Abstract
We describe Dixonius mekongensis sp. nov. from sandstone formations in Khong Chiam District, Ubon Ratchathani Province, in extreme eastern Thailand along the Laotian border. The new species differs from all currently recognized Dixonius by the following combination of morphological characters and pattern: maximal known snout-vent length of 51.2 mm; 16 longitudinal rows of dorsal tubercles; 32 to 34 paravertebral scales; 22 to 24 longitudinal rows of ventral scales across the abdomen; seven precloacal pores in males, no pores in females; a marked canthal stripe; and a spotted to uniform dorsal pattern. This description brings the number of Dixonius species to 13, with six species endemic to Thailand.
References
Annandale, N. (1905a) Notes on some Oriental geckos in the Indian Museum, Calcutta, with descriptions of new forms. The Annals and Magazine of Natural History, Series 7, 15 (85), 26–32.
https://doi.org/10.1080/03745480509443635
Annandale, N. (1905b) Contributions to Oriental herpetology II.- Notes on the Oriental lizards in the Indian Museum, with a list of the species recorded from British India and Ceylon. Part I. Journal & Proceedings of the Asiatic Society of Bengal, 1, 81–93, pls. I–II.
Bauer, A.M., Good, D.A. & Branch, W.R. (1997) The taxonomy of the Southern African Leaf-toed Geckos (Squamata: Gekkonidae), with a review of Old World “Phyllodactylus” and the description of five new genera. Proceedings of the California Academy of Sciences, 49 (14), 447–497.
Bauer, A.M., Sumontha, M., Grossmann, W., Pauwels, O.S.G. & Vogel, G. (2004) A new species of Dixonius (Squamata: Gekkonidae) from Kanchanaburi Province, western Thailand. Current Herpetology, 23 (1), 17–26.
https://doi.org/10.5358/hsj.23.17
Botov, A., Phung, T.M., Nguyen, Q.T., Bauer, A.M., Brennan, I.G. & Ziegler, T. (2015) A new species of Dixonius (Squamata: Gekkonidae) from Phu Quy Island, Vietnam. Zootaxa, 4040 (1), 48–58.
https://doi.org/10.11646/zootaxa.4040.1.4
Boulenger, G.A. (1898) Third report on additions to the lizard collection in the Natural History Museum. Proceedings of the Zoological Society of London, 1898, 912–923.
https://doi.org/10.1111/j.1096-3642.1898.tb03194.x
Das, I. (2004) A new species of Dixonius (Squamata: Gekkonidae) from southern Vietnam. The Raffles Bulletin of Zoology, 52 (2), 629–634.
Grossmann, W., Schäfer, C. & Harbig, P. (1996) Phyllodactylus siamensis Boulenger. Sauria, Supplement 18 (3), 357–360.
Mocquard, F. (1904) Lézards recueillis par M. A. Pavie en Indo-Chine. In: Pavie, A. (Ed.), Mission Pavie Indo-Chine 1879–1895. Études diverses. III. Recherches sur l’histoire naturelle de l’Indo-Chine orientale. Ernest Leroux, Paris, pp. 486–488, pl. XXXIII fig. 1.
Ngo, V.T. & Ziegler, T. (2009) A new species of Dixonius from Nui Chua National Park, Ninh Thuan Province, southern Vietnam (Squamata, Gekkonidae). Zoosystematics and Evolution, 85 (1), 117–125.
https://doi.org/10.1002/zoos.200800018
Nguyen, T.H., Luu, V.Q., Sitthivong, S., Ngo, H.T., Nguyen, T.Q., Le, M.D. & Ziegler, T. (2021) A new species of Dixonius (Squamata: Gekkonidae) from Vientiane Capital, Laos. Zootaxa. [in press]
Nguyen, T.H., Sitthivong, S., Ngo, H.T., Luu, V.Q., Nguyen, T.Q., Le, M.D. & Ziegler, T. (2020) A new species of Dixonius (Squamata: Gekkonidae) from the karst forest of Khammouane Province, central Laos. Zootaxa, 4759 (4), 530–542.
https://doi.org/10.11646/zootaxa.4759.4.4
Pauwels, O.S.G., Chomngam, N., Larsen, H. & Sumontha, M. (2020) A new limestone-dwelling leaf-toed gecko (Gekkonidae: Dixonius) from coastal hills in Cha-am, peninsular Thailand. Zootaxa, 4845 (1), 97–108.
https://doi.org/10.11646/zootaxa.4247.5.2
Singtuen, V. & Won-In, K. (2019) Geoheritage sites and geoconservation at Pha Chan – Sam Phan Bok Geopark, Ubon Ratchathani Province, Thailand. Geoconservation Research, 2 (1), 12–25.
https://doi.org/10.30486/gcr.2019.664490
Sumontha, M., Chomngam, N., Phanamphon, E., Pawangkhanant, P., Viriyapanon, C., Thanaprayotsak, W. & Pauwels, O.S.G. (2017) A new limestone-dwelling leaf-toed gecko (Gekkonidae: Dixonius) from Khao Sam Roi Yot massif, peninsular Thailand. Zootaxa, 4247 (5), 556–568.
https://doi.org/10.11646/zootaxa.4247.5.2
Sumontha, M. & Pauwels, O.S.G. (2020) A new leaf-toed gecko (Gekkonidae: Dixonius) from the city of Ranong, southwestern Thailand. Zootaxa, 4852 (2), 166–176.
https://doi.org/10.11646/zootaxa.4852.2.2
Taylor, E.H. (1962) New oriental reptiles. University of Kansas Science Bulletin, 43, 209–263.
https://doi.org/10.5962/bhl.part.13346
Taylor, E.H. (1963) The lizards of Thailand. The University of Kansas Science Bulletin, 44 (14), 687–1077.
Ziegler, T., Botov, A., Nguyen, T.T., Bauer, A.M., Brennan, I.G., Ngo, H.T. & Nguyen, Q.T. (2016) First molecular verification of Dixonius vietnamensis Das, 2004 (Squamata: Gekkonidae) with the description of a new species from Vinh Cuu Nature Reserve, Dong Nai Province, Vietnam. Zootaxa, 4136 (3), 553–566.
https://doi.org/10.11646/zootaxa.4136.3.7