Evolutionary History of Platyceps Racers Reveals South Asian Origin and Recurrent Westward Dispersals

Abstract

Aim The aim of this study was to elucidate the phylogenetic and evolutionary history of the colubrid genus Platyceps . Location Saharo–Arabian biogeographic realm. Taxon Genus Platyceps , Colubridae, Squamata. Methods We sequenced four mitochondrial (12S rRNA, cytb , ND4 + tRNA, COI ) and two nuclear ( c‐mos , NT3) markers of 19 species (115 newly analysed tissue samples) of the genus Platyceps , covering the entire distribution of the genus, to build both Maximum Likelihood (IQ‐Tree) and Bayesian inference (BEAST) trees. Furthermore, for the first time, we reconstructed the historical biogeography of this genus based on a time‐calibrated tree using the BioGeoBEARS package in R. Results Our results confirmed Platyceps to be monophyletic and that it is divided into four main groups ( plinii , ventromaculatus , karelini , and florulentus ). The genus diverged in the Early Miocene (around 19.9 million years ago) when the ancestor of the plinii group split. This was followed by the separation of the three main groups ( ventromaculatus , karelini , and florulentus ) around 18.6 million years ago. The genus's representatives then spread from their most probable place of origin in South Asia to the entire Saharo‐Arabian biogeographic realm. Main Conclusions The genus originated most likely in South Asia from where it expanded three independent times through the Arabian Peninsula to northeastern Africa. The dispersal events were likely enabled by the existence of temporary land bridges between Africa and Arabia. Considering that many of the Platyceps species are well adapted to arid conditions, the distribution was also affected by the Miocene climatic changes and the increasing aridification of the North African and Arabian arid belt.

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