Evolution in karst massifs: Cryptic diversity among bent-toed geckos along the Truong Son Range with descriptions of three new species and one new country record from Laos

Abstract

Species designated as 'cryptic' share a similar morphotype, and are often only clearly separable by molecular data. Cyrtodactylus, the most diverse gecko genus of the family Gekkonidae, is a prime example, because many morphologically similar taxa have only recently been identified as new species as a result of available genetic evidence. However, while cryptic diversity of Cyrtodactylus is already well documented on the Vietnamese side of the Truong Son range, only scarce data is available from central Laos. In this study, we address this issue by means of an integrative approach, which employs morphological, molecular, and ecological data to distinguish cryptic species of the Cyrtodacylus phongnhakebangensis species group primarily distributed along the northern Truong Son Range. Our analyses based on 12 selected morphological characters, a partial mitochondrial gene (COI), and five ecological parameters revealed three undescribed cryptic Cyrtodactylus species from Hin Nam No National Protected Area, which are described as Cyrtodactylus calamei sp. nov., Cyrtodactylus hinnamnoensis sp. nov., and Cyrtodactylus sommerladi sp. nov. A fourth discovered Cyrtodactylus population in Hin Nam No proved to be the first country record of C. cryptus for Laos. Our results highlight the importance of applying an integrative approach to resolving the taxonomy of complex and cryptic species groups, and the role of the Truong Son Range in maintaining the high level of biodiversity over time.

老挝东北部喀斯特地貌发现弯趾虎属一新种（爬行纲：壁虎科）

“…encountered three geckos that differed in color pattern and scalation from known species, and which we show hereafter to belong to an undescribed species. Morphological characters, such as scalation and dorsal color and pattern, indicate that this newly discovered Cyrtodactylus population clearly belongs to the C. phongnhakebangensis species group sensu Luu et al ( 2016a ), which includes a dozen species from Laos and Vietnam. In agreement with the definition of this group provided by Luu et al ( 2016a : 132), this new species exhibits a maximum adult SVL comprised between 73.0 and 100.6 mm, 0 or 1 supranasal, a DorTub (14–18) between 10 and 24, no webbing between fingers or toes, tubercles nearly absent on forelimbs but present on hind limbs, precloacal and femoral pores in males (in total 47) between 20 and 60, number of postcloacal tubercles (5 or 6 in male) between 3 and 8, enlarged subcaudals, and dorsum displaying well-defined dark bands.…”

“…The mitochondrial cytochrome oxidase subunit I ( COI ) was selected as a genetic marker to clarify the taxonomic position of the newly discovered population of Cyrtodactylus . A total of 655 bp of COI was amplified using a mitochondrial marker widely used as a barcoding marker for vertebrates, including both reptiles and amphibians ( Murphy et al, 2013 ; Nagy et al, 2012 ; Smith et al, 2008 ), and which proved to be useful for species identification and assessment of cryptic diversity in various groups of lizards, including the genus Cyrtodactylus ( Brennan et al, 2017 ; Hartmann et al, 2013 ; Luu et al, 2016a ; Nazarov et al, 2012 , 2014 ; Nguyen et al, 2013 , 2014 , 2017 ; Solovyeva et al, 2011 ). Primers used both for PCR and sequencing were the VF1-d (5′-TTCTCAACCAACCACAARGAYATYGG-3′) and the VR1-d (5′-TAGACTTCTGGGTGGCCRAARAAYCA-3’) (following Ivanova et al, 2006 ).…”

“…The ML analyses were conducted using Treefinder ( Jobb et al, 2004 ). The COI sequence of Cyrtodactylus elok Dring was used as an outgroup following Luu et al ( 2016a ). Confidence in tree topology was tested by non-parametric bootstrap analysis (ML BS) with 1 000 replicates ( Felsenstein, 2004 ).…”

“…Moreover, several species remain to be named in Vietnam, in particular within the Cyrtodactylus irregularis species complex ( Nguyen et al, 2017 ). Although Laos is located between these two species-rich countries and harbors a varied geological relief propitious to micro-endemism, its Cyrtodactylus fauna is currently known to include only 21 species ( Luu et al, 2016a ; Nazarov et al, 2014 ). Such low species number may be due to the fewer herpetological surveys conducted in Laos compared to Vietnam and Thailand, particularly on the karst reliefs ( Teynié & David, 2014 ).…”

A new species of Cyrtodactylus (Squamata, Gekkonidae) from Cambodia’s Prey Lang Wildlife Sanctuary

“…Bent-toed Geckos of the genus Cyrtodactylus Gray are one of the most species-diverse genera of gekkonid lizards, with 292 recognized species (Uetz et al 2020). Much of the diversity within Cyrtodactylus has been described only during the past decade and from mainland Southeast Asia (Brennan et al 2017;Uetz et al 2020), and many of these newly-recognized species are thought to be highly localized with extremely narrow geographic ranges (e.g., Nazarov et al 2012;Luu et al 2016;Grismer et al 2017;Murdoch et al 2019).…”