Abstract
A new species of the Cyrtodactylus intermedius group, C. kiriromensis sp. nov., from Kirirom National Park of Phnom Sruoch in the Cardamom Mountains of Cambodia is delimited based on a mitochondrial (ND2) phylogeny and statistically diagnosed using meristic, morphometric, and color pattern characters. Cyrtodacytylus kiriromensis sp. nov. is the sister species of C. septimontium of southern Vietnam and forms part of a clade with six other site-specific endemic species from the mountains and islands of southeastern Cambodia and southwestern Vietnam. The ongoing discoveries of localized endemic species in the Cardamom Mountains underscores their fragmented nature and the importance of this landscape as a source of speciation as well as its notable contribution to the herpetological diversity of Cambodia. As such, it should be given special consideration as a conservation priority.
References
- Akil, M.A.M.M., Hong, Z., Sah, S.A.M., Ramli, R. & Grismer, L.L. (2025) Expanded morphological description of the Pawang Bent-toed Gecko Cyrtodactylus disjunctus of Thailand and a new country record for Malaysia. Zootaxa, 5637 (2), 260–270. https://doi.org/10.11646/zootaxa.5637.2.2
- Ampai, N., Aowphol, A., Yodthong, S., Termprayoon, K., Grismer, L.L. & Rujirawan, A. (2025) Description of a new forest-dwelling bent-toed gecko of the Cyrtodactylus intermedius group (Squamata: Gekkonidae) from the Sakaerat Biosphere Reserve, Nakhon Ratchasima Province, northeastern Thailand. Zootaxa, 5666 (3), 361–388. https://doi.org/10.11646/zootaxa.5666.3.3
- Ampai, N., Rujirawan, A., Yodthong, S., Termprayoon, K., Stuart, B.L. & Aowphol, A. (2024) A new species of karst-dwelling bent-toed gecko of the Cyrtodactylus intermedius group (Squamata, Gekkonidae) from eastern Thailand and the phylogenetic placement of C. intermedius. ZooKeys, 1211, 101–130.
- https://doi.org/10.3897/zookeys.1211.122563
- Barraclough, T.G., Birky, C.W., Jr. & Burt, A. (2003) Diversification in sexual and asexual organisms. Evolution, 57, 2166–2172. https://doi.org/10.1111/j.0014-3820.2003.tb00394.x
- Chan, K.O. & Grismer, L.L. (2022) GroupStruct: An R package for allometric size correction. Zootaxa, 5124 (4), 471–482. https://doi.org/10.11646/zootaxa.5124.4.4
- Chan, K.O. & Grismer, L.L. (2026) GroupStruct2: A User-Friendly Graphical User Interface for Statistical and Visual Support in Species Diagnosis. Systematic Biology. [In Press]
- Chhin, S., Neang, T., Cha, S., Kong, K., Ou, R., Samorn, V., Sor, R., Lou, V., Chhim, M., Stuart, B.L. & Grismer, L.L. (2024) A new species in the Cyrtodactylus intermedius (Squamata: Gekkonidae) group from an isolated limestone karst formation in southwestern Cambodia. Zootaxa, 5474 (1), 1–20.
- https://doi.org/10.11646/zootaxa.5474.1.1
- de Queiroz, K (2007) Species concepts and species delimitation. Systematic Biology, 56, 879–886. https://doi.org/10.1080/10635150701701083
- Frost, D.R. & Hillis, D.M. (1990) Species in concept and practice: herpetological application. Herpetologica, 46, 87–104. https://doi.org/10.1655/08-031r1.1
- Frost, D.R. & Kluge, A.G. (1994) A consideration of the epistemology in systematic biology, with special reference to species. Cladistics, 10, 259–294. https://doi.org/10.1111/j.1096-0031.1994.tb00178.x
- Grismer, L.L. (2025) Introducing multiple factor analysis (MFA) as a diagnostic taxonomic tool complementing principal component analysis (PCA). ZooKeys, 1248, 93–109. https://doi.org/10.3897/zookeys.1248.159516
- Grismer, L.L., Chan, K.O., Oaks, J.R., Neang, T., Sokun, L., Murdoch, M.L., Stuart, B.L. & Grismer, J.L. (2020) A new insular species of the Cyrtodactylus intermedius (Squamata: Gekkonidae) group from Cambodia with a discussion of habitat preference and ecomorphology. Zootaxa, 4830 (1), 75–102. https://doi.org/10.11646/zootaxa.4830.1.3
- Grismer, L.L., Chav T., Neang, T., Wood, Jr., P.L., Grismer, J.L., Youmans, T.M., Ponce, A., Daltry, J.C. & Kaiser, H. (2007) The herpetofauna of the Phnom Aural Wildelife Sanctuary and checklist of the herpetofauna of the Cardamom Mountains, Cambodia. Hamadryad, 31, 216–241.
- Grismer L.L., Geissler,P., Neang, T., Hartmann, T., Wagner, P. & Poyarkov, N.A. (2021b) Molecular phylogenetics, PCA, and MFA recover a new species of Cyrtodactylus (Squamata: Gekkonidae) from an isolated sandstone massif in northwestern Cambodia. Zootaxa, 4949 (2), 261–288. https://doi.org/10.11646/zootaxa.4949.2.3
- Grismer, L.L., Neang, T., Chav, T. & Grismer, J.L. (2008a) Checklist of the amphibians and reptiles of the Cardamom region of southwestern Cambodia. Cambodian Journal of Natural History, 1, 12–28.
- Grismer, L.L., Neang, T., Chav, T., Wood Jr, P.L., Oaks, J.R., Holden, J., Grismer, J.L., Szutz, T.R. & Youmans, T.M. (2008b) Additional amphibians and reptiles from the Phnom Samkos Wildlife Sanctuary in northwestern Cardamom Mountains, Cambodia, with comments on their taxonomy and the discovery of three new species. The Raffles Bulletin of Zoology, 56 (1), 161–175.
- Grismer, L.L., Pawangkhanant, P., Idiiatullina, S.S., Trofimets, A.V., Nazarov, R.A., Suwannapoom, C. & Poyarkov, N.A. (2023) 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. Zootaxa, 5352 (1), 109–136. https://doi.org/10.11646/zootaxa.5352.1.4
- Grismer, L.L.& Smith, J. (2023) 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. Zootaxa, 5346 (3), 307–316. https://doi.org/10.11646/zootaxa.5346.3.4
- Grismer, L.L., Wood, P.L., Jr., Myint K.T., Thaw, Z., Quah, E.S.H., Murdoch, M.L., Grismer, M.S., Aung, L., Htet, K. & Ngwe Lwin (2018) Twelve new species of Cyrtodactylus Gray (Squamata: Gekkonidae) from isolated limestone habitats in east- central and southern Myanmar demonstrate high localized diversity and unprecedented microendemism. Zoological Journal of the Linnean Society, 182, 862–959. https://doi.org/10.1093/zoolinnean/zlx057
- Grismer, L.L., Wood, Jr., P.L., Poyarkov, N.A., Le, M.D., Karunarathna, S., Chomdej, S., Suwannapoom, C., Qi, S., Liu, S., Che, J., Quah, E.S.H., Kraus, F., Oliver, P.M., Riyanto, A., Pauwels, O.S.G., Grismer, J.L. (2021a) Karstic landscapes are foci of species diversity in the World’s Third-Largest Vertebrate genus Cyrtodactylus Gray, 1827 (Reptilia: Squamata; Gekkonidae). Diversity, 13, 183. https://doi.org/10.3390/d13050183
- Hillis D.M. (2019) Species delimitation in herpetology. Journal of Herpetology, 53, 3–12. https://doi.org/10.1670/18-123
- Hoang, D.T., Chernomor, O., von Haeseler, A., Minh, B.Q. & Vinh, L.S. (2018) UFBoot2: Improving the ultrafast bootstrap approximation. Molecular Biology and Evolution, 35 (2), 518–522. https://doi.org/10.1093/molbev/msx281
- Holden, J. (2023) Amphibians of Cambodia. A Field Guide. Edition Chimaira, Frankfurt am Main. 256 pp.
- Huelsenbeck, J.P. & Ronquist, F. (2001) MRBAYES: Bayesian inference of phylogenetic trees. Bioinformatics, 17 (8), 754–755. https://doi.org/10.1093/bioinformatics/17.8.754
- Husson, F., Lê, S. & Pagès, J. (2017) Exploratory Multivariate Analysis by Example Using R. 2nd Edition. Chapman & Hall/CRC, Boca Raton, Florida, 262 pp. https://doi.org/10.1201/b21874
- Kalyaanamoorthy, S., Minh, B.Q., Wong, T.K., von Haeseler, A. & Jermiin, L.S. (2017) ModelFinder: fast model selection for accurate phylogenetic estimates. Nature Methods, 14, 587. https://doi.org/10.1038/nmeth.4285
- Kassambara, A. & Mundt, F. (2017) Factoextra: extract and visualize the result of multivariate data analyses. R package, version 1.0.5.999. Available from: http://cran.r-project.org/web/packages/factoextra/index.html (accessed 22 November 2025) https://doi.org/10.32614/cran.package.factoextra
- Lleonart, J., Salat, J. & Torres, G.J. (2000) Removing allometric effects of body size in morphological analysis. Journal of Theoretical Biology, 205, 85–93. https://doi.org/10.1006/jtbi.2000.2043
- Miller, M.A., Pfeiffe, W. & Schwartz, T. (2010) Creating the CIPRES Science Gateway for inference of large phylogenetic trees. In: Gateway Computing Environments Workshop (GCE), New Orleans (USA). November 2010. IEEE, New Orleans, Louisiana, pp. 1–8. https://doi.org/10.1109/GCE.2010.5676129
- Minh, Q., Nguyen, M.A.T. & von Haeseler A (2013) Ultrafast approximation for phylogenetic bootstrap. Molecular Biology and Evolution, 30, 1188–1195. https://doi.org/10.1093/molbev/mst024
- Murdoch, M.L., Grismer, L.L., Wood, Jr., P.L., Neang, T., Poyarkov, N.A., Tri, N.V., Nazarov, R.A., Aowphol, A., Pauwels, O.S.G., Nguyen, H.N. & Grismer, J.L. (2019) Six new species of the Cyrtodactylus intermedius complex (Squamata: Gekkonidae) from the Cardamom Mountains and associated highlands of Southeast Asia. Zootaxa, 4554 (1), 1–62. https://doi.org/10.11646/zootaxa.4554.1.1
- Neang, T., Grismer, L.L., Hun, S. & Phan C. (2015) New herpetofauna records and range extensions for Daboia siamensis (Smith, 1917) and Gekko petricolus Taylor, 1962 from Cambodia. Cambodian Journal of Natural History, 2015, 172–182.
- Ngo, V.T., Grismer, L.L. & Grismer, J.L. (2008) A new endemic cave dwelling species of Cyrtodactylus Gray, 1827 (Squamata: Gekkonidae) fron the Kien Giang Biosphere Reserve, Southwestern Vietnam. Zootaxa, 1967 (1), 53–62. https://doi.org/10.11646/zootaxa.1967.1.3
- Ngo, V.T., Grismer, L.L. & Grismer, J.L. (2010) A new species of Cyrtodactylus Gray, 1827 (Squamata: Gekkonidae) in Phu Quoc National Park, Kien Giang Biosphere Reserve, southwestern Vietnam. Zootaxa, 2604 (1), 37–51. https://doi.org/10.11646/zootaxa.2604.1.3
- Nguyen, L.T., Schmidt, H.A., von Haeseler, A. & Minh, B.Q. (2015) IQ-TREE: A fast and effective stochastic algorithm for estimating maximum likelihood phylogenies. Molecular Biology and Evolution, 32, 268–274. https://doi.org/10.1093/molbev/msu300
- Oksanen, J., Blanchet, F.G, Friendly, M., Kindt, R., Legendre, P., McGlinn, D., Minchin, P.R., O’Hara, R.B., Simpson, G.L., Solymos, P., Stevens, M.H.H., Szoecs, E. & Wagner, H. (2020) Package ‘vegan’. Version 2.5–7. Available from: https://cran.r-project.org/web/packages/vegan/ (accessed 22 November 2025)
- Quah, E.S.H., Grismer, L.L., Sinovas, P., Chourn, P., Chhin, S., Hun, S., Cobos, A., Geissler, P., Ching, C., Murdoch, M.L., Thi, S., Gregory, J.J., Nguyen, E., Hernandez, A.P., Kaatz, A. & Grismer, J.L. (2025) Geographically structured genetic and morphological variation in a new species of Cyrtodactylus (Squamata, Gekkonidae) from a karstic archipelago in western Cambodia. ZooKeys, 1240, 73–115. https://doi.org/10.3897/zookeys.1240.139691
- R Core Team (2024) R: A language and environment for statistical computing. R foundation for statistical computing, Vienna. Available from: https://www.R-project.org (accessed 22 November 2025)
- Rambaut, A. & Drummond, A.J. (2013) TreeAnnotator v1.8.0 MCMC Output Analysis. http://dx.doi.org/10.1017/cbo9780511819049.020
- Reist, J.D. (1986) An empirical evaluation of coefficients used in residual and allometric adjustment of size covariation. Canadian Journal of Zoology, 64, 1363–1368. https://doi.org/10.1139/z86-203
- Ronquist, F., Teslenko, M., Van Der Mark, P., Ayres, D.L., Darling, A., Höhna, S., Larget, B., Liu, L., Suchard, M.A. & Huelsenbeck, J.P. (2012) MrBayes 3.2: Efficient Bayesian phylogenetic inference and model choice across a large model space. Systematic Biology, 61 (3), 539–542. https://doi.org/10.1093/sysbio/sys029
- Skalski, J.R., Richins, S.M. & Townsend, R.L. (2018) A statistical test and sample size recommendations for comparing community composition following PCA. PLoS ONE, 13, e0206033. https://doi.org/10.1371/journal.pone.0206033
- Smith, M.A. (1917) Descriptions of new reptiles and a new batrachian from Siam. Siamese Journal of the Natural History Society of Siam, 2, 221–225.
- Stuart, B.L.& Emmett, D.A. (2006) A collection of amphibians and reptiles from the Cardamom Mountains, southwestern Cambodia. Fieldiana, New Series, Zoology, 109, 1–27. https://doi.org/10.3158/0015-0754(2006)109[1:acoaar]2.0.co;2
- Thorpe, R.S. (1975) Quantitative handling of characters useful in snake systematics with particular reference to intraspecific variation in the Ringed Snake Natrix natrix (L.). Biological Journal of the Linnean Society, 7, 27–43. https://doi.org/10.1111/j.1095-8312.1975.tb00732.x
- Thorpe, R.S. (1983) A review of the numerical methods for recognising and analysing racial differentiation. In: Felsenstein, J. (Ed.), Numerical Taxonomy. NATO ASI Series. Vol. 1. Springer, Berlin, Heidelberg, pp. 404–423. https://doi.org/10.1007/978-3-642-69024-2
- Turan, C. (1999) A note on the examination of morphometric differentiation among fish populations: The Truss System. Turkish Journal of Zoology, 23, 259–263.
- Tran, T.G., Lam, N.Q., Nguyen, T.M.N., Nguyen, N.T., Nguyen, T.T.P., Smith, J., Nguyen, V.D.H. & Grismer, L.L. (2024) A new granite cave dwelling endemic species of the Cyrtodactylus intermedius group (Squamata: Gekkonidae) from Hon Son Island, Kien Giang Province, Vietnam. Zootaxa, 5541(4), 485–512. https://doi.org/10.11646/zootaxa.5541.4.4
- Trifinopoulos, J., Nguyen, L.T., von Haeseler, A. & Minh, B.Q. (2016) W-IQ-TREE: a fast online phylogenetic tool for maximum likelihood analysis. Nucleic Acids Research, 44, 232–235. https://doi.org/10.1093/nar/gkw256
- Wilcox, T., Zwickl, D.J., Heath, T.A. & Hillis, D.M. (2002) Phylogenetic relationships of the Dwarf Boas and a comparison of Bayesian and bootstrap measures of phylogenetic support. Molecular Phylogenetics and Evolution 25, 361–371. https://doi.org/10.1016/s1055-7903(02)00244-0
