Zoosyst. Evol. 100 (1) 2024, 141-154 | DOI 10.3897/zse.100.116601 pg tuseue ror BERLIN 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!2 1 Animal Systematics and Ecology Speciality Research Unit, Department of Zoology, Faculty of Science, Kasetsart University, Bangkok 10900, Thailand 2 Biodiversity Center, Kasetsart University, Bangkok 10900, Thailand 3 Department of Biological Science, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand 4 School of Allied Health Sciences, University of Suffolk, 19 Neptune Quay, Ipswich, IP4 1QJ, UK https://zoobank. org/F 3 1F C865-S68 E-4A 74-8C4D-52DE7C37FF49 Corresponding author: Anchalee Aowphol (fsciacl@ku.ac.th) Academic editor: Justin Bernstein # Received 30 November 2023 # Accepted 15 January 2024 Published 30 January 2024 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, re- spectively; 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 report- ed, including B. candidus (Linnaeus, 1758), B. fasciatus (Schneider, 1801), B. flaviceps Reinhardt, 1843, B. slow- inskii Kuch, Kizirian, Nguyen, Lawson, Donnelly & Mebs, 2005 and B. wanghaotingi Pope, 1928 (Smith 1943; Tay- lor 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. candi- dus/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, Copyright Aksornneam, A. et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. 142 Ding & Shi, 2021 from Yunnan Province, China (Chen et al. 2021). Yuan et al. (2022) also investigated the molec- ular 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 1s located at Suan Phueng Dis- trict, 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 High- ness Princess Maha Chakri Sirindhorn’s Projects 2005; Pawangkhanant et al. 2018; Grismer et al. 2020b; Phut- thai et al. 2021). Recently, several new species of herpeto- fauna 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. Aksornneam, A. et al.: New species of Bungarus from western Thailand 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/multicinc- tus/wanghaotingi complex in color pattern. The combina- tion of morphological and molecular analyses revealed that the Ratchaburi specimens differed from all recognized Bun- garus species. Thus, we herein describe it as a new species. Methods Sampling Three Bungarus samples were collected during field sur- veys 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 ty > \ se by rN Ry r . i X i j Figure 1. Map showing the type locality of Bungarus sagittatus sp. nov. (orange star) in Khao Krachom, Suan Phueng District, Ratchaburi Province. zse.pensoft.net Zoosyst. Evol. 100 (1) 2024, 141-154 each specimen were collected using a Garmin GPSMAP 64*. Ambient air temperature and relative humidity were collected with Kestrel 4000 Weather Meter. The specimens were humanely euthanized using tricaine methanesulfon- ate (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 anal- ysis. 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 tis- sue samples were deposited in herpetological collection of Zoological Museum, Kasetsart University, Bangkok, Thai- land (ZMKU). An additional specimen was examined at herpetological collection of the Rabbit in the Moon Foun- dation (RIM), Suan Phueng District, Ratchaburi Province. DNA extraction and PCR amplification We extracted genomic DNA from liver tissue of three in- dividuals 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), us- ing the light strand primer L14910 (5’-AACCACCGTTG- TACATCAACT-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 sec- ond 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 am- plifications were carried out in a Mastercycler® nexus gra- dient 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 Pu- rification Kit (Qiagen, Germany). PCR products were se- quenced in both forward and reverse directions using the same amplifying primers at Biobasic Asia Inc. (Singapore) on an ABI 3730XL automatic sequencer (Applied Biosys- tems, CA, USA). Bidirectional sequences were visually checked and edited in Geneious Prime 2022.2.1 (Biomat- ters, 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 acces- sion numbers PP131180 to PP131182 (Suppl. material 1). Phylogenetic analyses Additional homologous cyt 6 sequences from 43 indi- viduals 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). 143 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 func- tion (Edgar 2004) with default setting in Geneious Prime 2022.2.1 (Biomatters, Ltd, Auckland, New Zealand). The aligned dataset was partitioned into three partitions (1s-3" cyt b codon positions). We used ModelFinder (Kalyaanamoorthy et al. 2017) to identify the best-fit model of sequence evolution for each partition as de- termined 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 6 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 CIP- RES Science Gateway V. 3.3 (Miller et al. 2010) with de- fault prior setting. Two independent runs, each with three heated and one cold chain, were performed using Me- tropolis-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 Fig- Tree 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 cal- ipers 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 mor- phometric 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 zse.pensoft.net 144 horizontal length of eye ball; distance between eyes (DE), was measured from the margin of upper eye contacting su- praocular 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; supralabi- als (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: Slow- inski 1994; Leviton et al. 2003; Kuch et al. 2005; Faiz et al. 2010; Cox et al. 2012, 2018; Chanhome 2013; Abtin 99/1 95/1 100/1 100/1 99/1 ZMKU R 01089 Bungarus s ZMKU R 01088 Bungarus sa ZMKU R 01090 Bungarus sa it MN165143 B. suzhenae Yunnan, China Aksornneam, A. et al.: New species of Bungarus from western Thailand 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 5 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 max- imum 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 sup- ported monophyletic lineage (100 UFB, 1.00 BPP) and nested within the genus Bungarus. The Ratchaburi pop- ulation was a strongly supported sister lineage (97 UFB, AY188016 Elapsoidea sundevallii DQ343648 Naja naja AJ749351_ B. flaviceps Malaysia AJ749306 8B. slowinskii Vietnam AY973270 B. bungaroides Tibet, China 0Q266796 B. fasciatus Mizoram, India 97/1] OQ266797 B. fasciatus Mizoram, India AJ749349 8B. fasciatus Java, Indonesia AJ749350 B. fasciat va, Indonesia MN165141 B. suzhenae Yunnan, China 97/1 100/1 51/0.51~ 20/ - - 70/0.62 91/1 81/0.64 95/0.99 0.07 substitution/site 100/1 MN165140 B. suzhenae Yunnan, China MN165142_B. suzhenae Yunnan, China AJ749345 B. suzhenae Myanmar AJ749304 B. niger Nepal MW596473 8B. niger Mizoram, India MW596474 B. niger Mizoram, India AJ749346 B. sindanus Pakistan MW596472 B. lividus Meghalaya, India KC347457 B. ceylonicus Sri Lanka 91/0.94-~~ AJ749305 B. caeruleus Pakistan MN165135._ B. multicinctus Hainan, China MN165139 B. multicinctus Fujian, China MN165138 8B. multicinctus Fujian, China AJ565002 8B. multicinctus Captive AJ749344 8B. multicinctus Zhejiang, China MN165136 8B. multicinctus Guangxi, China MN165137 B. multicinctus Guangxi, China 98/1 MN165133 8. candidus Johor, Malaysia AJ749339 B. candidus Bali, Indonesia AJ749341 B. candidus Java, Indonesia AJ749329 B. candidus Java, Indonesia AJ749337 B. wanghaotingi Laos AJ749336 B. wanghaotingi Thailand AJ749331 B. wanghaotingi Thailand AJ749308 B. wanghaotingi Vietnam AJ749309 B. wanghaotingi Vietnam MN165132 B. wanghaotingi Thailand AJ749338 B. wanghaotingi Laos KY952766 B. wanghaotingi Yunnan, China MN165146 B. wanghaotingi Yunnan, China MN165145 B. wanghaotingi Yunnan, China MN165144 B. wanghaotingi Yunnan, China 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. zse.pensoft.net Zoosyst. Evol. 100 (1) 2024, 141-154 1.00 BPP) to a clade containing B. caeruleus (Schneider, 1801), B. candidus/multicinctus/wanghaotingi complex, B. ceylonicus Gunther, 1864, B. lividus Cantor, 1839, B. niger Wall, 1908, B. sindanus Boulenger, 1897 and B. suzhenae. However, the relationships among the In- dian subcontinent clade (B. caeruleus, B. ceylonicus, B. lividus, B. niger and B. sindanus), B. candidus/mul- ticinctus/wanghaotingi complex clade and B. suzhenae were not resolved representing as a polytomy. Uncor- rected pairwise genetic divergences (p-distances) among Bungarus species ranged from 1.77—20.46% (Suppl. ma- terial 2). The uncorrected p-distances between Ratchabur1 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%. 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/F 19C3493-FA00-4F4A-A9B1-4A39B5C5FFOA Figs 3-5 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 Naiduang- chan, Kritsada Rungrot, Purinut Numuan, Suphap Sisuk and Goe Wongdee. Paratypes (Figs 4, 5A-D). ZMKU R 01088 (sub- adult 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 Aksorn- neam and Naka Taou. Referred specimen (Fig. 5E, F). RIMO0012 (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 po- sition and having enlarged, hexagonal-shaped, midbody vertebrae scales (Smith 1943; Slowinski 1994). This spe- cies can be distinguished from other species of Bungarus 145 by the following combination of characters: 15—15—15 dorsal scale rows; 215—217 ventral scales; 48-56 undi- vided subcaudal; prefrontal suture 2.4—2.6 times length of internasal suture; anterior chin shields larger than poste- rior chin shields; head of adult uniform black while juve- nile 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 |.5—3.0 and 4.5—6.0 vertebral scales, respective- ly; 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. A-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 post- nasal 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, prefron- tals 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 posto- cular, parietal, frontal and prefrontal. Parietals large and long, 2 times longer than wide, 1.6 times longer than fron- tal 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 postocu- lar, 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 bor- dering 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 zse.pensoft.net 146 Aksornneam, A. et al.: New species of Bungarus from western Thailand Figure 3. Holotype of Bungarus sagittatus sp. nov. (ZMKU R 010839) in preservation. A. Lateral view; B. Dorsal view and C. Ven- tral view; D. Dorsal view; E. Ventral view. Scale bars: 20 mm. preoculars; on right side, lower postocular bordered by orbit, fourth and fifth supralabials, anterior temporal, pa- rietal and upper postocular; on left side, lower postocular bordered by orbit, fourth and fifth supralabials, anterior temporal and upper postocular; on right side, upper pos- tocular 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 subhexag- onal-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 supral- abials, lower posterior temporal, upper posterior temporal and parietal. Posterior temporals 2/2 surrounded by pari- etals, anterior temporals, sixth and seventh supralabials and dorsal scales. Supralabials 7/7, the third and fourth su- zse.pensoft.net pralabials touching lower margin of orbit: first supralabi- als small, subtriangular, 1.2 times wider than height; other supralabials in different pentagonal shapes; second supra- labials 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; sev- enth 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 pentago- nal-shaped, long and narrow, 1.6 times longer than wide, in contact behind the mental and anterior chin shields; sec- ond infralabials square-shaped, one-third size of the first, 2.1 times longer than wide, in contact with anterior chin Zoosyst. Evol. 100 (1) 2024, 141-154 147 Figure 4. Paratypes in life showing the variation in different age class. A. Subadult female (ZMKU R 01088); B. Juvenile (ZMKU R 01090). shields; the third infralabials enlarged, in contact with an- terior 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 in- fralabial, 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 su- ture 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 near- ly immaculate creamy white. The white bands cover 0.5 to 2.0 times vertebral scales (average 1.5+0.4, n= 26; 1.5 ver- tebral scales at midbody), bands widening on flanks before merging with the immaculate creamy white ventral scales. The first white band starts at 16" ventral, 11 vertebral scales between first and second bands and five vertebral scales be- tween 25" and 26" bands. A dark spot is present at the junc- tion between white bands and ventral scales at midbody po- sitions. 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. zse.pensoft.net 148 Aksornneam, A. et al.: New species of Bungarus from western Thailand Figure 5. Paratypes and referred specimen in preservation. A. Dorsal and B. Ventral view of subadult female (ZMKU R 01088); C. Dor- sal and D. Ventral view of juvenile (ZMKU R 01090); E. Dorsal and F. Ventral view of subadult male (RIM00012). Scale bars: 20 mm. zse.pensoft.net Zoosyst. Evol. 100 (1) 2024, 141-154 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 dor- sum 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 varia- tions in measurements, meristics and color pattern among the type series and referred specimen are shown in Table 1. 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 RIMO00012) were collected in hill ev- ergreen forest (834 m to 987 m elevation; Fig. 6) between 149 2050 and 2210 h with air temperature 24.1 °C and relative humidity 91.7%. One juvenile (ZMKU R 01090) was col- lected 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). The new species was found sympatrically with other snake species such as Ahaetulla prasina (Boie, 1827), Boiga cyanea (Dumeéril, Bibron & Dumeril, 1854), Coelo- gnathus flavolineatus (Schlegel, 1837), Gonyosoma oxy- cephalum (Boie, 1827), Lycodon ophiophagus Vogel, Da- vid, Pauwels, Sumontha, Norval, Hendrix, Vu & Ziegler, 2009, Ptyas carinata (Gunther, 1858), Rhabdophis chrys- argos (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 dis- tinguished 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 Table 1. Descriptive measurement (millimeters), meristics (left/right) and color pattern of Bungarus sagittatus sp. nov. Morpholog- ical abbreviations are defined in Methods. Character ZMKUR01089 ZMKURO1088 ZMKUR0O1090 RIMO00012 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 I e2 8.1 12.6 HH 10v7 7.0 525 9.0 ED 2:6 2.1 1.8 2 DE 9.2 6.7 4.6 74 IS 1.6 V2 0.8 133 PS 4.1 2.9 1.9 Se Tal/TL 0.143 0.143 0.140 0.143 PS/IS 2.56 2.42 2.38 2.46 Meristics SE 7/71 Tfi 7/1 7/1 IL 7/1 Ly 7/1 Ti DSR 15/15/15 Reva Reva lc; 15/15/15 15/15/15 VS 216 215 216 2VF 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 Vertebral scales covered by white bands at midbody 1.5 scales Vertebral scales covered by black bands at midbody 6.0 scales Black with small dim Black with small dim white patches 3.0 scales 5.5 scales white patches 1.5 scales 6.0 scales Uniform black 1.5 scales 4.5 scales zse.pensoft.net Figure 6. Habitat of Bungarus sagittatus sp. nov. A. Macrohab- itat 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 lo- cality, in hill evergreen forest at 1,049 m elevation. Red arrows indicate the tail part of skink. 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. bunga- roides by having 215—217 ventral scales (vs. 220-237), zse.pensoft.net Aksornneam, A. et al.: New species of Bungarus from western Thailand TaL/TL 0.140-0.143 (vs. 0.114~-0.130); subcaudals undi- vided (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. caeru- leus (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 in- ternasal 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 verte- bral 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 intrud- ing 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 ven- trals 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. slight- ly 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. mag- nimaculatus Wall & Evans, 1901 by having 48—56 sub- caudals (vs. 40-48); TaL/TL 0.140-0.143 (vs. 0.115); Zoosyst. Evol. 100 (1) 2024, 141-154 and 25-31 narrow white body bands (vs. 11—14 broad white bands). Bungarus sagittatus sp. nov. differed from B. multicinc- tus 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 ven- trals less than 0.5 times of width of outer dorsal scales (vs. 1.22.0 times); ventral surface of body tmmaculate white (vs. white with dense brown pigments); and ventral sur- face of tail creamy white with a row of dark brown triangu- lar 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 Ab- tin, 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); lo- real 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. s/owinskii 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 irreg- ular yellowish white pattern). Bungarus sagittatus sp. nov. differed from B. suzhe- nae by having prefrontal suture 2.4—2.6 times of interna- sal 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. wangha- otingi by having TaL/TL 0.140—0.143 (vs. 0.114—0.132); dorsal body black bands not intruding ventrals or intrud- ing ventrals less than 0.5 times of width of outer dorsal scales (vs. 0.5—1.5 times); head of juvenile black with 151 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. arow 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/wanghaotin- gi complex, but phylogenetic analyses revealed that the new species 1s 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 Knier- im 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 ven- om composition ts 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 need- ed 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 rep- tiles, 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 zse.pensoft.net 152 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 re- search. Parinya Pawangkhanant, Mali Naiduangchan, Pat- tarawich 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. 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Current Herpetology 41(1): 114-124. https://doi.org/10.5358/hsj.41.114 Supplementary material | Samples used in the molecular analyses Authors: Akrachai Aksornneam, Attapol Rujirawan, Yik- Hei Sung, Siriporn Yodthong, Anchalee Aowphol Data type: pdf Explanation note: Samples used in the molecular analy- ses, including their locality, voucher number and Gen- Bank accession number. Copyright notice: 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 us- ers 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. Link: https://do1.org/10.3897/zse.100.116601.suppl1 zse.pensoft.net Aksornneam, A. et al.: New species of Bungarus from western Thailand Supplementary material 2 Mean (minimum-maximum) percentages of uncorrected pairwise sequence divergences (p-distances) of Bungarus species compared to Bungarus sagittatus sp. nov. Authors: Akrachai Aksornneam, Attapol Rujirawan, Yik- Hei Sung, Siriporn Yodthong, Anchalee Aowphol Data type: pdf Explanation note: Mean (minimum-maximum) percent- ages of uncorrected pairwise sequence divergences (p-distances) of Bungarus species compared to Bun- garus sagittatus sp. nov., based on 1,137 aligned char- acters of the mitochondrial cytochrome b gene. Intra- specific p-distances are in bold font. Key: NA = data unavailable or not applicable. Copyright notice: 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 us- ers 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. Link: https://doi.org/10.3897/zse.100.116601.suppl2 Supplementary material 3 Diagnostic morphological and color pattern characteristics distinguishing Bungarus Sagittatus sp. nov. from other Bungarus species Authors: Akrachai Aksornneam, Attapol Rujirawan, Yik- Hei Sung, Siriporn Yodthong, Anchalee Aowphol Data type: pdf Explanation note: Diagnostic morphological and color pattern characteristics distinguishing Bungarus sagit- tatus sp. nov. from other Bungarus species. Key: / = data unavailable or not applicable. Morphological ab- breviations are defined in Methods. Copyright notice: 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 us- ers 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. Link: https://doi.org/10.3897/zse.100.116601.suppl3