A redescription and range extension of Trimeresurus caudornatus Chen, Ding, Vogel & Shi, 2020 (Serpentes: Viperidae)

Abstract

The pitviper species Trimeresurus caudornatus was recently described based on only two specimens from Nabang Town, Yingjiang County, Yunnan Province, China. Here, we provide additional data on this species based on a re-examination of 19 preserved specimens, 16 specimens reported in earlier literature sources, and additional photo-documented records from northern Myanmar (Burma) and adjacent China. All new specimens were previously identified as Trimeresurus albolabris sensu lato or Trimeresurus septentrionalis sensu lato. Molecular analyses based on mitochondrial DNA supported the morphological findings in establishing conspecificity with T. caudornatus. The newly identified specimens have a pairwise distance of only 0.4-2.6% from those of the type series of T. caudornatus (based on the cytochrome b gene). Based on these findings, we confirm the presence of T. caudornatus from Myanmar and update its diagnostic characters and distribution. We suggest the species should be considered as Least Concern (LC) following the IUCN's Red List categories. Further studies reassessing the populations of the Trimeresurus albolabris complex are required.

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ISSN 1175-5326 (print edition)
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Accepted by K. Tamar: 6 Sept. 2024; published: 27 Sept. 2024 201
Zootaxa 5514 (3): 201–231
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Copyright © 2024 Magnolia Press Article
https://doi.org/10.11646/zootaxa.5514.3.1
http://zoobank.org/urn:lsid:zoobank.org:pub:4530DFA0-52E0-4557-8A13-36122AD3F81A
A redescription and range extension of Trimeresurus caudornatus Chen, Ding,
Vogel & Shi, 2020 (Serpentes: Viperidae)
TAN VAN NGUYEN1,2,*, SABIRA S. IDIIATULLINA3, WIN PAING OO4, JUSTIN L. LEE5, NIKOLAY A.
POYARKOV3,6,*, PATRICK DAVID7 & GERNOT VOGEL8,*
1 Institute for Research and Training in Medicine, Biology and Pharmacy, Duy Tan University, Da Nang, 550000, Vietnam
2 College of Medicine and Pharmacy, Duy Tan University, 120 Hoang Minh Thao, Lien Chieu, Da Nang, 550000, Vietnam
3 Department of Vertebrate Zoology, Lomonosov Moscow State University, Leninskiye Gory, GSP–1, Moscow 119991, Russia
4 Native Species Conservation and Identification in Myanmar, Mandalay, Myanmar
5 Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, 48109, United States
6 Joint Vietnam - Russia Tropical Science and Technology Research Centre, 63 Nguyen Van Huyen Road, Nghia Do, Cau Giay, Hanoi, Vietnam
7Institut de Systématique, Évolution et Biodiversité (ISYEB), Muséum National d’Histoire Naturelle, Sorbonne Université, École
Pratique des Hautes Études, Université des Antilles, CNRS, CP 30, 57 rue Cuvier, F-75005 Paris, France.
8 Society for South East Asian Herpetology, Im Sand-3, D-69115 Heidelberg, Germany
Tan Van Nguyen: https://orcid.org/0000-0001-5413-968X
Sabira S. Idiiatullina: https://orcid.org/0000-0003-1647-7754
Win Paing Oo: https://orcid.org/0009-0006-9916-3169
Justin L. Lee: https://orcid.org/0000-0002-9782-8503
Nikolay A. Poyarkov: https://orcid.org/0000-0002-7576-2283
Patrick David: https://orcid.org/0000-0001-7562-684X
Gernot Vogel: https://orcid.org/0000-0002-4542-518X
*
Corresponding authors:
�
tan.sifasv@gmail.com;
�
n.poyarkov@gmail.com;
�
Gernot.Vogel@t-online.de
Abstract
The pitviper species Trimeresurus caudornatus was recently described based on only two specimens from Nabang Town,
Yingjiang County, Yunnan Province, China. Here, we provide additional data on this species based on a re-examination
of 19 preserved specimens, 16 specimens reported in earlier literature sources, and additional photo-documented records
from northern Myanmar (Burma) and adjacent China. All new specimens were previously identified as Trimeresurus
albolabris sensu lato or Trimeresurus septentrionalis sensu lato. Molecular analyses based on mitochondrial DNA
supported the morphological findings in establishing conspecificity with T. caudornatus. The newly identified specimens
have a pairwise distance of only 0.4–2.6% from those of the type series of T. caudornatus (based on the cytochrome b
gene). Based on these findings, we confirm the presence of T. caudornatus from Myanmar and update its diagnostic
characters and distribution. We suggest the species should be considered as Least Concern (LC) following the IUCN’s
Red List categories. Further studies reassessing the populations of the Trimeresurus albolabris complex are required.
Key words: morphology, Myanmar, new record, phylogeny, taxonomy, Trimeresurus albolabris, T. salazar
Introduction
Asian pit vipers of the genus Trimeresurus Lacépède, 1804 represent one of the most widespread and diverse
radiations of medically significant venomous snakes, with 53 species currently recognized (Mirza et al. 2023;
Chan et al. 2023; Idiiatullina et al. 2023, 2024a-c). Members of Trimeresurus have a broad distribution, extending
from northeast India and Nepal in the west, to China and the Lesser Sunda Islands in the east and south-east
(Gumprecht et al. 2004; Vogel, 2006; Poyarkov et al. 2023; Uetz et al. 2024). The taxonomic diversity of the genus
Trimeresurus remains both underestimated and controversial, in part because many taxa are morphologically similar
to one another.
The systematics of the Trimeresurus albolabris species complex is especially intricate (Vogel et al. 2023). This
complex of species is widely distributed across the Indo-Himalayan region of India and Nepal, the southern-half of

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China, and the majority of Southeast Asia. Members of this complex are characterized by the combination of a long
papillose or calyculate hemipenis, a first supralabial partially or totally fused with nasal scale, uniform green dorsal
colouration, a lateral stripe present on the first few dorsal scale rows in one or both sexes, relatively small eyes,
supraoculars narrower than the internasals, and an elongate oval-shaped head in lateral profile (Regenass & Kramer,
1981; Malhotra & Thorpe, 2004; Malhotra et al. 2011; Vogel et al. 2022, 2023). Throughout the past two decades,
several pit vipers related to T. albolabris have been elevated to species rank or described as new species (Zhu et al.
2016; Chen et al. 2020, 2021; Mirza et al. 2020, 2023). However, the exact distributional limits between many of
these species are poorly understood.
FIGURE 1. Map showing distributions of Trimeresurus caudornatus (red star: type locality). Notes: numbers indicate the
different localities where this species has been recorded (see Appendix Table S8 for details of localities).
The Ornamental-tailed Pitviper, Trimeresurus caudornatus Chen, Ding, Vogel & Shi, 2020 belongs to the
Trimeresurus albolabris species complex based on morphological and genetic data (Chen et al. 2020). This species
was described based on one male and one female specimen, both originating from Nabang Town in Yingjiang County,
Yunnan Province, China (Chen et al. 2020; see Fig. 1). The species is characterized by having a dark green dorsum
with a lighter green lip; an absence of postocular streaks; a faint green yellow ventrolateral stripe present on the first
row of dorsal scales; a golden yellow iris; and orange-red midventral stripe along the underside of the tail. Recent
molecular phylogenies have demonstrated that populations previously identified as Trimeresurus albolabris Gray,
1842 and T. septentrionalis Kramer, 1977 from northern Myanmar (i.e., Mandalay Region and Kachin State) cluster
within the same lineage as the holotype of T. caudornatus (Mallik et al. 2021; Vogel et al. 2022; Mirza et al. 2023).
These results suggest that T. caudornatus has a more expansive distribution than currently recognized. However,
most of these molecular studies were unaware that some of their genetic samples corresponded with T. caudornatus
at the time of their publication, or did not provide morphological data associated with the specimens they sampled.
Vogel et al. (2023) included preliminary morphological and distributional data suggesting that northern Myanmar

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populations of T. albolabris and T. septentrionalis belonged to T. caudornatus but did not
provide a detailed
description of their material, as the scope of their paper was the description of neighboring species Trimeresurus
uetzi Vogel, Nguyen & David. As a consequence, the morphological diagnosis of T. caudornatus has remained
limited to the holotype and paratype, and the status of several populations of Trimeresurus from northern Myanmar
has remained unresolved until now. To address this issue, we re-examined specimens previously identified as T.
albolabris or T. septentrionalis from northern Myanmar (Sagaing and Mandalay regions, and Kachin State) deposited
in five natural history collections, including all of the specimens that were included in Vogel et al. (2023). We also
refer to data of 16 specimens of T. “albolabris” from northwest Yunnan Province that were reported in the literature
by Zhao et al. (1998). Our results confirm that the specimens from Myanmar, as well as Longchuan and Tengchong
counties, Yunnan Province, China, should be re-identified as T. caudornatus. We herein confirm the occurrence of T.
caudornatus in Myanmar, update the distribution of this species and revise its diagnostic characters.
Material and Methods
Material examined. We examined 19 specimens that were previously registered as Trimeresurus albolabris or T.
septentrionalis from northern Myanmar (see Table 1), and three digital images (DTU 651 from Yingjiang County,
Dehong City, Yunnan Province, China; DTU 652 from Chuxiong City, Yunnan Province, China and DTU 653 from
Mandalay City, Mandalay Region, Myanmar) of genuine specimens of T. caudornatus. Morphological comparisons
were based on literature data from Kramer (1977), Chen et al. (2020, 2021); Mirza et al. (2020), Rathee et al. (2021),
Vogel et al. (2023), Biakzuala et al. (2024), and 339 preserved specimens of other members of the Trimeresurus
albolabris species complex (see Appendix Table S1 and Appendix II of Vogel et al. 2023 for a list of specimens
examined for this study).
Morphological analyses: Altogether, 45 morphological characters (see Appendix Table S2) were considered,
either as raw variables or derived from the raw characters listed above. Measurements were taken with a slide-caliper
to the nearest 0.1 mm, except body and tail lengths, which were measured to the nearest of 1 mm with a measuring
tape. Ventral scale numbers were counted according to Dowling (1951). Half ventrals were counted as a single scale.
The enlarged shield(s) anterior to the first ventral were regarded as preventral(s). We regard the first subcaudal scale
as the first scale on the underside of the tail posterior to the vent that meets an opposite scale and did not include the
unpaired terminal scute (tail tip) in subcaudal counts. The dorsal scale rows were counted at one head length behind
the head, at midbody approximately one-half the body length of each specimen, and at one head length before the
vent. Values for paired head characters were recorded on both sides of the head and are reported in left / right order.
The eye diameter (ED) was measured horizontally (the greatest diameter of the orbit); the distance from the eye to
the nostril (EN) was measured from the anterior margin of the eye to the posterior margin of the nostril; the distance
from the eye to the lip (SL) was measured from the ventral margin of the middle of the eye to the ventral margin of
the upper labial below it; the head width (HW) was measured at the widest part of the head on posterior side. The sex
was determined by dissection of the ventral tail base in preserved specimens and with a probe in live individuals.
To determine whether Trimeresurus caudornatus and other species related to T. albolabris and T. septentrionalis
(including type specimens of the three species, in total 142 adult males specimens and 197 adult females specimens)
exhibit significant morphological differences, we ran univariate statistical analyses on four scale counts (VEN, SC,
VEN+SC, SL, and IL) and one body measurement ratio (TaL/TL). Since most of these variables represent meristic
data, no size-correction on the morphological data was conducted for statistical analyses and both juvenile and
adult specimens were included in all analyses. Males (N = 142) and females (N = 197) were analyzed separately
in each analysis owing to the presence of sexual dimorphism present within many members of Trimeresurus (Zhu
et al. 2022). We first subjected each character (separated by male and female specimen series) to Shapiro–Wilks
Tests and Levene’s Tests to determine if each data exhibits normality and homoscedasticity, respectively. Since
most of the characters exhibited both non-normal and non-homoscedastic distributions, we employed pairwise
Mann–Whitney U Tests (the non-parametric alternative to Student’s t–tests) to determine whether scale counts and
measurements exhibited statistically significant differences between species. In all cases, we considered characters
to be significantly different if corresponding p–values were less than or equal to 0.05.
Molecular phylogeny. We synthesized previously published sequences of Trimeresurus albolabris complex
members from GenBank to estimate the phylogenetic relationships of the genus Trimeresurus and genetically identical
samples referrable to T. caudornatus. We focused on sequences for the mitochondrial DNA gene cytochrome b (cyt

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b) as it is phylogenetically informative for most viperids and has the largest availability of any gene for Trimeresurus.
We updated the taxonomic identities of the gene sequences to current taxonomy (Vogel et al. 2023; this work),
regardless of what it had been originally submitted as. We aligned the cyt b sequences of 40 species of Trimeresurus
species representing all major groups within the genus, ten species of the genus Craspedocephalus Kuhl & Hasselt;
we used the sequence of Azemiops feae Boulenger and Protobothrops elegans (Gray) to root the tree (GenBank
accession numbers, voucher specimens, locality, and source information are summarized in Appendix Table S3).
We initially aligned nucleotide sequences in MAFFT v.6 (Katoh et al. 2019) with default parameters,
subsequently checked them by eye in BioEdit 7.0.5.2 (Hall, 1999) and slightly adjusted sequences for translation
whenever required. Uncorrected pairwise genetic distances (p-distances) between sequences were calculated with
MEGA 6.0. (Tamura et al. 2013) based on the cyt b sequences of all Trimeresurus subgenus samples, and missing
data or gaps were affected by the pairwise deletion option. When the same model was proposed for different codon
partitions of a given gene, they were treated as a single partition.
Phylogenetic trees were inferred using Bayesian inference (BI) and maximum likelihood (ML) approaches. We
used the IQ-TREE webserver (Trifinopoulos et al. 2016) to generate the ML-tree and evaluate the confidence in
tree topology by 1000 ultrafast-bootstrap replications (UFBS). The best-fit substitution models for the dataset were
selected for gene and codon positions in ModelFinder using the Akaike information criterion (AIC) in IQ-TREE.
We conducted BI in MrBayes 3.1.2 (Huelsenbeck & Ronquist 2001) using the same partition scheme inferred for the
ML analysis. Metropolis-coupled Markov chain Monte Carlo (MCMCMC) analyzes were run with one cold chain
and three heated chains for one million generations and sampled every 1000 generations. The run was checked to
ensure the effective sample sizes (ESS) were all above 200 by exploring the likelihood plots using Tracer v. 1.7
(Rambaut et al. 2018). We discarded the initial 1000 trees as burn-in. For BI-analysis we assessed the confidence
in tree topology by the posterior probability (PP) (Huelsenbeck & Ronquist 2001). We a priori considered tree
nodes with UFBS values of 95% or higher and PP values over 0.95 as strongly supported; UFBS values between
95% and 90% and PP values between 0.95 and 0.90 as moderately supported, and any values lower than these were
considered as lacking node support (Huelsenbeck & Hillis 1993).
Abbreviations. Morphology and morphometry. DSR: dorsal scale rows; IL: infralabials; SC: number of
subcaudals excluding terminal scute; SL: number of supralabials; SVL: snout ventral length from snout to last
ventral scale; TaL: tail length from anal to tail tip; TL: total length from the tip of the snout to the end of the tail;
TL/TaL: ratio of total length to tail length; VEN: number of ventrals. Other abbreviations. Mt.: mount; NP: National
Park; WS: Wildlife Sanctuary.
Institutions and museums acronyms. CAS: California Academy of Sciences, San Francisco, USA; CESS:
Centre for Ecological Sciences, Bangalore, India; KIZ: Kunming Institute of Zoology, Chinese Academy of Sciences,
Yunnan, China; MHNG: Muséum d’Histoire Naturelle de la Ville de Genève, Genève, Switzerland; MNHN: Muséum
national d’Histoire naturelle, Paris, France; MSNG: Museo Civico di Storia Naturale “Giacomo Doria” Genova,
Liguria, Italy; NHMUK (formerly BMNH): The Natural History Museum, London, UK; NHMW (formerly NMW)
= Naturhistorisches Museum Wien, Vienna, Austria; QSMI: Queen Saovabha Memorial Institute, Thai Red Cross
Society, Bangkok, Thailand; RMNH: Nationaal Natuurhistorisch Museum (Naturalis), Leyden, The Netherlands;
SMF: Natur-Museum und Forschungs Institut Senckenberg, Frankfurt-am-Main, Germany; SYS: Sun Yat-Sen
University, Guangdong, China; USNM: National Museum of Natural History, Smithsonian Institution, Washington,
USA; ZFMK: Zoologisches Forschungsmuseum Alexander Koenig, Bonn, Germany; ZMB: Zoologisches Museum
für Naturkunde der Humboldt-Universität zu Berlin, Berlin, Germany; ZMH: Zoologisches Museum Hamburg,
Universität Hamburg, Hamburg, Hamburg, Germany; ZMNH: Zhejiang Museum of Natural History, Zhejiang,
China; ZSI: Zoological Survey of India, Kolkata [Calcutta], West Bengal, India
Results
Phylogenetic relationships
The ML and BI analyses recovered trees with similar topologies, but minor discrepancies associated in deeper and
shallower nodes were observed (Fig. 2). With respect to the position of T. caudornatus, our phylogenetic results
mostly conform to those of Zhu et al. (2016), Chen et al. (2020), Mirza et al. (2023), and Vogel et al. (2022), who
focused on relationships among Trimeresurus albolabris and T. septentrionalis, to which T. caudornatus belongs.
The reconstructed phylogenetic relationship indicates that four species: T. caudornatus, T. salazar Mirza, Bhosale,

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FIGURE 2. Maximum Likelihood (ML) tree of Trimeresurus derived from the analysis of cyt b mitochondrial DNA gene
sequences. For voucher specimen information and GenBank accession numbers see Appendix Table S3. Numbers at tree nodes
correspond to ML UFBS/BI PP support values, respectively.
Phansalkar, Sawant, Gowande & Patel, T. septentrionalis, and T. uetzi Vogel, Nguyen & David are nested within a
single monophyletic clade (Fig. 2); however, the nodes connecting each species in this clade received poor support
in the ML analysis (UF BS = 55) and exhibited different phylogenetic positions in the BI genealogy. Despite

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the low branch support of the clade containing all four species, the internal nodes of each species within that
clade were all strongly supported, including T. caudornatus (100/1.0). The uncorrected p-distances of the cyt b
gene fragment among members of the Trimeresurus albolabris and T. septentrionalis species groups are presented
in see Appendix Table S4. Three sequences of Trimeresurus spp. (KP999351 [CAS 216144], KP999351 [CAS
216173], and ON804486 [CAS 235956], respectively) reported from Sagaing Region and Kachin State, Myanmar,
respectively, were approximately 0.4–2.6% divergent from the type series of Trimeresurus caudornatus from Nabang
Town, Yingjiang County, Yunnan Province, China. These intraspecific distances are consistent with other species
related to T. albolabris and T. septentrionalis (Appendix Table S4), with the geographically adjacent species T. uetzi
having intraspecific distances ranging from 0.0–3.6% and T. albolabris having a much wider span of intraspecific
divergences (0.1–4.3%). Genetic distances between T. caudornatus and related species were consistent with other
pairwise distances between other related Trimeresurus. Specifically, T. caudornatus was 5.3–7.3% divergent from
T. salazar, 5.9–6.9% divergent from T. septentrionalis, and 5.8–7.0% divergent from T. uetzi. These results strongly
suggest that the northern Myanmar populations of Trimeresurus are genetically conspecific with T. caudornatus.
Morphological analysis
With the exception of relative tail length (TaL/TotalL), statistically significant differences were found between
all Trimeresurus in the remaining four morphological characters we examined (see Suppl. material 1: table S5 for
more details). However, most of these differences were subtle, and overlaps between scale counts are present. Both
male and female Trimeresurus caudornatus had a statistically higher number of ventrals (p < 0.0001 in males; p =
0.0163 in females) relative to T. albolabris. Male T. caudornatus have a slightly lower number of subcaudals than T.
septentrionalis (p = 0.0289). Female T. caudornatus also have a statistically lower number of ventrals (p = 0.0039)
and subcaudals (p = 0.0077) than female T. septentrionalis, and a slightly higher number of subcaudals (p = 0.0020)
and infralabials (p = 0.047) than female Trimeresurus uetzi. We also examined the morphology of other Trimeresurus
specimens previously registered as T. albolabris or T. septentrionalis from Myanmar, including specimen CAS
216144 (see Fig. 3 E–F), which was sequenced for genetic data, and found that they were all morphologically
referrable to T. caudornatus. The Burmese specimens of Trimeresurus share the presence of a distinct midventral
stripe on the underside of the tail and have a faint ventrolateral stripe on the first scale row of the dorsal surface, all
of which match the type series from Yunnan Province (Chen et al. 2020). Moreover, live photographs of specimens
from Myanmar lack a distinct postorbital streak and have a golden yellow iris, characters that are not found in other
closely related species such as T. salazar and T. uetzi. These results support our hypothesis that previous records of T.
albolabris (restricted to southern China, Vietnam, Laos, Cambodia, Thailand, and Indonesia) and T. septentrionalis
(restricted to western and central Himalayan regions of Nepal and northern India) in northern Myanmar (Sagaing,
Mandalay, and Kachin) and northwestern Yunnan (Longchuan and Tengchong counties), China, should be referred
to as T. caudornatus. In conjunction with our genetic results, we extend the distribution of Trimeresurus caudornatus
to Myanmar and provide an expanded diagnosis and description below.
Taxonomic account
Trimeresurus caudornatus
(Table 1; Figs. 3–5)
Trimeresurus caudornatus Chen, Ding, Vogel & Shi in Chen et al. (2020: 116, Fig. 2A-B, 3A-D & 4A-D). Holotype: ZMNH
AR1238, adult male, collected by L. Ding and Z. Chen on 17 September 2018. Type locality: Nabang Town, Yingjiang
County, Dehong City, Yunnan Province, China (24.6973°N, 97.5805°E; elevation 389 m asl.).
Chresonymy
Trimeresurus gramineus (non Coluber gramineus Shaw, 1802)—Wall (1925: 821; 1926: 566, both in part).
Trimeresurus albolabris (non Trimesurus albolabris Gray, 1842)—Smith (1943: 523, in part); Zhao et al. (1998: 448, in part);
Orlov et al. (2002: 189, in part); Leviton et al. (2003: 444, in part, 462); David et al. (2003: 157, in part), Gumprecht et
al. (2004: 30, in part); Wogan & Win (2005: 72, in part); Vogel (2006: 83, in part); Stuart et al. (2012: 1 & 3, in part);
Yang & Rao (2008: 336, in part); Wallach et al. (2014: 726, in part); Zhu et al. (2022: 32, in part); Uetz et al. (2024, page
“Trimeresurus albolabris”, in part);
Cryptelytrops albolabris—David et al. (2001, 221, in part), Leviton et al. (2008: 71, in part).

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Trimeresurus albolabris albolabris—David & Vogel (1998: 87, in part), Regenass & Kramer (1981: 168 & 169, in part); David
& Tong (1997: 26, in part).
Trimeresurus septentrionalis (non Trimeresurus septentrionalis Kramer, 1977)—Orlov et al. (2002: 352; in part); Zhu et al.
(2016: 253, 256, 258 & 259, in part).
Trimeresurus caudornatus—Chen et al. (2021: 167, 172, 175 & Tables S1–S2); Mallik et al. (2021: 580); Vogel et al. (2022:
344, 347, 358, 363, 365); Vogel et al. (2023).
Specimens examined (n=19, all from Myanmar): Sagaing Region: CAS 244953 (adult male) from Homalinn,
Khandi District, USNM 537444 (adult male) and USNM 524076 (adult female) from Chatthin W.S., Kanbalur
Township. Mandalay Region: CAS 216144 (subadult female) from Shwe U Daung, Pyin Oo Lwin District. Kachin
State: CAS 230260, CAS 232425 (two subadut females), CAS 241264 (subadult male), CAS 245234 (subadult
female) from Indawgyi Lake, Myitkyina District; CAS 221549 (subadult male), CAS 224646 (adult male) and CAS
230233 (adult female) from Putao District; MNHN RA-1893.0415, MSNG 30533-B (two adult males) & MNHN
RA-1893.0416, MSNG 2180, MSNG 30533-A (three adult females) from Bhamo District; NHMUK 1974.907
(adult male) from Sumprabum District; MSNG 30814 (sub adult female) from Teinzo, Bhamo District; NHMUK
1974.906 (adult female) from N’Changyang District (remark: for more information details of CAS specimens see
Appendix Table S6).
Additional material (n=3). DTU 651 (Digital images) photo taken by Spark T on 29 August 2023 in Pingyuan
Town, Yingjiang County, Dehong City, Yunnan Province, China. DTU 652 (Digital images) photo taken by Fan Gao
on 14 May 2021 in Chuxiong City, Yunnan Province, China. DTU 653 (Digital images) photo taken by Kyaw Zin
Htet on 13 Jun 2023 in Mandalay City, Mandalay Region, Myanmar.
Referred material (n=16; all from Yunnan Province, China, based on specimens cited by Zhao et al. 1998).
Longchuan County: KIZ 74I0024 (adult male), KIZ 74I0032-33 (two subadult males), KIZ 74I0045-46 (two adult
males), KIZ 74I0006, KIZ 74I0010, KIZ 74I0018, KIZ 74I0027-28 (five adult females), KIZ 74I0012 (subadult
female). Tengchong County: KIZ 741I0358 (adult female).
Revised diagnosis. A species of Trimeresurus inhabiting Yunnan Province (China) and Northern Myanmar
showing the following combination of characters: head and body generally dark green, upper labials light green;
postocular stripes absent in both sexes; ventrolateral stripe faint green-yellow, present on the first row of DSR in both
sexes; iris golden yellow in both sexes; dorsal surface of the tail mostly dark red, lateral and ventral surfaces green;
an orange-red medial stripe present across the underside of the tail; DSR 21(rarely 22 or 23)–21–15; VEN 158–167
in males, 158–174 in females; SC 53–74 in males, 52–68 in females; ratio TaL/TL 0.17–0.22 in males, 0.14–0.18 in
females; Cep 10–12; first upper labial partially fused to the nasal; hemipenes elongated, bilobed at the level of the
6th subcaudal, tips reaching SC 37–38, small spines present posterior to the bifurcation, sulcus spermaticus shallow,
visible, divides at the base of the organ (based on Zhao et al. 1998; Chen et al. 2020, and our material).
Comparisons. Trimeresurus caudornatus is morphologically similar to Trimeresurus salazar, a species
described from Pakke Tiger Reserve, East Kameng District, Arunachal Pradesh State, India, which is widely
distributed across central and northeastern India, eastern Nepal, Bhutan, and Bangladesh (Mirza et al. 2020; Vogel
et al. 2022). Trimeresurus caudornatus differs from T. salazar by having a dark green dorsum (vs. usually green-
yellow, more so in females); ventrolateral stripes faint, green-yellow and poorly contrasting dorsal ground color (vs.
stripes distinct, brick red ventrally plus white dorsally, and conspicuous); presence of an irregular, red-orange stripe
on the midventral surface of the tail (vs. absent); iris golden yellow (vs. copper) and tip of the hemipenes reaching
SC 37–38 (vs. 12–13).
Trimeresurus caudornatus differs from Trimeresurus albolabris s. str. (restricted to southeastern China, Vietnam
[throughout except the northwest], Laos [central and southern], Cambodia [throughout], and Thailand [eastern and
central]) by having faint ventrolateral stripes that are greenish-yellow and poorly contrasted (vs. distinct, white,
conspicuous); postocular streak absent in males (vs. present); iris golden yellow (vs. copper); tip of hemipenes
reaching SC 37–38 (vs. 15–18) and small scales absent in front of the pit (vs. usually present).
Trimeresurus caudornatus differs from T. erythrurus (Cantor), a species present in Myanmar, India, Bangladesh,
possibly in Bhutan, by having: ventrolateral body stripes faint, greenish-yellow, poorly contrasted (vs. distinct,
white, conspicuous); postocular stripe absent in males (vs. present); iris golden yellow (vs. copper); temporal scales
and dorsal body scales feebly keeled (vs. strongly keeled); lower number of mid-body scale rows (21 vs. 23 [rarely
21, 24, 25]).

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TABLE 1. Main measurements and meristic characters of Trimeresurus caudornatus from China and Myanmar.
No.Previous
identification
New
identification
Locality Voucher
number
Sex Status SVL
(mm)
TaL
(mm)
1T. albolabris T. caudornatus Yingjiang, Yunnan, China ZMNH AR1238 M Holotype 573 122
2T. septentrionalis T. caudornatus Indawgyi Lake, Myitkyina, Kachin, MyanmarCAS 241264 M 436 110
3T. albolabris T. caudornatus Putao, Kachin, Myanmar CAS 221549 SM 333 72
4T. albolabris T. caudornatus Putao, Kachin, Myanmar CAS 224646 M 601 168
5T. albolabris T. caudornatus Homalinn, Khandi, Sagaing, Myanmar CAS 244953 M 507 141
6T. albolabris T. caudornatus Bhamo, Kachin, Myanmar MNHN
1893.0415
M 546 143
7T. albolabris T. caudornatus Bhamo, Kachin, Myanmar MSNG 30533-B M 463 116
8T. albolabris T. caudornatus Sumprabum, Kachin, Myanmar NHMUK
1974.907
M 523 141
9T. albolabris T. caudornatus Chatthin WS, Kanbalur, Sagaing, Myanmar USNM 537444 M 425 114
10 T. albolabris T. caudornatus Longchuan, Yunnan, China KIZ 74I0024 M 420 108
11 T. albolabris T. caudornatus Longchuan, Yunnan, China KIZ 74I0032 SM 378 95
12 T. albolabris T. caudornatus Longchuan, Yunnan, China KIZ 74I0033 SM 363 85
13 T. albolabris T. caudornatus Longchuan, Yunnan, China KIZ 74I0045 M 425 120
14 T. albolabris T. caudornatus Longchuan, Yunnan, China KIZ 74I0046 M 465 130
15 T. caudornatus T. caudornatus Yingjiang, Yunnan, China ZMNH AR1239 F Paratype 425 77
16 T. yunnanensis T. caudornatus Hukaung WS, Myitkyina, Kachin, Myanmar CAS 230260 SF 283 55
17 T. albolabris T. caudornatus Ta Ruing, Ta Nai, Myitkyina, Kachin,
Myanmar
CAS 232425 SF 297 59
18 T. septentrionalis T. caudornatus Shwe U Daung, Pyin Oo Lwin, Mandalay,
Myanmar
CAS 216144 SF 322 55
19 T. albolabris T. caudornatus Chipwe, Myitkyina, Kachin, Myanmar CAS 245234 SF 279 50
20 T. albolabris T. caudornatus Madanbaw, Putao, Kachin, Myanmar CAS 230233 F 534 98
21 T. albolabris T. caudornatus Bhamo, Kachin, Myanmar MSNG 30533-A F 702 74+
22 T. albolabris T. caudornatus Bhamo, Kachin, Myanmar MSNG 2180 F 660 136
23 T. albolabris T. caudornatus Teizo, Kachin, Myanmar MSNG 30814 SF 332 58
24 T. albolabris T. caudornatus Bhamo, Kachin, Myanmar MNHN
1893.0416
F 625 130
25 T. albolabris T. caudornatus N’Changyang, Kachin, Myanmar NHMUK
1974.906
F 679 133
26 T. albolabris T. caudornatus Chatthin WS, Kanbalur, Sagaing, Myanmar USNM 524076 SF 329 58
27 T. albolabris T. caudornatus Longchuan, Yunnan, China KIZ 74I0006 F 538 95
28 T. albolabris T. caudornatus Longchuan, Yunnan, China KIZ 74I0010 F 470 75
29 T. albolabris T. caudornatus Longchuan, Yunnan, China KIZ 74I0012 SF 310 69
30 T. albolabris T. caudornatus Longchuan, Yunnan, China KIZ 74I0018 F 568 106
31 T. albolabris T. caudornatus Longchuan, Yunnan, China KIZ 74I0027 F 474 83
32 T. albolabris T. caudornatus Longchuan, Yunnan, China KIZ 74I0028 F 540 105
33 T. albolabris T. caudornatus Tengchong, Yunnan, China KIZ 741I0358 F 442 93
34 T. albolabris T. cf. caudornatus Jingdong, Yunnan, China KIZ 75II0358 M 600 142
35 T. albolabris T. cf. caudornatus Yongde, Yunnan, China KIZ 79I501 M 400 99
36 T. albolabris T. cf. caudornatus Kunming, Yunnan, China KIZ 740005 F ? ?
37 T. albolabris T. cf. caudornatus Yongde, Yunnan, China KIZ 79I207 F 500 92
......continued on the next page

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TABLE 1. (Continue)
No.New identification Voucher number Sex DSR VEN SC SL IL Source
1T. caudornatus ZMNH AR1238 M 21– 21– 15 163 72 10/10 13/12 Chen et al. (2020)
2T. caudornatus CAS 241264 M 21– 21– 15 162 66 10/10 12/11 This study
3T. caudornatus CAS 221549 SM 21– 21– 15 162 66 10/10 14/13 This study
4T. caudornatus CAS 224646 M 21– 21– 15 161 71 10/11 12/13 This study
5T. caudornatus CAS 244953 M 21– 21– 15 164 71 10/10 13/13 This study
6T. caudornatus MNHN 1893.0415 M 21– 21– 15 161 62 10/10 12/12 This study
7T. caudornatus MSNG 30533-B M 23– 19– 15 165 69 11/10 11/12 This study
8T. caudornatus NHMUK 1974.907 M 23– 21– 17 158 67 12/11 12/11 This study
9T. caudornatus USNM 537444 M 23– 21– 15 166 53 11/11 13/14 This study
10 T. caudornatus KIZ 74I0024 M 21– 21– 15 158 69 10/10 12/12 Zhao et al. (1998)
11 T. caudornatus KIZ 74I0032 SM 19– 21– 15 160 69 11/10 13/13 Zhao et al. (1998)
12 T. caudornatus KIZ 74I0033 SM 23– 21– 17 167 74 11/10 14/13 Zhao et al. (1998)
13 T. caudornatus KIZ 74I0045 M 21– 21– 15 163 73 11/11 13/14 Zhao et al. (1998)
14 T. caudornatus KIZ 74I0046 M 21– 21– 15 164 71 10/10 12/13 Zhao et al. (1998)
15 T. caudornatus ZMNH AR1239 F 21– 21– 15 161 52 10/11 13/14 Chen et al. (2020)
16 T. caudornatus CAS 230260 SF 19– 21– 15 158 61 11/11 13/12 This study
17 T. caudornatus CAS 232425 SF 21– 21– 15 159 60 11/10 12/12 This study
18 T. caudornatus CAS 216144 SF 21– 21– 15 169 55 10/9 13/13 This study
19 T. caudornatus CAS 245234 SF 21– 21– 15 158 57 10/10 13/13 This study
20 T. caudornatus CAS 230233 F 21– 21– 15 164.00 57.00 11/11 12/13 This study
21 T. caudornatus MSNG 30533-A F 23– 21– 17 173 ? 11/10 11/12 This study
22 T. caudornatus MSNG 2180 F 23– 21– 15 174 68 11/11 13/14 This study
23 T. caudornatus MSNG 30814 SF 23– 21– 15 162 60 ? ? This study
24 T. caudornatus MNHN 1893.0416 F 21– 21– 15 165 66 10/10 13/13 This study
25 T. caudornatus NHMUK 1974.906 F 21– 21– 15 160 55 11/11 13/13 This study
26 T. caudornatus USNM 524076 SF 21– 21– 15 160 53 11/11 12/12 This study
27 T. caudornatus KIZ 74I0006 F 21– 21– 15 160 53 12/10 13/14 Zhao et al. (1998)
28 T. caudornatus KIZ 74I0010 F 21– 21– 15 159 54 13/13 15/16 Zhao et al. (1998)
29 T. caudornatus KIZ 74I0012 SF 21– 21– 15 161 57 11/11 13/14 Zhao et al. (1998)
30 T. caudornatus KIZ 74I0018 F 21– 21– 15 168 55 10/10 13/12 Zhao et al. (1998)
31 T. caudornatus KIZ 74I0027 F 21– 21– 15 161 ? 11/12 12/13 Zhao et al. (1998)
32 T. caudornatus KIZ 74I0028 F 21– 21– 15 164 61 11/11 12/12 Zhao et al. (1998)
33 T. caudornatus KIZ 741I0358 F 21– 21– 15 159 52 11/11 13/13 Zhao et al. (1998)
34 T. cf. caudornatus KIZ 75II0358 M 21– 21– 15 163 67 10/10 12/14 Zhao et al. (1998)
35 T. cf. caudornatus KIZ 79I501 M 22– 21– 15 161 69 10/9 13/13 Zhao et al. (1998)
36 T. cf. caudornatus KIZ 740005 F 21– 21– 15 155 54 10/11 14/15 Zhao et al. (1998)
37 T. cf. caudornatus KIZ 79I207 F 22– 21– 15 162 57 10/11 13/14 Zhao et al. (1998)
Trimeresurus caudornatus differs from T. guoi Chen, Shi, Vogel & Ding by having a golden yellow eye color
(vs. always firebrick-red); tip of hemipenes reaching SC 37–38 (vs. 23–32).
Trimeresurus caudornatus differs from T. septentrionalis, a species now restricted to Nepal and north-western
India, by having a lower number of subcaudals in males (53–74, 68.07 ± 5.38 vs. 71–80, 76.67 ± 3.50) and females
(52–68, 57.41 ± 4.69 vs. 56–66, 63.07±2.53), and tip of hemipenes reaching SC 37–38 (vs. 5–7).

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FIGURE 3. The head of preserved Trimeresurus caudornatus from Myanmar in lateral right and lateral left views: (A–B)
specimen CAS 224646, adult male, and (C–D) specimen MSNG 30533-B, adult male, from Myitkyina and Bhamo, Kachin,
respectively; (E–F) specimen CAS 216144, subadult female, from Pyin Oo Lwin, Mandalay; (G–H) specimen NHMUK
1974.907, adult female, from Sumprabum, Kachin. Photos by G. Vogel (A, B, E–H) and J. Lee (C–D).

REDESCRIPTION OF TRIMERESURUS CAUDORNATUS Zootaxa 5514 (3) © 2024 Magnolia Press · 211
FIGURE 4. Trimeresurus caudornatus in preservative: specimen CAS 241264 (subadult male) from Myitkyina, Kachin,
Myanmar. (A–B) Dorsolateral and ventral views of body, respectively; (C–F) head in lateral right, lateral left, dorsal, and ventral
aspects, respectively; (G–H): Ventral view of the tail with the everted hemipenes. Photos by G. Vogel.
Trimeresurus caudornatus differs from T. uetzi, a species recently described from central and southern Myanmar,
also present in Northeast India, by having the tip of the hemipenes reaching the 37th–38th SC (vs. 6th–8th SC);
postocular stripe absent in males (vs. present); ventrolateral body stripe faint, greenish-yellow, poorly contrasted

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(vs. present, white, conspicuous); in life, iris golden yellow in male (vs. copper in male); and the presence of an
irregular, red-orange stripe in the middle of the ventral surface (vs. no median stripe on the lower surface of the tail)
(see Appendix Table S7).
Description based on examined specimens from Myanmar (n=19).
Morphology. Body moderately elongate, slender [the longest known specimen is 776+ mm long, (SVL 702 mm,
TaL 74+ mm, female; MSNG 30533-A, incomplete tail); the longest known male is 769 mm long (SVL 601 mm,
TaL 168 mm; CAS 224646); tail typically cylindrical in cross section, fairly short, prehensile, tapering (TaL/TL
0.17–0.22 in males (n=9) and 0.15–0.17 in females (n=8)). Head triangular and elongate, flattened, clearly distinct
from neck. Snout moderate, overall flattened from top and side view, rounded from top view, truncate when seen
from lateral side, canthus rostralis distinct, eye moderate.
Body scalation. DSR 21 (rarely 23)–21 (rarely 19)–15 scales, rhomboid, moderately keeled except for the first
row which is smooth; VEN 158–166 in males (n=9), 158–174 in females (n=9); SC 53–71 in males (n=9), 55–66 in
females (n=8), paired; single cloacal plate.
Head scalation. Rostral subtriangular, slightly visible when viewed from above; nasal large, sub-rectangular,
undivided, half-separated from the first upper labial by a suture behind the nostril; one pair of enlarged internasals,
in good contact with each other, slightly broader than long; second and third supralabial and three preoculars
encompass the loreal pit; the lower preocular forms the lower margin of the loreal pit; one elongate and narrow
supraocular; cephalic scales small, irregular, subimbricate, smooth; occipital scales smooth; temporals feebly keeled
and subequal; subocular crescent shaped; 9–13 supralabials; SL1 not fused with nasal scale, 2nd much higher than
1st, 3rd SL largest, longest of all, about twice as long as 2nd SL, longer than high, in contact with the subocular, 4th SL
distinctly shorter, more than 2/3 time as high as 3rd one, 5th and other posterior SL slightly smaller than 4th; both 4th
and 5th SL separated from the subocular by one scale row, others in contact with the first lowest row of temporals;
11–16 infralabials, the first pair in contact with each other; the first three pairs in contact with anterior chin shields;
six pairs of chin shields, each pair in contact medially; separated from infralabials by 1–6 scale rows.
Coloration in life (Fig. 5): Dorsal body dark green. Lateral body green above and gradually pale green yellow
below. Ventral body greenish yellow, paler in anterior part, light green in posterior part. Dorsal part of the tail dark
red, about 2 dorsal scale rows wide and not mottled. Lateral and ventral part of the tail green. Ventrally, a thin orange
red stripe extends across the posterior third of the tail. Tail tip uniformly red. Iris golden yellow (based on DTU
651–653 from Yunnan Province, China as well as Mandalay Region, Myanmar, all unknown sex).
Coloration in preservative (see Figs. 3–4): Dorsal body black gray or light blue without ventrolateral body
stripes. Ventral body uniformly cream. The head dorsally back gray or light blue; without postocular streak, but a
clear boundary below the eyes, olive above and grass green below. The chin and throat are white (based on CAS
241264 [male] and CAS 216144 [female], respectively).
Distribution (Fig. 1). Trimeresurus caudornatus was previously known only from Nabang Town, Yingjiang
County, Yunnan Province, China (Chen et al. 2020). We here add a second and third Chinese locality from Yunnan
Province: Tongbiguan Township, Yingjiang County, Longchuan, Tengchong countys and Chuxiong City (see the
Discussion). The new location in Chuxiong City is ca. 390 airline kilometers east of the type locality. We also
present several records of this species from Myanmar. T. caudornatus is currently known from the Mandalay and
Sagaing regions, and from Kachin State. Given its geographic proximity, it likely occurs in Shan State as well.
Detailed localities within each first-level regions of Myanmar are presented in Appendix Table S8.
Natural history notes. Prior to this study, the biological data of Trimeresurus caudornatus were very limited;
it was only reported from an altitude of 389 m a.s.l. at the type locality (Chen et al. 2020). According to metadata
associated with specimens deposited in the California Academy of Sciences collections (accessible at https://
researcharchive.calacademy.org/research/herpetology/catalog/Index.asp), specimens of T. caudornatus were
collected between 16h09 to 22h30 local time on trees, shrubs, or branches. The air temperature when specimens were
observed varied from 24.7ºC to 30ºC and the relative humidity from 69–92%. This species seems to be distributed
at low and medium elevations ranging from 169 to 560 m a.s.l. The stomach of CAS 221549 contained a skink
Sphenomorphus indicus (Gray). An adult male specimen CAS 224646 was inactive ca. 25 cm below ground level
inside a termite mound located near a trail in an agricultural area next to a subtropical evergreen forest (see Wogan
& Win 2005).

REDESCRIPTION OF TRIMERESURUS CAUDORNATUS Zootaxa 5514 (3) © 2024 Magnolia Press · 213
FIGURE 5. Adult Trimeresurus caudornatus alive (all uncollected and sex unknown). (A–C) from Chuxiong, Yunnan, China
(digital image DTU 652); (D) from Pingyuan, Yingjiang, Dehong, Yunnan, China (digital image DTU 651); (E) from Mandalay,
Mandalay, Myanmar (digital image DTU 653). Photos by: Fan Gao (A–C), Spark Thomas (D), and Kyaw Zin Htet (E).
Conservation status. Trimeresurus caudornatus is reliably known from 14 localities, including one national
park and three wildlife sanctuaries in northern Myanmar. Outside of these protected regions, we predict habitat loss,
habitat degradiation and killing/persecution by humans may act as conservation threats for this species. The actual
extent of distribution, population trends, reproductive behavior, ecology, toxicology of this species remain poorly
known. For now, based on its much more extensive distribution covering multiple protected areas in two countries,
we suggest Trimeresurus caudornatus be considered as Least Concern (LC) following the criteria provided in the
IUCN’s Red List categories (IUCN 2024).

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214 · Zootaxa 5514 (3) © 2024 Magnolia Press
Discussion
In this study, we re-examined specimens that were previously assigned to Trimeresurus albolabris sensu lato or
Trimeresurus septentrionalis sensu lato from northern Myanmar (Kachin State, Mandalay and Sagaing regions)
and found that all of them should be assigned to the recently described Trimeresurus caudornatus. These also
include records of T. albolabris and T. septentrionalis reported from northern Myanmar by Wall (1925; 1926),
Smith (1943), Regenass & Kramer (1981), David & Tong (1997), Orlov et al. (2002), Leviton et al. (2003, 2008),
Gumprecht et al. (2004), Vogel (2006), and Zhu et al. (2016). Presently T. albolabris s. str., should be restricted to
southeastern China and adjacent Indochina (Laos (centre and south), Cambodia (throughout), Vietnam (throughout
except the northwest), and Thailand (eastern and central) whereas T. septentrionalis s. str. should be restricted to
the western Himalayan regions of Nepal and India (Vogel et al. 2022, 2023). As previously mentioned, historical
records of Trimeresurus from central Myanmar and adjacent parts of northeastern India (Mizoram State) were
recently described/re-classified as T. uetzi (David et al. 2023; Biakzuala et al. 2024). Morphologically, the presence
of a red or orange midventral stripe on the underside of the tail and the lack of conspicuous white ventrolateral
and postocular striping appear to be consistent across Trimeresurus caudornatus in both sexes. These two traits
remain the easiest methods of identification for this species, especially relative to its geographically proximate
congeners Trimeresurus salazar and T. uetzi. Some female Trimeresurus uetzi also have inconspicuous ventrolateral
and postocular striping, but the absence of the red midventral stripe in that species should act to distinguish it from
T. caudornatus if the former characters overlap.
Previous accounts (Zhao et al. 1998; Yang & Rao 2008; Zhu et al. 2022) reported that the species Trimeresurus
albolabris is widely distributed in the northwestern region of Yunnan Province, China such as Longchuan County
in Dehong City, Tuantian Town in Tengchong City. However, according to the morphological data of specimens
from these two localities (Table 1), they belong to Trimeresurus caudornatus, rather than T. albolabris. Other
populations in northwestern Yunnan Province with similar morphological characteristics as T. caudornatus (such
as those reported from Yongde and Shuangjiang counties in Lincang City, Jingdong County in Puer City, and
Kunming City, see Table 1) should also be re-examined for verification, and molecular data. These specimens,
which were mentioned by Zhao et al. (1998), are included in the referred material of T. caudornatus, but are not
included in our redescription until further confirmation. In addition, Li et al. (2020) followed by Wu et al. (2023),
recorded Trimeresurus albolabris from Tongbiguan Township, Yingjiang County, Yunnan Province, China based
on specimen SYS r001228 (or CHS 661) under Genbank numbers MK194130 (16S) and MK064805 (COI) as a
lineage distinct from Trimeresurus albolabris s. str. and T. guoi. As these specimens were sequenced for separate
mitochondrial genes, we did not include them in our genetic analyses. Nevertheless, the location of the specimen
(Tongbiguan, Yingjiang County) is very close to the type locality of Trimeresurus caudornatus (approximately 28
km). We suspect that SYS r001228 is referrable to Trimeresurus caudornatus, but a re-examination of the specimen
is required to verify this.
In addition, our molecular results support the existence of two clades that were originally identified as Trimeresurus
albolabris: the first from Peninsular Thailand, and the second from Mengzi City, Yunnan Province, China. Both
clades were recovered separately from the respective clades of T. albolabris sensu stricto and topotypic T. guoi.
The first clade of Trimeresurus albolabris (from Peninsular Thailand) was also recovered in a more comprehensive
phylogeny by Zhu et al. (2016), there labeled as Clade B, sister to their remaining samples of T. albolabris (Clade
A in their study all correspond to samples of T. guoi). In contrast, samples of the second clade (from Mengzi City,
Yunnan Province, China) were published a year earlier (Guo et al. 2015) and were not included in Zhu et al. (2016);
however, their geographic location is certainly within the range of Trimeresurus guoi. Based on the position of each
clade in our phylogeny, we tentatively identify these populations as Trimeresurus cf. albolabris and Trimeresurus
cf. guoi, respectively. Both clades exhibit moderate genetic distances that are somewhat higher than the intraspecific
distances of species such as Trimeresurus albolabris (see Appendix Table S4) and may represent cryptic species.
However, the phylogenetic positions of both clades could be due to poor genetic coverage, as our molecular dataset
only included a single genetic marker and do not replicate the topological results of Zhu et al. (2016), which
place samples of Trimeresurus guoi sister to the clade containing T. cf. albolabris in this study. We await a more
comprehensive genetic and morphological assessment of the Thai and southern Yunnan populations of Trimeresurus
before making any further taxonomic decisions.

REDESCRIPTION OF TRIMERESURUS CAUDORNATUS Zootaxa 5514 (3) © 2024 Magnolia Press · 215
Acknowledgements
We are deeply grateful to Spark Thomas (China), Fan Gao (Nanjing University, China) and Kyaw Zin Htet (Native
Species Conservation & Identification, Myanmar) for providing information and photos of Trimeresurus caudornatus
in Myanmar and China. We also warmly thank Ngoc Quynh Nguyen and Thinh Gia Tran (SIFASV, Vietnam) for help
in the preparation of the figures and map. We thank Patrick Campbell (NHMUK), Jens Vindum, Lauren Scheinberg,
Erica Ely, Alan Leviton (CAS), Andreas Schmitz (MHNG), Alain Dubois and Annemarie Ohler (MNHN), Giuliano
Doria and Massimo Petri (MSNG), Silke Schweiger, Richard Gemel and Georg Gassner (NHMW), Pim Arntzen
and Esther Dondorp (RMNH), Esther Langan, Addison Wynn, George R. Zug (USNM), Mark-Oliver Rödel and
Frank Tillack (ZMB), and Jakob Hallermann (ZMH) for permission to examine specimens from their collections.
We thank Olivier S. G. Pauwels (RBINS, Belgium), Sumaithangi R. Ganesh (Tamil Nadu, India), and Karin Tamar
(SMNH, Israel) for kindly reviewing a previous version of the manuscript. This research is supported in part by the
Rufford Foundation (Grant No. 39897-1: data analysis) and the Russian Science Foundation (RSF grant No. 22-14-
00037: data analysis).
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REDESCRIPTION OF TRIMERESURUS CAUDORNATUS Zootaxa 5514 (3) © 2024 Magnolia Press · 219
Appendix Table S1. Comparative materials examined of Trimeresurus albolabris and T. septentrionalis species groups.
No. Species Collection number Country Locality Sex Status
1T. albolabris NHMUK 1946.1.19.85 China Hong Kong M Lectotype
2T. albolabris MNHG 1400.69 China Guangdong M
3T. albolabris NHMW 23927 China Koksingas Port M
4T. albolabris NHMW 23926.5 China Hong Kong M
5T. albolabris ZMB 66283 China Guangdong M
6T. albolabris ZMB 52600 China Nam Fung Wan, Hong Kong M
7T. albolabris NHMW 23905.2 China Tingan, Hainan M
8T. albolabris NHMW 23905.8 China Wuzhi Mt., Hainam M
9T. albolabris ZFMK 86454 Vietnam Phong Nha Ke Bang, Quang Binh M
10 T. albolabris ZFMK 101038 Vietnam Bach Long Vy, Hai Phong M
11 T. albolabris NHMUK 1946.1.23.73 China Hong Kong F Paralectotype
12 T. albolabris MNHG 1464.88 China Guangdong F
13 T. albolabris NHMW 23905.3 China Tingan, Hainan F
14 T. albolabris NHMW 23905.4 China Tingan, Hainan F
15 T. albolabris NHMW 23905.5a China Tingan, Hainan F
16 T. albolabris NHMW 23905.6 China Tingan, Hainan F
17 T. albolabris NHMW 23905.5b China Tingan, Hainan F
18 T. albolabris NHMW 23905.7 China Tingan, Hainan F
19 T. albolabris NHMW 23905.9 China Tingan, Hainan F
20 T. albolabris SMF 21224 China Hainan F
21 T. albolabris SMF 21222 China Hainan F
22 T. albolabris NHMW 23926.4 China Hong Kong F
23 T. albolabris ZMB 66282 China Guangdong F
24 T. albolabris ZMB 27669 China Guangdong F
25 T. albolabris MNHN 1999.9030 China Guangdong F
26 T. albolabris MNHN 1999.9031 China Guangdong F
27 T. albolabris DTU 602 Vietnam Bac Huong Hoa, Quang Tri F
28 T. albolabris S 0093-1 China Guangdong F
29 T. albolabris S 0093-2 China Guangdong F
30 T. albolabris S 0093-3 China Guangdong F
31 T. albolabris MNHN 1904.0404 Vietnam Bao Lac, Cao Bang F
32 T. albolabris MNHN 1904.0405 Vietnam Bao Lac, Cao Bang F
33 T. caudornatus MNHN 1893.0415 Myanmar Bhamo, Kachin M
34 T. caudornatus CAS 232425 Myanmar Myitkyina, Kachin SM
35 T. caudornatus CAS 241264 Myanmar Indawgyi Lake, Myitkyina, Kachin M
36 T. caudornatus CAS 221549 Myanmar Putao, Kachin SM
37 T. caudornatus CAS 224646 Myanmar Putao, Kachin M
38 T. caudornatus CAS 244953 Myanmar Homalinn, Khandi, Sagaing M
39 T. caudornatus MSNG 30533-B Myanmar Bhamo, Kachin M
40 T. caudornatus NHMUK 1974.907 Myanmar Sumprabum, Kachin M
41 T. caudornatus USNM 537444 Myanmar Chatthin WS, Sagaing M
42 T. caudornatus USNM 524076 Myanmar Chatthin WS, Sagaing F
43 T. caudornatus CAS 216144 Myanmar Shwe U Daung, Pyin Oo Lwin, Mandalay F
44 T. caudornatus CAS 245234 Myanmar Myitkyina, Kachin F
45 T. caudornatus CAS 230233 Myanmar Madanbaw, Putao, Kachin F
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Appendix Table S1. (Continued)
No. Species Collection number Country Locality Sex Status
46 T. caudornatus MNHN 1893.0416 Myanmar Bhamo, Kachin F
47 T. caudornatus MSNG 30533-A Myanmar Bhamo, Kachin F
48 T. caudornatus MSNG 2180 Myanmar Bhamo, Kachin F
49 T. caudornatus MSNG 30814 Myanmar Teizo, Kachin F
50 T. caudornatus NHMUK 1974.906 Myanmar N’Changyang, Kachin F
51 T. caudornatus CAS 230260 Myanmar Hukaung WS, Myitkyina, Kachin F
52 T. davidi Not collected India Chuckchucka, Nicobar M
53 T. davidi NHMUK 1936.7.7.47 India Nicobar M
54 T. davidi NHMUK 1936.7.7.48 India Andaman M
55 T. davidi NHMUK 1936.7.7.46 India Nicobar M
56 T. davidi BNHS3304 India Chuckchucka, Nicobar F
57 T. davidi NHMUK 1936.7.7.40 India Chuckchucka, Nicobar F
58 T. davidi NHMUK 1936.7.7.41 India Chuckchucka, Nicobar F
59 T. davidi NHMUK 1936.7.7.42 India Chuckchucka, Nicobar F
60 T. davidi Not collected India Chuckchucka, Nicobar F
61 T. davidi Not collected India Chuckchucka, Nicobar F
62 T. davidi DOSMB 05104 India Chuckchucka, Nicobar F
63 T. davidi NHMW 23925:1 India Nicobar F
64 T. davidi NHMW 23925:2 India Nicobar F
65 T. guoi MNHN 1935.0464 Vietnam Sapa, Lao Cai M
66 T. guoi MNHN 1935.0464 Vietnam Sapa, Lao Cai M
67 T. guoi PSUaa 0046 Thailand Chiang Mai M
68 T. guoi PSUaa 0046 Thailand Chiang Mai M
69 T. guoi ZFMK 70442 Thailand Phu Luang, Loei M
70 T. guoi ZFMK 74282 Thailand Samoeng, Chiang Mai M
71 T. guoi ZFMK 74283 Thailand Samoeng, Chiang Mai M
72 T. guoi NHMW 23926.6 Thailand Phu Kin Mt, Chiang Rai M
73 T. guoi NHMW 23926.9 Thailand Phu Kin Mt, Chiang Rai M
74 T. guoi NHMW 23926.7 Thailand Phu Kin Mt, Chiang Rai M
75 T. guoi NHMW 23926.8 Thailand Phu Kin Mt, Chiang Rai M
76 T. guoi NHMW 23903.3 Myanmar Mt Caren (Karen Hills), Shan M
77 T. guoi NHMW 23920.1 Myanmar Mawlamyine, Mon M
78 T. guoi CAS 222595 Myanmar Mudon, Mawlamyine, Mon M
79 T. guoi MNHN 1935.0465 Vietnam Lao Cai F
80 T. guoi MNHN 1935.0466 Vietnam Lao Cai F
81 T. guoi QSMI 0761 Thailand Chiang Mai F
82 T. guoi NHMW 23930.1 Thailand Phu Kin Mt, Chiang Rai F
83 T. guoi NHMW 23930.2 Thailand Phu Kin Mt, Chiang Rai F
84 T. guoi NHMW 23926.10 Thailand Phu Kin Mt, Chiang Rai F
85 T. guoi ZFMK 70443 Thailand Phu Luang, Loei F
86 T. guoi ZMH R06267 Myanmar Mt Caren (Karen Hills), Shan F
87 T. guoi MNHN 1935.0465 Vietnam Lao Cai F
88 T. guoi MNHN 1935.0466 Vietnam Lao Cai F
89 T. guoi QSMI 0761 Thailand Chiang Mai F
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Appendix Table S1. (Continued)
No. Species Collection number Country Locality Sex Status
90 T. insularis ZMH R06938 Indonesia Java M
91 T. insularis NHMW 23928 Indonesia Sumba M
92 T. insularis NHMW 23929 Indonesia Sumbawa M
93 T. insularis SMF 21229 Indonesia Sumbawa M
94 T. insularis SMF76353 Indonesia Florès M
95 T. insularis MNHN 4056 Indonesia Timor M
96 T. insularis MNHN 4057 Indonesia Timor M Lectotype
97 T. insularis NHMW 39581 Indonesia Bali F
98 T. insularis NHMW 23924 Indonesia Kisser Isl F
99 T. insularis SMF 73324 Indonesia Bali, near Tangu F
100 T. insularis SMF 48734 Indonesia Bali F
101 T. insularis SMF 23374 Indonesia Sumbawa, Batoe Doelang F
102 T. insularis SMF 21220 Indonesia Timor F
103 T. insularis SMF76352 Indonesia Florès F
104 T. insularis MNHN 2002.0402 Indonesia Wetar F
105 T. insularis SMF 106707 Indonesia Flores Korabewa F
106 T. insularis SMF 106708 Indonesia Flores Korabewa F
107 T. insularis SMF 106706 Indonesia Flores Korabewa F
108 T. insularis SMF 106705 Indonesia Flores Korabewa F
109 T. salazar NHMUK 72.4.17.379 India Darjeeling, West Bengal M
110 T. salazar NHMUK 1908.6.23.99 India Dibrugarh, Assam F
111 T. salazar NHMUK 1937.3.1.14 India Central Prov F
112 T. septentrionalis MHNG 1404.31 Nepal Pokhara M Holotype
113 T. septentrionalis MHNG 1400.24 Nepal Pokhara M Paratype
114 T. septentrionalis MHNG 1400.31 Nepal Pokhara M Paratype
115 T. septentrionalis MHNG 1400.47 Nepal Pokhara M Paratype
116 T. septentrionalis SH 762 Nepal No specific M
117 T. septentrionalis MHNG 1400.29 Nepal Pokhara M Paratype
118 T. septentrionalis CAS 135750 Nepal Pokhara F Paratype
119 T. septentrionalis MNHG 1400.18 Nepal Pokhara F Paratype
120 T. septentrionalis MHNG 1400.35 Nepal Pokhara F Paratype
121 T. septentrionalis MHNG 1400.34 Nepal Pokhara F Paratype
122 T. septentrionalis MHNG 1400.26 Nepal Pokhara F Paratype
123 T. septentrionalis MHNG 1400.32 Nepal Pokhara F Paratype
124 T. septentrionalis MHNG 1400.38 Nepal Pokhara F Paratype
125 T. septentrionalis MHNG 1400.45 Nepal Pokhara F Paratype
126 T. septentrionalis MHNG 1400.39 Nepal Pokhara F Paratype
127 T. septentrionalis MHNG 1400.36 Nepal Pokhara F Paratype
128 T. septentrionalis MHNG 1400.25 Nepal Pokhara F Paratype
129 T. septentrionalis MHNG 1400.37 Nepal Pokhara F Paratype
131 T. septentrionalis MHNG 1400.30 Nepal Pokhara F Paratype
130 T. septentrionalis SH 688 Nepal No specific F
131 T. septentrionalis SH 1166 Nepal No specific F
132 T. septentrionalis SH 761 Nepal No specific F
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Appendix Table S1. (Continued)
No. Species Collection number Country Locality Sex Status
133 T. uetzi CAS 232480 Myanmar Pyin Mana, Naypyidaw M Paratype
134 T. uetzi CAS 204846 Myanmar Mandalay, Mandalay M
135 T. uetzi CAS 204847 Myanmar Mandalay, Mandalay M
136 T. uetzi CAS 246991 Myanmar Myingchan, Kandaw, Mandalay M
137 T. uetzi CAS 215907 Myanmar Taung Aoe, Magway M
138 T. uetzi CAS 210665 Myanmar Kyaukpadaung, Mandalay M
139 T. uetzi CAS 242723 Myanmar Yangon-Pyay, Bago M
140 T. uetzi CAS 220124 Myanmar Mindat, Chin M
141 T. uetzi CAS 243055 Myanmar Gangaw, Pakhokku, Magway M Paratype
142 T. uetzi CAS 243159 Myanmar Gangaw, Pakhokku, Magway M
143 T. uetzi CAS 243024 Myanmar Gangaw, Pakhokku, Magway M Holotype
144 T. uetzi CAS 215400 Myanmar Pyaro, Yin Ma Bin, Sagaing F
145 T. uetzi CAS 213722 Myanmar Le Kaing, Pwint Byu, Min Bu, Magway F
146 T. uetzi CAS 215343 Myanmar Ma Bin, Sagaing F
147 T. uetzi CAS 214110 Myanmar Popa Mt. Mandalay F
148 T. uetzi CAS 210691 Myanmar Kyaukpadaung, Mandalay F
149 T. uetzi CAS 235954 Myanmar Nyaungshwe, Taunggyi, Shan F Paratype
150 T. uetzi CAS 214110 Myanmar Popa Mt. Mandalay F
151 T. uetzi CAS 210691 Myanmar Kyaukpadaung, Mandalay F Paratype
152 T. uetzi CAS 210690 Myanmar Kyaukpadaung, Mandalay F
153 T. uetzi CAS 246953 Myanmar Yesagyo, Pakhokku, Magway F
154 T. uetzi CAS 242985 Myanmar Gangaw, Pakhokku, Magway F
155 T. uetzi CAS 234852 Myanmar Mindat, Chin F Paratype
156 T. uetzi CAS 215540 Myanmar Mon Ywa, Sagaing F Paratype
157 T. uetzi CAS 215472 Myanmar Mon Ywa, Sagaing F Paratype
158 T. uetzi CAS 210109 Myanmar Alaungdaw Kathapa, Sagaing F Paratype
159 T. uetzi CAS 235958 Myanmar Phalum, Chin F

REDESCRIPTION OF TRIMERESURUS CAUDORNATUS Zootaxa 5514 (3) © 2024 Magnolia Press · 223
Appendix Table S2. List of morphological variables recorded from each specimen studied.
Number Abbreviation Meaning Code
1Sex Sex 1: male; 2: female; 3: unsexed
2SVL Snout-vent length value
3TaL Tail-length value
4TL Total length value
5TaL/TL ratio tail length / TL value
7Ven Number of ventrals value
9Sc Number of subcaudals value
11 ASR Number of scale-rows on neck value
12 MSR Number of scale-rows at midbody value
13 DSR Number of scale rows before vent value
14 KSR Keeling of dorsal scales at midbody in males 0: smooth; 1: weakly keeled; 2
distinctly keeled
16 SL-l Number of supralabials at left value
17 SL-r Number of supralabials at right value
18 Σ SL Total number of supralabials value
19 C3SL/SubOc-l Number of scales between 3rd SL and subocular (left) value
20 C3SL/SubOc-r Number of scales between 3rd SL and subocular (right) value
19 C4SL/SubOc-l Number of scales between 4th SL and subocular (left) value
20 C4SL/SubOc-r Number of scales between 4th SL and subocular (right) value
27 C45SL/SubOc-l Number of scales between 4th and 5th SL and subocular (left) value
28 C45SL/SubOc-r Number of scales between 4th and 5th SL and subocular (right) value
31 CEP Number of cephalic scales value
32 SC/SpOc-l Number of scales surrounding the supraocular at left value
33 SC/SpOc-r Number of scales surrounding the supraocular at right value
34 Σ SC/SpOc Total number of scales surrounding both supraoculars value
35 K-Occ Keeling of occipital scales in males 0: smooth; 1: weakly keeled; 2:
distinctly keeled
37 K-Tem Keeling of temporal scales in males 0: smooth; 1: weakly keeled; 2:
distinctly keeled
39 IN-sep Number of scale(s) between the internasals value
40 Sn-SC Number of scales on the snout value
41 He-SC Number of scales on upper head value
42 IL-l Number of infralabials at left value
43 IL-r Number of infralabials at right value
44 Σ IL Total number of infralabials value
45 HL Head length value
46 HL/SVL Ratio head length / snout-vent length in males value
48 SnL Snout length value
49 SnL/HL Ratio snout length / head length in males value
51 ED Eye diameter (vertical) value
52 DEL Distance eye-lip value
53 SnL/ED Ratio snout length / eye diameter in males value
55 ED/DEL Ratio eye diameter / distance eye-lip in males value
57 D E-nostril Distance eye-nostril value
58 D E-pit Distance eye-pit value
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Appendix Table S2. (Continued)
Number Abbreviation Meaning Code
59 D E-nostril/HL Ratio distance eye-nostril / head length in males value
61 D E-pit/HL Ratio distance eye-pit / head length in males value
63
D E-pit/D E-
nostril
Ratio distance eye-pit / distance eye-nostril in males
value
65 W-In Width of internasal value
66 L-SpOc Length of supraocular(s) value
67 W-SpOc Width of supraocular(s) value
68 L-SpOc/W-SpOc Ratio length of SupOc / Width of SupOc value
69 W-In/W-SpOc Ratio width of internasals / Width of SupOc value
70 W-SpOc/W-In Ratio width of SupOc / Width of internasals value
71 L-3SL Length of 3rd supralabial value
72 H-3SL Height of 3rd supralabial value
73 L-3SL/H-3SL Ratio length of 3rd supralabial / height of 3rd supralabial value
74 L-3SL/HL Ratio length of 3rd SL / head length in males value
76 H-4SL Height of 4th supralabial value
77 H-4SL/H-3SL Ratio height of 4th supralabial / heigth of 3rd supralabial value
78 BoCol Body color 1: green
79 DorBan Presence of dark dorsal bands 0: absent; 1: present
80 DorDots Presence of white vertebral dots 0: absent; 1: present
81 EyeCol
Eye color 1: red; 2: yellow, gold or greenish
yellow; 3: green; 4: orange
82 POcStr Postocular streak 0: absent; 1: present
83 COLPOcStr
Postocular streak 0: absent; 1: white; 2: red above, white
below
84 VLSTRIPE Ventrolateral stripe 0: absent; 1: present
85 COLVLSTRIPE
Ventrolateral stripe 0: absent; 1: cream or bluish-white; 2:
white above, red below
86 TAILPAT Tail pattern (dorsal surface)
1: blotched, no sharp limit with green;
2: uniform, sharp limit with green

REDESCRIPTION OF TRIMERESURUS CAUDORNATUS Zootaxa 5514 (3) © 2024 Magnolia Press · 225
Appendix Table S3. Sequences and voucher specimens of the genus Trimeresurus and outgroup taxa used in this study.
No. Taxon Collection ID Locality Cytb Source
Subgenus Trimeresurus
1T. albolabris AM A157 Hong Kong, China AF171884 Malhotra & Thorpe (2000)
2T. albolabris AM B6 Cilacap, Java, Indonesia AF517186 Creer et al. (2003)
3T. albolabris AM B22 Nonthaburi, Thailand AF517189 Creer et al. (2003)
4T. albolabris AM B117 Ho Chi Minh, Vietnam AF517190 Creer et al. (2003)
5T. albolabris ROM 30854 Tam Dao, Vinh Phuc, Vietnam AY352769 Malhotra & Thorpe (2004)
6T. albolabris ROM 34544 Gia Lai, Vietnam AY352770 Malhotra & Thorpe (2004)
7T. albolabris GP 1087 Cenxi, Guangxi, China KP999364 Zhu et al. (2016)
8T. albolabris GP 1472 Sekong, Laos KP999370 Zhu et al. (2016)
9T. albolabris GP 2534 Fujian, China KP999403 Zhu et al. (2016)
10 T. albolabris GP 5 Hainan, China KP999410 Zhu et al. (2016)
11 T. albolabris GP 977 Guangxi, China KP999420 Zhu et al. (2016)
12 T. albolabris ROM 27475 Kon Tum, Vietnam KP999428 Zhu et al. (2016)
13 T. albolabris ROM 34545 Gia Lai, Vietnam KP999432 Zhu et al. (2016)
14 T. albolabris ROM 35300 Hai Duong, Vietnam KP999435 Zhu et al. (2016)
15 T. albolabris ROM 35323 Cao Bang, Vietnam KP999438 Zhu et al. (2016)
16 T. albolabris SYS r001526 Guangdong, China MK201514 Li et al. (2020)
17 T. albolabris GV 2019111704 Tam Dao, Vinh Phuc, Vietnam MN746390 Chen et al. (2021)
18 T. cf. albolabris AM B47 Phetburi, Thailand AF517187 Creer et al. (2003)
19 T. cf. albolabris AM B 20 Nakhon Si Thammarat, Thailand GQ428474 Malhotra et al. (2010)
20 T. andersoni AM A77 Andam, India AF171922 Malhotra & Thorpe (2000)
21 T. cantori AM A85 Nicobar, India AF171889 Malhotra & Thorpe (2000)
22 T. caudornatus CAS 216144 Mandalay, Myanmar KP999351 Zhu et al. (2016)
23 T. caudornatus CAS 216173 Mandalay, Myanmar KP999352 Zhu et al. (2016)
24 T. caudornatus ZMNH AR1238 Yingjiang, Yunnan, China MK575036 Chen et al. (2020)
25 T. caudornatus ZMNH AR1239 Yingjiang, Yunnan, China MK575037 Chen et al. (2020)
26 T. caudornatus CAS 235956 Indawgyi, Kachin, Myanmar ON804486 Chan et al (2022)
27 T. erythrurus CAS 239745 Rakhine, Myanmar KP999357 Zhu et al. (2016)
28 T. fasciatus AM B212 Tanadjampea, Indonesia GQ428475 Malhotra et al. (2010)
29 T. guoi AM A165 Loei, Thailand AF517185 Creer et al. (2003)
30 T. guoi AM A229 Pha Yao, Thailand AY059566 Malhotra & Thorpe (2004)
31 T. guoi CAS 222595 Mon, Myanmar KP999354 Zhu et al. (2016)
32 T. guoi KIZ 05191 Mengla, Yunnan, China KP999424 Zhu et al. (2016)
33 T. guoi ROM 39389 Lao Cai, Vietnam KP999440 Zhu et al. (2016)
34 T. guoi YNJC0012 Yunnan, China MN746393 Chen et al. (2020)
35 T. guoi JCR 2019062401 Jiangcheng, Yunnan, China MN746395 Chen et al. (2020)
36 T. guoi DL 20190906 Simao, Yunnan, China MN746396 Chen et al. (2020)
37 T. cf. guoi GP 3565 Mengzi, Yunnan, China KT216372 Guo et al. (2015)
38 T. cf. guoi GP 3566 Mengzi, Yunnan, China KT216374 Guo et al. (2015)
39 T. cf. guoi GP 3567 Mengzi, Yunnan, China KT216375 Guo et al. (2015)
40 T. insularis AM B7 Timor, Indonesia AY059568 Malhotra & Thorpe (2004)
41 T. purpureomaculatus AM B139 Perak, Malaysia AY352771 Malhotra & Thorpe (2004)
42 T. ayeyarwadyensis CAS 212246 Ayeyarwade, Myanmar AY352772 Malhotra & Thorpe (2004)
43 T. salazar AM A100 Mahattari, Nepal AF171909 Malhotra & Thorpe (2000)
44 T. salazar CESS 331 Meghalaya, India MT762236 Mallik et al. (2021)
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Appendix Table S3. (Continued)
No. Taxon Collection ID Locality Cytb Source
45 T. septentrionalis CESS 388 Foothills of Himalayas, India MT762239 Mallik et al. (2021)
46 T. septentrionalis V 39 Mussoorie, Uttarakhand, India MG995825 Vaishnavi et al. unpublished
47 T. septentrionalis AM B487 Kathmandu, Nepal AY352755 Malhotra & Thorpe (2004)
48 T. uetzi CAS 215472 Sagaing, Myanmar KP999348 Malhotra & Thorpe (2004)
49 T. uetzi CAS 215540 Sagaing, Myanmar KP999349 Zhu et al. (2016)
50 T. uetzi CAS 215604 Sagaing, Myanmar KP999350 Zhu et al. (2016)
51 T. uetzi CAS 220124 Chin, Myanmar KP999353 Zhu et al. (2016)
52 T. uetzi CAS 232480 Mandalay, Myanmar KP999355 Zhu et al. (2016)
53 T. uetzi CAS 234852 Chin, Myanmar KP999356 Zhu et al. (2016)
54 T. uetzi CAS 243051 Magway, Myanmar KP999360 Zhu et al. (2016)
55 T. uetzi CAS 243086 Magway, Myanmar KP999361 Zhu et al. (2016)
56 T. uetzi CAS 243144 Magway, Myanmar KP999362 Zhu et al. (2016)
57 T. uetzi CAS 210301 Alaungdaw, Kathapa, Sagaing,
Myanmar
ON804499 Zhu et al. (2016)
58 T. uetzi CAS 243175 Gangaw, Magway, Myanmar ON804500 Zhu et al. (2016)
Out group
59 Trimeresurus (Viridovipera)
gumprechti KIZ 047083 Jingdong, Yunnan, China KT216398 Guo et al. (2015)
60 Trimeresurus (Viridovipera)
stejnegeri GP 475 Qimen, Anhui, China KX019099 Guo et al. (2015)
61 Trimeresurus (Viridovipera)
truongsonensis
VNUH 190606
= AM B659
Phong Nha-Ke Bang, Quang Binh,
Vietnam EU443815
Dawson et al. (2008)
62 Trimeresurus (Viridovipera)
yunnanensis
SCUM 035114
=GP 38
Huili, Sichuan, China EF597523 Dawson et al. (2008)
63 Trimeresurus (Viridovipera)
sichuanensis
GP 07 Hejiang, Sichuan, China
HQ850447
Guo & Wang (2011)
64 Trimeresurus (Viridovipera)
mayaae BNHS-365 Ri-Bhoi, Meghalaya, India OM966860 Rathee et al. (2022)
65 Trimeresurus (Viridovipera)
medoensis KIZ YPX46123 Tibet, China MW133479
Che et al. unpublished
66 Trimeresurus (Viridovipera)
vogeli
AM B97 Nakhon Si Ratchasima, Thailand AY059574 Malhotra & Thorpe (2004)
67 Trimeresurus (Trimeresurus)
kuiburi
N.a Kui Buri, Prachuap Khiri Khan,
Thailand MW806923
Sumontha et al. (2021)
68 Trimeresurus (Trimeresurus)
venustus
AM A241 Nakhon Si Thammarat, Thailand AF171914 Malhotra & Thorpe (2000)
69 Trimeresurus (Trimeresurus)
kanburiensis
AM B522 Kanchanaburi, Thailand AY289225 Malhotra & Thorpe (2000)
70 Trimeresurus (Trimeresurus)
macrops
AM B27 Bangkok, Thailand AF517184 Creer et al. (2003)
71 Trimeresurus (Himalayophis)
arunachalensis
APF/SFRI–1871 Arunachal Pradesh, India MK720609 Captain et al. (2019)
72 Trimeresurus (Himalayophis)
tibetanus
ZMB 65641
= AM B258
Helambu, Nepal AY352749 Malhotra & Thorpe (2004)
73 Trimeresurus (Popeia) sabahi
barati
MZB-OPHI5197 Jambi, Sumatra, Indonesia KP899264 Wostl et al. (2016)
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REDESCRIPTION OF TRIMERESURUS CAUDORNATUS Zootaxa 5514 (3) © 2024 Magnolia Press · 227
Appendix Table S3. (Continued)
No. Taxon Collection ID Locality Cytb Source
74 Trimeresurus (Popeia) sabahi
fucatus
A203 Thung Song, Nakhon Si
Thammarat, Thailand
AY371796 Sanders et al. (2006)
75 Trimeresurus (Popeia) sabahi
buniana
LSUHC 6118 Pulau Tioman, Pahang, Malaysia KX660502 Figueroa et al. (2016)
76 Trimeresurus (Popeia) sabahi
sabahi
B344 Mt Kinabalu, Sabah, Malaysia AY371815 Sanders et al. (2006)
77
Trimeresurus (Popeia) sabahi toba
MZB-OPHI5342 Sumatra Utara, Indonesia KP899266 Wostl et al. (2016)
78 Trimeresurus (Popeia) popeiorum DL 2017070101 Yingjiang, Yunnan, China MH779875 Chen et al. (2019)
79 Trimeresurus (Popeia)
tenasserimensis
USNM 587988 Lenya, Tanintharyi, Myanmar MF476867 Mulcahy et al. (2017)
80 Trimeresurus (Popeia) lanna GP 3328 Mengla, Yunnan, China KT216361 Guo et al. (2015)
81 Trimeresurus (Popeia)
phuketensis
LSUHC 7566 Thailand KX660505 Figueroa et al. (2016)
82 Trimeresurus (Popeia) nebularis LSUHC 10268 Cameron Highlands, Pahang,
Malaysia
KX660506 Figueroa et al. (2016)
83 Trimeresurus (Parias)
flavomaculatus
AM B4 Mindanao, Philippines AY352764 Figueroa et al. (2016)
84 Trimeresurus (Parias) mcgregori AM B289 Batan, Philippines AY371831 Sanders et al. (2004)
85 Trimeresurus (Parias) malcolmi AM B349 Mt. Kinabalu, Sabah, Borneo,
Malaysia
AY371832 Sanders et al. (2004)
86
Trimeresurus (Parias) sumatranus
B367 Bengkulu, Sumatra, Indonesia AY371824 Sanders et al. (2004)
87 Trimeresurus (Parias) schultzei AM B210 Palawan, Philippines AY352756 Malhotra & Thorpe (2004)
88 Trimeresurus (Parias) hageni AM B33 Songhkla, Thailand AY059567 Malhotra & Thorpe (2004)
89 Craspedocephalus gramineus CESS 056 Amboli, Maharashtra, India MT762212 Mallik et al. (2021)
90 Craspedocephalus occidentalis CESS 040 Karnataka, India MT762208 Mallik et al. (2021)
91
Craspedocephalus trigonocephalus
RAP0453 Sri Lanka KC347479 Pyron et al. (2013)
92 Craspedocephalus strigatus CESS142 Kerala, India MT762220 Mallik et al. (2021)
93 Craspedocephalus malabaricus CESS273 Karnataka, India MT762234 Mallik et al. (2021)
94 Craspedocephalus travancoricus CESS074 Kerala, India MT762213 Mallik et al. (2021)
95 Craspedocephalus peltopelor CESS108 Kerala, India MT762218 Mallik et al. (2021)
96 Craspedocephalus borneensis B301 East, Malaysia AY352754 Malhotra & Thorpe (2004)
97 Craspedocephalus wiroti No number Thailand DQ646788 David et al. (2006)
98 Craspedocephalus puniceus B 392 Indonesia AY352757 Malhotra & Thorpe (2004)
99 Azemiops feae AM B499 China AY352747 Malhotra & Thorpe (2004)
100 Protobothrops elegans UMMZ 199970 Japan AY223575 Parkinson et al. (2002)

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Appendix Table S4. Uncorrected p-distances (percentage) between the sequences of cyt b mtDNA gene of species of the
complex of Trimeresurus albolabris and T. septentrionalis species groups distributed in Indo-Burma area included in the
phylogenetic analyses of this study.
No. Species 1 2 3 4 5 6 7 8 9
1T. caudornatus 0.0–2.6%
2T. albolabris 6.7–9.6% 0.1–4.3%
3T. cf. albolabris 5.8–7.3% 3.4–6.2% 1.40%
4T. cf. guoi 5.9–6.5% 2.6–3.2 2.5–4.7% 0
5T. guoi 5.6–7.2% 3.6–6.0% 2.8–4.2% 2.3–3.3% 0.0–1.8%
6T. salazar 5.3–7.3% 7.5–10.2% 7.3–8.5% 7.1–7.8% 6.9–8.5% 1.20%
7T. septentrionalis 5.9–6.9% 7.0–8.7% 6.2–7.4% 6.0–6.8% 5.9–7.4% 5.9–6.9% 0.4–1.6%
8T. uetzi 5.8–7.0% 6.9–9.9% 6.1–6.9% 6.1–7,3% 6.5–8.2% 5.9–7.6% 6.4–6.9% 0.0–3.6%
9T. insularis 7.3–8.4% 7.8–10.1% 8.0–8.2% 7.60% 6.5–7.2% 8.0–8.6% 7.2–8.0% 8.3–9.0% 0
Appendix Table S5. Statistically significant differences between Trimeresurus caudornatus and the remaining members
of Trimeresurus in the T. albolabris and T. septentrionalis species groups based on Mann–Whitney U Tests. See Appendix
Table S2 for acronyms of morphological characters. Data left of the gray line represent male specimens, whereas data
right of the gray line represent female specimens. Data with an asterisk (*) represent test results with p-values less than
0.01.
Taxon albolabris caudornatus guoi salazar septentrionalis uetzi
albolabris – VEN, VEN+SC – – VEN*, SC*, VEN+SC* VEN*, SC*, SL*, IL
caudornatus VEN*, VEN+SC – – – VEN*, SC*, VEN+SC* SC*, IL
guoi VEN* – – SC*, VEN+SC* VEN, SC
salazar VEN* VEN – – –
septentrionalis VEN*, SC*, VEN+SC* SC SC*, VEN+SC – – VEN*, VEN+SC*
uetzi VEN* – SC –

REDESCRIPTION OF TRIMERESURUS CAUDORNATUS Zootaxa 5514 (3) © 2024 Magnolia Press · 229
Appendix Table S6. Detailed infomation on Trimeresurus caudornatus specimens from Myanmar preserved at CAS
(see: https://researcharchive.calacademy.org/research/herpetology/catalog/Index.asp or http://portal.vertnet.org/search?q
=Trimeresurus+CAS+Myanmar)
Collection
number
Verified by
molecular
Verified by
morphology
Previous ID Proposed ID Field number Sex Date collected Elevation
CAS 216144 yes yes T. septentrionalis T. caudornatus JBS-5776 adult female 4/10/2000 No data
CAS 216173 no yes T. septentrionalis T. caudornatus JBS-5847 adult male 12/10/2000 No data
CAS 216173 yes no T. albolabris T. caudornatus JBS-5847 adult male 12/10/2000 No data
CAS 221549 no yes T. septentrionalis T. caudornatus JBS-10322 adult male 17/9/2001 No data
CAS 224646 no yes T. septentrionalis T. caudornatus JBS-12289 adult male 13/4/2002 560 m
CAS 230260 no yes T. yunnanensis T. caudornatus JBS-13002 adult female 13/6/2002 No data
CAS 232425 no yes T. septentrionalis T. caudornatus JBS-16900 adult female 2/4/2003 234 m
CAS 235956 yes yes T. erythrurus T. caudornatus JBS-17204 adult female 7/5/2003 169 m
CAS 241264 no yes Trimeresurus sp. T. caudornatus MHS-25907 adult male 19/7/2008 215 m
CAS 244953 no yes T. septentrionalis T. caudornatus JBS-15459 adult male 1/11/2002 155 m
CAS 245234 no yes T. septentrionalis T. caudornatus MHS-28046 subadult female 7/7/2009 304 m
Appendix Table S6. (Continue)
Collection
number
Collecter (CAS team) Biology Location
CAS 216144 H. Win & T. Thin 1940 hrs. Air temp. 76.5 F.
Relative humidity 92%. In tree.
Myanmar: Mandalay Region: Pyin Oo Lwin District:
Tha Bake Kyin Township, Shwe U Daung Wildlife
Sanctuary, N 22 52 28.4, E 96 05 25.2
CAS 216173 H. Win, T. Thin & S.L. Oo 2040 hrs. Air temp. 84.2 F.
Relative humidity 69%. In shrub.
Myanmar: Mandalay Region: Pyin Oo Lwin District: Tha
Bake Kyin Township, Shwe U Daung Wildlife Sanctuary,
Kyauk Kyi Village, N 22 58 37.4, E 96 05 54.3
CAS 216173 H. Win, T. Thin and S.L.
Oo
2040 hrs. Air temp. 84.2 F.
Relative humidity 69%. In shrub.
Myanmar: Mandalay Division: Pyin Oo Lwin District:
Tha Bake Kyin Township, Shwe U Daung Wildlife
Sanctuary, Kyauk Kyi Village, N 22 58 37.4, E 96 05 54.3
CAS 221549 K.S. Lwin & H. Tun
Stomach contained a
Sphenomorphus indicus (in
separate vial), swallowed tail first.
Myanmar: Kachin State: Putao Dist.: Putao Township:
Ahtonga Village, 27 15 41.8 N, 97 48 10.0 E
CAS 224646 H. Win, Y.N.T. Na, H.
Ram & S. Di
1609 hrs. In termite mound, 10
inches deep.
Myanmar: Kachin State: Putao District: Nagmung Township:
Nagmung Town, 27 30 36.5 N, 97 49 50.4 E, 1840 ft
CAS 230260 H. Win, K.S. Lwin, A.K.
Shein & H. Tun
No data Myanmar: Kachin State: Tanai Township, Ma Kaw
Village; along the Lero Road, in Hukaung Valley
Sanctuary, N 26 27 00.0 E 96 41 35.5
CAS 232425 H. Win, K.S. Lwin & A.K.
Shein
Under log. Myanmar: Kachin State: Ta Nai Township, Ta Ruing
Village, N 26 35 24.6, E 96 29 19.3, 770 ft
CAS 235956
G.O.U. Wogan, J.A.
Wilkinson, J.V. Vindum, H.
Win, T. Thin, K.S. Lwin,
A.K. Shein & W. Aung
2206 hrs. Air temp. 79 F, 78%
relative humidity. In bush, 1 m
above ground.
Myanmar: Kachin State: Mohnyin Township, Lone Ton
Village, Indawgyi Wildlife Sanctuary, 25 05 54.2 N, 96
17 20.1 E, 557 ft
CAS 241264 K.T. Kyaw, M. Win, Y.M.
Win & S.L. Oo
2230 hrs. Air temp. 84.0 F, 89%
relative humidity.
Myanmar: Kachin State: Mohnyin Township, Indawgyi
Wildlife Sanctuary, NW of Nyang Bin village, 25 16
09.8 N, 96 20 32.7 E, 707 ft
CAS 244953 T. Thin, K.S. Lwin & H.
Tun
1948 hrs. Air temp. 75.2 F. 85%
relative humidity. On boat beside river.
Myanmar: Sagaing Region: Homalin Township, North of
Swekawngaw, 25 22 19.6 N, 95 21 44.9 E, 510 ft
CAS 245234 M. Hlaing, S.L. Oo, Z.H.
Aung, Y.M. Win & K.S.
Lwin
2105 hrs. Air temp. 86.0 F, 75%
relative humidity.
Myanmar: Kachin State: Myitkyina District, Chipwe
Township: East side of Chipwe Town, 25 52 54.2 N, 98
07 55.2 E, 998 ft

NGUYEN ET AL.
230 · Zootaxa 5514 (3) © 2024 Magnolia Press
Appendix Table S7. Comparison of morphological characteristics of Trimeresurus caudornatus with those of the Trimeresurus albolabris and T. septentrionalis species groups
distributed in Indo-Burma area.
Species Body pattern Ventral
color
Ventrolateral
body stripes
Postocular
stripe in males
1 or 2 small scales
in front of the pit
Temporal
scales
Dorsal body
scales
Iris color MSR TaL/TL (Males) TaL/TL (Females)
caudornatus verdant green yellow green absent absent absent hardly keeled feebly keeled golden yellow 21 (22 or 23) 0.18–0.22 (0.20±0.02, n=14) 0.14–0.18 (0.16±0.01, n=19)
albolabris multicolor (verdant
green, yellowish-
green, cream)
yellow present present usually present hardly keeled moderately
keeled
copper 21 (19) 0.19–0.21 (0.20±0.01, n=55) 0.14–0.17 (0.15±0.01, n=81)
guoi yellow green yellow green absent absent absent hardly keeled moderately
keeled
Firebrick-red 21 0.14–0.22 (0.19±0.22, n=23) 0.15–0.20 (0.16±0.01, n=18)
salazar Yellowish- green yellowish
green
present present absent hardly keeled moderately
keeled
copper 21 (19) 0.15–0.20 (0.18±0.02, n=6) 0.14–0.15 (0.15±0.01, n=3)
septentrionalis
verdant green yellow green absent or
present
absent absent hardly keeled feebly keeled green gold or
copper
21 0.19–0.23 (0.21±0.02, n=6) 0.15–0.17 (0.16±0.01, n=14)
uetzi verdant green or
yellowish green
yellowish
green
present present absent hardly keeled moderately
keeled
copper or
green gold
21 0.16–0.22
(0.20±0.02, n=10)
0.14–0.16
(0.15±0.01, n=11)
Appendix Table S7. (Continue)
Species VEN (Males) VEN (Females) SC (Males) SC (Females) VEN+SC (Males) VEN+SC (Females) Hemipenes Distribution Sources
caudornatus 158–167
(162.43±2.71, n=14)
158–174
(162.89±4.86, n=19)
53–74 (68.07±5.38,
n=14)
52–68 (57.41±4.69,
n=17)
219–241
(230.50±5.96, n=14)
211–242 (219.82±7.88,
n=17) reaching SC 37–38 China, Myanmar Zhao et al. (1998); Chen et
al. (2020); our data
albolabris 146–162
(154.93±4.67, n=70)
151–172
(158.80±4.78, n=112)
40–75 (63.08±8.44,
n=67)
49–64 (53.54±3.71,
n=104)
210–232
(218.00±11.04, n=64)
200–232 (211.58±7.34,
n=104) reaching SC 15–18
China, Vietnam,
Laos, Cambodia,
Thailand, Indonesia
Vogel et al. (2023); our
data
guoi 154–167
(159.95±4.19, n=27)
155–167
(161.07±3.73, n=18)
52–75 (66.37±5.25,
n=25)
53–69 (58.64±4.68,
n=18)
210–242
(226.00±7.67, n=25)
210–228 (219.71±5.98,
n=18) reaching SC 23–32
China, Vietnam,
Laos, Thailand,
Myanmar
Chen et al. (2021); our data
salazar 163–170
(166.40±2.88, n=6)
167–171
(169.33±2.08, n=3)
62–73 (68.80±4.21,
n=6)
56–59 (58.00±1.73,
n=3)
225–241
(235.20±6.22, n=6)
223–230 (227.33±3.79,
n=3) reaching SC 12–13
India, Nepal,
Bhutan,
Bangladesh?
Mirza et al. (2020); Rathee
et al. (2021); our data
septentrionalis
164–170
(165.00±4.56, n=6)
162–173
(168.94±2.59, n=16)
71–80 (76.67±3.50,
n=6)
56–66 (63.07±2.53,
n=14)
238–250
(241.67±7.76, n=6)
224–237 (231.79±3.68,
n=14) reaching SC 5–7 Nepal, India Kramer (1977); our data
uetzi 154–172
(163.27±5.61, n=11)
157–171
(164.14±3.84, n=16)
60–71 (66.90±3.35,
n=10)
50–55
(52.08±1.62, n=14)
216–240
(230.4±7.88, n=10)
209–223
(216.08±3.99, n=14)
reaching SC 6–8
(n=2) Myanmar, India
Vogel et al. (2023);
Biakzuala et al. (2024)

REDESCRIPTION OF TRIMERESURUS CAUDORNATUS Zootaxa 5514 (3) © 2024 Magnolia Press · 231
Appendix Table S8. Literature used for the revised distribution of Trimeresurus caudornatus. Remark: ?: requested
verification
Nr on
the map
Verified by
morphology
Verified by
molecular
Locality Sources
1no no Nabang, Yingjiang, Dehong, Yunnan,
China
(type locality)
Chen et al. (2020)
2no yes Tongbiguan, Yingjiang, Dehong,
Yunnan, China
Li et al. (2020)
3yes no Chuxiong Yi, Yunnan, China Vogel et al. (2023); our data
4yes no Putao, Kachin, Myanmar Vogel et al. (2023); our data
5yes no Hukaung WS, Myitkyina , Kachin,
Myanmar
our data
6yes no Chipwe, Myitkyina, Kachin,
Myanmar
our data
7yes no Htingnan, Kachin, Myanmar Smith (1940); our data
8yes yes Indawgyi Lake, Myitkyina, Kachin,
Myanmar
Vogel et al. (2023); our data
9yes no Bhamo, Kachin, Myanmar our data
10 yes no Homalinn, Khandi, Sagaing,
Myanmar
Vogel et al. (2023); our data
11 no yes Chatthin WS., Sagaing, Myanmar our data
12 yes yes Shwe U Daung, Pyin Oo Lwin,
Mandalay, Myanmar
Vogel et al. (2023); our data
13? no yes Longchuan, Dehong, Yunnan, China Zhao et al. (1998); Zhang & Rao (2008); Zhu et al. (2022)
14? no yes Tuantian, Tengchong, Baoshan,
Yunnan, China
Zhao et al. (1998); Zhang & Rao (2008); Zhu et al. (2022)