Molecular phylogeny and intraspecific differentiation of the Trapelus agilis species complex in Iran (Squamata: Agamidae) inferred from mitochondrial DNA sequences.

Michael Wink,Nasrullah Rastegar-Pouyani,Eskandar Rastegarpouyani,Seyyed Saeed Hosseinian Yousefkhani,Ali-Asghar Shahamat

doi:10.7717/peerj.8295

Michael Wink, Nasrullah Rastegar-Pouyani + Show 3 more

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https://doi.org/10.7717/peerj.8295

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Abstract

Background Trapelus agilis consists of different morphotypes with restricted distributions in the Iranian Plateau. The phylogeny of the species complex has not been resolved so far, but recently Trapelus sanguinolentus were elevated from this complex into a full species. Other populations of the species complex need to be evaluated taxonomically.MethodsIn the present study, several populations of this species complex along with specimens of its closely related taxa in Iran, T. sanguinolentus, T. ruderatus and T. persicus, were examined using partial nucleotide sequences of two mitochondrial genes (cytb and ND2) (total length 1,322 bp).ResultPopulations of T. sanguinolentus clustered within the T. agilis species complex, thus indicating its paraphyly, but T. sanguinolentus was previously determined to be a species based on morphological features. The T. agilis species complex forms two distinct major clades, each of which is represented by several local populations on the Iranian Plateau. At least five distinct taxa can be identified within this traditional group. Our biogeographic evaluation of the molecular dataset suggested that the Trapelus complex originated in the Late Oligocene (30 mya) and subsequently diversified during the early to middle Miocene (22–13 mya). At first, the predominantly western clade of Trapelus ruderatus diverged from the other clades (22 mya). Afterward, Trapelus persicus diverged around 18 mya ago. The broader T. agilis complex started to diverge about 16 mya, forming several clades on the Iranian Plateau and in Central Asia. The different lineages within this species complex appear to be the result of vicariance events and dispersal waives. The corresponding vicariance events are the formation of the Zagros and Kopet Dagh basins (16–14 mya), and consequently, the aridification of the Iranian Plateau in the late Miocene (11–6 Mya).

Highlights

The history of the Iranian Plateau extends back to about 40 mya, when the Tethys Sea began to close creating the Alborz Mountains (Alaei, 2006)
We acknowledge the limitation of our data for making formal changes in taxonomic status of the studied populations, because both genetic markers used in this study are from the single locus mitochondrial DNA
The findings of the present study strongly suggest that the taxonomic status of populations within the agilis/sanguinolentus species complex in the area needs a fundamental revision

Summary

Introduction

The history of the Iranian Plateau extends back to about 40 mya, when the Tethys Sea began to close creating the Alborz Mountains (Alaei, 2006). The genus Trapelus consists of 13 species (Uetz, 2019), which are distributed from northwestern Africa, along the Saharan border, through the Near East to southwest and central Asia (Rastegar-Pouyani, 1999; Rastegar-Pouyani, 2005; Wagner, 2006; Wagner & Crochet, 2009) They constitute one of the major components of the Iranian Plateau and central Asian fauna and are highly adapted to steppe, semi deserts, and desert environments (Macey et al, 2000). The broader T. agilis complex started to diverge about 16 mya, forming several clades on the Iranian Plateau and in Central Asia. The corresponding vicariance events are the formation of the Zagros and Kopet Dagh basins (16–14 mya), and the aridification of the Iranian Plateau in the late Miocene (11–6 Mya)

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