Oligodon albocinctus ( Cantor, 1839 )

Oligodon albocinctus ( Cantor, 1839) View in CoL

Figs. 1–2 View FIGURE 1 View FIGURE 2 , 5–10 View FIGURE 5 View FIGURE 6 View FIGURE 7 View FIGURE 8 View FIGURE 9 View FIGURE 10

Coronella albocincta Cantor T. E. 1839: 50 , In: Spicilegium serpentium indicorum [part 2]. Proceedings of the Zoological Society of London , part. 7 (1839), 49–55. Holotype. Lost (see below), depicted in watercolor sketch in “ Indian Serpents– Innocuous –Collected, figured & described (1831–1837) ” archived in the Bodleian Library, Oxford University [Type Locality: “Chirra Púnji, Asám ” (=Cherrapunji, East Khasi Hills District, Meghalaya, India)] ( Fig. 1A View FIGURE 1 ).

Xenodon purpurascens View in CoL ( nec Xenodon purpurascens Schlegel, 1837 View in CoL ).— Cantor 1847: 914; Blyth 1854: 289–290.

Coronella puncticulatus Gray, J. E. 1853: 389 View in CoL , In: Descriptions of some undescribed species of reptiles collected by Dr. Joseph Hooker in the Khassia mountains , East Bengal, and Sikkim Himalaya. Annals and Magazine of Natural History, including Zoology, Botany, and Geology, Series 2, 12, 386–392. Holotype. NHMUK 1946.1 About NHMUK .4.26 [Type Locality: “Khasiya” (=Khasi Hills, Meghalaya, India)].

Simotes purpurascens var. D.—Günther 1858: 25.

Simotes purpurascens var. E.—Günther 1858: 25.

Simotes punctulatus [sic].— Günther 1864: 217; Theobald 1868b: 47; Anderson 1871: 33; Theobald 1876: 152

Simotes albocinctus View in CoL . — Theobald 1868b: 47; Theobald 1876: 153; Boulenger 1890: 312; Sclater 1891: 23; Boulenger 1894: 220; Evans 1905: 169–170; Wall 1909: 348; Wall 1910: 898; Venning 1910: 338; Annandale 1912: 48; Wall 1914: 756–761, pl. 20.

Simotes albocinctus var. juglandifer View in CoL . Wall F. 1909: 349, In: Notes on snakes from the neighbourhood of Darjeeling. Journal of the Bombay Natural History Society, 19(2), 337–357 + 1 pl. Lectotype. BNHS 814 View Materials A [= BNHS 210 View Materials ] [Type Locality: “ Tindharia , Durjeeling ” (= Tindharia Estate, Darjeeling District, West Bengal, India)].

Simotes juglandifer View in CoL . — Wall 1911: 1163; Wall 1914: 756 (in part).

Oligodon albocinctus View in CoL . — Wall 1923a: 326; Wall 1923b: 631; Wall 1925: 815; Wall 1926: 563; Smith 1943: 211; Constable 1949: 129; Acharji & Kripalani 1950: 97; Swan & Leviton 1962: 114; Deoras 1965: 87; Deoras 1970: 85; Wagner 1975: 65 (in part); Deoras 1977: 95; Kramer 1977: 743; Zhao et al. 1977: 69; Whitaker 1978: 113; Majupuria 1982: 163–164, 176; Daniel 1983: 84, pls. 4–6 (pg. 79); Mahendra 1984: 200 (treats O. juglandifer View in CoL as synonym); Yang & Inger 1986: 3; Dowling & Jenner 1988: 5; Welch 1988: 78; Zhao & Adler 1993: 243, 312; Mathew 1992: 288; Mathew 1995: 452; Singh 1995: 136; Zhao & Yang 1997: 234; Zhao et al. 1998: 193; Iskandar & Colijn 2001: 70; Shrestha 2001: 31, 173; Daniel 2002: 102; Jha & Thapa 2002: 39; Schleich & Kästle 2002: 85, 446 (Plate 95, Figs. 283–285), 477 (pl. 126, Fig. 372), 892–894 (treats O. juglandifer View in CoL as a junior synonym), 1064; Ao et al. 2004: 158; Whitaker & Captain 2004: 23, 160–161; Borang et al. 2005: 21; Zhao et al. 2005: 252, pl. 2; Zhao 2006: 223 (vol. 1), 162–163 (vol. 2); Sharma 2007: 156; Laltanpuia et al. 2008: 118; Yang & Rao 2008; Mitra 2009: 16–17, Fig. 2A View FIGURE 2 ; Agarwal et al. 2010: 83, 85; Green 2010: vii, 7, 86, 156, Fig. 1.3 View FIGURE 1 ; Green et al. 2010: 3; Murthy 2010: 36, 331; David et al. 2011: 2, 11; Lalremsanga et al. 2011: 266; Purkayastha et al. 2011: 197; Wangyal 2011: 121; Zhang et al. 2011: 428; Bhupathy et al. 2013: 184; Hasan et al. 2013: 77–80; Kästle et al. 2013: 307, 509, Fig. 121; Rahman et al. 2013: 46; Lalremsanga et al. 2014: 210, 213 (Fig. 23); Wallach et al. 2014: 493; Wangyal 2014: 23; Ahsan et al. 2015: 8162; Das et al. 2016: 24–27, Figs. 1–2 View FIGURE 1 View FIGURE 2 ; Harit 2018: 135–136; Lalronunga et al. 2018: 37–38; Purkayastha 2018: 12306, 12308 (Image 36); Che et al. 2020: Appendix 2 (R30-1.); Hakim et al. 2020: 1258–1259 View Cited Treatment , Fig. 9C View FIGURE 9 ; Hmar et al. 2020: 823, Fig. 3A View FIGURE 3 ; Purkayastha et al. 2020a: 221; Purkayastha et al. 2020b: 228, 231 ( Fig. 4 View FIGURE 4 ); Wang et al. 2020: 13; Khan et al. 2021; Sinha et al. 2021: 414, pl. 2; Wangyal & Das 2021: 67; Huang 2023: 478–479; Mahananda et al. 2023: 23038; Basfore et al. 2024a: 1–2; Basfore et al. 2024b: 26135; Lee et al. 2024: 7 ( Fig. 2 View FIGURE 2 ), 9, 12, 15; Patel et al. 2025: 143; Thapa et al. 2025: 4, 6 ( Fig. 4I View FIGURE 4 ).

Oligodon juglandifer View in CoL . — Wall 1923a: 327; Wall 1923b: 630; Smith 1943: 207; Deoras 1965: 87; Deoras 1970: 85; Wagner 1975: 65 (in part); Deoras 1977: 95; Whitaker 1978: 113; Welch 1988: 81; Schleich & Kästle 2002: 125; Sharma 2007: 156; Mitra 2009: 17; Green 2010: 112, 156; David et al. 2011: 1, 11; Wallach et al. 2014: 498; Wangyal 2014: 23; Sapkota & Sharma 2017: 590; Chandramouli et al. 2021: 19608; Das et al. 2021; Wangyal & Das 2021: 69; Wangyal et al. 2022: 6; Lee et al. 2024: 15; Patel et al. 2025: 143.

Holarchus albocinctus . — Pope 1935: 289.

Oligodon sp. — Wangyal 2011: 121; Zhang et al. 2011: 428 (later recognized as Oligodon lipipengi View in CoL ); Wangyal 2014: 23.

Oligodon cyclurus View in CoL ( nec Coronella cyclura Cantor, 1839 View in CoL ).— Lalremsanga et al. 2011: 26135; Das et al. 2016: 30, Figs. 1 View FIGURE 1 , 5 View FIGURE 5 ; Hakim et al. 2020: 1259 View Cited Treatment (also recorded true O. cyclurus View in CoL ); Hmar et al. 2020: 823, Fig. 3C View FIGURE 3 ; Kalita et al. 2020: 150; Lee et al. 2024: 7 ( Fig. 2 View FIGURE 2 ; unpublished GenBank sample MN418884.1 originally identified as O. cyclurus View in CoL ).

Oligodon lipipengi Jiang K., Wang Y., Li, C., Ding, X., Ding, L., & Che J. 2020: 701 View in CoL , In: Che J., Jiang K., Yan, F., & Zhang Y.-P. ( Eds.) Amphibians and Reptiles in Tibet — Diversity and Evolution. Science Press, Beijing, 701–705 pp. Holotype. KIZ 011055 View Materials [Type Locality: Beibeng, Medog County, Tibet ( Xizang Autonomous Region   GoogleMaps ) ( 29.239° N, 95.176° E, 680 m elevation)].

Oligodon lipipengi View in CoL . — Che et al. 2020: Appendix 2 (R30-1.); Xu et al. 2021: 2 ( Fig. 1 View FIGURE 1 ); Huang 2023: 496–497; Lee et al. 2024: 9, 15 (recovered paraphyly with O. albocinctus sensu lato); Patel et al. 2025: 143 (in part, synonymizes name under O. juglandifer View in CoL ).

Oligodon chinensis View in CoL ( nec Simotes chinensis Günther, 1888 View in CoL ).— Wangyal et al. 2020: 796; Wangyal et al. 2022: 6.

Oligodon cf. cyclurus View in CoL . —Biakzuala et al. 2023: 142.

Oligodon albocinctus View in CoL clade 1.— Lee et al. 2024: 7 ( Fig. 2 View FIGURE 2 ).

Holotype. Adult from “Chirra Púnji, Asám ” [=Cherrapunji, East Khasi Hills District , Meghalaya, India] ( Cantor 1839) ( Fig. 1A View FIGURE 1 ). Specimen depicted in a watercolor illustration housed in the Bodleian Library, Oxford University, drawn as part of Theodore Cantor’s unpublished manuscript “ Indian Serpents–Innocuous –Collected, figured & described (1831–1837) ”. The holotype is drawn in a coiled position across a branch. The head and body are depicted in dorsal profile showing the head scalation and banded color pattern. The remaining body and tail depict the ventral surface. Ten pages of handwritten notes accompany the drawing, which include a brief Latin diagnosis and a larger section in English. A digitized version of Cantor’s description is provided in Appendix 4, and the watercolor sketch is reproduced in Fig. 1A View FIGURE 1 .

The specimen mentioned by both Cantor (1839) and his unpublished manuscript has not been traced and is considered lost. The holotype Cantor based his illustration from was obtained by a “Mr. Grant” (Appendix 4). This probably refers to John William Grant (1788–1865), an astronomer and public servant of the British East India Company who Cantor (1839) mentioned as a donor of specimens from Cherrapunji. It is presumed that the specimen obtained by Grant was collected earlier than 6 May 1836, as this is the date mentioned below the watercolor sketch of the holotype (Appendix 4). Wallach et al. (2014) considered the specimen figured in Cantor’s unpublished illustration of Coronella albocincta to be the lectotype, citing Smith (1943) as the designating author. Smith (1943) does mention the Bodleian Library sketch in his account of O. albocinctus , and Kramer (1977) designated the Bodleian Library plate as the lectotype, which would satisfy the stipulations for lectotype designation under the edition of the Code used at that time (Article 74 of Anonymous 1964). However, the original description of Coronella albocincta ( Cantor 1839) makes no indication that more than one specimen was involved, so the designation by Kramer (1977) cannot be considered valid. The unpublished notes on Coronella albocincta in “ Indian Serpents ” does indicate Cantor examined additional individuals from “ Assam ” collected by naturalist William Griffith (1810– 1845) (Appendix 4), but Cantor’s manuscript cannot be considered a published work under Article 8.1 of the Code. Because of this, the specimen depicted in the Bodleian library sketch should be considered the holotype ( Fig. 1A View FIGURE 1 ), not the lectotype. We note that Cantor (1839, plus handwritten notes) stated the holotype had 65 subcaudal scales, but the specimen depicted in the illustration has approximately 49 paired scales ( Fig. 1A View FIGURE 1 ).

For completion, we also include a transliteration of the handwritten description (Appendix 5) and figure the digitized watercolor sketch of Coronella cyclura ( Oligodon cyclurus ) ( Fig. 1B View FIGURE 1 ), which has been taxonomically confused with the blotched morphotype of O. albocinctus described herein.

Referred material ( N = 138). Refer to Appendix 2 for a full list of specimens we refer to Oligodon albocinctus , including directly examined specimens and material from the literature.

Diagnosis. A moderate to large sized Oligodon with a relatively long tail and high variation in body and head scalation. Maximum total length 916 mm, relative tail length 0.135 –0.227 ( 0.154 –0.227 in males, 0.135 –0.215 in females). Dorsal scales normally 19–19–15 rows, all smooth. Ventral scales 174–207 ( 174–200 in males, 180–207 in females) without distinct keeling; cloacal plate undivided; subcaudal scales 47–70, paired; total body scales 235–264; subcaudal ratio 0.194 –0.275 ( 0.206 –0.275 in males, 0.194 –0.261 in females). Maxillary teeth 8–12. Loreal normally present (exceptionally absent due to fusion with prefrontal), preocular 1/1, presubocular normally absent (exceptionally two preocular scales or one presubocular), postoculars 2/2 (exceptionally three); temporals 1+2 (exceptionally 2+2 on one side of head). Supralabials 7 (rarely 6–8) with the third and fourth scale normally in contact with eye (rarely 4+5 or 2+3, exceptionally third or fourth scale only). Infralabials 9–10 (rarely 7–8), with 4–5 scales in contact with anterior pair of chin shields (exceptionally 3 or 6).

Dorsal color pattern variable, characterized into two morphotypes. Typical morph red or reddish brown, larger specimens may be brown to dusky gray ( Figs. 5–6 View FIGURE 5 View FIGURE 6 ). Dorsal surface with a series of white, tan or yellow bands, their margins edged with black forming a tricolored pattern. Blotched morphotype gray-brown or brown, dark brown crossbands or blotches across body and tail, each edged with black ( Figs. 7–9 View FIGURE 7 View FIGURE 8 View FIGURE 9 ). Size and shape of blotches variable, ranging from narrow crossbars to broad oval-shaped spots. In both morphotypes, number of bands/blotches range from 16–26 on body to 4–9 on tail (total = 20–33). Interspace between each band/blotch 6–9 vertebral dorsal scales long at midbody. First band/blotch begins between ventral scale 7–19. Ventral surface typically plain white to cream, occasionally hued with red pigment in life. Small dark brown or black rectangular blotches on lateral margins of ventral scales. In adults, ventral surface typically darkens posteriorly from cream to dark gray until cloacal region. Underside of tail plain, rectangular spots present anteriorly. Hemipenis bilobed, sulcus spermaticus simple, proximal third calyculate, remaining two-thirds and apices of lobes broad, subtriangular and covered with horizontal rows of flounces ( Fig. 10 View FIGURE 10 ). Detailed comparisons with other chromatically similar species are provided in the discussion section.

General description and variation. SVL 151–784 mm, TailL 31–175 mm, TotalL 185–916 mm. The largest specimen is an adult female (CAS 221529) measuring 784 mm SVL and 132 mm TailL. The largest male specimen (KIZ 19520) measured 730 mm SVL and 170 mm TailL. HeadL 10.4–25.1 mm, HeadW 5.2–17.4 mm, SnL 3.5–7.7 mm, SnW 2.3–6.6 mm, EyeD 1.7–3.6 mm, FrontalL 3.8–6.7 mm, FrontalW 2.9–6.0 mm, InterorbD 4.0– 9.2 mm. TailLR 0.135 –0.227 ( x̄ = 0.180 ± 0.024, N = 124), in males 0.154 –0.227 ( x̄ = 0.196 ± 0.015, N = 70), in females 0.135 –0.215 ( x̄ = 0.159 ± 0.015; N = 54).A single specimen reported by Yang & Rao (2008) had an abnormally short relative tail length of 0.106 (KIZ 74I006) but was excluded from statistical analyses as it is uncertain whether tail may have been broken or not. HeadW/L 0.45–0.79, SnL/HL 0.28–0.43, EyeD/SnL 0.39–0.56 (one outlier, MZMU untagged 12, has a ratio of 0.72), EyeD/HeadL 0.12–0.22, FrontalL/W 1.01–1.39. Sexual dimorphism was recorded for relative tail length (TailLR).

Dorsal scales smooth, scale row formula normally 19–19–15, rarely 19–19–17 ( N = 8). Some specimens may have 21 anterior scale rows before one head length (e.g., MZMU 2831, reduction from 21 to 19 scale rows occurs at 14 th ventral). One specimen reported by Das et al. (2016) as O. cyclurus had 19–17–15 scale rows (AD/ AS 33). Yang & Rao (2008) recorded one specimen (KIZ 2003114) from Yunnan Province, China with 17–19–15 dorsal scale rows. Reduction from row 19 to 17 at ventral scale 85–127 (0.46–0.67 of ventrals), 17 to 15 at ventral scale 114–190 (0.64–0.95 of ventrals). Ventral scales 174–207 ( x̄ = 189.9 ± 7.3; N = 134), in males 174–200 ( x̄ = 186.5 ± 6.5; N = 73), in females 180–207 ( x̄ = 193.9 ± 6.1; N = 61), no distinct keeling. Subcaudal scales 47–70 ( x̄ = 58.1 ± 6.3; N = 124), in males 52–70 ( x̄ = 62.8 ± 3.3; N = 70), in females 47–64 ( x̄ = 52.2 ± 3.4; N = 54), all paired. Cloacal plate undivided. Total body scales 235–264 ( x̄ = 248.2 ±7.4; N = 124). Subcaudal ratio 0.194 –0.275 ( x̄ = 0.234 ± 0.023; N = 124), in males 0.206 –0.275 ( x̄ = 0.251 ± 0.012; N = 70), in females 0.194 –0.261 ( x̄ = 0.212 ± 0.012; N = 54). Sexual dimorphism was only recorded for ventral scale counts and subcaudal ratio values.

Maxillary teeth 8–12 ( N = 27). Anteriormost teeth small, gradually enlarged in size posteriorly. Last two or three teeth greatly enlarged relative to remaining maxilla, with a sharp, narrow carina running across the posterolateral edge. Palatine teeth 6/7 (CAS 221511) to 9/9 (CAS-SUR 12408) based on CT-scans, with an anterior edentulous space around one or two tooth sockets in length present. Pterygoid teeth 15/14 (CAS 221511) 16/16 (CAS-SUR 12408) based on CT-scans, no edentulous space present. Dentary teeth 15/16 (CAS 221511), 16/16 (CAS-SUR 12408). Unpublished tooth count data taken by F. W. Wagner were for palatine teeth 6–9 ( N = 20), pterygoid teeth 14–20 ( N = 20), and dentary teeth 14–18 ( N = 17). Wall (1911, 1923a) gave the following tooth counts from his specimens: for palatine teeth 6–10, pterygoid teeth 16–23, and dentary teeth 13–18.

Head scalation variable, rare or exceptional counts noted separately. Rostral height/width equal, posterior suture bordering internasals obtuse angled forming a gull-wing or deep V-shape dorsally (108–121º). Nasal subpentagonal, normally divided above and below nostril, longer than high, anterior suture higher than posterior suture. One specimen has an entire nasal on one side of the head (MZMU 2831). In most cases nasal in contact with rostral, internasal, prefrontal, loreal, and first to second supralabial. Internasals paired, trapezoidal, entire scale wider than long and wider than length of median suture. Anterior and posterior internasal sutures straightened or weakly concave. Each internasal contacts prefrontal, rostral, and nasal. Prefrontals paired, subhexagonal, entire scale wider than long, wider than length of median suture. Median suture of prefrontals longer than median suture of internasals. Each prefrontal contacting internasal, nasal, loreal, preocular, supraocular and frontal. Supraoculars subrectangular, longer than wide, in contact with preocular, prefrontal, frontal, uppermost postocular, and parietal. Posterior supraocular suture wider than anterior suture. Frontal pentagonal, shield shaped, longer than median parietal suture. Anterior frontal suture positioned in front of eye sockets. Posterior vertex of frontal bordering parietals acute to weakly obtuse angled (82–102º). Parietals paired, subpentagonal, entire scale longer than wide and longer than frontal, median suture longer than scale width. Anterior suture bordering frontal and supraoculars straight, obtuse angled (127–140º), its ray oriented laterally. Posterior suture of each parietal slightly bent. 7–9 scales (excluding postoculars) surround parietals.

Loreal usually 1/1, square, height and width equal, posterior suture higher than anterior suture. Loreal contacts nasal, preocular, prefrontal and third supralabial. Loreal in six specimens from Mizoram State, India fused with the prefrontal on both sides on the head ( MZMU untagged 12, MZMU 90 L, MZMU 951 , MZMU 1208 , MZMU 1302 , MZMU 1905 ). Exceptionally one specimen with two loreals on left side of head ( MZMU 943 ) . Preocular normally 1/1, rectangular, higher than long. Exceptionally 2/2 preoculars on both sides of head in three specimens ( NHMUK 1853.8 About NHMUK .12.31 (A), NHMUK 1908.6 About NHMUK .23.35, and BNHS 835 View Materials fide Patel et al. 2025), one specimen each with 1/2 ( CIB 9898 View Materials ) and 2/1 scales ( NMHW 25818 :1). All but one specimen lacks a presubocular scale, but 1/ 1 in one specimen from Mizoram State, India ( MZMU 2836 [SE 29]). Postoculars normally 2/2, subrectangular, uppermost scale slightly larger than lowermost. Exceptionally 1/1 postoculars due to fusion between both scales ( NHMUK 1870.11 About NHMUK .30.17, NHMUK 1870.11 About NHMUK .30.19 [A]), or 1/2 scales ( NHMUK unnumbered specimen). Temporal formula normally 1+2, uppermost posterior temporal longer than lowermost. Exceptionally two anterior temporals on left side of head in three specimens from Medog County, China ( CIB unnumbered specimen, CIB 9898 View Materials , SYS r001827), one posterior temporal in three specimens ( BNHS 814 View Materials A, MZMU 943 , NHMUK 1870.11.30.9) .

Supralabials 6–8, normal condition 7/7. Four specimens with 6/6 supralabials ( NHMUK 1858.6 About NHMUK .24.2, 1870.11.30.17, NHMUK 1880.11 About NHMUK .10.138, NHMUK 1891.9.11.17), two specimens with 6/7 ( MZMU 973 , NHMUK 1860.3.10.1431), another with 7/6 ( CAS 233187 About CAS ) . Other supralabial combinations include 8/ 8 in two specimens ( NHMUK 1908.6 About NHMUK .23.33, MZMU 2827 ), 7/8 ( CAS 221529 About CAS ) and 8/6 ( MZMU 3045 ) . In most cases the third and fourth (3+4) supralabials contact the eye. The fourth and fifth supralabial (4+5) contact the eye on both sides of the head in two specimens ( MZMU 2827 , NHMUK 1908.6.23.33), the left side of head in NMHW 25817 :5 (4+5/3+4), and the right side of head in CAS 221529 About CAS (3+4/4+5). Exceptionally, one individual ( MZMU 3045 ) has supralabials 4+5/2+ 3 in contact with the eye, and two others have a single supralabial scale contacting the eye on one side of the head (3/3+ 4 in MZMU 973 ; or 3+4/ 4 in MZMU 1209 ). Infralabials 7–10, most frequent combinations either 8/8 ( N = 51) or 9/9 ( N = 50), rarely 8/9 ( N = 13) or 9/8 ( N = 8). Four specimens with 7/8 infralabials ( CIB 9894 View Materials , CIB 9897 View Materials , MZMU 2826 , MZMU untagged specimen 10), one with 8/7 ( MZMU 943 ) , two specimens with 7/7 ( MZMU untagged specimen 12, NHMUK 1913.5.22.4). Three additional specimens with 10/9 infralabials ( MZMU 2412 , MZMU 2827 , NHMUK 1908.6.23.34). First 3–6 infralabials contact anterior chin shields, normally 4/4 ( N = 70) or 5/5 ( N = 55), rarely 4/5 ( N = 4) or 5/4 ( CIB 9896 View Materials , NMHW 25817 :3). Exceptionally 3/ 4 in one specimen ( CIB 9894 View Materials ) or 6/ 5 in two specimens ( MZMU 2412 , MZMU 2827 ) . First pair of infralabials contact medially. Mental scale triangular, wider than long. Anterior chin shields rectangular, longer than wide. Posterior chin shields smaller than anterior, each shield in contact at midline for one-half to three-quarters their length, suture bordering gular scales concave. Poorly defined mental groove present between first infralabials and both pairs of chin shields.

Dorsal color pattern may be characterized into two morphotypes: a typical banded morph ( Figs. 5–6 View FIGURE 5 View FIGURE 6 ), and a blotched morph where dorsal markings are arranged as blotches or crossbars ( Figs. 7–9 View FIGURE 7 View FIGURE 8 View FIGURE 9 ). Traits that apply to both morphotypes are described first. Across all specimens, the number of bands, crossbars or blotches range from 16–26 on body ( x̄ = 22.0 ± 2.1, N = 101) to 4–9 on tail ( x̄ = 5.6 ± 1.2, N = 101), totaling to 20–33 ( x̄ = 27.5 ± 2.6, N = 101). No significant differences between the number of bands or blotches between morphotypes were noted. Insertion of first light band/first body blotch begins above ventral scale 7–19 ( x̄ = 10.2 ± 2.3; N = 95). Width of light bands 1.0 dorsal scales long, black edges 0.5–1.0 dorsal scales. Interspace between each band 6–9 vertebral dorsal scales at midbody ( x̄ = 7.2 ± 0.8; N = 95). Head markings consist of one ocular bar, a paired temporal streak, and one nuchal chevron, the colors of which vary based on each morphotype. Ocular bar begins within the supralabials immediately below the eye and extends upwards through the prefrontals, anterior edges of supraoculars and anterior edge of frontal, and occasionally the posterior edge of the internasals. Each temporal bar begins at the anterolateral edge of the parietal, continuing through the posterior temporals before terminating ventrolaterally. Anterior end of nuchal chevron lanceolate or acuminate, extending from nape through the median suture of parietal and frontal. The chevron in some individuals may be broken or incomplete resulting in a small series of spots present in the median portion of the frontal and posterior edges of each parietal. Underside of head and body white or tan, edges of ventral scales with small brown subtriangular spots, sparser and weakly developed anteriorly but typically present on every or every other ventral scale by midbody. The posterior half of the ventral surface in some specimens may be completely smeared with dark brown or black pigment (see BNHS 814B) ( Fig. 8A View FIGURE 8 ). Lateral margins of ventral scales same color as dorsal surface. Underside of tail white or tan, small dark brown spotting present anteriorly, otherwise immaculate.

In preservative, dorsal surface of typical morphotype brown to reddish brown ( Fig. 5 View FIGURE 5 ). Large adults vary from light brown, mahogany or dusky gray. Poorly preserved or bleached individuals fade to light brown or tan. A series of light bands with black edges result in a tricolored pattern with a pattern of dyads (arrangement of each color as follows: red-black-light-black-red; see Savage & Slowinski 1992). Light portions of bands white, tan, or yellow, though larger individuals may have bands obfuscated by brown or gray pigment (see CAS 221511, NMHW 25817:1) ( Figs. 5A, 5C View FIGURE 5 ). Each body band extends across the dorsal surface until the outermost 1–3 dorsal scale rows and do not continue ventrally. Light portions of each band approximately 0.5–1.0 vertebral dorsal scales long, black edges narrower or approximately equal in length. Pattern aberrations noted across specimens include fused body bands (which normally result in “Y” or “T” shaped markings) or bands that are reduced to small spots or ocelli, especially on the tail (NMHW 25817:1) ( Fig. 5C View FIGURE 5 ). In other examples, the black edges of each band constrict medially causing the light pigmentation within to fragment (BNHS 814A). Most specimens have a faint series of dark paravertebral and lateral stripes, each arranged in pairs from nape to tail. When visible, lateral stripes are 1–2 dorsal scales wide and are usually present on the outermost 3–4 dorsal scale rows. Paravertebral stripes are 1–2 dorsal scales wide with a light, narrow middorsal line along the vertebral dorsal scale row present between each stripe. Both series of stripes may be indiscernible in juvenile (NHMUK 1925.12.22.38–40) and adult examples (BNHS 814A, CAS 221511, NHMUK 1946.1.4.26) or are weakly developed. Northern populations from Bhutan, northeast India ( Arunachal Pradesh, Assam, Sikkim, West Bengal) and northern Myanmar ( Kachin State) tend to possess patches of light dorsolateral pigmentation, which occasionally coalesce to form weakly developed secondary crossbars separate from each light/black-edged band. Dorsal color of tail same as body, dark brown margins of subcaudals and outermost dorsocaudal scales form a weakly developed ventrolateral line on the tail ( Fig. 5B View FIGURE 5 ). Small light rectangular spotting occasionally visible above ventrolateral line. Dorsal surface of head light brown, tan or yellow. Adult individuals tend to have dark pigmentation mottled across the head (CAS 221511, NMHW 25817:1) ( Figs. 5A, 5C View FIGURE 5 ), whereas juvenile examples are more immaculate, especially towards the snout. Head markings same color as body, narrowly edged with dark brown or black. Posterior edge of nuchal chevron continuous with remaining body.

Specimens bearing the blotched morphotype are various shades of brown in preservative, with a transverse series of blotches or crossbars in place of the typical tricolored arrangement observed in the banded morphotype ( Fig. 7–9 View FIGURE 7 View FIGURE 8 View FIGURE 9 ). Size and shape of both blotches and crossbars vary. In most cases, body and tail blotches brown with black margins, broader middorsally (2–4 vertebral dorsal scales long). Each blotch extends to the outermost 1– 3 dorsal scale rows but in some individuals blotched pigmentation is absent across the flanks (CIB 9895, SYS r001827) ( Fig. 8B View FIGURE 8 ). Blotch shapes range from oval to rhombic and are generally notched or bisected middorsally. Incompletely notched/bisected blotches appear “walnut” shaped, while fully bisected blotches may persist as two to three distinct spots (this is the case in the holotype of Simotes juglandifer BNHS 814A, and NMHW 25817:1, 25817:5–6 from adjacent Sikkim, India) ( Fig. 8A View FIGURE 8 ). Body and tail crossbars solid black, 1–2 vertebral dorsal scales in length. Crossbars less prominent on flanks than middorsally in some examples (MZMU 2965, ZMH 769) ( Fig. 7C View FIGURE 7 , Fig. 8C View FIGURE 8 ). Blotched/crossbarred patterning is never completely absent from the dorsal surface, yet in one specimen (NMHW 25817:5) blotches are only visible anteriorly and the remaining dorsal surface is brown with dense black speckling. Populations from the upper Himalayan foothills formerly referrable to O. juglandifer and O. lipipengi from Bhutan, southwest China ( Xizang AR), northern India ( Sikkim, West Bengal), and Nepal, are more heavily blotched, though at least one individual from “Himalayas” (ZMH 769) also has a crossbarred pattern ( Fig. 8C View FIGURE 8 ). Likewise, populations from northeast India ( Meghalaya, Mizoram State) frequently display crossbars (MZMU 2965) or narrow blotches (MZMU R.165) ( Fig. 7B–C View FIGURE 7 ). A sole specimen from Kachin State, Myanmar (CAS 225819) has narrow blotches with dense black margins that are incompletely notched middorsally ( Fig. 7A View FIGURE 7 ). Between blotches/ crossbars, black or dark brown markings present along edges of each dorsal scale, resulting in conspicuous speckling across the body. These speckles frequently coalesce on the body into “secondary” crossbars in many specimens ( Fig. 7A, 7C View FIGURE 7 ; Fig. 8C View FIGURE 8 ), but they are difficult to discern in others (these markings were not included in the final band/blotch counts). As many as three rows of “secondary” crossbars can be present (CAS 225819, MZMU R.165), in most cases just one row is visible (BNHS 814B, MZMU 2965). Paravertebral and lateral stripes dark brown, more developed in blotched/crossbarred specimens. Middorsal line present between paravertebral stripes lighter and broader on the tail. Color of vertebral line tan in CAS 225819 ( Fig. 7A View FIGURE 7 ), orange in MZMU 2965 ( Fig. 7C View FIGURE 7 ). Dorsal markings on head bolder than typical morphotype, margins occasionally black. Color of nuchal chevron separate from remaining nape, in the blotched morphotype present as a pronounced “V” or “Y” shaped marking, lanceolate anteriorly, dividing ventrolaterally towards the throat.

In life, dorsal ground color in typical morphotype pink, red, reddish brown, or light brown ( Fig. 6 View FIGURE 6 ). Dorsal color in juvenile specimens more intense, usually red. Body and tail bands white, tan or yellow, their edges always black. Paravertebral and lateral stripes darker than dorsal ground color when present ( Fig. 6B–C View FIGURE 6 ), normally reddish brown or dark brown. Secondary crossbar patches visible on flanks are typically lighter than ground color, occasionally demarcated by inconspicuous brown or black margins along dorsal scale edges. Dorsal surface of head light gray, white or tan, frequently with small brown mottling. Markings on head same as body, occasionally edged with dark brown. In the blotched morphotype, specimens generally range from light brown, gray brown or olive brown in life with prominent speckling on dorsal scale edges colored dark brown or black ( Fig. 9 View FIGURE 9 ). No ontogenetic change in color was detected in life. Lighter white or yellow speckling may also be present on dorsal scale edges and interstitial skin ( Fig. 9D View FIGURE 9 ). Interior portions of body and tail blotches brown to reddish brown, their edges black. Dorsal crossbars black, in some specimens the interior portions of each bar occasionally engulfed with plain brown pigment ( Fig. 9A–B View FIGURE 9 ). Paravertebral and lateral stripes are dark brown ( Fig. 9D View FIGURE 9 ). The middorsal line may be broader than the paravertebral stripes in several specimens. Examples reported as O. juglandifer by Patel et al. (2025) have broad paravertebral stripes starting at the nape and continuing across the entire tail. This pattern combination was also observed in some crossbarred specimens from Mizoram ( Fig. 9C–D View FIGURE 9 ). Markings on head either dark brown or black. Anterior edges of the ocular and temporal bars occasionally bordered with light brown or white pigmentation. In all specimens, ventral surface white or tan, dark ventral spotting black, dark pigmentation in some specimens dark brown or black by midbody.

Description of hemipenis. Based on retracted and everted organs ( Fig. 10 View FIGURE 10 ). Retracted hemipenis unilobed upon dissection, length of organ inside tail base 13–28 subcaudal scales long ( N = 9). 14–16 poorly developed horizontally arranged flounces in retracted organ (based on MCZ R-22378) ( Fig. 10A View FIGURE 10 ). Everted hemipenis bilobed, noncapitate and proximally calyculate ( Fig. 10B View FIGURE 10 ). Proximal one quarter to one third of organ cylindrical, with small irregular rows of calyces. The hemipenis greatly expands in width along the remaining distal one half to two thirds of its length. Long horizontally arranged flounces are present in asulcate and sulcate profiles across remaining hemipenial body. Each lobe is broad, more than two thirds of hemipenial length, longer than wide, and terminate as a small subtriangular awn. Apex of each lobe nude. The shape of the hemipenis according to Zhang et al. (2011) can be either ‘bulbous’ or ‘rod-shaped’ (our translation), though the organs available to us largely fall under the former category. Sulcus spermaticus simple, starting at organ base, extending medially until terminating at bifurcation point between lobes. Sulcus channel present as a narrow and indistinct groove across the median portion of the hemipenial body. A small depression between individual lobes is visible in apical profile of MZMU 3045 but is considered separate from the sulcus channel ( Fig. 10B View FIGURE 10 ).

Distribution and Natural History. The distribution of Oligodon albocinctus largely corresponds with moist, low to mid-elevation portions of the Indo–Himalayan foothills, including central and western Nepal, Bhutan, northeast India (in the states of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland, Sikkim, Tripura, and West Bengal), and eastern Bangladesh ( Smith 1943; Mahendra 1984; Schleich & Kästle 2002; Whitaker & Captain 2004; Wangyal 2011; Hasan et al. 2013) (Appendix 6). Further east its distribution extends through the northern half of Myanmar ( Chin, Kachin and Shan States, and the Sagaing Region) and southwestern China ( Yunnan Province, Xizang Autonomous Region) ( Wall 1923a; Zhao et al. 1998; Che et al. 2020; Huang 2023). The westernmost records known to us derive from central Nepal in Bagmati Province (see Schleich & Kästle 2002). In Myanmar, reports of O. albocinctus exist along the Chin Hills as far south as Hakha in the Mindat District of Chin State ( Venning 1910) and continue northwards across the Sagaing Region in Zalon Taung Pagoda, and multiple localities in Kachin and Shan States. Wall (1926) also reported a specimen from “Maymyo” (Pyin Oo Lwin, Mandalay Region). Its vertical distribution extends from sea level to approximately 2110 meters above sea level ( Wangyal 2011), and another individual photo-documented from Tawang, Arunachal Pradesh, India (iNaturalist obs. 222610705) was reported at approx. 2586 meters.

We consider literature reports of O. albocinctus reported in Vietnam to be based on misidentifications with other Oligodon taxa, particularly the O. cinereus species complex. The two Vietnamese records of this species derive from Vinh Phuc Province ( Orlov et al. 2000; Nguyen et al. 2009) and Phu Tho Province ( Tung et al. 2022). Both reports appear to be based on specimens in the Oligodon cinereus species complex, which can display color patterns that are similar to the white-banded morphotype of O. albocinctus ( Bourret 1936; Yushchenko et al. 2023a). No photographs or morphological data accompany the records cited in Orlov et al. (2000), but the specimen from Phu Tho Province reported by Tung et al. (2022) was noted to have 17–17–15 dorsal scale rows, a diagnostic trait of O. cinereus complex members from Indochina that is not seen in any specimens of O. albocinctus . Consequently, we recommend removing O. albocinctus from the snake fauna of Vietnam, a decision that follows recently published herpetofaunal checklists of the country ( Poyarkov et al., 2023). A few photo-documented records O. albocinctus from Bhutan were reported as misidentified or unidentified species ( Wangyal et al. 2020; Wangyal et al. 2022). This is the case for records of “ Oligodon sp. 2 ” and “ Oligodon sp. 3 ” from Wangyal et al. (2022), which all share typical characteristics of the blotched color morphotype of O. albocinctus . A photographed individual of Oligodon chinensis from Zhemgang District, Bhutan reported by Wangyal et al. (2020) and Wangyal & Das (2021) is also misidentified and represents a blotched variant of O. albocinctus based on the arrangement of the temporal bars and nuchal chevron, although the pattern of the body blotches is abnormally connected across the dorsal surface. We cannot comment further on the record of Oligodon venustus ( Jerdon, 1853) from the same publication ( Wangyal et al. 2020), or records such as Oligodon fasciolatus ( Günther, 1864) reported in Wangyal et al. (2022) and Oligodon taeniolatus ( Jerdon, 1853) from Wangyal & Tenzin (2009). Given that the nearest reports for each of these species occur hundreds to thousands of kilometers from Bhutan, their status should be re-evaluated based on a re-examination of the photographs or specimens from which they are based on.

Several kukri snakes identified as Oligodon cyclurus by previous authors represent blotched morphotypes of Oligodon albocinctus . The morphological data of the O. cyclurus recorded in Das et al. (2016) are one such example, and the photographed specimen figured within their study match the crossbanded patterning seen in many O. albocinctus specimens we examined from northeast India. Hakim et al. (2020) recorded both banded O. albocinctus and blotched O. albocinctus (as O. cyclurus ) from Lawachara National Park, Bangladesh (true exemplars of O. cyclurus were also recorded by these authors; Hakim et al. 2020: Fig. 9d View FIGURE 9 ). In Mizoram State, two authors recorded diet items in the stomachs of misidentified blotched O. albocinctus specimens ( Kalita et al. 2020; Biakzuala et al. 2023; see below), and Hmar et al. (2020) provided data and photographs of blotched O. albocinctus under the name O. cyclurus .

Oligodon albocinctus View in CoL is generally a common snake where it occurs ( Wall 1914; Jha & Thapa 2002; Whitaker & Captain 2004) and has been reported from disturbed habitats such as university campuses and the vicinity of urban centers, tea gardens, as well as more pristine monsoon forests and lower montane forests ( Wall 1909; Purkayastha et al. 2011, 2018; Sinha et al. 2021). O. albocinctus View in CoL has a broader diet than other members of its genus. Wall (1923a) recorded three specimens with rodent remains in their stomachs. From Myanmar, Wall (1925) reported a mouse in the stomach of one specimen, as well as the remains of one lizard egg and a large brown cricket in two additional individuals. Wall (1926) later dissected the stomachs of three individual O. albocinctus View in CoL and found that two of his specimens contained four eggs he referred to Rhabdophis subminiatus ( Schlegel, 1837) View in CoL [now Rhabdophis helleri ( Schmidt, 1925) View in CoL ]. The third specimen also had the remains of snake or lizard eggs, noting one such egg (approx. 25 mm long) was “impacted in the mouth” while another was swallowed. In Assam State, India, Kalita et al. (2020) notably reported the remains of a bat ( Pipistrellus coromandra Gray, 1838 View in CoL ) regurgitated from a blotched morphotype specimen [as O. cyclurus View in CoL ]. Another blotched individual from Mizoram State (reported as Oligodon cf. cyclurus View in CoL by Biakzuala et al. 2023) had the skink species Sphenomorphus maculatus ( Blyth, 1853) View in CoL swallowed head-first in its stomach. We report another specimen collected from Manipur State, India (MZMU untagged no. 13) that had the remains of an unidentified shrew (Eulioptyphla) in its stomach. Quite interestingly, the specimen was swallowed tail-first. Like all other Oligodon View in CoL , this species is oviparous. A gravid female reported in July by Wall (1923a) from Dibrugarh, Assam, India had three developed follicles. Another report by Lalronunga et al. (2018) describes a clutch of five eggs from a gravid female specimen from Mizoram State. Another specimen collected in October 2021 from Tlangnuam, Mizoram State (MZMU 2831) appears to be gravid, but no data on clutch size was recorded.

Conservation Status. The most recent assessment of Oligodon albocinctus View in CoL from the IUCN Red List of Threatened Species ( Khan et al. 2021) lists this species as Least Concern (LC) based on its wide distribution and local abundance. Das et al. (2021) recommended a listing of Vulnerable (VU) for the formerly recognized Oligodon juglandifer View in CoL due to its documentation at only six localities and threat of habitat loss. Our revised conception of O. albocinctus View in CoL has a distribution that encompasses multiple protected areas across its range ( Agarwal et al. 2010; Rahman et al. 2013; Purkayastha et al. 2020a –b; Khan et al. 2021; Patel et al. 2025; Thapa et al. 2025) and many of the factors that influenced its earlier conservation listing still stand. As such, we recommend the continued maintenance of this species under the listing of Least Concern (LC).

Comments. We agree BNHM 210 is a juvenile specimen. Wallach et al. (2014), likely referencing Wall (1923b), but not citing this work, claimed BNHM 210 measured 717 mm in length. Wall (1923b) does mention a “Length.— 717 mm ” below mention of the line “Type.—In the Bombay Natural History Society’s collection…” in his account of O. juglandifer , but that section appears to be describing the maximum length of the species and not the length of the type specimen. This interpretation is strengthened by the fact that Wall (1923b) provided a range of values for other morphological characteristics such as ventral and subcaudal scales in the same account, and that many other “Length.” values for Oligodon species mentioned in that work match the maximum lengths provided in an earlier publication he made on the same genus ( Wall 1923a), as stated by Patel et al. (2025). Wall (1923a) referred Simotes amabilis to his “Variety (B)” of Oligodon albocinctus yet described this variant as having “intermediate and less conspicuous series of cross-bars”. These chromatic traits are not characteristic of the Simotes amabilis holotype.