Expanded morphological description of the Drogons False Garden Lizard, Pseudocalotes drogon (Squamata: Agamidae) from Peninsular Malaysia.

Species in the genus Pseudocalotes are generally rare and known only from a few specimens. Pseudocalotes drogon was described based on a single male from Frasers Hill, Pahang, Peninsular Malaysia. During a recent field survey at Frasers Hill, a female specimen was collected and identified as P. drogon based on morphological characters and a molecular phylogenetic analysis. The morphological description of P. drogon is expanded here, based on the male holotype and the newly collected female specimen.

Advertisement calls from species of the Limnonectes hascheanus-limborgi complex (Anura: Dicroglossidae) from Peninsular Malaysia.

Limnonectes hascheanus and Limnonectes limborgi are two very similar-looking and closely related species and are sometimes referred to as the Limnonectes hascheanus-limborgi complex (Inger & Stuart 2010). Inger & Stuart (2010) tackled the systematics of the complex and confirmed the status of L. limborgi as a distinct species and not a junior synonym to L. hascheanus by providing molecular data and morphological characters of its distinctiveness. The geographic ranges of the two species were also reported to be distinct where L. hascheanus is mainly restricted to the southern part of the Thai-Malay Peninsula while L. limborgi is distributed from southern Myanmar north into northern Thailand and Laos before curving around into central Laos, northeastern Thailand, Cambodia, and southern Vietnam (Inger & Stuart 2010).

Variation in claw morphology among the digits of Bent-toed geckos (Cyrtodactylus: Gekkota: Gekkonidae).

BACKGROUND: Ecomorphological studies of lizards have increasingly employed comparison of claw morphology among species in relation to spatial niche use. Typically, such studies focus on digit IV of the autopodia, especially the pes. Uniformity of claw morphology among digits is more often implicitly assumed than tested. RESULTS: Using four species of Cyrtodactylus, comprising two generalist and two scansorial taxa that use different substrates, we examined whether claw morphology is uniform among digits and among species. We found that, within each species, ventral claw curvature is uniform across all digits whereas there are small but insignificant differences in ventral claw length and claw depth. The claws of the pes of each species are longer and deeper than those of the corresponding digits of the manus. The claw of digit I of each species is significantly shorter and shallower on both autopodia compared to those on digits IV and V (digit I, including its claw, is idiosyncratically variable among lizards in general). CONCLUSIONS: We conclude that digit IV is an adequate representative of claw form in each species and exhibits variation among species, thereby serving as an exemplar for use in studies of potential discrimination between ecomorphological types in studies of Cyrtodactylus.

Two new karst-adapted species in the Cyrtodactyluspulchellus group (Reptilia, Gekkonidae) from southern Thailand.

The exploration of unsurveyed areas in southern Thailand discovered two new karst-adapted species, Cyrtodactylussungaiupesp. nov. and Cyrtodactyluswangkhramensissp. nov., from Thung Wa and La-ngu Districts, Satun Province, respectively. These new species are members of the C.pulchellus group that occur along the Thai-Malay Peninsula. The new species can be distinguished from all other congeners by their key morphological characters and genetic divergence. Morphologically, Cyrtodactylussungaiupesp. nov. and Cyrtodactyluswangkhramensissp. nov. can be diagnosed from other members by having a combination of differences in body size; degree of dorsal tuberculation; absence of tubercles on ventral surfaces; number of ventral scales, paravertebral tubercles and femoroprecloacal pores in males only; deep precloacal groove only in males; absence of a scattered pattern of white dorsal tubercles; number of dark body bands; and the extent of caudal tubercles on an original tail. Although the two species are sister taxa and have nearly identical morphologies, they are considered to be different species, based on a relatively high uncorrected pairwise genetic divergence of the mitochondrial ND2 gene (6.59-6.89%), statistically significant univariate and multivariate morphological differences (PERMANOVA and ANOVA) and diagnostic characteristics of caudal tuberculation on the original tail. Moreover, Cyrtodactylussungaiupesp. nov. and Cyrtodactyluswangkhramensissp. nov. are currently restricted to their karstic type localities which may serve as a geographic barrier to dispersal and gene flow.

A new species of Hemiphyllodactylus (Squamata, Gekkonidae) from Ha Giang Province, Vietnam.

An integrative analysis recovered a new species of the Hemiphyllodactylustypus group from a karst formation in Lung Cu Commune, Dong Van District, Ha Giang Province, northeastern Vietnam. Hemiphyllodactyluslungcuensissp. nov. is embedded within clade 6 of the typus group, bearing an uncorrected pairwise sequence divergence of 4.6-20.2% from all other species based on a 1,038 base pair segment of the mitochondrial NADH dehydrogenase subunit 2 gene (ND2). It is diagnosable from other species in clade 6 by statistically significant mean differences in normalized morphometric, meristic, and categorical characters. A multiple factor analysis using the three aforementioned character types recovered its unique, non-overlapping placement in morphospace as statistically significantly different from that of all other species in clade 6. The description of this new Hemiphyllodactylus species contributes to a growing body of literature underscoring the high degree of herpetological diversity and endemism in karst landscapes in Vietnam as well as in the genus Hemiphyllodactylus.

Comments on the taxonomic status of Cyrtodactylus zebraicus Taylor, 1962 (Squamata: Gekkonidae) from Northern Peninsular Malaysia.

The taxonomic status of Cyrtodactylus zebraicus in Peninsular Malaysia has been plagued with uncertainty over the last three decades owing to a lack of vouchered material. Recent collections confirmed the presence of this species in the northernmost state of Perlis and for the country. An expanded description of the newly collected Peninsular Malaysian specimens as well as the holotype of C. zebraicus is provided along with a comparison with other Cyrtodactylus species in the country. This study adds to the growing number of herpetofaunal species with Indo-Burmese affinities discovered in northern states of the country and the biogeographic importance of this region for the exchange of fauna and flora. The findings also highlight the importance of continued field work along the biogeographic interchange of the Banjaran Nakawan that separates southwestern Thailand from northwestern Peninsular Malaysia and the need to sample and collect voucher specimens that can be deposited in proper scientific collections for current and future research.

A new species of the genus Hemiphyllodactylus Bleeker, 1860 (Squamata: Gekkonidae) from a lowland monsoon forest in Southern Vietnam.

An integrative taxonomic analysis delimits and diagnoses the new species Hemiphyllodactylus cattien sp. nov. from Cat Tien National Park, Dong Nai Province, southern Vietnam-the eighth species of Hemiphyllodactylus to be described from Vietnam. The new species is recovered as the sister species to a clade comprised of H. indosobrinus from Laos and H. flaviventris from Thailand based on phylogenetic analyses using ND2 mtDNA gene sequences. Unlike the vast majority of Hemiphyllodactylus which are site-restricted upland endemics, Hemiphyllodactylus cattien sp. nov. is a lowland species collected from one of the most well-surveyed regions in Vietnam. Its discovery further emphasizes the need for continued re-sampling of survey sites already considered to be well-explored.

Two new species of Dixonius from Vietnam and Laos with a discussion of the taxonomy of Dixonius (Squamata, Gekkonidae).

Integrated analyses using maximum likelihood (ML), Bayesian inference (BI), principal component analysis (PCA), discriminate analysis of principal components (DAPC), multiple factor analysis (MFA), and analysis of variance (ANOVA) recovered two new diagnosable species of gekkonid lizards in the genus Dixonius, one from the Central Highlands, Gia Lai Province, Vietnam and another from the Vientiane Province, Laos. Phylogenetic analyses based on the mitochondrial NADH dehydrogenase subunit 2 gene (ND2) and adjacent tRNAs showed that Dixoniusgialaiensissp. nov. is the sister species of D.minhlei from Dong Nai Province, Vietnam and is nested within a clade that also includes the sister species D.siamensis and D.somchanhae. Dixoniusmuangfuangensissp. nov. is the sister species to D.lao from Khammouane Province, Laos and is embedded in a clade with D.vietnamensis, D.taoi, and undescribed species from Thailand. Multivariate (PCA, DAPC, and MFA) and univariate (ANOVA) analyses using combinations of 15 meristic (scale counts), six morphometric (measurements), and five categorical (color pattern and morphology) characters from 44 specimens encompassing all eight species of Dixonius from Vietnam and Laos clearly illustrate Dixoniusgialaiensissp. nov. and Dixoniusmuangfuangensissp. nov. are statistically different and discretely diagnosable from all closely related species of Dixonius. These integrative analyses also highlight additional taxonomic issues that remain unresolved within Dixonius and the need for additional studies. The discovery of these new species further emphasizes the underappreciated herpetological diversity of the genus Dixonius and illustrates the continued need for field work in these regions.

A new species of the Cyrtodactylusbrevipalmatus group (Squamata, Gekkonidae) from Tak Province, northwestern Thailand.

An integrative taxonomic analysis was used to delimit and diagnose a new species of the Cyrtodactylusbrevipalmatus group from Tak Province in western Thailand. Although Bayesian phylogenetic analyses place C.denticulatussp. nov. within the brevipalmatus group, the new species is neither nested within nor is it the sister species of any other species in the brevipalmatus group. Furthermore, based on the mitochondrial NADH dehydrogenase subunit 2 gene (ND2) and adjacent tRNAs, it bears an uncorrected pairwise sequence divergence of 7.87-21.94% from all other species in the brevipalmatus group. Cyrtodactylusdenticulatussp. nov. is differetiated from all other species in the brevipalmatus group by having a number of unique charateristics such as denticulate ventrolateral body folds and ventrolateral subcaudal ridges, characters not seen in any other species of the group (n = 51 individuals). Additionally, based on a multiple factor anlaysis, C.denticulatussp. nov. does not overlap with any other species in multivariate space. The discovery of C.denticulatussp. nov. underscores the unrealized diversity of upland ecosystems across Thailand and the urgent need for increased exploration and conservation of these unique imperiled montane refugia, especially in this era of climate change.

A new species of the Cyrtodactylusbrevipalmatus group (Squamata, Gekkonidae) from the uplands of western Thailand.

An integrative systematic analysis recovered a new species of the Cyrtodactylusbrevipalmatus group from the uplands of Thong Pha Phum National Park, Kanchanaburi Province in western Thailand. Cyrtodactylusthongphaphumensissp. nov. is deeply embedded within the brevipalmatus group, bearing an uncorrected pairwise sequence divergence of 7.6-22.3% from all other species based on a 1,386 base pair segment of the mitochondrial NADH dehydrogenase subunit 2 gene (ND2) and adjacent tRNAs. It is diagnosable from all other species in the brevipalmatus group by statistically significant mean differences in meristic and normalized morphometric characters as well as differences in categorical morphology. A multiple factor analysis recovered its unique and non-overlapping placement in morphospace as statistically significantly different from that of all other species in the brevipalmatus group. The description of this new species contributes to a growing body of literature underscoring the high degree of herpetological diversity and endemism across the sky-island archipelagos of upland montane tropical forest habitats in Thailand, which like all other upland tropical landscapes, are becoming some of the most imperiled ecosystems on the planet.

Scratching the surface: a new species of Bent-toed gecko (Squamata, Gekkonidae, Cyrtodactylus) from Timor-Leste of the darmandvillei group marks the potential for future discoveries.

A new species of limestone-dwelling Bent-toed gecko (genus Cyrtodactylus) is described from Nino Konis Santana National Park in the far-east region of Timor-Leste. Both genetic and morphological data strongly support the evolutionary distinctness of the new species, which we describe herein as Cyrtodactylussantana sp. nov. Phylogenetic analysis based on the ND2 mitochondrial gene inferred the new species as part of the C.darmandvillei group with close genetic affinities to C.batucolus, C.seribuatensis, C.petani, C.sadleiri, and two undescribed lineages from the Moluccas in Indonesia. The new species represents the first species of Cyrtodactylus identified at the species level from Timor-Leste and fills an important gap in our understanding of the biogeography and evolutionary history of Cyrtodactylus especially in the Wallacean region. Our results strongly suggest that the diversity of Cyrtodactylus in Wallacea is still underestimated and many more unnamed species remain to be described.

Genetic and morphological concordance and discordance within the Cyrtodactylus brevipalmatus group (Squamata: Gekkonidae).

We use data sets from the Cyrtodactylus brevipalmatus group with limited genetic and morphological sampling to demonstrate that not accounting for sampling error may adversely influence decisions regarding species delimitation and diagnosis. Lack of geographic sampling between the endpoints of a species range may recover notable interpopulational genetic differentiation consistent with species-level differentiation. Additionally, small population sample sizes may fail recover statistically different diagnostic morphological differences. Combined, these types of sampling error can produce results seemingly consistent with the recognition of cryptic speciesgenetically delimited populations lacking diagnostic morphological characters. This is the current situation within some lineages of the C. brevipalmatus group whereas in others, sampling error is less problematic and does not jeopardize their taxonomy. We note the potential negative effects for comparative biology as a whole if sampling error is not taken into consideration prior to constructing taxonomies.

Additions to the herpetofauna of Hon Son Island, Rach Gia Bay, Kien Giang Province, southern Vietnam with a discussion of syntopy between the granite cave-adapted Bent-toed Gecko Cyrtodactylus eisenmanae and a new Cyrtodactylus of uncertain taxonomic status.

An updated herpetofaunal checklist of Hon Son Island, Rach Gia Bay, Kien Giang Province, southern Vietnam is presented which reports of new records for Kaloula pulchra, Sylvirana cf. mortenseni, Cyrtodactylus sp., and Gehyra mutilata bringing the island total to 21 species. Cyrtodactylus sp. is an unidentified granite-cave adapted species that occurs in syntopy with the granite-cave adapted C. eisenmanae, bringing the total number of Cyrtodactylus on this tiny island (11.5 km2) to three. The implications of highly specialized syntopic congeneric ecomorphs is discussed.

A new species of Cyrtodactylus Gray, 1827 (Squamata: Gekkonidae) from the Thai-Malay Peninsula and the independent evolution of cave ecomorphology on opposite sides of the Gulf of Thailand.

An integrative taxonomic analysis recovers a distinctive new species of the gekkonid genus Cyrtodactylus Gray, 1827 from Satun Province in extreme southern Thailand as the sister species to the Cyrtodactylus intermedius group of southern Indochina, approximately 600 km to the northeast across the Gulf of Thailand. Based on 1449 base pairs of the mitochondrial gene NADH dehydrogenase subunit 2 (ND2) and its flanking tRNAs, the new species, C. disjunctus sp. nov., bears a pairwise sequence divergence from the mean divergences of the intermedius group species ranging from 17.923.6%. Three different principal component analyses (PCA) and a multiple factor analysis (MFA) recover C. disjunctus sp. nov. as a highly distinctive karst cave-adapted species based on morphology and color pattern. Its sister species relationship to the intermedius groupto which it is added herefurther underscores a growing body of analyses that have recovered a trans-Gulf of Thailand connection across the submerged Sunda Shelf between the southern Thai-Malay Peninsula and southern Indochina. Fragmented karstic archipelagos stretching across Indochina have served as foci for the independent evolution of nearly 25% of the species of Cyrtodactylus. The description of C. disjunctus sp. nov. continues to highlight the fact that karstic habitats support an ever-increasing number of threatened site-specific endemics that compose much of the reptile diversity of many Asian nations but, as of yet, most of these landscapes have no legal protection.

A new species of stream toad of the genus Ansonia Stoliczka, 1870 (Anura: Bufonidae) from Nakhon Si Thammarat Range in southern Thailand.

An integrative taxonomic analysis confirmed the new species status of a recently discovered upland population of Ansonia from Thongsong, Thongsong District, Nakhon Si Thammarat Province, Thailand from the sky island archipelago south of the Isthmus of Kra. Ansonia infernalis sp. nov. is a member of the Thai-Burmese clade within the more inclusive Thai-Malaya Peninsula clade of western and southern Thailand. It is separated from all other species of Ansonia by a unique combination of morphometric and discrete morphological and color pattern characteristics and is the sister species of a clade of eight other species found north of the Isthmus of Kra. Ansonia infernalis sp. nov. is the newest member of a long list of range-restricted endemics from the sky island archipelago of the Thai-Malay Peninsula and continues to underscore the unexplored nature of this region and its need for conservation.

Description of two new species of Hemiphyllodactylus (Reptilia: Gekkonidae) from karst landscapes in Yunnan, China, highlights complex conservation needs.

Karst habitats are hotspots of diversity and endemism. Their naturally fragmented distributions across broad geographic landscapes have led to the complex array of smaller evolutionary ecosystems that present unique challenges from a conservation perspective. Comprehensive biodiversity assessments of karst habitats have revealed that these ecosystems contain an almost unparalleled level of endemism, and many site-restricted species remain undescribed, thus posing considerable challenges for effective conservation management. Small rock-dwelling species, such as geckos, may be particularly prone to such isolation. In this paper, we discuss one such genus, i.e., Hemiphyllodactylus, and explore its diversity across karst landforms in Yunnan Province, southwestern China. Based on morphological and genetic data, we describe two new species of Hemiphyllodactylus from karst habitats in Simao District and Yanshan County. A phylogenetic tree for Hemiphyllodactylus was constructed using 1 039 base pairs (bp) of the mitochondrial NADH dehydrogenase subunit 2 gene ( ND2). The Simao and Yanshan specimens can be distinguished from all other congeners within their respective subclades based on uncorrected genetic pairwise distances greater than 6.3% and 4.3% respectively, as well as significant morphological differences. The discovery and description of these two new species brings the total number of described Hemiphyllodactylus species in China to 14 and indicates many more undescribed species from unsurveyed karst regions await discovery. Our findings suggest that karst ecosystems in Yunnan support a higher diversity of Hemiphyllodactylus than previously known. This study also highlights the importance of karst ecosystems as refugia for site-specific endemic species and the need for heightened conservation efforts.

Cryptic extinction risk in a western Pacific lizard radiation.

Cryptic ecologies, the Wallacean Shortfall of undocumented species' geographical ranges and the Linnaean Shortfall of undescribed diversity, are all major barriers to conservation assessment. When these factors overlap with drivers of extinction risk, such as insular distributions, the number of threatened species in a region or clade may be underestimated, a situation we term 'cryptic extinction risk'. The genus Lepidodactylus is a diverse radiation of insular and arboreal geckos that occurs across the western Pacific. Previous work on Lepidodactylus showed evidence of evolutionary displacement around continental fringes, suggesting an inherent vulnerability to extinction from factors such as competition and predation. We sought to (1) comprehensively review status and threats, (2) estimate the number of undescribed species, and (3) estimate extinction risk in data deficient and candidate species, in Lepidodactylus. From our updated IUCN Red List assessment, 60% of the 58 recognized species are threatened (n = 15) or Data Deficient (n = 21), which is higher than reported for most other lizard groups. Species from the smaller and isolated Pacific islands are of greatest conservation concern, with most either threatened or Data Deficient, and all particularly vulnerable to invasive species. We estimated 32 undescribed candidate species and linear modelling predicted that an additional 18 species, among these and the data deficient species, are threatened with extinction. Focusing efforts to resolve the taxonomy and conservation status of key taxa, especially on small islands in the Pacific, is a high priority for conserving this remarkably diverse, yet poorly understood, lizard fauna. Our data highlight how cryptic ecologies and cryptic diversity combine and lead to significant underestimation of extinction risk. Supplementary Information: The online version contains supplementary material available at 10.1007/s10531-022-02412-x.

GroupStruct: An R Package for Allometric Size Correction.

The efficacy of an allometric growth model to correct for ontogenetic body size variation has been known for decades, yet this method remains relatively obscure and rarely applied. We optimize the implementation of this method through a newly developed and easy-to-use R package GroupStruct and further extend its application from intraspecific to interspecific datasets. Using empirical examples, we show that different size correction methods (i.e., ratios, residuals, and allometry) can result in vastly different conclusions. Our results demonstrate that choosing the appropriate size correction method is crucial as it can have significant impacts on downstream analyses and has the potential to alter biological interpretations.

The biogeography of bent-toed geckos, Cyrtodactylus (Squamata: Gekkonidae).

The gekkonid genus Cyrtodactylus is the third largest vertebrate genus on the planet with well over 300 species that range across at least eight biogeographic regions from South Asia to Melanesia. The ecological and morphological plasticity within the genus, has contributed to its ability to disperse across ephemeral seaways, river systems, basins, land bridges, and mountain ranges-followed by in situ diversification within specific geographic areas. Ancestral ranges were reconstructed on a mitochondrial phylogeny with 346 described and undescribed species from which it was inferred that Cyrtodactylus evolved in a proto-Himalaya region during the early Eocene. From there, it dispersed to what is currently Indoburma and Indochina during the mid-Eocene-the latter becoming the first major center of origin for the remainder of the genus that seeded dispersals to the Indian subcontinent, Papua, and Sundaland. Sundaland became a second major center of radiation during the Oligocene and gave rise to a large number of species that radiated further within Sundaland and dispersed to Wallacea, the Philippines, and back to Indochina. One Papuan lineage dispersed west to recolonize and radiate in Sundaland. Currently, Indochina and Sundaland still harbor the vast majority of species of Cyrtodactylus.