Bent-toed Gecko Research Articles

Sex Chromosome Turnover in Bent-Toed Geckos (Cyrtodactylus).

Lizards and snakes (squamates) are known for their varied sex determining systems, and gecko lizards are especially diverse, having evolved sex chromosomes independently multiple times. While sex chromosomes frequently turnover among gecko genera, intrageneric turnovers are known only from Gekko and Hemidactylus. Here, we used RADseq to identify sex-specific markers in two species of Burmese bent-toed geckos. We uncovered XX/XY sex chromosomes in Cyrtodactylus chaunghanakwaensis and ZZ/ZW sex chromosomes in Cyrtodactylus pharbaungensis. This is the third instance of intrageneric turnover of sex chromosomes in geckos. Additionally, Cyrtodactylus are closely related to another genus with intrageneric turnover, Hemidactylus. Together, these data suggest that sex chromosome turnover may be common in this clade, setting them apart as exceptionally diverse in a group already known for diverse sex determination systems.

Citizen Science Assisted Monitoring Provides New Data Concerning the Distribution of the Bulgarian Bent-toed Gecko, Mediodactylus danilewskii (Gekkonidae, Squamata), in North-East Bulgaria

The Bulgarian Bent-toed Gecko (Mediodactylus danilewskii Strauch, 1887) is one of the two species of geckos inhabiting the territory of Bulgaria. In the recent years, new information on its distribution was published and big amount of data were collected. We organized an information platform for sharing data on the biology and live-range of M. danilewskii in inland North-East Bulgaria. This gecko is a highly synanthropic species which is often observed by citizens. Here we report on four new observation spots and also confirm the presence of the species from recently published localities. All data were recorded by volunteers, hence we discuss on the methods for documentation of the specimens and the critical role of the citizen science to assess the range of distribution of the species.

On a bent-toed gecko (Cyrtodactylus sp.) from south-eastern Bali, Indonesia

On a bent-toed gecko (Cyrtodactylus sp.) from south-eastern Bali, Indonesia

Origin, diversity, and conservation of karst-associated Bent-toed Geckos (Genus Cyrtodactylus) in Myanmar (Burma)

Fifty-eight percent of the 43 known species of the Bent-toed Geckos (Cyrtodactylus) from Myanmar are found only in karstic habitats in the Shan Plateau and Salween and Ayeyarwady basins. A stochastic character mapping analysis indicated that the occupation of karstic habitats evolved at least four times independently in Burmese lineages with both Sundaic and Indian origins. Karstic habitats not only serve as foci for speciation but are refugia for species extirpated from the surrounding forested habitats due to agricultural development. Despite the high levels of biodiversity and site-specific endemism in karstic habitats in Myanmar, they are some of the least protected ecosystems. The immense financial returns from unsustainable resource extraction (cement manufacturing) makes the challenge of legal karst conservation extremely difficult. Sadly, their continued exploitation for limestone shows no signs of abating. Until karst habitats in Myanmar are thoroughly investigated, a significant portion of this country’s herpetological diversity will remain underestimated and unprotected.

Integrative taxonomic and geographic variation analyses in Cyrtodactylus aequalis (Squamata: Gekkonidae) from southern Myanmar (Burma): one species, two different stories

The historical accuracy of building taxonomies is improved when they are based on phylogenetic inference (i.e., the resultant classifications are less apt to misrepresent evolutionary history). In fact, taxonomies inferred from statistically significant diagnostic morphological characters in the absence of phylogenetic considerations, can contain non-monophyletic lineages. This is especially true at the species level where small amounts of gene flow may not preclude the evolution of localized adaptions in different geographic areas while underpinning the paraphyletic nature of each population with respect to the other. We illustrate this point by examining genetic and morphological variation among three putatively allopatric populations of the granite-dwelling Bent-toed Gecko Cyrtodactylus aequalis from hilly regions in southeastern Myanmar. In the absence of molecular phylogenetic inference, a compelling argument for three morphologically diagnosable species could be marshaled. However, when basing the morphological analyses of geographic variation on a molecular phylogeny, there is a more compelling argument that only one species should be recognized. We are cognizant of the fact however, that when dealing with rare species or specimens for which no molecular data are possible, judicious morphological analyses are the only option—and the desired option given the current worldwide biodiversity crisis.

Ecological characteristics of a recently described, critically endangered gecko species, endemic to Central Highland, Vietnam

Gia Lai bent-toed gecko (Cyrtodactylus gialaiensis) was firstly described in 2017, and is an endemic species with very restricted distributional range, estimated to be less than 10 km2 in coffee plantation in Gia Lai province, Central Highland of Vietnam. This species is listed as Critically Endangered (CR) in the IUCN Red List. To date, the natural history of this species is totally unknown. In this paper, we provide the first-of-ever natural history data on this highly threatened gecko species, with emphasis on morphometrics, habitat preferences, thermal ecology, and activity patterns. In 23 days of surveys, we captured 42 C. gialaiensis individuals and recaptured 4 of them. Sex ratio was not skewed from equality and juveniles accounted for 23.8% of the observed individuals. The two sexes did not differ in terms of mean Snout-to-Vent Length, Tail Length and weight, but the adult females had longer head than adult males. Geckos were observed at a mean substratum temperature of 24.2±1°C (n=14), and exhibited a mean body temperature of 29.5±2.5°C (n=14). There was no significant correlation between substratum and body temperatures. Body temperatures were significantly higher than substratum temperatures. The study species exhibited a clearly nocturnal above-ground activity, with main peak occurring between 20:00-21:30 h.

Taxonomic evaluation of two similar bent-toed geckos Squamata: Gekkonidae: Cyrtodactylus Gray, 1827) from East Java, Indonesia.

The bent-toed geckos of the genus Cyrtodactylus are the most speciose land vertebrates of Southeast Asia (about 300 species so far) and new species continue to be recognized at a rapid rate. Within the last decade three new species were described from Java, Indonesia, C. semiadii, C. petani, and C. klakahensis. The latter two are very similar, except for differences in the precloacal depression in adult males. These two species have relatively close type localities, separated from each other by only about 50 km, and with similar habitat type and elevation. Our study aimed to evaluate the taxonomic status of C. klakahensis and C. petani using both morphological and genetic evidence. These two species are genetically similar, with a genetic divergence of only 1.5 to 1.6%. This divergence is well below the level of typically characterizes sister species of Cyrtodactylus (approximately 4% in the mitochondrial ND2 gene), and is more in line with population variation due to geographic distance. Further examination of specimens, from both type localities, showed no diagnostic morphological characters between the two species. Thus, we conclude that C. klakahensis and C. petani are conspecific, and following article 23 of the ICZN, C. klakahensis is herein considered a junior synonym of C. petani.

A new species of Cyrtodactylus (Squamata: Gekkonidae) from southern Vietnam.

We describe a new species of Cyrtodactylus on the basis of four specimens collected from Phu My, Binh Dinh Province, southern Vietnam. Cyrtodactylus phumyensis sp. nov. is distinguished from the remaining Indochinese bent-toed geckos by a combination of the following characters: size small (SVL up to 66.8 mm); two internasals; dorsal tubercle rows 18 or 19 at midbody; ventral scale rows 33-41; ventrolateral folds slightly developed; each thigh with 5-7 enlarged femoral scales; femoral pores absent in males and female; a series of 5-7 precloacal pores plus a pitted, enlarged precloacal scale in males; 6 pitted, enlarged precloacal scales in female; paravertebral tubercles 20-23; lamellae under toe IV 18-21; small subcaudal scales, not transversely enlarged; two irregular dark longitudinal stripes on shoulder. In phylogenetic analyses, the new species is recovered as a member of the Cyrtodactylus irregularis species group, and strongly supported as a sister taxon of C. cucdongensis from Khanh Hoa Province.

A NEW BENT-TOED GECKO SPECIES OF THE GENUS Cyrtodactylus GRAY, 1827 (SQUAMATA : GEKKONIDAE) FROM THE WEST BALI NATIONAL PARK, BALI, INDONESIA

A new bent-toed gecko species of the genus Cyrtodactylus is described herein from West Bali National Park on the island of Bali, Indonesia. The Cyrtodactylus from Bali have been recognized as C. fumosus for nearly a century. However, recent detailed examination of the type material of C. fumosus has revealed that Balinese Cyrtodactylus represent at least one different species. A morphological examination of the new species and samples from different biogeographic regions revealed that the new species is similar to C. seribuatensis from Pulau Seribuat in West Malaysia. Morphologically, the new species can be distinguished from its congener by having 40–43 femoro-precloacal pores (vs 10–12 precloacal pores, 14–16 femoral pores), 40–48 ventral scales between ventrolateral folds (vs 28–39), 24–29 rows of dorsal tubercles (vs 27–35), and presence of tubercles on lateral skinfold (vs absent).

A new endemic insular Bent-toed Gecko (Squamata: Gekkonidae: Cyrtodctylus) from Quang Nam Province, Central Vietnam.

A new species of insular Bent-toed Gecko, Cyrtodactylus culaochamensis sp. nov. of the C. irregularis group is described from Cu Lao Cham Mountain, from Hon Lao Island, Hoi An City, Quang Nam Province, Cham Islands, central Vietnam. Cyrtodactylus culaochamensis sp. nov. is the sister species of C. pseudoquadrivirgatus from Ba Na Nui Chua from Danang City, central Vietnam. It differs from all congeners by having a maximum SVL of 79.8 mm (n=5); dark spots on the head edged in white; a fragmented nuchal loop; irregularly shaped, broad, completed or broken dorsal bands; 19-21 interorbital scales across the frontal bone; 28-32 scales between the eye and nostril; 45-50 rows of ventral scales between the ventrolateral folds; scattered, smooth tubercles; 20-22 irregular, longitudinal rows of weakly keeled tubercles at midbody between the ventrolateral folds; seven or eight precloacal pores in a chevron pattern in males; no enlarged femoral scales, no femoral pores; 13-15 subdigital lamellae on first toe; 20-23 subdigital lamellae on fourth toe; and very slightly enlarged subcaudal scales.

A new potentially endangered limestone-associated Bent-toed Gecko of the Cyrtodactylus pulchellus (Squamata: Gekkonidae) complex from northern Peninsular Malaysia.

A survey of a limestone forest at Gunung Baling, Kedah, West Malaysia lead to the discovery of an undescribed species of Bent-toed Gecko from the Cyrtodactylus pulchellus complex. Cyrtodactylus evanquahi sp. nov. can be distinguished from all other species in the C. pulchellus complex by a suite of morphological and color pattern characteristics: prominent tuberculation, higher number of dark body bands, and a smaller maximum SVL. It is further differentiated from all other species as follows; no tubercles on the ventral surface of the forelimbs, gular region, or in the ventrolateral folds; 31-34 paravetebral dorsal tubercles; 18-23 longitudinal rows of tubercles; 29-33 ventral scales; 22-23 subdigital lamellae on the fourth toe; 32-36 femoroprecloacal pores; a shallow precloacal groove in males; body bands and nuchal loop edged with a thin white line bearing tubercles; no scattered white spots on the dorsum; six or seven dark body bands much thinner than interspaces; 9-11 dark caudal bands on original tail; bands on the original tail separated by immaculate white caudal bands. It is further differentiated by an uncorrected pairwise genetic divergence of 6.50-15.67% from all other congeners in the C. pulchellus complex. It is most closely related to C. pulchellus from Penang Island ∼76 km to the southwest. In addition to the new samples from Gunung Baling, we added four samples of C. bintangrendah from the new locality of Belukar Semang, Perak. The discovery of yet another new species of the C. pulchellus complex from a limestone habitat continues to underscore the high degree of endemism and the importance of these unique habitats for biodiversity, and the continued need for their conservation.

Easternmost Locality Record and Morphological Data of Cyrtopodion scabrum (Heyden, 1827) (Squamata: Gekkonidae) in southeastern Anatolia, Turkey

<p class="ql-align-justify">The locality record of the Rough Bent-toed Gecko (Cyrtopodion scabrum) from the Silopi District of the Şırnak Province of Turkey was provided in the present study. The new locality record extended the distribution area of the species 40 km to the east. Data based on meristic pholidosis characters, metric measurements and color-patter features of the specimens from Silopi were given in detail and compared with data given in the previous literature.

A new species of Cyrtodactylus Gray (Gekkonidae: Squamata) from Manus Island, and extended description and range extension for Cyrtodactylus sermowaiensis (De Rooij).

Systematic investigations of vertebrate faunas from the islands of Melanesia are revealing high levels of endemism, dynamic biogeographic histories, and in some cases surprisingly long evolutionary histories of insularity. The bent-toed geckos in the Cyrtodactylus sermowaiensis Group mainly occur in northern New Guinea and nearby islands, however a further isolated population occurs on Manus Island in the Admiralty Archipelago approximately 300 km to the north of New Guinea. Here we first present a review of the genetic diversity, morphological variation and distribution of Cyrtodactylus sermowaiensis from northern New Guinea. Genetic structure and distributional records within Cyrtodactylus sermowaiensis broadly overlap with underlying Terranes in northern New Guinea, suggesting divergence on former islands that have been obscured by the infill and uplift of sedimentary basins since the late Pleistocene. Based on a combination of genetic and morphological differentiation we then describe the population from Manus Island as a new species, Cyrtodactylus crustulus sp. nov. This new species emphasises the high biological endemism and conservation significance of the Admiralty Islands, and especially Manus Island.

A new species of Cyrtodactylus (Squamata: Gekkonidae) from central New Guinea.

We describe a new species of bent-toed gecko in the genus Cyrtodactylus from hill forest in Southern Highlands Province, Papua New Guinea. Cyrtodactylus manos sp. nov. can be distinguished from all congeners in New Guinea by its small size in combination with aspects of colouration and body and tail scalation. The new species adds to the growing number of vertebrate species known only from karstic mountains along the southern edge of New Guinea's Central Cordillera, suggesting that this region holds previously overlooked endemic karst-associated biota.

Gastrointestinal Tract and Accessory Organs in the Spotted Bent-toed Gecko, Cyrtodactylus peguensis (Boulenger, 1893): A Histological and Histochemical Study

AbstractThe spotted bent-toed gecko Cyrtodactylus peguensis is one of the exploited reptiles in Thailand. In order to provide basic information for the digestive system of this species, we have examined histologically the gastrointestinal and accessory organs of C. peguensis using routine methods. The gastrointestinal region of this reptile started from the stomach and the intestine. The stomach was separated into fundic and pyloric regions. In both regions, the stomach wall was formed by four distinct tissue layers, including mucosa, submucosa, muscularis, and serosa layers. Mucous neck cells and oxynticopeptic cells were identified as glycoprotein-producing cells in the stomach by Periodic acid-Schiff (PAS) staining. The small and large intestines shared many histological characteristics, but the former contained more intestinal folds, while the latter had more PAS-positive goblet cells. Histological characteristics of accessory organs, liver and pancreas, were also provided. Overall, the gastrointestinal and accessory organs of C. peguensis were largely similar to those from other reptiles, but fine structural information will open up considerable opportunities to further studies related to the endocrinology, the physiology, and the conservation of this species.

A new species of forest-dwelling Cyrtodactylus Gray (Squamata: Gekkonidae)from the Indawgyi Wildlife Sanctuary, Kachin State, Myanmar.

A herpetological survey of the Indawgyi Wildlife Sanctuary in Kachin State, Myanmar resulted in the discovery of a new species of Cyrtodactylus Gray along the eastern watershed of the Mokso Mountains. An integrative taxonomic analysis based on the mitochondrial ND2 gene, morphology, and color pattern recovered this new species, Cyrtodactylus mombergi sp. nov., as the sister taxon to an undescribed species from Miao, Arunachal Pradesh, India. Bayesian and maximum likelihood analyses recovered notable genetically divergent (4.7%) phylogeographic structure between northern and southern populations of C. mombergi sp. nov. across only 14 km of continuous habitat. Conversely, genetic divergence did not exceed 9.2% between C. mombergi sp. nov. and the undescribed species from Miao from across 355 km of habitat. Cyrtodactylus mombergi sp. nov. belongs to a well-supported, mitochondrial clade of 18 other species which now compose an expanded and redefined C. gansi group. Cyrtodactylus mombergi sp. nov. is only the third species of Bent-toed Gecko reported from Kachin State and indicates that additional herpetological surveys are needed in unexplored forested areas.

Two more new species of the Cyrtodactylus peguensis group (Squamata: Gekkonidae) from the fringes of the Ayeyarwady Basin, Myanmar.

Two new species of Bent-toed Geckos of the Cyrtodactylus peguensis group are described from foothill areas occurring on opposite sides of the Ayeyarwady Basin. Cyrtodactylus nyinyikyawi sp. nov. from the Shwe Settaw Wildlife Sanctuary, Magway Region in the east and C. pyadalinensis sp. nov. from the Panluang-Pyadalin Wildlife Sanctuary, Shan State in the west bear unique suits of morphological and color pattern character states separating them from all species in the peguensis group. Additionally, a molecular phylogeny based on the mitochondrial gene ND2 indicates that neither species is nested within, nor sister to any known species in the group. This study augments recent and ongoing studies showing that the Ayeyarwady Basin is herpetologically more diverse than previously considered and should be incorporated into ongoing discussions concerning conservation efforts in Myanmar.

Diversification of bent-toed geckos (Cyrtodactylus) on Sumatra and west Java

Complex geological processes often drive biotic diversification on islands. The islands of Sumatra and Java have experienced dramatic historical changes, including isolation by marine incursions followed by periodic connectivity with the rest of Sundaland across highland connections. To determine how this geological history influenced island invasions, we investigated the colonization history and diversification of bent-toed geckos (genus Cyrtodactylus) on Sumatra and west Java. We used mitochondrial and nuclear sequence data to explore species boundaries, estimate phylogenetic relationships and divergence times, and to reconstruct ancestral range evolution. We found that Sumatran and Javan Cyrtodactylus were closely related to species from the Thai-Malay Peninsula, rather than from Borneo, and that Cyrtodactylus most likely dispersed to Sumatra three times during the late Oligocene and early Miocene. Similarly, Cyrtodactylus invaded west Java from Sumatra once in the early Miocene. Our results suggest that despite isolation by marine incursions during much of the Miocene, Cyrtodactylus dispersed to and from Sumatra and west Java likely via land bridges, and that in situ diversification occurred several times on Sumatra.

A new species of Cyrtodactylus (Squamata: Gekkonidae) from northwestern Vietnam.

We describe a new species of Cyrtodactylus on the basis of seven specimens collected from karst forests of Son La and Dien Bien provinces, Vietnam. Cyrtodactylus taybacensis sp. nov. is distinguished from the remaining Indochinese bent-toed geckos by a combination of the following characters: medium size (SVL up to 97.5 mm); dorsal tubercles in 13-16 irregular rows; ventral scale rows 30-38; ventrolateral folds present without interspersed tubercles; each thigh with 11-13 enlarged femoral scales; femoral pores absent in males and females; precloacal pores 11-13 in males, five or 15 pitted scales in females, in a continuous row; postcloacal tubercles two or three; lamellae under toe IV 16-20; subcaudal scales transversely enlarged; dorsal head with dark brown marking, oval, triangle and arched shape; five brown dorsal bands between limb insertions. In phylogenetic analyses, the new species is recovered as a member of the Cyrtodactylus wayakonei species group, and strongly supported as the sister taxon of C. cf. bichnganae from Son La City in all analyses.

A NEW DISTRIBUTION RECORD OF Cyrtodactylus soni Le, Nguyen, Le &amp; Ziegler, 2016 (Reptilia: Squamata: Gekkonidae) FROM HOA BINH PROVINCE AND THREATS TO THE POPULATION

A new population of the Son’s Bent-toed Gecko (Cyrtodactylus soni), an endemic species of Vietnam is reported for the first time from Hoa Binh Province based on three male adult specimens collected in June 2018 within a karst cave of Dong Tam commune, Lac Thuy District. The population of this species in Hoa Binh Province is threatened by habitat loss through converting forest to agriculture and quarrying of limestone. Assessment of population status and threats to the population in the study area is urgently needed to provide scientific data for conservation measures.