A new species of krait of the genus Bungarus (Squamata, Elapidae) from Ratchaburi Province, western Thailand

Akrachai Aksornneam; Attapol Rujirawan; Siriporn Yodthong; Yik-Hei Sung; Anchalee Aowphol

doi:10.3897/zse.100.116601

Abstract

We described a new species of elapid snake genus Bungarus from the Tenasserim Mountain Range in Ratchaburi Province, western Thailand. Bungarus sagittatus sp. nov. can be distinguished from all congeners by having the combination of 15 dorsal scale rows; 215–217 ventral scales; 48–56 undivided subcaudal; prefrontal suture 2.4–2.6 times length of internasal suture; anterior chin shields larger than posterior chin shields; head of adult uniform black while juvenile black with small dim white patches on temporal and parietal areas; dorsal body black, with 25–31 white narrow bands, white and black bands at midbody covering 1.5–3.0 and 4.5–6.0 vertebral scales, respectively; dorsal body black bands not intruding ventrals or intruding ventrals less than 0.5 times of width of outer dorsal scales; ventral surface of body immaculate white; ventral side of tail white with a row of dark brown triangular patches on middle pointing posteriorly; tail relatively long, tail length/total length 0.140–0.143. Genetically, the new species has uncorrected pairwise divergences of ≥ 8.29% of the mitochondrial cytochrome b from other Bungarus species. Currently, the new species is only known from the type locality.

Key Words

biodiversity, snake, Southeast Asia, systematics, Tenasserim

Introduction

The kraits, genus Bungarus Daudin, 1803, are a group of highly venomous snakes in the family Elapidae, with 17 recognized species that are distributed across Asia, from Southeast Asia and China, westwards through the South Asia to Iran (Smith 1943; Slowinski 1994; Abtin et al. 2014; Ahsan and Rahman 2017; Chen et al. 2021; Uetz et al. 2023). In Thailand, five species are currently reported, including B. candidus (Linnaeus, 1758), B. fasciatus (Schneider, 1801), B. flaviceps Reinhardt, 1843, B. slowinskii Kuch, Kizirian, Nguyen, Lawson, Donnelly & Mebs, 2005 and B. wanghaotingi Pope, 1928 (Smith 1943; Taylor 1965; Cox 1991; Leviton et al. 2003, 2008; Das 2010; Cox et al. 2012, 2018; Smits and Hauser 2019; Chen et al. 2021). Among the members of the genus Bungarus, the species with black-and-white crossbands are some of the most taxonomically confusing groups due to their highly similar color patterns and morphological characteristics (Pope 1928; Leviton et al. 2003, 2008; Xie et al. 2018; Chen et al. 2021; Yuan et al. 2022). Recently, Chen et al. (2021) investigated the taxonomic status of the B. candidus/multicinctus/wanghaotingi complex (black-and-white banded kraits) from China and some parts of Southeast Asia using the multiple lines of evidence (mitochondrial DNA, external morphology and cranial osteology). The combination of molecular phylogeny and morphological data supported the validity of three species in the complex (B. candidus, B. multicinctus and B. wanghaotingi) and uncovered a new species, B. suzhenae Chen, Shi, Vogel, Ding & Shi, 2021 from Yunnan Province, China (Chen et al. 2021). Yuan et al. (2022) also investigated the molecular phylogeny of B. multicinctus Blyth, 1861 in Hong Kong and verified the occurrence of B. multicinctus and B. wanghaotingi.

Khao (mountain) Krachom is part of Tenasserim Mountain Range that is located at Suan Phueng District, Ratchaburi Province, western Thailand. The area lies on the Thai–Myanmar border and contains a variety of forest habitats ranging from 200 meters to more than 1,100 meters in elevation (The Office of Her Royal Highness Princess Maha Chakri Sirindhorn’s Projects 2005; Pawangkhanant et al. 2018; Grismer et al. 2020b; Phutthai et al. 2021). Recently, several new species of herpetofauna were described from the area (e.g., Pawangkhanant et al. 2018; Grismer et al. 2020a, 2020b, 2021; Poyarkov et al. 2020, 2022; Suwannapoom et al. 2021), indicating a high diversity of herpetofauna.

During our field surveys in 2022, specimens of black-and-white banded Bungarus were collected from Suan Phueng District, Ratchaburi Province in western Thailand. These specimens closely resemble B. candidus/multicinctus/wanghaotingi complex in color pattern. The combination of morphological and molecular analyses revealed that the Ratchaburi specimens differed from all recognized Bungarus species. Thus, we herein describe it as a new species.

Methods

Sampling

Three Bungarus samples were collected during field surveys by hand and pitfall trap from Khao Krachom, Suan Phueng District, Ratchaburi Province from, May to June 2022 (Fig. 1). Geographical coordinates with elevation of each specimen were collected using a Garmin GPSMAP 64^st. Ambient air temperature and relative humidity were collected with Kestrel 4000 Weather Meter. The specimens were humanely euthanized using tricaine methanesulfonate (MS-222) solution (Simmons 2015). Liver tissue was immediately cut from a euthanized individual, preserved in 95% ethyl alcohol, and stored at -20 °C for genetic analysis. Voucher specimens were then initially fixed in 10% formaldehyde solution and later transferred to 70% ethyl alcohol for long-term preservation. All type series and tissue samples were deposited in herpetological collection of Zoological Museum, Kasetsart University, Bangkok, Thailand (ZMKU). An additional specimen was examined at herpetological collection of the Rabbit in the Moon Foundation (RIM), Suan Phueng District, Ratchaburi Province.

Figure 1.

Map showing the type locality of Bungarus sagittatus sp. nov. (orange star) in Khao Krachom, Suan Phueng District, Ratchaburi Province.

DNA extraction and PCR amplification

We extracted genomic DNA from liver tissue of three individuals of Bungarus from Ratchaburi Province (Suppl. material 1) using the DNeasy (Qiagen, German) Blood and Tissue Kit according to manufacturer’s protocol. A 1,041 base pairs of mitochondrial cytochrome b (cyt b) was amplified by the polymerase chain reaction (PCR), using the light strand primer L14910 (5’-AACCACCGTTGTACATCAACT-3’) and heavy strand primer H16064 (5’-CTTTGGCTTACAAGAACAATGCTTTA-3’) (Burbrink et al. 2000). PCR conditions were as follows: initial denaturation at 95 °C for 2 min, followed by a second denaturation at 95 °C for 40 s, annealing at 57 °C for 25 s, followed by a cycle extension at 72 °C for 15 s, for 35 cycles with a final extension at 72 °C for 2 min. PCR amplifications were carried out in a Mastercycler^® nexus gradient thermocycler (Eppendorf SE, Germany). Amplified PCR products were run on a 1.5% agarose gel and viewed with a Molecular Imager^® Gel Doc^™ XR system (Bio-Rad Laboratories, USA) to confirm the PCR amplification. PCR products were purified using a QIAquick PCR Purification Kit (Qiagen, Germany). PCR products were sequenced in both forward and reverse directions using the same amplifying primers at Biobasic Asia Inc. (Singapore) on an ABI 3730XL automatic sequencer (Applied Biosystems, CA, USA). Bidirectional sequences were visually checked and edited in Geneious Prime 2022.2.1 (Biomatters, Ltd, Auckland, New Zealand). The protein-coding region of cyt b was translated to amino acids and checked to confirm the lack of premature termination codons. All new sequences were deposited in GenBank under accession numbers PP131180 to PP131182 (Suppl. material 1).

Phylogenetic analyses

Additional homologous cyt b sequences from 43 individuals of Bungarus species and the outgroups were downloaded from GenBank, based on previous Bungarus studies (Kuch et al. 2005; Xie et al. 2018; Biakzuala et al. 2021b, 2023; Chen et al. 2021) (Suppl. material 1). Naja naja (Linnaeus, 1758) and Elapsoidea sundevallii Smith, 1848 were selected as outgroups to root the tree following Xie et al. (2018) and Chen et al. (2021). The three newly generated Bungarus sequences and GenBank dataset were aligned using the MUSCLE alignment function (Edgar 2004) with default setting in Geneious Prime 2022.2.1 (Biomatters, Ltd, Auckland, New Zealand). The aligned dataset was partitioned into three partitions (1^st–3^th cyt b codon positions). We used ModelFinder (Kalyaanamoorthy et al. 2017) to identify the best-fit model of sequence evolution for each partition as determined by the Bayesian Information Criterion (BIC). The best-fit evolutionary models were TIM2+F+G4, TN+F+G4 and TN+F+I+G4 for cyt b codon position 1, 2, and 3, respectively.

Maximum Likelihood (ML) and Bayesian Inference (BI) were used to estimate phylogenetic relationships. The ML analysis was conducted using the IQ-TREE 1.6.12 web server available at “http://iqtree.cibiv.univie.ac.at” (Trifinopoulos et al. 2016) with 1,000 bootstrap replicates using the ultrafast bootstrap analysis (Minh et al. 2013; Hoang et al. 2018). The BI analysis was carried out using MrBayes v3.2 (Ronquist et al. 2012) on CIPRES Science Gateway V. 3.3 (Miller et al. 2010) with default prior setting. Two independent runs, each with three heated and one cold chain, were performed using Metropolis-coupled Markov Chain Monte Carlo (MCMC). The MCMC chains were run for 10,000,000 generations, with trees sampled every 1,000 generations, and the first 25% of each run was discarded as burn-in. Stationarity was evaluated by ensuring that effective sample sizes (ESS) exceeded 200 for all parameters in Tracer v. 1.7 (Rambaut et al. 2018). Nodal support for ML and BI was quantified using Ultrafast bootstrap support values (UFB) and Bayesian posterior probabilities (BPP), respectively. UFB values ≥ 95 and BPP ≥ 0.95 are considered highly supported (Huelsenbeck and Ronquist 2001; Wilcox et al. 2002; Minh et al. 2013). The phylogenetic trees from the ML and BI analyses were visualized and edited using FigTree v. 1.4.4 (http://tree.bio.ed.ac.uk/software/figtree/). Uncorrected pairwise sequence divergences (p-distances) were calculated in MEGA 11 (Tamura et al. 2021) using the pairwise deletion option to remove gaps and missing data from the alignment prior to analysis.

Morphological analyses

Morphological measurements were taken with digital calipers to the nearest 0.1 mm (except SVL and TaL, which were measured to the nearest 1 mm). The morphological characters and abbreviations used were modified from the previous studies of the genus Bungarus (Slowinski 1994; Kuch et al. 2005; Chen et al. 2021). The following morphometric and meristic characters were recorded: snout–vent length (SVL); tail length (TaL); head length (HL), from the tip of snout to the posterior edge of mouth; head width (HW), the widest part of head; head height (HH), the highest part of head in vertical; eye diameter (ED), the horizontal length of eye ball; distance between eyes (DE), was measured from the margin of upper eye contacting supraocular to opposite side; the length of internasal suture (IS), the length of suture between left and right internasal scales; the length of prefrontal suture (PS), the length of suture between left and right prefrontal scales; supralabials (SL); infralabials (IL); dorsal scale rows (DSR), were counted at one head length behind the angle of jaw, at midbody, and at one head length before the cloaca; ventral scales (VS), were counted following Dowling (1951); and subcaudals (SC). The number of white bands on dorsal body (BB) and white bands on tail (TB) were counted, while incomplete white bands were counted as one.

Comparative morphological data from other species of Bungarus were obtained from the original descriptions and literature (Boulenger 1890, 1897; Wall 1907, 1908; Pope 1928; Smith 1943; Biswas and Sanyal 1978; Slowinski 1994; Leviton et al. 2003; Kuch et al. 2005; Faiz et al. 2010; Cox et al. 2012, 2018; Chanhome 2013; Abtin et al. 2014; Knierim et al. 2017; Luu and Ha 2018; Xie et al. 2018; Smits and Hauser 2019; Biakzuala et al. 2021b; Chen et al. 2021) (Suppl. material 3).

Results

The final alignment of cyt b contained 1,137 characters of 46 taxa (44 individuals of Bungarus and two individuals of the outgroup species). The standard deviation of split frequencies among the four Bayesian runs was 0.003186 and the ESS values of all parameters were greater than or equal to 6,531. The best tree in ML analysis had a maximum likelihood value of -6,833.101. The ML and BI analyses recovered trees with similar topologies (Fig. 2). The three Ratchaburi samples formed a strongly supported monophyletic lineage (100 UFB, 1.00 BPP) and nested within the genus Bungarus. The Ratchaburi population was a strongly supported sister lineage (97 UFB, 1.00 BPP) to a clade containing B. caeruleus (Schneider, 1801), B. candidus/multicinctus/wanghaotingi complex, B. ceylonicus Günther, 1864, B. lividus Cantor, 1839, B. niger Wall, 1908, B. sindanus Boulenger, 1897 and B. suzhenae. However, the relationships among the Indian subcontinent clade (B. caeruleus, B. ceylonicus, B. lividus, B. niger and B. sindanus), B. candidus/multicinctus/wanghaotingi complex clade and B. suzhenae were not resolved representing as a polytomy. Uncorrected pairwise genetic divergences (p-distances) among Bungarus species ranged from 1.77–20.46% (Suppl. material 2). The uncorrected p-distances between Ratchaburi population and all other Bungarus species ranged from 8.29–19.42%, being most similar to B. suzhenae and most distant to B. bungaroides (Cantor, 1839). The uncorrected p-distances within the Ratchaburi population were 0.00%.

Figure 2.

The best tree resulting from Maximum Likelihood analysis of 1,137 aligned characters of the mitochondrial cytochrome b gene of Bungarus species. Nodal support is indicated by Ultrafast bootstrap (UFB) values and Bayesian posterior probabilities (BPP), respectively. GenBank accession numbers and locality data for sequenced samples are provided in Suppl. material 1.

Taxonomic hypotheses

The samples of Bungarus from Suan Phueng District, Ratchaburi Province, western Thailand differed from congeners in mtDNA and morphological comparisons (see below). Based on these corroborated lines of support, we hypothesize that this population represents a distinct species, which is described as a new species below.

Taxonomy

Bungarus sagittatus sp. nov.

https://zoobank.org/F19C3493-FA00-4F4A-A9B1-4A39B5C5FF0A

Figs 3, 4, 5

Type material

Holotype (Fig. 3). ZMKU R 01089, adult female collected from Thailand, Ratchaburi Province, Suan Phueng District, Suan Phueng Subdistrict, Khao Krachom (13°33'57"N, 99°11'43"E, 834 m elevation), on 15 May 2022 by Akrachai Aksornneam, Mali Naiduangchan, Kritsada Rungrot, Purinut Numuan, Suphap Sisuk and Goe Wongdee.

Figure 3.

Holotype of Bungarus sagittatus sp. nov. (ZMKU R 01089) in preservation. A. Lateral view; B. Dorsal view and C. Ventral view; D. Dorsal view; E. Ventral view. Scale bars: 20 mm.

Paratypes (Figs 4, 5A–D). ZMKU R 01088 (subadult female) bear the same locality data as the holotype. ZMKU R 01090 (juvenile) collected from Thailand, Ratchaburi Province, Suan Phueng District, Suan Phueng Subdistrict, Khao Krachom (13°33'41"N, 99°12'18"E, 619 m elevation), on 15 June 2022, by Akrachai Aksornneam and Naka Taou.

Figure 4.

Paratypes in life showing the variation in different age class. A. Subadult female (ZMKU R 01088); B. Juvenile (ZMKU R 01090).

Figure 5.

Paratypes and referred specimen in preservation. A. Dorsal and B. Ventral view of subadult female (ZMKU R 01088); C. Dorsal and D. Ventral view of juvenile (ZMKU R 01090); E. Dorsal and F. Ventral view of subadult male (RIM00012). Scale bars: 20 mm.

Referred specimen

(Fig. 5E, F). RIM00012 (subadult male) collected from Thailand, Ratchaburi Province, Suan Phueng District, Suan Phueng Subdistrict, Khao Krachom (13°34'53"N, 99°10'43"E, 987 m elevation), on 16 April 2021, by Parinya Pawangkhanant and Boontorn Wongdee.

Diagnosis

Bungarus sagittatus sp. nov. is assigned to the genus Bungarus by its recovered phylogenetic position and having enlarged, hexagonal-shaped, midbody vertebrae scales (Smith 1943; Slowinski 1994). This species can be distinguished from other species of Bungarus by the following combination of characters: 15–15–15 dorsal scale rows; 215–217 ventral scales; 48–56 undivided subcaudal; prefrontal suture 2.4–2.6 times length of internasal suture; anterior chin shields larger than posterior chin shields; head of adult uniform black while juvenile black with small dim white patches on temporal and parietal areas; dorsal surface of body black, with 25–31 white narrow bands, white and black bands at midbody covering 1.5–3.0 and 4.5–6.0 vertebral scales, respectively; dorsal black bands of body not intruding ventrals or intruding ventrals less than 0.5 times of width of outer dorsal scales; ventral surface immaculate white; ventral side of tail white with a row of dark brown triangular patches on middle pointing posteriorly; tail relatively long, tail length/total length = 0.140–0.143.

Description of holotype

Adult female. Head length 19.9 mm, head width 16.8 mm; head height 10.7 mm, head 1.2 times longer than wide, distance between eyes 9.2 mm. Body length (SVL) 791 mm; tail incomplete, 132 mm; total length 923 mm.

Body scalation. Dorsal scales smooth, in 15–15–15 rows; vertebral scales enlarged, hexagonal, largest at midbody, wider than long. Ventrals 216, preventrals 3, anterior edge of first ventral starting at level of oral rictus. Cloacal plate undivided. Subcaudals 48 undivided, tail incomplete.

Head. Head scales smooth. Λ-shaped rostral visible from above 1.6 times wider than tall. Nasal large, divided into one irregular quadrilateral-shaped prenasal and one crescent-shaped postnasal on both side; prenasal and postnasal bordered by internasal and first supralabial; prenasal contacted with rostral; postnasal surrounded by prefrontal, preocular and second supralabial. External nares large, vertically oval-shaped, about half size of eye diameter. Preoculars 1/1 (left/right) hexagonal-shaped, bordered by orbit, supraocular, prefrontal, postnasal, second and third supralabials. Two internasals, 1.03 times wider than long, surrounded by rostral, prenasal, postnasal and prefrontal. Prefrontals large, 1.06 times wider than long, prefrontals suture length 2.6 times of internasals suture. Frontal shield-shaped, pointing backward to parietals, 1.3 times longer than wide, bordered by prefrontals, supraoculars and parietals; anterior suture of frontal pointed toward prefrontal suture. Supraocular 1/1 small, 1.6 times longer than wide, in contact with preocular, orbit, upper postocular, parietal, frontal and prefrontal. Parietals large and long, 2 times longer than wide, 1.6 times longer than frontal length; left parietal anteriorly and laterally bordered by frontal, supraocular, upper postocular, anterior temporal and upper posterior temporal; right parietal anteriorly and laterally bordered by frontal, supraocular, upper postocular, lower postocular, anterior temporal and upper posterior temporal; posterolateral margins of parietals bordered by 1/1 enlarged elongate scales that anteriorly contact upper posterior temporals; posteriormost extensions of parietals pointed, divided by one of three small dorsal scales bordering posterior end of parietals. Eyes small, oval-shaped, horizontal diameter 2.6 mm, vertical diameter 2.3 mm. Postoculars 2/2, relatively small with one-third size of preoculars; on right side, lower postocular bordered by orbit, fourth and fifth supralabials, anterior temporal, parietal and upper postocular; on left side, lower postocular bordered by orbit, fourth and fifth supralabials, anterior temporal and upper postocular; on right side, upper postocular bordered by orbit, lower postocular, parietal and supraocular; on left side, upper postocular bordered by orbit, lower postocular, anterior temporal, parietal and supraocular. Anterior temporals 1/1, long and subhexagonal-shaped, 1.6 times longer than wide; right anterior temporal bordered by lower postocular, fifth and sixth supralabials, lower posterior temporal, upper posterior temporal and parietal; left anterior temporal bordered by upper postocular, lower postocular, fifth and sixth supralabials, lower posterior temporal, upper posterior temporal and parietal. Posterior temporals 2/2 surrounded by parietals, anterior temporals, sixth and seventh supralabials and dorsal scales. Supralabials 7/7, the third and fourth supralabials touching lower margin of orbit; first supralabials small, subtriangular, 1.2 times wider than height; other supralabials in different pentagonal shapes; second supralabials height pentagonal-shaped, larger than the first, 1.8 times higher than wide; the third supralabial larger than first, second and fourth supralabials, 1.3 times higher than wide; fourth supralabials with 1.5 times higher than wide; fifth and sixth supralabials are two largest, both height equal to width, but fifth supralabials wider at lower part while the sixth supralabials is wider at the upper part; seventh supralabials is the third largest, 1.2 times higher than wide. Mental triangular-shaped, 1.4 times shorter than width of rostral, in contact with first infralabials, mental groove distinct. Infralabials 7/7, first infralabials pentagonal-shaped, long and narrow, 1.6 times longer than wide, in contact behind the mental and anterior chin shields; second infralabials square-shaped, one-third size of the first, 2.1 times longer than wide, in contact with anterior chin shields; the third infralabials enlarged, in contact with anterior chin shields, 1.1 times longer than wide; the fourth is largest infralabial, pentagonal shaped, in contact with anterior and posterior chin shields, 1.2 times longer than wide; fifth infralabials in form of a square, half size of the fourth, 1.2 times longer than wide; the sixth is widest infralabial, 1.9 times wider than long; seventh infralabials is smallest, 1.4 times wider than long. Anterior chin shields larger than posterior chin shields; anterior chin shield suture 2 times the length of the posterior chin shield suture; posterior chin shields bordered by anterior chin shields, fourth infralabials, 2/2 sublabials and three gulars. Three gulars between first ventral and posteriormost extension of posterior chin shield; one gular and three preventrals between first ventral and suture of posterior chin shields.

Coloration in preservative

Dorsal surface and lateral sides of head, including upper part of supralabial, upper part of rostral uniform black; lower part of head, including portions of lower supralabials and rostral to ventral head uniform creamy white. Dorsal body black with 26 white crossbands (the fifth band incomplete). Some white bands on the body scattered with few dark spots, most bands nearly immaculate creamy white. The white bands cover 0.5 to 2.0 times vertebral scales (average 1.5 ± 0.4, n = 26; 1.5 vertebral scales at midbody), bands widening on flanks before merging with the immaculate creamy white ventral scales. The first white band starts at 16^th ventral, 11 vertebral scales between first and second bands and five vertebral scales between 25^th and 26^th bands. A dark spot is present at the junction between white bands and ventral scales at midbody positions. Black bands on body wide, covering 6.0 vertebral scales at midbody positions, generally not intruding white ventral scales; some bands slightly intruding ventral scales less than 0.5 times width of outer lateral dorsal scales.

Dorsal surface of tail black with eight creamy white bands on dorsal part, covering 1.0–1.5 times of vertebral scales. Ventral surface of tail creamy white with a row of dark brown triangular patches pointing posteriorly at the middle of subcaudals, starting from second subcaudal to the tip of tail.

Variation

Paratypes and referred specimens closely resemble the holotype in general aspects of morphology and color pattern. First and second white bands on dorsum of ZMKU R 01090 (juvenile) are disconnected. In ZMKU R 01088 (subadult female), the first white band on dorsum is disconnected; the second and third are incompletely connected on lateral side of body. Twentieth white band on dorsum of RIM00012 (subadult male) is incomplete (present only on left side). Juvenile (ZMKU R 01090) head black with small dim white patches on temporal and parietal areas. A row of dark brown triangular patches on ventral surface of tail in juvenile is indistinct. Other variations in measurements, meristics and color pattern among the type series and referred specimen are shown in Table 1.

Table 1.

Download as

CSV

XLSX

Descriptive measurement (millimeters), meristics (left/right) and color pattern of Bungarus sagittatus sp. nov. Morphological abbreviations are defined in Methods.

Character	ZMKU R 01089	ZMKU R 01088	ZMKU R 01090	RIM00012
Sex	Female	Subadult female	Juvenile	Subadult male
Type	Holotype	Paratype	Paratype	Referred specimen
Measurement
SVL	791	550	300	710
TaL	132	92	49	118
HL	19.9	15.0	10.2	17.8
HW	16.8	11.2	8.1	12.6
HH	10.7	7.0	5.5	9.0
ED	2.6	2.1	1.8	2.1
DE	9.2	6.7	4.6	7.4
IS	1.6	1.2	0.8	1.3
PS	4.1	2.9	1.9	3.2
Tal/TL	0.143	0.143	0.140	0.143
PS/IS	2.56	2.42	2.38	2.46
Meristics
SL	7/7	7/7	7/7	7/7
IL	7/7	7/7	7/7	7/7
DSR	15/15/15	15/15/15	15/15/15	15/15/15
VS	216	215	216	217
SC	48	53	56	55
BB	26	25	25	31
TB	8	7	11	12
Color pattern
Black bands intruding ventrals	Yes	No	No	No
Head color	Uniform black	Black with small dim white patches	Black with small dim white patches	Uniform black
Vertebral scales covered by white bands at midbody	1.5 scales	3.0 scales	1.5 scales	1.5 scales
Vertebral scales covered by black bands at midbody	6.0 scales	5.5 scales	6.0 scales	4.5 scales

Etymology

The specific epithet sagittatus is derived from sagittata (L.) meaning arrow and in reference to the dark triangular shape on subcaudals which resembles a barbed arrow.

Distribution

Bungarus sagittatus sp. nov. is currently known from type locality: Khao Krachom, Suan Phueng District, Ratchaburi Province. The area is part of Tenasserim Mountain Range, which lies on Thai-Myanmar borderline.

Ecology

Most observations of Bungarus sagittatus sp. nov. occurred at night, three specimens (ZMKU R 01088, ZMKU R 01089 and RIM00012) were collected in hill evergreen forest (834 m to 987 m elevation; Fig. 6) between 2050 and 2210 h with air temperature 24.1 °C and relative humidity 91.7%. One juvenile (ZMKU R 01090) was collected in a pitfall trap at daytime in mixed deciduous forest (619 m elevation). One subadult (not collected) was found swallowing an adult scincid lizard, Scincella reevesii (Gray, 1839), on forest floor in hill evergreen forest (1,049 m elevation) on 6 November 2022 at 2154 h (Fig. 7).

Figure 6.

Habitat of Bungarus sagittatus sp. nov. A. Macrohabitat at Khao Laem Summit (1,130 m elevation), Khao Krachom, Suan Phueng District, Ratchaburi Province; B. Hill evergreen forest at 1,000 m elevation.

Figure 7.

Feeding behavior of Bungarus sagittatus sp. nov. (not collected) on smooth skink (Scincella reevesii) from the type locality, in hill evergreen forest at 1,049 m elevation. Red arrows indicate the tail part of skink.

The new species was found sympatrically with other snake species such as Ahaetulla prasina (Boie, 1827), Boiga cyanea (Duméril, Bibron & Duméril, 1854), Coelognathus flavolineatus (Schlegel, 1837), Gonyosoma oxycephalum (Boie, 1827), Lycodon ophiophagus Vogel, David, Pauwels, Sumontha, Norval, Hendrix, Vu & Ziegler, 2009, Ptyas carinata (Günther, 1858), Rhabdophis chrysargos (Schlegel, 1837), Psammodynastes pulverulentus (Boie, 1827), Pareas carinatus Wagler, 1830, Argyrophis diardii (Schlegel, 1839), Naja kaouthia Lesson, 1831, Bungarus flaviceps, Ophiophagus hannah (Cantor, 1836) and Trimeresurus cf. popeiorum Smith, 1937.

Comparison

Bungarus sagittatus sp. nov. is distinguished from all other Bungarus by a combination of morphological and color pattern characteristics (see Suppl. material 3). Bungarus sagittatus sp. nov. differed from B. andamanensis Biswas & Sanyal, 1978 by having 215–217 ventral scales (vs. 192–197); 48–56 subcaudals (vs. 45–47); TaL/TL 0.140–0.143 (vs. 0.156–0.161); 25–31 narrow white body bands (vs. 39–47 yellow or white bands mottled with brown); head uniform black (vs. head brown chocolate); and ventral surface of body immaculate white (vs. anterior and margin of ventral scales tinged with brown).

Bungarus sagittatus sp. nov. differed from B. bungaroides by having 215–217 ventral scales (vs. 220–237); TaL/TL 0.140–0.143 (vs. 0.114–0.130); subcaudals undivided (vs. divided); dorsal body with 25–31 narrow white bands (vs. 46–60 narrow white bands consisting of small white spots); dorsal body with larger black bands covering 4.5–6.0 vertebral scales at midbody (vs. 3.0–4.5 vertebral scales); and ventral surface of body immaculate white (vs. blackish with irregular yellowish white pattern).

Bungarus sagittatus sp. nov. differed from B. caeruleus (Schneider, 1801) by having TaL/TL 0.140–0.143 (vs. 0.111); 25–31 narrow white body bands (vs. 29–65 white bands); and white bands not in pairs (vs. white bands in pairs).

Bungarus sagittatus sp. nov. differed from B. candidus by having prefrontal suture length 2.4–2.6 times of internasal suture (vs. 1.4–2.4 times); TaL/TL 0.140–0.143 (vs. 0.112–0.130); white bands on dorsal body covering 1.5–3.0 vertebral scales at midbody (vs. 3.0–5.0 vertebral scales); black bands on dorsal body covering 4.5–6.0 vertebral scales at midbody (vs. 3.0–5.0 vertebral scales); dorsal body black bands not intruding ventrals or intruding ventrals less than 0.5 times of width of outer dorsal scales (vs. 1.0–2.0 times); adult head uniform black (vs. temporal area and lateral neck stained white); juvenile head black with small dim white patches on temporal and parietal areas (vs. creamy white head); and ventral surface of tail creamy white with a row of dark brown triangular patches on middle (vs. broad dark crossbars).

Bungarus sagittatus sp. nov. differed from B. ceylonicus by having 215–217 ventral scales (vs. 219–235); 48–56 subcaudals (vs. 33–40); 25–31 narrow white body bands (vs. 15–21 narrow white bands); TaL/TL 0.140–0.143 (vs. 0.087); and ventral surface of body immaculate white (vs. broad dark crossbands).

Bungarus sagittatus sp. nov. differed from B. fasciatus by having 48–56 subcaudals (vs. 23–39); TaL/TL 0.140–0.143 (vs. 0.074–0.096); dorsal body and tail black with narrow white bands (vs. broad yellow and black bands); ventral surface of body immaculate white (vs. yellow and black bands); dorsal body black bands not intruding ventrals or intruding ventrals less than 0.5 times of width of outer dorsal scales (vs. black bands encircling ventrals); and ventral surface of tail creamy white with a row of dark brown triangular patches on middle (vs. yellow and black bands).

Bungarus sagittatus sp. nov. differed from B. flaviceps by having 15 dorsal scale rows (vs. 13 rows); dorsal body and tail black with narrow white bands (vs. body black with or without light vertebral and paraventral stripes, tail bright red); and head uniform black (vs. head red).

Bungarus sagittatus sp. nov. differed from B. lividus by having vertebral scales distinctly enlarged (vs. slightly enlarged on the anterior body); 48–56 subcaudals (vs. 35–43); TaL/TL 0.140–0.143 (vs. 0.118); and dorsal body black with narrow white bands (vs. black without bands).

Bungarus sagittatus sp. nov. differed from B. magnimaculatus Wall & Evans, 1901 by having 48–56 subcaudals (vs. 40–48); TaL/TL 0.140–0.143 (vs. 0.115); and 25–31 narrow white body bands (vs. 11–14 broad white bands).

Bungarus sagittatus sp. nov. differed from B. multicinctus by having 25–31 white bands on dorsal body (vs. 31–50); black bands on dorsal body covering 4.5–6.0 vertebral scales at midbody (vs. 3.0–4.0 vertebral scales); dorsal body black bands not intruding ventrals or intruding ventrals less than 0.5 times of width of outer dorsal scales (vs. 1.2–2.0 times); ventral surface of body immaculate white (vs. white with dense brown pigments); and ventral surface of tail creamy white with a row of dark brown triangular patches on middle (vs. dense black bands and patches).

Bungarus sagittatus sp. nov. differed from B. niger by having dorsal body black with mostly complete narrow white bands (vs. body bands absent); and ventral surface of tail creamy white with a row of dark brown triangular patches on middle (vs. immaculate white).

Bungarus sagittatus sp. nov. differed from B. percicus Abtin, Nilson, Mobaraki, Hosseini & Dehgannejhad, 2014 by having 15 dorsal scale rows (vs. 17); 215–217 ventral scales (vs. 236–238); TaL/TL 0.140–0.143 (vs. 0.127–0.134); loreal scale absent (vs. present); and dorsal body black with mostly complete narrow white bands (vs. black with light triangular-shaped crossbars, ending in pairs of rectangular whitish dots or crossbars along the vertebral area).

Bungarus sagittatus sp. nov. differed from B. sindanus by having 15 dorsal scale rows (vs. 17); 215–217 ventral scales (vs. 220–237); and dorsal body black with mostly complete narrow white bands (vs. black with white bands formed by series of white spots).

Bungarus sagittatus sp. nov. differed from B. slowinskii by having 215–217 ventral scales (vs. 225–230); 48–56 subcaudals (vs. 33–41); TaL/TL 0.140–0.143 (vs. 0.120); subcaudals undivided (vs. divided); ventral surface of body immaculate white (vs. black bands encircling with irregular yellowish white pattern); and ventral surface of tail creamy white with a row of dark brown triangular patches on middle (vs. black bands encircling with irregular yellowish white pattern).

Bungarus sagittatus sp. nov. differed from B. suzhenae by having prefrontal suture 2.4–2.6 times of internasal suture (vs. 2.7–3.4 times); 215–217 ventral scales (vs. 220–229); 25–31 narrow white body bands (vs. 26–38); head of juvenile black with small dim white patches on temporal and parietal areas (vs. uniform black head); and ventral surface of tail creamy white with a row of dark brown triangular patches on middle (vs. immaculate white or with small brown dots).

Bungarus sagittatus sp. nov. differed from B. walli Wall, 1907 by having 15 dorsal scale rows (vs. 17); 215–217 ventral scales (vs. 198–207); and dorsal body black with mostly complete narrow white bands (vs. black with white bands formed by series of white spots).

Bungarus sagittatus sp. nov. differed from B. wanghaotingi by having TaL/TL 0.140–0.143 (vs. 0.114–0.132); dorsal body black bands not intruding ventrals or intruding ventrals less than 0.5 times of width of outer dorsal scales (vs. 0.5–1.5 times); head of juvenile black with small dim white patches on temporal and parietal areas (vs. light brown); and ventral surface of tail creamy white with a row of dark brown triangular patches on middle (vs. a row of small light brown dots on middle).

Discussion

The combination of phylogenetic and morphological analyses revealed that the populations of Bungarus from Ratchaburi Province should be recognized as a distinct species, which is described here as Bungarus sagittatus sp. nov. Based on general morphology and color pattern, Bungarus sagittatus sp. nov. superficially resembles the members of the B. candidus/multicinctus/wanghaotingi complex, but phylogenetic analyses revealed that the new species is not closely related to those species. Moreover, the new species has high uncorrected pairwise divergences based on cyt b gene (≥ 8.29%) from other Bungarus species whereas members of the B. candidus/multicinctus/wanghaotingi complex have uncorrected pairwise divergences of 1.6–3.3% (in Chen et al. 2021) and 1.8–3.1% (this study; Suppl. material 2).

In this study, the new species was observed preying on scincid lizard, Scincella reevesii, which revealed that the new species could prey on other reptiles or non-snake prey animals e.g., amphibians, rodents or birds (not strictly on snakes) as reported in other Bungarus species (see Knierim et al. 2017; Luu and Ha 2018; Biakzuala et al. 2019a, 2019b, 2021a; Mohalik et al. 2019; Pandey et al. 2020; Hong et al. 2021; Hruaia et al. 2023; Subba et al. 2023). The ecology and natural history of this species should be further investigated. Furthermore, the report on their venom composition is still lacking. Since kraits are recognized as highly venomous snakes, this data is needed for snake bite management and development of effective antivenom (Fry et al. 2003; Sunagar et al. 2021; Talukdar et al. 2023).

Bungarus sagittatus sp. nov. is currently known only from the lowland hill forest at 600 meters to over 1,000 meters elevation in Khao Krachom, Suan Phueng District, Ratchaburi Province, western Thailand. Additional field surveys in the Tenasserim Range including Thai-Myanmar border and examination of museum specimens are needed to investigate the geographic range of the new species. Description of Bungarus sagittatus sp. nov. brings the total number of Bungarus to 18 species (Chen et al. 2021; Uetz et al. 2023). The discovery of this new Bungarus species and recent studies from Tenasserim Range highlight that this area is a potential stronghold for amphibians and reptiles, and also act as an important herpetofaunal exchange (dispersal) between Indochina and Sundaland in the past (see Grismer et al. 2017, 2020a; Suwannapoom et al. 2018).

Acknowledgements

This research is funded by Kasetsart University through the Graduate School Fellowship Program and National Research Council of Thailand (NRCT). AR and AA were supported by Office of the Permanent Secretary, Ministry of Higher Education, Science, Research and Innovation (RGNS 64-038). The research protocol was approved by Institutional Animal Care and Use Committee, Kasetsart University (ACKU65-SCI-032). We thank the Rabbit in the Moon Foundation, Charnchai Bindusen, Juthamas Wangaryattawanich and Suthep Kraithep (Suan Phueng Nature Education Park initiated by Her Royal Highness Princess Maha Chakri Sirindhorn) for supporting this research. Parinya Pawangkhanant, Mali Naiduangchan, Pattarawich Dawwrueng and Kawin Jiaranaisakul for their assistance and useful suggestions. Bangroh Taou, Naka Taou, Goe Wongdee, Pree Wongdee, Boontorn Wongdee, Krarok Wongdee, Suphap Sisuk, Cherd Manora, Kritsada Rungrot and Purinut Numuan assisted the fieldwork. Lal Biakzuala and Evan S.H. Quah improved the manuscript.

References

Abtin E, Nilson G, Mobaraki A, Hosseini AA, Dehgannejhad M (2014) A new species of krait, Bungarus (Reptilia, Elapidae, Bungarinae) and the first record of that genus in Iran. Russian Journal of Herpetology 21(4): 243–250.

Ahsan MF, Rahman MM (2017) Status, distribution and threats of kraits (Squamata: Elapidae: Bungarus) in Bangladesh. Journal of Threatened Taxa 9(3): 9903–9910. https://doi.org/10.11609/jott.2929.9.3.9903-9910

Biakzuala L, Lalrinsanga, Lalremsanga HT, Romalsawma, Vanlalhrima, Laltlanchhuaha H (2019a) Bungarus fasciatus (banded krait). Diet. Herpetological Review 50(4): 797.

Biakzuala L, Lalrinsanga, Lalremsanga HT, Romalsawma, Vanlalhrima, Sailo V, Laltlanchhuaha H (2019b) Bungarus niger (greater black krait). Diet and elevation. Herpetological Review 50(4): 797–798.

Biakzuala L, Malsawmtluanga M, Lalremsanga HT (2021a) Ophiophagy by banded krait (Bungarus fasciatus) exposed by a road kill. Taprobanica 10(2): 127. https://doi.org/10.47605/tapro.v10i2.262

Biakzuala L, Purkayastha J, Rathee YS, Lalremsanga HT (2021b) New data on the distribution, morphology, and molecular systematics of two venomous snakes, Bungarus niger and Bungarus lividus (Serpentes: Elapidae), from north-east India. Salamandra (Frankfurt) 57(2): 219–228.

Biakzuala L, Lalremsanga HT, Santra V, Dhara A, Ahmed MT, Mallick ZB, Kuttalam S, Amarasinghe AAT, Malhotra A (2023) Molecular phylogeny reveals distinct evolutionary lineages of the banded krait, Bungarus fasciatus (Squamata, Elapidae) in Asia. Scientific Reports 13(2061): 2061. https://doi.org/10.1038/s41598-023-28241-8

Biswas S, Sanyal DP (1978) A new species of krait of the genus Bungarus Daudin, 1803 (Serpentes: Elapidae) from the Andaman Island. Journal of the Bombay Natural History Society 75: 179–183.

Boulenger GA (1890) The fauna of British India, including Ceylon and Burma. Reptilia and Batrachia. Taylor & Francis, London, 541 pp. https://doi.org/10.5962/bhl.title.100797

Boulenger GA (1897) A new krait from Sind (Bungarus sindanus). Journal of the Bombay Natural History Society 11: 73–74.

Burbrink FT, Lawson R, Slowinski JB (2000) Mitochondrial DNA phylogeography of the polytypic North American rat snake (Elaphe obsoleta): A critique of the subspecies concept. Evolution; International Journal of Organic Evolution 54(6): 2107–2118. https://doi.org/10.1554/0014-3820(2000)054[2107:MDPOTP]2.0.CO;2

Chanhome L (2013) Reproduction of the red-headed krait (Bungarus flaviceps) in captivity. Tropical Natural History 13(1): 59–63.

Chen ZN, Shi SC, Vogel G, Ding L, Shi JS (2021) Multiple lines of evidence reveal a new species of krait (Squamata, Elapidae, Bungarus) from Southwestern China and Northern Myanmar. ZooKeys 1025: 35–71. https://doi.org/10.3897/zookeys.1025.62305

Cox MJ (1991) The snakes of Thailand and their husbandry. Krieger Publishing Company, 526 pp.

Cox MJ, Hoover MF, Chanhome L, Thirakupt K (2012) The snakes of Thailand. Chulalongkorn University Museum of National History, Bangkok, Thailand, 845 pp.

Cox MJ, Hoover MF, Chanhome L, Thirakupt K, Pongcharoen C (2018) A field guide to the venomous snakes of mainland ASEAN nations. Parbpim Limited Partnership, Bangkok, Thailand, 82 pp.

Das I (2010) A field guide to the reptiles of Thailand and South-east Asia. New Holland Publishers, 376 pp.

Dowling HG (1951) A proposed standard system of counting ventrals in snakes. British Journal of Herpetology 1: 97–99.

Edgar RC (2004) MUSCLE: Multiple sequence alignment with high accuracy and high throughput. Nucleic Acids Research 32(5): 1792–1797. https://doi.org/10.1093/nar/gkh340

Faiz A, Ghose A, Ahsan F, Rahman R, Amin R, Hassan MU, Chowdhury AW, Kuch U, Rocha T, Harris JB, Theakston RDG, Warrell DA (2010) The greater black krait (Bungarus niger), a newly recognized cause of neuro-myotoxic snake bite envenoming in Bangladesh. Brain 133(11): 3181–3193. https://doi.org/10.1093/brain/awq265

Fry BG, Winkel KD, Wickramaratna JC, Hodgson WC, Wüster W (2003) Effectiveness of snake antivenom: Species and regional venom variation and its clinical impact. Journal of Toxicology: Toxin Reviews 22(1): 23–34. https://doi.org/10.1081/TXR-120019018

Grismer LL, Wood Jr PL, Aowphol A, Cota M, Grismer MS, Murdoch ML, Aguilar C, Grismer JL (2017) Out of Borneo, again and again: biogeography of the stream toad genus Ansonia Stoliczka (Anura: Bufonidae) and the discovery of the first limestone cave-dwelling species. Biological Journal of the Linnean Society, Linnean Society of London 120(2): 371–395. https://doi.org/10.1111/bij.12886

Grismer LL, Yushchenko PV, Pawangkhanant P, Naiduangchan M, Nazarov RA, Orlova VF, Suwannapoom C, Poyarkov NA (2020a) A new species of Hemiphyllodactylus Bleeker (Squamata; Gekkonidae) from Peninsular Thailand that converges in morphology and color pattern on Pseudogekko smaragdinus (Taylor) from the Philippines. Zootaxa 4816(2): 171–190. https://doi.org/10.11646/zootaxa.4816.2.2

Grismer LL, Yushchenko PV, Pawangkhanant P, Nazarov RA, Naiduangchan M, Suwannapoom C, Poyarkov NA (2020b) A new species of Cnemaspis Strauch (Squamata: Gekkonidae) of the C. siamensis group from Tenasserim Mountains, Thailand. Zootaxa 4852(5): 547–564. https://doi.org/10.11646/zootaxa.4852.5.3

Grismer LL, Suwannapoom C, Pawangkhanant P, Nazarov RA, Yushchenko PV, Naiduangchan M, Le MD, Luu VQ, Poyarkov NA (2021) A new cryptic arboreal species of the Cyrtodactylus brevipalmatus group (Squamata: Gekkonidae) from the uplands of western Thailand. Vertebrate Zoology 71: 723–746. https://doi.org/10.3897/vz.71.e76069

Hoang DT, Chernomor O, von Haeseler A, Minh BQ, Vinh LS (2018) UFBoot2: Improving the ultrafast bootstrap approximation. Molecular Biology and Evolution 35(2): 518–522. https://doi.org/10.1093/molbev/msx281

Hong Z, Anuar S, Grismer LL, Quah ESH (2021) Preliminary report on the herpetofaunal diversity of Batu Hampar Recreational Forest, Kedah, Malaysia. Check List 17(3): 791–814. https://doi.org/10.15560/17.3.791

Hruaia V, Tochhawng L, Laltlanchhuaha H, Decemson HT, Lalremsanga HT, Biakzuala L (2023) Bungarus niger (greater black krait). Diet. Herpetological Review 54(1): 131–132.

Huelsenbeck JP, Ronquist F (2001) MRBAYES: Bayesian inference of phylogenetic trees. Bioinformatics (Oxford, England) 17(8): 754–755. https://doi.org/10.1093/bioinformatics/17.8.754

Kalyaanamoorthy S, Minh BQ, Wong TKF, von Haeseler A, Jermiin LS (2017) ModelFinder: Fast model selection for accurate phylogenetic estimates. Nature Methods 14(6): 587–589. https://doi.org/10.1038/nmeth.4285

Knierim T, Barnes CH, Hodges C (2017) Bungarus fasciatus (banded krait). Diet/scavenging. Herpetological Review 48(1): 204–205.

Kuch U, Kizirian D, Truong NQ, Lawson R, Donnelly MA, Mebs D (2005) A new species of krait (Squamata: Elapidae) from the red river system of northern Vietnam. Copeia 2005(4): 818–833. https://doi.org/10.1643/0045-8511(2005)005[0818:ANSOKS]2.0.CO;2

Leviton AE, Wogan GOU, Koo MS, Zug GR, Lucas RS, Vindum JV (2003) The dangerously venomous snakes of Myanmar illustrated checklist with keys. Proceedings of the California Academy of Sciences 54(24): 407–462.

Leviton AE, Zug GR, Vindum JV, Wogan GOU (2008) Handbook to the dangerously venomous snakes of Myanmar. California Academy of Sciences, 122 pp.

Luu VQ, Ha NV (2018) Bungarus fasciatus (banded krait). Diet. Herpetological Review 49(3): 543.

Miller MA, Pfeiffer W, Schwartz T (2010) Creating the CIPRES Science Gateway for inference of large phylogenetic trees. In: 2010 Gateway Computing Environments Workshop (GCE), 1–8. https://doi.org/10.1109/GCE.2010.5676129

Minh BQ, Nguyen MAT, von Haeseler A (2013) Ultrafast approximation for phylogenetic bootstrap. Molecular Biology and Evolution 30(5): 1188–1195. https://doi.org/10.1093/molbev/mst024

Mohalik RK, Sahu SB, Arif M, Kar NB (2019) Bungarus caeruleus (common krait). Coloration and diet. Herpetological Review 50(1): 150–151.

Pandey DP, Bhattarai P, Piya RC (2020) Food spectrum of common kraits (Bungarus caeruleus): An implication for snakebite prevention and snake conservation. Journal of Herpetology 54(1): 87–96. https://doi.org/10.1670/18-054

Pawangkhanant P, Poyarkov NA, Duong TV, Naiduangchan M, Suwannapoom C (2018) A new species of Leptobrachium (Anura, Megophryidae) from western Thailand. PeerJ 6: e5584. https://doi.org/10.7717/peerj.5584

Phutthai T, Thananthaisong T, Daonurai K, Srisom P, Suddee S, Hughes M (2021) Begonia sirindhorniana (Begoniaceae) a new species from Thailand. Thai Forest Bulletin 49(2): 201–205. https://doi.org/10.20531/tfb.2021.49.2.07

Pope CH (1928) Four new snakes and a new lizard from South China. American Museum Novitates 325: 1–4.

Poyarkov NA, Pawangkhanant P, Gorin VA, Juthong W, Suwannapoom C (2020) A new species of miniaturised narrow-mouth frog of the genus Microhyla Tschudi, 1838 (Amphibia: Anura: Microhylidae) from northern Tenasserim, Thailand. Journal of Natural History 54(23–24): 1525–1558. https://doi.org/10.1080/00222933.2020.1804005

Poyarkov NA, Nguyen TV, Pawangkhanant P, Yushchenko PV, Brakels P, Nguyen LH, Nguyen HN, Suwannapoom C, Orlov N, Vogel G (2022) An integrative taxonomic revision of slug-eating snakes (Squamata: Pareidae: Pareineae) reveals unprecedented diversity in Indochina. PeerJ 10: e12713. https://doi.org/10.7717/peerj.12713

Rambaut A, Drummond AJ, Xie D, Baele G, Suchard MA (2018) Posterior summarization in Bayesian phylogenetics using Tracer 1.7. Systematic Biology 67(5): 901–904. https://doi.org/10.1093/sysbio/syy032

Ronquist F, Teslenko M, van der Mark P, Ayres DL, Darling A, Höhna S, Larget B, Liu L, Suchard MA, Huelsenbeck JP (2012) MrBayes 3.2: Efficient Bayesian phylogenetic inference and model choice across a large model space. Systematic Biology 61(3): 539–542. https://doi.org/10.1093/sysbio/sys029

Simmons JE (2015) Herpetological collecting and collections management, 3^rd ed. Society for the Study of Amphibians and Reptiles Herpetological Circular No. 42. Salt Lake City, UT, 191 pp.

Slowinski JB (1994) A phylogenetic analysis of Bungarus (Elapidae) based on morphological characters. Journal of Herpetology 28(4): 440–446. https://doi.org/10.2307/1564956

Smith MA (1943) The fauna of British India, Ceylon and Burma, including the whole of the Indo-Chinese Sub-Region. Reptilia and Amphibia. Vol. 3 (Serpentes). Taylor and Francis, London, 583 pp.

Smits T, Hauser S (2019) First record of the krait Bungarus slowinskii Kuch, Kizirian, Nguyen, Lawson, Donelly and Mebs, 2005 (Squamata: Elapidae) from Thailand. Tropical Natural History 19(2): 43–50.

Subba A, Luitel S, Rai TP, Limbu KP (2023) Bizarre record: Banded krait, (Bungarus fasciatus) (Schneider 1801), feeding on other krait species. Reptiles & Amphibians : Conservation and Natural History 30(1): e18661. https://doi.org/10.17161/randa.v30i1.18661

Sunagar K, Khochare S, Laxme RRS, Attarde S, Dam P, Suranse V, Khaire A, Martin G, Captain A (2021) A wolf in another wolf’s clothing: Post-genomic regulation dictates venom profiles of medically-important cryptic kraits in India. Toxins 13(69): 69. https://doi.org/10.3390/toxins13010069

Suwannapoom C, Sumontha M, Tunprasert J, Ruangsuwan T, Pawangkhanant P, Korost DV, Poyarkov NA (2018) A striking new genus and species of cave-dwelling frog (Amphibia: Anura: Microhylidae: Asterophryinae) from Thailand. PeerJ 6: e4422. https://doi.org/10.7717/peerj.4422

Suwannapoom C, Grismer LL, Pawangkhanant P, Naiduangchan M, Yushchenko PV, Arkhipov DV, Wilkinson JA, Poyarkov NA (2021) Hidden tribe: a new species of stream toad of the genus Ansonia Stoliczka, 1870 (Anura: Bufonidae) from the poorly explored mountainous borderlands of western Thailand. Vertebrate Zoology 71: 763–779. https://doi.org/10.3897/vz.71.e73529

Talukdar A, Malhotra A, Lalremsanga HT, Santra V, Doley R (2023) Bungarus fasciatus venom from eastern and north-east India: Venom variation and immune cross-reactivity with Indian polyvalent antivenoms. Journal of Proteins and Proteomics 14: 61–76. https://doi.org/10.1007/s42485-022-00104-2

Tamura K, Stecher G, Kumar S (2021) MEGA11: Molecular evolutionary genetics analysis version 11. Molecular Biology and Evolution 38(7): 3022–3027. https://doi.org/10.1093/molbev/msab120

Taylor EH (1965) The serpents of Thailand and adjacent waters. The University of Kansas Science Bulletin 4: 609–1096.

The Office of Her Royal Highness Princess Maha Chakri Sirindhorn’s Projects (2005) Model scheme: the Suan Phueng Nature Education Park, initiated by Her Royal Highness Princess Maha Chakri Sirindhorn, Suan Phueng District, Ratchaburi Province, 2000–2004 (in Thai), 30 pp.

Trifinopoulos J, Nguyen LT, von Haeseler A, Minh BQ (2016) W-IQTREE: A fast online phylogenetic tool for maximum likelihood analysis. Nucleic Acids Research 44(W1): W232–W235. https://doi.org/10.1093/nar/gkw256

Uetz P, Freed P, Hosek J (2023) The reptile database. https://reptile-database.org [accessed 5 July 2023]

Wall F (1907) A new krait from Oudh (Bungarus walli). Journal of the Bombay Natural History Society 17: 608–611.

Wall F (1908) A popular treatise of the common Indian snakes. Journal of the Bombay Natural History Society 18: 711–735.

Wilcox TP, Zwickl DJ, Heath TA, Hillis DM (2002) Phylogenetic relationships of the dwarf boas and a comparison of Bayesian and bootstrap measures of phylogenetic support. Molecular Phylogenetics and Evolution 25(2): 361–371. https://doi.org/10.1016/S1055-7903(02)00244-0

Xie Y, Wang P, Zhong G, Zhu F, Liu Q, Che J, Shi L, Murphy RW, Guo P (2018) Molecular phylogeny found the distribution of Bungarus candidus in China (Squamata: Elapidae). Zoological Systematics 43(1): 109–117.

Yuan FL, Prigge TL, Sung YH, Dingle C, Bonebrake TC (2022) Two genetically distinct yet morphologically indistinct Bungarus species (Squamata, Elapidae) in Hong Kong. Current Herpetology 41(1): 114–124. https://doi.org/10.5358/hsj.41.114

Supplementary materials

Supplementary material 1

Samples used in the molecular analyses

Akrachai Aksornneam, Attapol Rujirawan, Yik-Hei Sung, Siriporn Yodthong, Anchalee Aowphol

Data type: pdf

Explanation note: Samples used in the molecular analyses, including their locality, voucher number and GenBank accession number.

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.

Download file (180.13 kb)

Supplementary material 2

Mean (minimum-maximum) percentages of uncorrected pairwise sequence divergences (p-distances) of Bungarus species compared to Bungarus sagittatus sp. nov.

Akrachai Aksornneam, Attapol Rujirawan, Yik-Hei Sung, Siriporn Yodthong, Anchalee Aowphol

Data type: pdf

Explanation note: Mean (minimum-maximum) percentages of uncorrected pairwise sequence divergences (p-distances) of Bungarus species compared to Bungarus sagittatus sp. nov., based on 1,137 aligned characters of the mitochondrial cytochrome b gene. Intraspecific p-distances are in bold font. Key: NA = data unavailable or not applicable.

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.

Download file (233.26 kb)

Supplementary material 3

Diagnostic morphological and color pattern characteristics distinguishing Bungarus sagittatus sp. nov. from other Bungarus species

Akrachai Aksornneam, Attapol Rujirawan, Yik-Hei Sung, Siriporn Yodthong, Anchalee Aowphol

Data type: pdf

Explanation note: Diagnostic morphological and color pattern characteristics distinguishing Bungarus sagittatus sp. nov. from other Bungarus species. Key: / = data unavailable or not applicable. Morphological abbreviations are defined in Methods.

This dataset is made available under the Open Database License (http://opendatacommons.org/licenses/odbl/1.0/). The Open Database License (ODbL) is a license agreement intended to allow users to freely share, modify, and use this Dataset while maintaining this same freedom for others, provided that the original source and author(s) are credited.

Download file (491.85 kb)