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https://doi.org/10.11646/zootaxa.4613.3.9
http://zoobank.org/urn:lsid:zoobank.org:pub:D9CF5E43-22C7-4658-A747-286DAAE4CC9E
578 Accepted by S. Carranza: 13 May 2019; published: 6 Jun. 2019
Article ZOOTAXA
ISSN 1175-5326 (print edition)
ISSN 1175-5334 (online edition)
Zootaxa 4613 (3): 579–586
https://www.mapress.com/j/zt/
Copyright © 2019 Magnolia Press
A new species of Opisthotropis from northern Vietnam
previously misidentified as the Yellow-spotted Mountain Stream
Keelback O. maculosa Stuart & Chuaynkern, 2007 (Squamata: Natricidae)
THOMAS ZIEGLER1,2,10, CUONG THE PHAM3,4, TAN VAN NGUYEN3, TRUONG QUANG NGUYEN3,4,
JIAN WANG5, YING-YONG WANG5, BRYAN L. STUART6 & MINH DUC LE7,8,9
1AG Zoologischer Garten Köln, Riehler Strasse 173, D–50735 Cologne, Germany. E-mail: ziegler@koelnerzoo.de
2Institute of Zoology, University of Cologne, Zülpicher Strasse 47b, D–50674 Cologne, Germany
3Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi,
Vietnam. E-mail: nqt2@yahoo.com, cuongiebr@gmail.com
4Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi,
Vietnam
5State Key Laboratory of Biocontrol / The Museum of Biology, School of Life Sciences, Sun Yat-sen University, Guangzhou 510275,
P.R. China
6North Carolina Museum of Natural Sciences, 11 West Jones Street, Raleigh, NC 27601, USA
E-mail: bryan.stuart@naturalsciences.org
7Faculty of Environmental Sciences, Hanoi University of Science, Vietnam National University, 334 Nguyen Trai Road, Hanoi, Viet-
nam. E-mail: le.duc.minh@hus.edu.vn
8Central Institute for Natural Resources and Environmental Studies, Hanoi National University, 19 Le Thanh Tong, Hanoi, Vietnam
9Department of Herpetology, American Museum of Natural History, Central Park West at 79th Street, New York, New York 10024
10Corresponding author. E-mail: ziegler@koelnerzoo.de
Abstract
The Yellow-spotted Mountain Stream Keelback Opisthotropis maculosa was originally described based on a single male
specimen from northeastern Thailand. Recently, based on morphological data, new records of this species were published
initially from southern China and subsequently from northern Vietnam. In this study, we provide the first molecular
comparisons between the holotype and other populations in China and Vietnam using the mitochondrial cytochrome b
gene and use an integrative taxonomic approach to show that the population from Vietnam represents a distinct taxon.
Opisthotropis haihaensis sp. nov. is characterized by a combination of the following characters: internasal not in contact
with loreal; prefrontal not touching supraocular; frontal touching preocular; one preocular; one postocular; one anterior
temporal; one posterior temporal; eight supralabials, fourth and fifth in contact with eye; 24 maxillary teeth; anterior pair
of chin shields longer than posterior pair; 169 ventrals + 2 preventrals); 79 subcaudals, paired; 15 dorsal scale rows at
neck, at midbody and before vent; body and tail scales smooth; chin shields yellow with brownish black mottling; body
and tail dorsum dark with each a light spot per scale. Phylogenetically, the new species is supported as the sister taxon
to “O. maculosa” from China (but separated by approximately 10% uncorrected pairwise sequence divergence) and
is distantly related to O. maculosa sensu stricto from Thailand, warranting a taxonomic revision of the maculosa-like
species. According to our results, O. maculosa should be delisted from the herpetofauna of Vietnam, which currently
consists of nine Opisthotropis species. Five species, O. cucae, O. daovantieni, O. haihaensis, O. tamdaoensis, and O.
voquyi, are endemic to the country.
Key words: Opisthotropis maculosa, Opisthotropis haihaensis sp. nov., morphology, phylogeny, taxonomy
Introduction
Members of the genus Opisthotropis, referred to as the Mountain Stream Keelbacks, are aquatic snakes inhabiting
flowing streams of hills and mountains in tropical and subtropical Asia. Mountain Stream Keelbacks can be found
across the mainland of Southeast Asia to Sumatra (Indonesia), the Philippines and the Ryukyu Archipelago of Japan.
The genus, which currently consists of 24 species, is still poorly known (Teynié et al., 2013; Ren et al., 2017; Wang
et al., 2017; Ziegler et al., 2018). Eight species have been discovered in the past eleven years: O. laui Yang, Sung &
A NEW OPISTHOTROPIS FROM NORTHERN VIETNAM Zootaxa 4613 (3) © 2019 Magnolia Press · 579
Chan, O. shenzhenensis Wang, Guo, Liu, Lyu, Wang, Luo, Sun & Zhang and O. zhaoermii Ren, Wang, Jiang, Guo &
Li from China, O. maculosa Stuart & Chuaynkern from Thailand, O. durandi Teynie, Lottier, David, Nguyen & Vogel
from Laos, as well as O. cucae David, Pham, Nguyen & Ziegler, O. tamdaoensis Ziegler, David & Vu and O. voquyi
Ziegler, David, Ziegler, Pham, Nguyen & Le from Vietnam (Stuart & Chuaynkern, 2007; Ziegler et al., 2008; David
et al., 2011; Teyni et al., 2013; Yang et al., 2013; Ren et al., 2017; Wang et al., 2017; Ziegler et al., 2017, 2018). Nine
species of the Mountain Stream Keelbacks have been recorded so far from Vietnam (David et al., 2011, Ziegler et al.,
2017; Nguyen et al., 2018; Ziegler et al., 2018); most of them are uncommon or at least rarely collected.
One of the aforementioned species, O. maculosa, was recently reported to occur in Vietnam (Nguyen et al.,
2018) after it was recorded from China several years ago (Yang et al., 2011). Yang et al. (2011) provided an extend-
ed diagnosis for the species, which was originally described based on a single specimen from northeastern Thailand
(Stuart & Chuaynkern 2007). Although there were some differences in scalation compared with the holotype of O.
maculosa, Nguyen et al. (2018) regarded their record from Vietnam as conspecific owing to the lack of information
on intraspecific variation. In addition, the overall phenotypic resemblance of the newly collected specimen from
Vietnam to the revised diagnosis for O. maculosa given by Yang et al. (2011) was apparent. To clarify the taxonomy
of this apparently geographically widespread taxon, we herein applied an integrative taxonomic approach by com-
bining the detailed morphological data with those from molecular analyses. We were able to include sequences of
the mitochondrial cytochrome b gene from both the newly collected sample from Vietnam and the holotype of O.
maculosa from northeastern Thailand. The newly discovered specimen from Hai Ha District, Quang Ninh Province,
Vietnam was shown to differ morphologically and genetically from the holotype of O. maculosa. Therefore, we re-
vised the identification of Nguyen et al. (2018) and described the Quang Ninh Province specimen as a new species
of Opisthotropis.
Material and methods
Sampling. This study is based on a single specimen from the forest near Tai Chi Village, Quang Son Commune,
Hai Ha District, Quang Ninh Province, Vietnam. It was euthanized in a closed vessel with a piece of cotton wool
containing ethyl acetate (Simmons 2002), fixed in 85% ethanol and subsequently stored in 70% ethanol. A tissue
sample was preserved separately in 90% ethanol. The female specimen was deposited in the herpetological collec-
tion of the Institute of Ecology and Biological Resources (IEBR), Hanoi, Vietnam as IEBR A.2016.34 (Field no.
QN 2016.91).
Morphological examination. Sex was determined by dissection (inspection of gonads and presence or absence
of hemipenes). Snout-vent length and tail length were measured after preservation using a measuring tape; head
length was taken with a caliper to the nearest 0.1 mm. The number of ventral scales was counted according to Dowl-
ing (1951). The number of dorsal scale rows was counted at one head length behind head, at midbody, and at one
head length before vent, respectively. Maxillary teeth were counted by dissecting the right maxilla for teeth/sockets.
Scalation and maxillary teeth were examined by using a binocular dissecting microscope. We herein use the term
cloacal instead of anal. Bilateral values were given as left/right.
Abbreviations of morphological characters used in the text are as follows:—Measures and ratios: HL: head length
(from tip of snout to posterior edge of parietals).—SVL: snout-vent length (from tip of snout to cloaca).—TaL: tail
length (from cloaca to tip of tail).—TL: total length (SVL + TaL).—TaL/TL: ratio tail length/total length.
Morphological comparisons of the new species with other species of the genus Opisthotropis and Hebius anna-
mensis (formerly Parahelicops annamensis; see Kizirian et al. 2018) were based on data from Stuart & Chuaynkern
(2007), David et al. (2011), Teynié et al. (2013), Nguyen et al. (2017), Ren et al. (2017), Wang et al. (2017), and
Ziegler et al. (2018).
Molecular analyses. The mitochondrial cytochrome b gene was employed in this study because it has been
successfully used in previous molecular analyses of Natricidae, with dense sampling of Opisthotropis (e.g., Guo et
al. 2012, Wang et al. 2017, Ziegler et al. 2018). We included four new sequences consisting of the sample collected
from Hai Ha, Quang Ninh Province, Vietnam; the holotype of O. maculosa from Phu Wua Wildlife Sanctuary,
Boong Klar District, Nong Khai Province, Thailand (Thailand Natural History Museum, THNHM 05343, cross-
cataloged at the Field Museum of Natural History, FMNH 265798); and a sample each of O. durandi and O. daovan-
tieni Orlov, Darevsky & Murphy. Other sequences of related species were obtained from Wang et al. (2017), Ziegler
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580 · Zootaxa 4613 (3) © 2019 Magnolia Press
et al. (2017), and Ziegler et al. (2018). Two species of the genus Aspidura, A. drummondhayi (Boulenger) and A.
trachyprocta (Cope) were used as outgroups following Figueroa et al. (2016). Details of samples sequenced for the
mitochondrial cytochrome b gene and their associated GenBank accession numbers are presented in Table 1.
We used the protocols of Le et al. (2006) for DNA extraction, amplification, and sequencing. A fragment of the
mitochondrial cytochrome b gene was amplified and sequenced using the primers L14910 and H16064 (Burbrink
et al., 2000). Sequences were aligned by ClustalX v2 (Thompson et al. 1997). Phylogenies were reconstructed us-
ing maximum parsimony (MP) and maximum likelihood (ML) criteria as implemented in PAUP*4.0b10 (Swofford
2001), and combined and partitioned (by codon position) Bayesian inference (BI) as implemented in MrBayes v3.2
(Ronquist et al., 2012). Settings for MP, ML, and BI followed Le et al. (2006), except that the number of generations
in BI was increased to 1×107. For MP analysis, heuristic analysis was conducted with 100 random taxon addition
replicates using tree-bisection and reconnection (TBR) branch swapping algorithm, with no upper limit set for the
maximum number of trees saved. Bootstrap support was calculated using 1000 pseudo-replicates and 100 random
taxon addition replicates. All characters were equally weighted and unordered. The optimal model for nucleotide
evolution was set to TrN+I+G for combined ML and BI as selected by ModelTest v3.7 (Posada & Crandall 1998).
For the partitioned dataset, selected models were TVM+G, TIM+G, and HKY+I+G for the first, second, and third
codon position, respectively. The cutoff point for the burn-in function was set to 18 in both combined and partitioned
Bayesian analyses, as –lnL scores reached stationarity after 18,000 generations in both analyses. Nodal support
was evaluated using bootstrap replications (BP) as estimated in PAUP*4.0b10 and posterior probabilities (PP) in
MrBayes v3.2. BP ≥ 70 and PP ≥ 95% were regarded as strong support for a clade (Hillis & Bull, 1993; Ronquist et
al., 2012). Uncorrected pairwise sequence divergences (p-distances) were calculated in PAUP*4.0b10.
Results
The aligned matrix of molecular data contained 1,100 characters, of which 425 were parsimony informative. The
alignment did not contain insertion-deletions. The MP analysis recovered a single most parsimonious tree. Topolo-
gies of the MP and ML trees and BI 50% majority rule consensus tree were highly congruent to each other and to
tree topologies presented in Wang et al. (2017) and Ziegler et al. (2018).
The Opisthotropis specimen from Quang Ninh Province, Vietnam, was recovered with strong statistical support
in all analyses (Fig. 1) as the sister taxon to an Opisthotropis population from Guangdong Province, China, that was
previously referred to O. maculosa by Yang et al. (2011) and Wang et al. (2017). Neither the Vietnam nor China
populations that were previously referred to O. maculosa were found to be closely related to O. maculosa sensu
stricto (Fig. 1). The sister lineages from Vietnam and China had uncorrected p-distances of approximately 10% in
the cytochrome b gene fragment.
The genetic distinction of the Opisthotropis from Quang Ninh Province, Vietnam, to the taxon from Guangdong
Province, China, and the phylogenetic distinctiveness of both of these to O. maculosa sensu stricto, implies that
taxonomic revision of these snakes is required. Despite the superficial similarities of the Thailand, Vietnam, and
China populations, we corroborate the molecular findings with distinct morphological differences among these lin-
eages. Herein, we describe the specimen from Vietnam as a new species, and recommend taxonomic re-assessment
of the Chinese specimens.
Opisthotropis haihaensis sp. nov.
Opisthotropis maculosa Nguyen, Nguyen, Pham & Ziegler 2018: 74.
Holotype. IEBR A.2016.34 [Field No. QN 2016.91], adult female, from the forest near Tai Chi Village, Quang Son
Commune, Hai Ha District, Quang Ninh Province, 950 m asl., Vietnam [exact locality and coordinates not provided
owing to threat from collection for the pet trade (below)], collected by Cuong The Pham and Tan Van Nguyen on 9
May 2016 (Figs. 2–3).
Diagnosis. A species of the genus Opisthotropis characterized by having the following combination of charac-
ters: (1) internasal not in contact with loreal; (2) prefrontal not touching supraocular; (3) frontal touching preocular;
A NEW OPISTHOTROPIS FROM NORTHERN VIETNAM Zootaxa 4613 (3) © 2019 Magnolia Press · 581
(4) one preocular; (5) one postocular; (6) one anterior temporal; (7) one posterior temporal; (8) supralabials eight,
fourth and fifth in contact with eye; (9) 24 maxillary teeth; (10) anterior pair of chin shields longer than posterior
pair; (11) ventrals 169 (+ 2 preventrals); (12) subcaudals 79; (13) 15 dorsal scale rows at neck, at midbody and be-
fore vent; (14) body and tail scales smooth; (15) chin shields yellow with brownish black mottling; (16) body and
tail dorsum dark with each a light spot per scale.
FIGURE 1. Fifty percent majority-rule consensus phylogram based on the combined Bayesian analysis. Numbers above and
below branches are MP/ML bootstrap values and combined/partitioned Bayesian posterior probabilities (>50%), respectively.
Asterisks (*) represent 100% values.
Description of the holotype. Body slender, round to oval in cross section; tail thin, pointed; head small, in-
distinct from neck, depressed, dorsally covered with large shields; nostrils in dorsal position and oblique, narrow,
piercing the upper middle of nasal, which is divided beneath; eye small, pupil round.
Size. HL: 13.7 mm; SVL: 396 mm; TaL: 113 mm; TL: 509 mm; ratio TaL/TL: 0.22.
Dentition. Maxillary teeth: right upper maxilla with 24 subequal teeth or sockets, teeth small, curved, without
diastema.
Body scalation. Dorsal scale rows 15–15–15, entirely smooth. Outer dorsal scales enlarged. All scales glossy.
169 ventrals (+ 2 preventrals); 79 subcaudals, all paired; cloacal divided.
Head scalation. Rostral heptagonal, wider than high, visible from above; nasals large, much longer than high,
weakly divided below nostril by a distinct furrow; nasals surrounded by the first two supralabials, rostral, internasal,
prefrontal and loreal; internasals two, strongly curved, longer than wide, in contact with rostral anteriorly, nasal, and
prefrontal; prefrontal single, heptagonal, anteriorly pointed, about twice as wide as long, in contact with internasals,
nasals, loreals, preoculars, and frontal; frontal pentagonal, 1.26 times wider than long, tapering posteriorly, equal to
its distance from tip of snout; parietals longer than wide, in contact approximately equal to the length of frontal, 1.88
times longer than frontal; 1 / 1 supraocular, distinctly wider than high, not in contact with prefrontal; 1 / 1 loreal,
pentagonal, wider than high, neither in contact with internasal nor eye, surrounded by second and third supralabials,
nasal, prefrontal and preocular; 1 / 1 preocular, large, hexagonal, higher than wide, reaching frontal, in broad contact
with prefrontal; subocular absent; 1 / 1 postocular, curved, higher than wide; 8 / 8 supralabials, anterior ones higher
than wide, fourth and fifth entering orbit, seventh largest; 1+1 / 1+1 temporals, anterior one very long and narrow,
in broad contact with SL 5–7 and parietals, posterior one more strongly developed; infralabials 8 / 8, first pair in
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582 · Zootaxa 4613 (3) © 2019 Magnolia Press
contact behind small mental, 1–4 / 1–5 in contact with anterior chin shields, IL 5 largest, apex directed posteriorly;
posterior chin shields shorter than anterior ones, separated from each other by a pair of small scales.
Coloration (in preservative). Ground colour of upper head and body surface dark brown, that of venter yel-
lowish-beige. Dorsal scales with light blotch in the centre each. From behind the neck, the dorsal blotches become
more elongated. The blotches become wider towards the body sides; they are largest at the outermost dorsal scale
row, where the light blotches stretch towards the posterior scale end. Dorsal tail scales likewise with light central
blotches. Dorsal head surface in part with indistinct light mottling that becomes more obvious on temporals. Ante-
rior supralabials with light mottling, supralabials 4–7 with distinct light blotch each. Infralabials, chin shields and
smaller throat scales anterior to ventrals brown with light mottling / blotches per scale. The belly with few, scat-
tered dark flecks. Outermost edges of light ventrals brown. Ground colour of subcaudals brown with transversally
enlarged light blotches at each scale end.
FIGURE 2. Holotype of Opisthotropis haihaensis sp. nov. (IEBR A.2016.34) in preserved state.
Coloration (in life). Eye black; scales on dorsal surface of head glossy black with scattered yellow flecking;
chin shields yellow with brownish black mottling; body and tail glossy black with iridescence above, with single
yellow spot on each scale, yellow spots becoming larger on sides of body; ventrals yellow with brownish black
lateral margins and scattered brown flecks; subcaudals yellow with brownish black anterior and lateral margins.
Comparisons. Only six other species of Opisthotropis and the related genus Hebius have 15 midbody dorsal
scale rows (see review in Ziegler et al. 2018): O. maculosa, O. jacobi Angel & Bourret, O. voquyi, O. guangxiensis
Zhao, Jiang & Huang, O. kikuzatoi (Okada & Takara), and H. annamensis Bourret (which may have 15 or 17 mid-
body dorsal scale rows).
Opisthotropis haihaensis sp. nov. differs from O. maculosa sensu stricto (adult male holotype from northeast-
ern Thailand, see Stuart & Chuaynkern 2007), with which the species was confused in the previous study (Nguyen
et al. 2018), by having prefrontal not touching supraocular (versus prefrontal touching supraocular in O. maculosa);
frontal touching preocular (versus frontal not touching preocular in O. maculosa); one postocular (versus two post-
A NEW OPISTHOTROPIS FROM NORTHERN VIETNAM Zootaxa 4613 (3) © 2019 Magnolia Press · 583
oculars in O. maculosa); fourth and fifth supralabials in contact with eye (versus fourth supralabial in contact with
eye in O. maculosa); anterior pair of chin shields longer than posterior pair (versus vice versa in O. maculosa);
lower number of ventrals (169 + 2 preventrals versus 182 + 2 preventrals in O. maculosa); higher number of sub-
caudals (79 versus 67 in O. maculosa); and chin shields yellow with brownish black mottling (versus yellow in O.
maculosa).
Opisthotropis haihaensis sp. nov. differs from O. jacobi by having 24 maxillary teeth (versus 19–23 in O. ja-
cobi); smooth dorsal scales on tail, without keels (versus few faint keels usually present in O. jacobi); body and tail
dorsum dark with a light spot per scale (versus dorsum uniformly dark in O. jacobi).
Opisthotropis haihaensis sp. nov. differs from O. voquyi by having one postocular (versus two in O. voquyi);
body and tail dorsum dark with each a light spot per scale (versus dorsal pattern dark, with dorsal scales posteriorly
more or less edged with pale brown in O. voquyi).
Opisthotropis haihaensis sp. nov. differs from O. guangxiensis by having eight supralabials (versus 9–10 in O.
guangxiensis); one postocular (versus two in O. guangxiensis); one posterior temporal in the new species (versus
two in O. guangxiensis); 15 dorsal scale rows at neck in the new species (versus 17 in O. guangxiensis); 79 subcau-
dals (versus 51–60 in O. guangxiensis); body and tail dorsum dark with a light spot per scale (versus dorsal colour
pattern dark with pale crossbars in O. guangxiensis).
Opisthotropis haihaensis sp. nov. differs from O. kikuzatoi by having eight supralabials (versus six in O. ki-
kuzatoi); one preocular (versus two in O. kikuzatoi); 169 ventrals and 79 subcaudals (versus 180–198 ventrals and
58–73 subcaudals in O. kikuzatoi); body and tail dorsum dark with a light spot per scale (versus dorsal colour pattern
dark with dorsolateral orange spots in O. kikuzatoi).
Opisthotropis haihaensis sp. nov. differs from H. annamensis by having one preocular (versus two in H. anna-
mensis); 15 dorsal scale rows at neck (versus 17–19 in H. annamensis); body scales smooth (versus keeled through-
out in H. annamensis); 79 subcaudals (versus 116–146 in H. annamensis); body and tail dorsum dark with a light
spot per scale (versus dorsum dark with orange bars and spots in H. annamensis).
Etymology. This species is named after its type locality in Hai Ha District, Quang Ninh Province, Vietnam.
Suggested common names. Hai Ha Mountain Stream Keelback (English) and Rắn trán hải hà (Vietnamese).
FIGURE 3. Head views of the holotype of Opisthotropis haihaensis sp. nov. (IEBR A.2016.34) in preserved state.
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Distribution. Opisthotropis haihaensis is currently known only from the type locality in Quang Ninh Province,
Vietnam (see Nguyen et al., 2018).
Natural history. The adult female holotype was found at night in a small rocky stream at 2130h. The surround-
ing habitat was secondary evergreen forest consisting of small hardwood trees, bamboo, and shrubs (see Nguyen
et al., 2018). The air temperature was 24–29°C and the relative humidity was 65–88%. Dissection revealed that the
holotype contained three large eggs having maximum length of 16.5 mm, with folded oviducts indicating that some
eggs had already been laid.
Discussion
This study provided additional evidence for cryptic diversity in Opisthotrophis, as shown in previous studies (e.g.,
Ziegler et al., 2018). Although the holotype of O. maculosa is an adult male and the holotype of O. haihaensis is an
adult female, and virtually nothing is known about sexual dimorphism in these taxa, the combination of morphologi-
cal and genetic differences strongly supports our hypothesis that they represent two separate species. Moreover, O.
haihaensis, which was previously misidentified with the superficially similar O. maculosa, was not even recovered
to be closely related to O. maculosa sensu stricto in our phylogenetic analyses. However, some relationships among
members of the genus remain uncertain (Fig. 1), and additional data beyond the cytochrome b gene, including
nuclear genes, are probably required to fully resolve them.
In addition, the previously recorded population of O. maculosa from China (Yang et al., 2011) might represent
another undescribed taxon of Opisthotrophis based on the high values of mitochondrial divergence between O.
haihaensis, and O. maculosa sensu stricto. In corroboration with the molecular data, the population from China
differs by having prefrontals not touching supraoculars (versus touching in O. maculosa sensu stricto) and frontal
touching preoculars (versus not touching in O. maculosa sensu stricto). When only males are compared, the Chinese
specimens differ from the Thai holotype of O. maculosa sensu stricto in having more subcaudals (83–97 versus 67),
a relatively longer tail (TaL/Tl ratio: 0.23–0.26 versus 0.21), and a smaller supraocular not in contact with preocular
and prefrontal (Yang et al. 2011).
When all individuals from the population in China are included, Chinese and Vietnamese specimens are rela-
tively similar in color pattern and scalation. However, when the female holotype of O. haihaensis is compared to
only the female specimen from China, there are distinct morphological differences, including the frontal not touch-
ing eye (versus touching eye in the female from China), and presence of a single postocular (versus presence of two
postoculars in the female from China). Thus, a taxonomic revision of “O. maculosa” from China is warranted.
Based on these findings, Opisthotropis maculosa should be delisted from the herpetofauna of Vietnam, which
otherwise contains nine species of Opisthotropis. Other species of Opisthotrophis have narrow geographic ranges,
and it is possible that O. haihaensis is endemic to Vietnam. Other endemic Opisthotropis species in the country in-
clude O. cucae, O. daovantieni, O. tamdaoensis and O. voquyi (Nguyen et al., 2009, 2017, Ziegler et al., 2018).
The forests of Hai Ha District harbor other highly threatened species, such as the Vietnamese Crocodile Lizard
(Shinisaurus crocodilurus vietnamensis van Schingen, Le, Ngo, Pham, Ha, Nguyen & Ziegler, see van Schingen
et al., 2016a, b), and we strongly recommend the establishment of a nature reserve of this currently unprotected
habitat. Unfortunately, and like the Vietnamese Crocodile Lizards, O. haihaensis has already been collected for
the pet trade by local residents, based on a 2018 advertisement for the species that was advertised on a pet dealer’s
website in Vietnam. To prevent further collection of this beautiful and seemingly rare snake species, we refrain from
publishing details of its locality.
Acknowledgements
We are grateful to the directorate of the Hai Ha Forest Protection Unit (Quang Ninh Province) for support of our
field work and issuing relevant permits. We thank L.T. Ly and D.V. Dang (Quang Ninh) for their assistance in the
field. We thank H.T. Ngo (Hanoi) for laboratory assistance, as well as A. Rauhaus (Cologne) for the arrangement of
the plate. For the fruitful cooperation within joint biodiversity research and conservation projects we cordially thank
S.V. Nguyen (IEBR, Hanoi), T. Pagel and C. Landsberg (Cologne Zoo). Cologne Zoo is partner of the World As-
A NEW OPISTHOTROPIS FROM NORTHERN VIETNAM Zootaxa 4613 (3) © 2019 Magnolia Press · 585
sociation of Zoos and Aquariums (WAZA): Conservation Project 07011 (Herpetodiversity Research). This research
was supported by the National Foundation for Science and Technology Development (NAFOSTED, Grant No.
106.05-2017.329). Field surveys in Quang Ninh Province were partially funded by the Cologne Zoo (Germany).
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