Biogeography of Arabian Geckos

Abstract

The Arabian region is renowned for its harsh, hot and arid climate, with massive deserts spanning across most of the interior, enclosed by mountain ranges on the margins of the peninsula. Geckos (Gekkota) form the most diverse reptile group in Arabia, found in a diverse array of habitats: sandy or gravel areas are occupied by genera such as Bunopus, Pseudoceramodactylus and Stenodactylus, while genera such as Asaccus and Ptyodactylus are restricted to mountain ranges and rocky surfaces. We present a general overview of the biogeography of geckos in Arabia as inferred via detailed phylogeographical analyses of multiple gecko genera, together with geological and environmental data. We show how the formation of various habitats within Arabia and episodic or continuous connections to Eurasia and Africa, have enabled dispersal and diversification of taxa, while creating biogeographical barriers and endemicity hotspots. Two major environmental events are hypothesized to have greatly influenced the distribution and diversification of the local fauna - The tectonic movement of the Arabian plate during the Oligocene, and the dramatic climatic changes that occurred during the Miocene-Pliocene. The former caused high geological instability and the detachment from Africa followed by a collision with Eurasia, while also prompting the orogeny of mountain ranges. The latter influenced the expansion and contraction of sand deserts, serving as a barrier to gene flow between the mountains. These events changed the Arabian landscape over time, creating an interesting composition of species diversity that we encounter today.