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Integrative Taxonomy and DNA Barcoding Reveal a New Species of Crab-Eating Snake, Fordonia Gray (Squamata, Homalopsidae) from Vietnam

Phuc Hong Chau, Vu Dang Hoang Nguyen, Khoa Dang Dang, Truong Minh Nhat Nguyen, Ngon Quang Lam, Thinh Gia Tran, Binh Huy Cao, Trung Van Phan, Nikolai L. Orlov, Thao Thi Phuong Nguyen

Abstract


Fordonia Gray, 1836 is widely distributed snake from India’s Nicobar Islands and the coastal regions of Bangladesh and Myanmar across Southeast Asia to New Guinea and northern Australia, and is currently regarded as a monotypic genus with Fordonia leucobalia Schlegel, 1837 as its only recognized species. By integrating morphological and molecular analyses, we describe Fordonia hoani sp. nov. from coastal southern Vietnam, thereby elevating the genus Fordonia to include two recognized species. Fordonia hoani sp. nov. is distinguished from F. leucobalia sensu stricto by the unique combination of the following morphological characteristics: medium-sized snake, elongated, and cylindrical; head depressed, slightly distinct from neck; tail short (TaL/SVL 10.3 – 12.9% in females); dorsal scale rows 25(27) – 25(27) – (21 – 23), smooth; ventrals 145 – 152, usually present 1 – 2 last ventrals divided; subcaudals 29 – 32, all paired or some single and some paired; anal divided; nasals separated by a single internasal; 5 supralabials; 7 infralabials; usually absent loreal; dorsum olive to gray brown with dark spots or uniform dark brown. The new species forms an independent clade on the phylogenetic tree and differs from F. leucobalia sensu stricto by a significant divergence in cytochrome b mitochondrial DNA gene sequences (4.73%). Additionally, we also provide DNA barcoding data for this species. Our finding provides a basis for re-evaluating the taxonomic status of previously synonymized populations with F. leucobalia and populations currently identified as «F. leucobalia» across other regions.

Keywords


Can Gio Mangrove Biosphere Reserve; Homalopsid; monotypic; southern Vietnam

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References


Aldhebiani A. Y. (2017), «Species concept and speciation», Saudi J. Biol. Sci., 25(3), 437 – 440. DOI: 10.1016/j.sjbs.2017.04.013

Alfaro M. E., Karns D. R., Voris H. K., Brock C. D., and Stuart B. L. (2008), «Phylogeny, evolutionary history, and biogeography of Oriental-Australian rear-fanged water snakes (Colubroidea: Homalopsidae) inferred from mitochondrial and nuclear DNA sequences», Mol. Phylogen. Evol., 46(2), 576 – 593. DOI: 10.1016/j.ympev.2007.10.024

Bickford D., Lohman D. J., Sodhi N. S., Nguyen P. K. L., Meier R., Winker K., Ingram K. K., and Das I. (2007), «Cryptic species as a window on diversity and conservation», Trends Ecol. Evol., 22(3), 148 – 155. DOI: 10.1016/j.tree.2006.11.004

Bernstein J. M., Murphy J. C., Voris H. K., Brown R. M., and Ruane S. (2021), «Phylogenetics of mud snakes (Squamata: Serpentes: Homalopsidae): A paradox of both undescribed diversity and taxonomic inflation», Mol. Phylogen. Evol., 160(11), 107109. DOI: 10.1016/j.ympev.2021.107109

Bernstein J. M., Voris H. K., Stuart B. L., Phimmachak S., Seateun S., Sivongxay N., Neang T., Karns D. R., Andrews H. L., Osterhage J., Phipps E. A., and Ruane S. (2022), «Undescribed diversity in a widespread, common group of Asian mud snakes (Serpentes: Homalopsidae: Hypsiscopus)», Ichthyol. Herpetol., 110(3), 561 – 574. DOI: 10.1643/h2022015

Bernstein J. M., Murphy R. W., Lathrop A., Nguyen S. N., Orlov N. L., and Stuart B. L. (2024), «Incorporating new datatypes to enhance species delimitation: a case study in Rice Paddy Snakes (Homalopsidae: Hypsiscopus)», Zootaxa, 5501(1), 39 – 55. DOI: 10.11646/zootaxa.5501.1.2

Boulenger G. A. (1896), Catalogue of the Snakes in the British Museum (Natural History). Vol. III, British Museum (Natural History), London.

Burbrink F. T., Lawson R., and Slowinski J. B. (2000), «Mitochondrial DNA phylogeography of the polytypic North American Rat Snake (Elaphe obsoleta): a critique of the subspecies concept», Evolution, 54(6), 2107 – 2118. DOI: 10.1111/j.0014-3820.2000.tb01253.x

Campden-Main S. M. (1970), A Field Guide to the Snakes of Vietnam, Smithsonian Institution, Washington, D.C.

Che J., Chen H. M., Yang J. X., Jin J. Q., Jiang K., Yuan Z. Y., Murphy R. W., and Zhang Y. P. (2012), «Universal COI primers for DNA barcoding amphibians», Mol. Ecol. Resources, 12(2), 247 – 258. DOI: 10.1111/j.1755-0998.2011.03090.x

Duméril A. M. C., Bibron G., and Duméril A. H. A. (1854), Erpétologie générale ou histoire naturelle complète des reptiles. Vol. VII, Librairie Encyclopédique de Roret, Paris.

Dowling H. G. (1951), «A proposed standard system of counting ventrals in snakes», Br. J. Herpetol., 1(5), 97 – 99.

Dayrat D. (2005), «Towards integrative taxonomy», Biol. J. Linn. Soc., 85(85), 407 – 415. DOI: 10.1111/j.1095-8312.2005.00503.x

Edgar R. C. (2004), «MUSCLE: multiple sequence alignment with high accuracy and high throughput», Nucleic Acids Res., 32(5), 1792 – 1797. DOI: 10.1093/nar/gkh340

Eckert R. J., Studivan M. S., and Voss J. D. (2019), «Populations of the coral species Montastraea cavernosa on the Belize Barrier Reef lack vertical connectivity», Sci. Rep., 9(1), 7200. DOI: 10.1038/s41598-019-43479-x

Frith C. B. and MacIver D. (1978), «The crab-eating Water Snake, Fordonia leucobalia Schlegel, another snake new to Thailand», Nat. Hist. Bull. Siam Soc., 27, 189 – 191.

Frost D. R. and Hillis D. M. (1990), «Species concept and practice: herpetological applications», Herpetologica, 46(1), 86 – 104.

Figueroa A. and McCleary R. J. R. (2021), «Descending from the trees onto the mud to feed: observation of ophiophagy by Trimeresurus purpureomaculatus (Gray, 1832) on Fordonia leucobalia (Schlegel, 1837)», Herpetol. Notes, 14, 1281 – 1285.

Ghiselin M. T. (2001) «Species concepts», in: J. Wiley and Sons (eds.), Encyclopedia of Life Sciences. DOI: 10.1038/npg.els.0001744

Gray J. E. (1842), «Monographic synopsis of the water snakes, or the family Hydridae», Zool. Miscellany, 1(2), 59 – 68.

Gray J. E. (1849), Catalogue of the Specimens of Snakes in the Collection of the British Museum, British Museum (Natural History), London.

Gyi K. K. (1970), «A revision of colubrid snakes of the subfamily Homalopsinae», Univ. Kansas Publ. Mus. Nat. Hist., 20(2), 47 – 223.

Hillis D. M. and Bull J. J. (1993), «An empirical test of bootstrapping as a method for assessing confidence in phylogenetic analysis», Syst. Biol., 42(2), 182 – 192. DOI: 10.1093/sysbio/42.2.182

Hoang D. T., Chernomor O., Haeseler V. A., Minh B. Q., and Le V. S. (2018), «UFBoot2: Improving the ultrafast bootstrap approximation», Mol. Biol. Evol., 35, 518 – 522. DOI: 10.1093/molbev/msx281

IUCN (2012), IUCN Red List Categories and Criteria: Version 3.1. 2nd edition, IUCN, Gland and Cambridge.

Karns D. R., Voris H. K., and Goodwin T. G. (2002), «Ecology of Oriental-Australian rear-fanged water snakes (Colubridae: Homalopsinae) in the Pasir Ris Park Mangrove Forest, Singapore», Raffles Bull. Zool., 50(2), 487 – 498.

Kopstein F. (1931), «IV. Fordonia leucobalia Schlegel und Cerberus rhynchops Schneider», Treubia, 13(1), 1 – 4.

Karbstein K., Kösters L., Hodaè L., Hofmann M., Hörandl E., Tomasello S., Wagner N. D., Emerson B. C., Albach D. C., Scheu S., Bradler S., de Vries J., Irisarri I., Li H., Soltis P., Mäder P., and Wäldchen J. (2024), «Species delimitation 4.0: integrative taxonomy meets artificial intelligence», Trends Ecol. Evol., 39(8), 771 – 784. DOI: 10.1016/j.tree.2023.11.002

Letunic I. and Bork P. (2024), «Interactive Tree of Life (iTOL) v6: recent updates to the phylogenetic tree display and annotation tool», Nucleic Acids Res., 52(W1), W78 – W82. DOI: 10.1093/nar/gkae268

Macleay W. (1877), «The ophidians of the Chevert Expedition», Proc. Linn. Soc. New South Wales, 2, 33 – 41.

Macleay W. (1878), «Notes on a collection of snakes from Port Darwin», Proc. Linn. Soc. New South Wales, 2, 219 – 222.

Murphy J. C. (2007), Homalopsid Snakes: Evolution in the Mud, Krieger Publishing Company, Malabar, FL.

Murphy J. C., Voris H. K., and Karns D. R. (2012), «The dog-faced water snakes, a revision of the genus Cerberus Cuvier, (Squamata, Serpentes, Homalopsidae), with the description of a new species», Zootaxa, 3484, 1 – 34. DOI: 10.11646/zootaxa.3484.1.1

Murphy J. C. and Voris H. K. (2014), «A checklist and key to the homalopsid snakes (Reptilia, Squamata, Serpentes), with the description of new genera», Fieldiana Life Earth Sci., 2014(8), 1 – 43.

Müller S. and Schlegel H. (1844) «Over de tot heden bekende eekhorens (Sciurus) van den Indischen Archipel», in: C. J. Temminck (ed.), Verhandelingen over de natuurlijke geschiedenis der Nederlandsche overzeesche bezittingen, door de Leden der Nauurkundige commissie in Indië en andere Schrijvers, Zoologie, In commissie bij. S. en J. Luchtmans en C. C. van der Hoek, Leiden, pp. 85 – 102.

Minh B. Q., Nguyen M. A. T., and Haeseler C. A. (2013), «Ultrafast approximation for phylogenetic bootstrap», Mol. Biol. Evol., 30(5), 1188 – 1195. DOI: 10.1093/molbev/mst024

Nixon K. C. and Wheeler Q. D. (1990), «An amplification of the phylogenetic species concept», Cladistics, 6(3), 211 – 223. DOI: 10.1111/j.1096-0031.1990.tb00541.x

Nylander J. A. A. (2004), MrModeltest v. 2, Evolutionary Biology Centre, Uppsala University.

Nguyen S. V., Ho C. T., and Nguyen T. Q. (2009), Herpetofauna of Vietnam, Edition Chimaira, Frankfurt.

Nguyen L. T., Schmidt H. A., Haeseler V. A., and Minh B. Q. (2015), «IQ-TREE: A fast and effective stochastic algorithm for estimating maximum likelihood phylogenies», Mol. Biol. Evol., 32(1), 268 – 274. DOI: 10.1093/molbev/msu300

Nguyen S. N., Le M. V., Lathrop A., Vo T. D. H., Murphy R. W., and Che J. (2024), «A new species of mud snake (Squamata: Homalopsidae: Myrrophis) from southern Vietnam», Vertebr. Zool., 74, 221 – 233. DOI: 10.3897/vz.74.e116992

Pauwels O. S. G. and Sumontha M. (2008), «Geographic distributon notes. Fordonia leucobalia (Crab-eating Snake)», Herpetol. Rev., 39(3), 371.

Quah E. S. H., Grismer L. L., Wood P. L., Thura M. K., Zin T., Kyaw H., Lwin N., Grismer M. S., and Murdoch M. L. (2017), «A new species of Mud Snake (Serpentes, Homalopsidae, Gyiophis Murphy et Voris, 2014) from Myanmar with a first molecular phylogenetic assessment of the genus», Zootaxa, 4238(4), 571 – 582. DOI: 10.11646/zootaxa.4238.4.5

Ronquist F., Teslenko M., Mark P. V. D., Ayres D. L., Darling A., Höhna S., Larget B., Liu L., Suchard M. A., and Huelsenbeck J. P. (2012), «MrBayes 3.2: efficient Bayesian phylogenetic inference and model choice across a large model space», Syst. Biol., 61(3), 539 – 542. DOI: 10.1093/sysbio/sys029

Rahman S. C., Reza A. A., Datta R., Jenkins C. L., and Luiselli L. (2014), «Niche partitioning and population structure of sympatric mud snakes (Homalopsidae) from Bangladesh», Herpetol. J., 24(2), 123 – 128.

Schlegel H. (1837), Essai sur la Physionomie des serpens. Vol. 1, 2, M. H. Schonekat, Amsterdam.

Smith M. A. (1943), The Fauna of British India, Ceylon, and Burma, Including the Whole of the Indo-chinese Sub-region: Reptilia and Amphibia. Vol. 3. Serpentes, Taylor and Francis, London.

Stucky B. J. (2012), «SeqTrace: a graphical tool for rapidly processing DNA sequencing chromatograms», J. Biomol. Techniques, 23(3), 90 – 93. DOI: 10.7171/jbt.12-2303-004

Theobald W. (1868), «Catalogue of the Reptiles of British Birma, embracing the Provinces of Pegu, Martaban, and Tenasserim; with descriptions of new or little-known species», Zool. J. Linn. Soc., 10(41), 4 – 67.

Taylor E. H. (1922), The Snakes of the Philippine Islands, Bureau of Printing, Manila.

Trifinopoulos J., Nguyen L. T., Haeseler V. A., and Minh B. Q. (2016), «W-IQTREE: A fast online phylogenetic tool for maximum likelihood analysis», Nucleic Acids Res., 44(W1), W232 – W235. DOI: 10.1093/nar/gkw256

Tamura K., Stecher G., and Kumar S. (2021), «MEGA11: Molecular Evolution ary Genetics Analysis version 11», Mol. Biol. Evol., 38(7), 3022 – 3027. DOI: 10.1093/molbev/msab120

Ukuwela K. D. B., Silva A. D., and Sanders K. L. (2017), «Further specimens of the mud snake, Gerarda prevostiana (Homalopsidae) from Sri Lanka with insights from molecular phylogenetics», Raffles Bull. Zool., 65, 29 – 34.

Uetz P., Freed P., Aguilar R., Reyes F., Kudera J., and Hošek J. (2025), The Reptile Database, http://www.reptile-database.org (accessed May 7, 2025).




DOI: https://doi.org/10.30906/1026-2296-2026-33-1-1-12

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