Phylogenetic analyses of distantly related clades of bent-toed geckos (genus Cyrtodactylus) reveal an unprecedented amount of cryptic diversity in northern and western Thailand

Siriwadee Chomdej,Parinya Pawangkhanant,Waranee Pradit,Jing Che,Korakot Nganvongpanit,Nikolay A Poyarkov,Yangchun Gao,Chatmongkon Suwannapoom,Shiping Gong

doi:10.1038/s41598-020-70640-8

Abstract

Cyrtodactylus species are the most diverse of the geckos and are widely distributed in Southeast Asia, including Thailand. However, their patterns of distribution, especially in northern and western parts of Thailand, remain unknown because few Cyrtodactylus species in these regions have been described. Thus, a data set of mitochondrial NADH dehydrogenase 2 (ND2) gene and flanking tRNAs from Cyrtodactylus found in northern and western Thailand, including contiguous areas, was assembled to elucidate phylogenetic relationships and identify the distribution patterns of these geckos. The results showed four well-supported clades, a northwestern clade (A), a northern clade (B), a western clade (C), and a special clade characterized by specific morphological features (D). Clades A–C were grouped with strong support by the geography of their localities from northern Thailand (Mae Hong Son and Chiang Mai Provinces) along the Tenasserim mountain ranges to Phang-Nga Province, Thailand. Clade D is a distinct clade of Cyrtodactylus species characterized by a tuberculate and prehensile tail and distributed widely in mainland Southeast Asia. Overall, the results suggest a pattern of geographic separation and distribution of Cyrtodactylus in northern and western Thailand. Additionally, this study provides evidence of a hidden biodiversity of Cyrtodactylus in these regions.

Highlights

Reptiles have a long, complex evolutionary history that has produced diverse species distributed throughout the world, both in water and on land[1]
As we found in our analysis, Cyrtodactylus species in the northwestern clade are closely related to those previously described from Mon State and Kayin state, Myanmar, which are categorized as the “sinyineensis group”[19]
The phylogeny presented in this study illustrates the relationship and distribution of Cyrtodactylus species in northern and western Thailand

Summary

Introduction

Complex evolutionary history that has produced diverse species distributed throughout the world, both in water and on land[1]. Accurate species delimitation is necessary to understand their speciation, diversification, and biogeography for conservation purposes This remains a challenge due to the existence of Bioscience and Veterinary Public Health, Faculty of Veterinary Medicine, Chiang Mai University, Chiang Mai 50100, Thailand. The Gekkonidae found in Thailand are highly diverse, and include approximately 90 species Among these species, 38 species of bent-toed geckos (Cyrtodactylus) are the most well-documented and show wide distribution in Thailand[17]. The bent-toed geckos are Asian geckos that are widely distributed on the Indian subcontinent and radiated eastward through Indochina and AustraloPapua[18] They are divided to two major groups depending on whether they inhabit forests or limestone caves. The results provide insights into the range of distribution of Cyrtodactylus in northern and western Thailand that will aid in the conservation of endemic bent-toed geckos

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Discussion

Conclusion