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Dixonius gialaiensis from Gia Lai Province, Central Highlands, Vietnam Dixonius muangfuangensis from Muangfuang District, Vientiane Province, Central Laos Luu, Nguyen, Le, Grismer, Ha, Sitthivong, Hoang & Grismer, 2023 |
Abstract
Integrated analyses using maximum likelihood (ML), Bayesian inference (BI), principal component analysis (PCA), discriminate analysis of principal components (DAPC), multiple factor analysis (MFA), and analysis of variance (ANOVA) recovered two new diagnosable species of gekkonid lizards in the genus Dixonius, one from the Central Highlands, Gia Lai Province, Vietnam and another from the Vientiane Province, Laos. Phylogenetic analyses based on the mitochondrial NADH dehydrogenase subunit 2 gene (ND2) and adjacent tRNAs showed that Dixonius gialaiensis sp. nov. is the sister species of D. minhlei from Dong Nai Province, Vietnam and is nested within a clade that also includes the sister species D. siamensis and D. somchanhae. Dixonius muangfuangensis sp. nov. is the sister species to D. lao from Khammouane Province, Laos and is embedded in a clade with D. vietnamensis, D. taoi, and undescribed species from Thailand. Multivariate (PCA, DAPC, and MFA) and univariate (ANOVA) analyses using combinations of 15 meristic (scale counts), six morphometric (measurements), and five categorical (color pattern and morphology) characters from 44 specimens encompassing all eight species of Dixonius from Vietnam and Laos clearly illustrate Dixonius gialaiensis sp. nov. and Dixonius muangfuangensis sp. nov. are statistically different and discretely diagnosable from all closely related species of Dixonius. These integrative analyses also highlight additional taxonomic issues that remain unresolved within Dixonius and the need for additional studies. The discovery of these new species further emphasizes the underappreciated herpetological diversity of the genus Dixonius and illustrates the continued need for field work in these regions.
Keywords: Gekkota, Indochina, integrative taxonomy, molecular phylogeny, morphology, new species, Southeast Asia
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| Dorsal views of Dixonius gialaiensis sp. nov. A adult male holotype VNUF R.2020.22 (Field no. GL02) B adult female paratype VNUF R.2020.33 (Field No. GL03) C juvenile male paratype VNUF R.2020.44 (Field No. GL04) in Chu Se Mountain Pass, Hbong Commune, Chu Se District, Gia Lai Province. |
Dixonius gialaiensis sp. nov.
Gialai leaf-toed gecko
Diagnosis: Dixonius gialaiensis sp. nov. can be separated from all other species of Dixonius by possessing the unique combination of having a maximum SVL of 47.4 mm; 19 longitudinal rows of dorsal tubercles at midbody; 19–21 longitudinal rows of ventrals across the abdomen; 7 or 8 supralabials, sixth in at midorbital position; 6 or 7 infralabials; 7 interorbital scales; 7 or 8 precloacal pores in males, femoral pores lacking; precloacal and femoral pores absent in female; 13–15 lamellae on fourth toe; dorsum olive grey color with more round brown blotches; canthal stripe continues behind orbit to back of head; lips with dark bars; two regularly disposed whitish tubercles along the sides near the flanks to tail tip. These characters are scored across all Dixonius species from Vietnam and Laos in Tables 6, 7.
Distribution: Dixonius gialaiensis sp. nov. currently is only known from the type locality of Chu Se Mountain Pass, H’Bong Commune, Chu Se District, Gia Lai Province, Central Highlands, Vietnam (Fig. 1).
Etymology: The new species is named after the type locality of Gia Lai Province, Central Highlands, Vietnam.
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| View of Dixonius muangfuangensis sp. nov. A adult male holotype VNUF R.2020.42 (Field no. MF.02) B adult female paratype VNUF R.2020.52 (Field no. MF. 03) C juvenile male paratype NUOL R.2022.01 (Field no. MF. 01) in Nadan Village, Muangfuang District, Vientiane Province, Central Laos. |
Dixonius muangfuangensis sp. nov.
Muangfuang leaf-toed gecko
Diagnosis: Dixonius muangfuangensis sp. nov. can be separated from all other species of Dixonius by possessing the unique combination of having a maximum SVL of 56.7 mm; 21–23 longitudinal rows of dorsal tubercles at midbody; 20 or 21 longitudinal rows of ventrals across the abdomen; 7 or 8 supralabials, sixth in at midorbital position; 6 or 7 infralabials; 7 interorbital scales; 7 or 8 precloacal pores in males, femoral pores lacking; precloacal and femoral pores absent in female; 15 lamellae on fourth toe; dorsum olive grey color with numerous small and irregular black blotches; head with brown spots; light spots irregularly arranged from the back of the head to base of tail; lips with dark bars; two regularly disposed whitish tubercles on each side on each side. These characters are scored across all Dixonius species from Vietnam and Laos in Tables 6, 7.
Distribution: Dixonius muangfuangensis sp. nov. currently is only known from the type locality of Nadan Village, Muangfuang District, Vientiane Province, Central Laos (Fig. 1).
Etymology: The specific epithet of the new species refers to the type locality of the new species in Muangfuang District, Vientiane Province, Central Laos.
Vinh Quang Luu, Thuong Huyen Nguyen, Minh Duc Le, Jesse L. Grismer, Hong Bich Ha, Saly Sitthivong, Tuoi Thi Hoang and L. Lee Grismer. 2023. Two New Species of Dixonius from Vietnam and Laos with A Discussion of the Taxonomy of Dixonius (Squamata, Gekkonidae). ZooKeys. 1163: 143-176. DOI: 10.3897/zookeys.1163.101230
