergence times dated from 8.9-17.1 Mya (16S) and 7.1-23.6 Mya (COI), respectively. SAMOVA and barrier analyses partitioned the populations into three groups. Our results highlight that, while there are probably only two Hyla species in Israel, one population of one of the species might qualify as a separate evolutionarily significant unit. Our findings elucidate the taxonomic status of Hyla frogs in Israel and provide the basis for determining appropriate management and conservation priorities.