Phylogeny and biogeography of the Hemiphyllodactylus harterti group (Squamata: Gekkonidae), with description of two new species from the sky-islands of Peninsular Malaysia

Phylogenetic analyses of newly discovered populations of Hemiphyllodactylus from sky-islands across Peninsular Malaysia using the mitochondrial gene ND2, recovered two new upland species embedded within the harterti group. Hemiphyllodactylus puncak sp. nov. from Langkawi Island and H. jeraiensis sp. nov. from Gunung Jerai are sister species with an uncorrected pairwise sequence divergence of 3.6% between them. Together, they formed the sister lineage to H. cicak from Penang Hill, with an uncorrected pairwise sequence divergence of 3.9–4.8% and 4.5–5.7%, respectively. Given that these three populations occur on mountain tops isolated by lowland habitat and the Straits of Malacca, gene flow between them is highly unlikely, and there are unique combinations of characters that differentiate them from one another, as well as from all other species of the harterti group. The time-calibrated BEAST phylogeny shows that the harterti group diversified across the uplands of Peninsular Malaysia in the Oligocene and Pleistocene, which is consistent with climatic fluctuations during this period. During the Middle Oligocene, the ancestral population of the harterti group diverged into two distinct populations, one in the Banjaran Titiwangsa and another in the Banjaran Timur. These two populations then radiated independently across Peninsular Malaysia, giving rise to at least nine additional species within the harterti group.