A morphological and molecular review of the genus Goniurosaurus, including an identification key

Abstract

The genus Goniurosaurus (tiger geckos) currently consists of 23 species distributed in China, Japan and Vietnam. Several species complexes and recent discoveries of cryptic species pose challenges to the species identification, which is crucial to effectively implement the recent listing of the species from China and Vietnam in CITES Appendix II and the species from Japan in CITES Appendix III. Based on the results of our field work in northern Vietnam and data compiled from literature, we herein provide a taxonomic review of the genus Goniurosaurus. Our phylogenetic analyses showed that all recorded populations of tiger geckos from Vietnam, which were found to be monophyletic with low intra-specific genetic divergences, are assigned to one of the four species: G. catbaensis, G. huuliensis, G. lichtenfelderi or G. luii. Both genetic and morphological analyses confirm that the species from China and Vietnam can be split into three major groups. Based on the newly collected data, we provide an extended morphological description of the Vietnamese species. In addition, we provide an identification key for all Goniurosaurus species from China, Japan and Vietnam in order to assist authorities in the enforcement of the recent CITES listing.

Living under the risk of extinction: population status and conservation needs assessment of a micro–endemic tiger gecko in Vietnam

“…In view of the ongoing severe human impacts, conservation measures to safeguard wild populations of the target species are urgently required. Recent studies on trade (Ngo et al, 2019b), taxonomy (Ngo et al, 2021b), ecology (Ngo et al, in press), impacts of climate change (Ngo et al, 2021a), and population status (this study) fill the gaps in basic knowledge on the biology of G. huuliensis. On the basis of findings from such research, in-situ and ex-situ conservation actions can be simultaneously implemented more effectively in the future.…”

“…Combined with the projected results of environmentally suitable habitats (climate and vegetation cover) (Ngo et al, 2021a), inhabited elevation ranges and karst formations (Ngo et al, in press), we were able to estimate the global population size of G. huuliensis. Similar to other tiger gecko species, the population size of G. huuliensis was predicted to be extremely small (Ngo et al, 2016b(Ngo et al, , 2019a(Ngo et al, , 2021b.…”

“…Population densities of G. huuliensis were calculated per kilometer (indiv./km) with reference to each surveyed transect, and per day (indiv./km/day). To assess the age structure of the G. huuliensis population, geckos were categorized into two classes based on their snout-vent length (juveniles with SVL < 85 mm and adults with SVL ≥ 85 mm) (Ngo et al, 2021b). The sex of each captured individual was determined based on the presence of large swollen hemipenal bulges and 25-30 precloacal pores in males, and the lack of these characteristics in females (Orlov et al, 2008;Ngo et al, 2021b).…”

“…To assess the age structure of the G. huuliensis population, geckos were categorized into two classes based on their snout-vent length (juveniles with SVL < 85 mm and adults with SVL ≥ 85 mm) (Ngo et al, 2021b). The sex of each captured individual was determined based on the presence of large swollen hemipenal bulges and 25-30 precloacal pores in males, and the lack of these characteristics in females (Orlov et al, 2008;Ngo et al, 2021b). To test for significant differences in the age and sex structures between surveyed periods, we used a Chi-square test.…”

“…Besides serving as preferred habitat and refugia for almost tiger gecko species under impacts of climate change, the karstic ecosystem containing complex topographies and unique micro-environmental conditions is considered the ancestral habitat of Goniurosaurus species (Grismer et al, 2021;Ngo et al, 2021b). Karst formations indeed are identified as the exclusive habitat of G. huuliensis (Ngo et al, in press); as such, its existence depends entirely on the integrity of karstic habitats.…”