Diversification of Hemidactylus geckos (Squamata: Gekkonidae) in coastal plains and islands of southwestern Arabia with descriptions and complete mitochondrial genomes of two endemic species to Saudi Arabia

The systematic, phylogenetic, and biogeographic aspects of the rich squamate fauna of the Arabian Peninsula are becoming increasingly well understood. The Arabian members of the gecko genus Hemidactylus, the most diverse genus among Arabian squamates, have been the subject of several phylogenetic revisions in recent years. However, large parts of the peninsula lacked thorough sampling, for example, the coastal hyper-arid plains along the Red Sea and some offshore islands. In this study, we examine the genetic, morphological, and ecological diversification of a Hemidactylus clade that straddles the Red Sea and contains ten Arabian and three African species. We compiled a genetic dataset of seven markers (two mitochondrial and five nuclear) to reconstruct their phylogenetic relationships and collected morphological data to assess the level of interspecific morphological disparification. Our results support the existence of four yet undescribed species within the clade - two from Arabia and two from Ethiopia. We provide taxonomic descriptions of the two new Arabian species, one from the western Asir Mountains foothills and one from the Farasan Islands. The new species from the Asir Mountains foothills highlights the role of the southern Arabian coastal desert as an important yet often overlooked local biodiversity hotspot. The new species from the Farasan Islands represents the second vertebrate species endemic to the archipelago. Together with the descriptions of the diagnostic features of both species, we provide complete annotated mitochondrial genomes of both holotypes and of holotypes of two other species from the clade to characterize their mitogenomic composition and architecture.

Automated summary

This study investigates the genetic, morphological, and ecological diversification of a Hemidactylus clade in the Arabian Peninsula and Africa. The researchers discovered four undescribed species within the clade, two from Arabia and two from Ethiopia. The study also highlights the underestimated role of the southern Arabian coastal desert as a local biodiversity hotspot.