Sang Ngoc Nguyen

Dr. Sang Ngoc Nguyen


Research Focus & Metrics

Academic Career Length

14Years (2013-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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9 January 2019 in Zootaxa
Verified
Journal Article
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LNLuan Nguyen
Luan Nguyen
NPNikolay A. Poyarkov
Nikolay A. Poyarkov
TNTiep Tan Nguyen
Tiep Tan Nguyen
TNTam Ai Nguyen
Tam Ai Nguyen
VTVy Huu Tran
Vy Huu Tran
SNSang Ngoc Nguyen
Sang Ngoc Nguyen
We describe a new species of Microhyla from Tram Lap forest, Gia Lai Province, Central Vietnam based on morphological, molecular, and acoustic data. The new species resembles M. butleri morphologically, but differs from all congeners by a combination of the following morphological attributes: (1) medium-sized adult snout–vent length 25.2–27.0 mm in 15 males and 30.5 mm in a single female; (2) body habitus moderately stocky; (3) head flat, snout rounded, slightly prominent in ventral profile; (4) dorsum and flanks slightly shagreened with evenly scattered tiny tubercles, ventral skin smooth; (5) first finger well developed, more than one-half the length of the second finger; (6) tips of three outer fingers slightly enlarged, forming weak disks and tips of all toes distinctly dilated into wide disks with narrow peripheral grooves; (7) finger and toe disks with dorsal median longitudinal grooves; (8) three palmar tubercles and two metatarsal tubercles; (9) tibiotarsal articulation of adpressed limb reaching slightly beyond the orbit; (10) webbing formula: I 1¾–2 II 1½–2¾ III 2–31/3 IV 3¼–1½ V; (11) in life, chin and throat yellowish to bright-orange with tiny dark brown speckling laterally; and (12) a call consisting of 15–26 pulses with a dominant frequency of 1.8–2.2 kHz (recorded at 18.5ºC). We also provide a preliminary genealogy of Microhyla based on analysis of a 2644 bp fragment of 12S–16S rRNA mitochondrial DNA. Based on the examed data, the new species and M. butleri are sister-species (genetic p-distance: 9.0%) and it can be distinguished from M. butleri by its morphology (size, webbing on toes, color) and advertisement call. Interspecific genetic p-distances between the new species and its congeners vary from 9.0% to 14.8%. Microhyla aurantiventris sp. nov. occurs in evergreen montane tropical forests at elevations around 1200 m a.s.l. and is known only from the type locality. The new species appears to be threatened due to intensive logging and agriculture plantation.

26 March 2014 in Zootaxa
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Journal Article
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SNSang Ngoc Nguyen
Sang Ngoc Nguyen
JYJun-Xiao Yang
Jun-Xiao Yang
TLThanh-Ngan Thi LE
Thanh-Ngan Thi LE
LNLuan Nguyen
Luan Nguyen
NONikolai L. Orlov
Nikolai L. Orlov
YZYa-Ping Zhang
Ya-Ping Zhang
Species of bent-toed gecko (Cyrtodactylus) in Vietnam have been described at a rate of nearly four species per year since 2007 mostly based on morphological data. A tool that guides species delimitation will accelerate the rate of documentation, and at a time when the recognition of species greatly benefits conservation. We use DNA barcoding using COI (550 bp) to re-examine the levels of genetic divergence and taxonomic status of 21 described species of Vietnamese bent-toed geckos. Tree-based analyses resolve all sampled species and identify potential undescribed taxa. Kimura 2-parameter genetic distances between the described species average 21.0±4.2% and range from 4.3% to 28.7%. Further, our analyses discover two potentially new species from Vietnam, two from Laos and one from China. Herein we describe the new species Cyrtodactylus puhuensis sp. nov. from Vietnam on the basis of both genetics and morphology. Genetically, it differs from the remaining species by an average K2P distance of 24.0±1.8%. Morphologically, the new species is diagnosed by its medium-size (snout-vent length 79.24 mm and tail length 82.59 mm, for the single known individual), in having a series of moderately enlarged transverse subcaudals and a series of moderately enlarged femoral scales that extend from precloacal scales, in possessing femoral scales without pores, with males having five precloacal pores, and in exhibiting 8 supralabials, 10 infralabials, 23 narrow subdigital lamellae on its fourth toe, and 36 transverse ventrals.

20 July 2016 in Zootaxa
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Journal Article
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SNSang Ngoc Nguyen
Sang Ngoc Nguyen
VNVu Dang Hoang Nguyen
Vu Dang Hoang Nguyen
SLSon Hong LE
Son Hong LE
RMRobert W. Murphy
Robert W. Murphy
We describe a new kukri snake, Oligodon condaoensis sp. nov., from Con Dao Islands, southern Vietnam based on the morphological characters of four specimens. It differs from other congeners by a combination of the following characters: medium size in adults (total length up to 552 mm); 17–17–15 dorsal scale rows; deeply forked hemipenes without spines and papillae, extending to subcaudal 13 or 14; 11–13 maxillary teeth, the posterior three being enlarged; cloacal plate undivided; head scalation complete; nasal divided; presubocular absent; 168–176 ventrals; 33–37 subcaudals; overall dorsal coloration dark gray, faint body stripes present or absent; and ventral coloration cream to dark gray without rectangular blotches. We also provide a list of 43 species of amphibians and terrestrial reptiles recorded from Con Dao Islands.

30 July 2019 in Zootaxa
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Journal Article
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SNSang Ngoc Nguyen
Sang Ngoc Nguyen
VNVu Dang Hoang Nguyen
Vu Dang Hoang Nguyen
LNLuan Nguyen
Luan Nguyen
RMRobert W. Murphy
Robert W. Murphy
Ba Den is an isolated mountain in southern Vietnam and home to two endemic species of lizards. Herein, we describe another endemic species, a new skink of the genus Scincella Mittleman, 1950, from the area based on morphological data, including hemipenial characters and nucleotide sequences of COI. The following morphological characters diagnose Scincella badenensis sp. nov.: medium size in adults (snout-vent length up to 64.4 mm); toes reach to fingers when limbs adpressed; midbody scale rows 32–36, smooth; paravertebral scales 67–71; dorsal scales not enlarged; ventral scale rows 68–74; supraoculars four; prefrontals in broad contact with one another; loreal scales two; tympanum deeply sunk, without auricular lobules; two enlarged anterior temporal scales; smooth lamellae beneath toe IV 18–20; pair of enlarged precloacal scales; hemipenes short, smooth and forked near the tip with two short lobes and two small terminal papillae; no dorsal pattern in males; and females with black interruptive vertebral line. The new species differs from its congeners by at least 10.4% uncorrected p-distance in COI sequences.

28 October 2020 in Zootaxa
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Journal Article
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SNSang Ngoc Nguyen
Sang Ngoc Nguyen
VNVu Dang Hoang Nguyen
Vu Dang Hoang Nguyen
LNLuan Nguyen
Luan Nguyen
RMRobert W. Murphy
Robert W. Murphy
A new skink of the genus Scincella Mittleman, 1950, from Binh Phuoc Province, southern Vietnam is described based on morphological data, including hemipenial characters, and nucleotide sequences from COI. The following morphological characters diagnose Scincella baraensis sp. nov.: relatively small size in adults (snout-vent length up to 49.2 mm); when limbs adpressed, toes do not or just reach fingers; 30 smooth midbody scale rows and dorsal scales not enlarged; 66–70 paravertebral scales; 64–66 ventral scale rows; 7 supralabials, the fifth and sixth below the center of the eye; enlarged temporal scales 1+2; nuchals present; ear with small auricular lobules; 18–20 smooth lamellae beneath toe IV; hemipenis smooth, short, and unforked; dorsum with faint black dots. The new species differs from its congeners by an uncorrected p-distance in COI sequences of at least 16.2%.

21 October 2022 in Zootaxa
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Journal Article
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SNSang Ngoc Nguyen
Sang Ngoc Nguyen
MVManh Le Van
Manh Le Van
TVThi-Dieu-Hien Vo
Thi-Dieu-Hien Vo
RMRobert W. Murphy
Robert W. Murphy
We describe a new species of kukri snake from Da Lat City and its vicinity in Lam Dong Province, southern Vietnam on the basis of morphological characters of four specimens, including two males and two females. Oligodon tuani sp. nov. differs from other congeners by a combination of the following characters: large size in adults (TL ≤ 888 mm); 19 dorsal scale rows at midbody; ventrals 173–179 in males and 187–193 in females; subcaudals 58 or 59 in males and 44 or 45 in females; presubocular present; 8 supralabials, fourth and fifth entering orbit; cloacal plate undivided; 10 maxillary teeth, posterior three enlarged; vertebral stripe present; temporal streak present but faint and interrupted; long and deeply forked hemipenes, extending to 25th subcaudal, without spines and papillae; and 13–15+3–4 dorsal blotches.