Taxonomic revision of the Boiga ceylonensis group (Serpentes: Colubridae): reexamination of type specimens, redefinition of nominate taxa and an updated key Author Ganesh, S. R. Chennai Snake Park, Chennai, Tamil Nadu, India Author Achyuthan, N. S. Centre for Ecological Sciences, Indian Inst. of Science, Bangalore, India Author Chandramouli, S. R. Dept. of Ecology & Environmental Sciences, Pondicherry University, India Author Vogel, Gernot Society for South East Asian Herpetology, Im Sand- 3, Heidelberg, Germany text Zootaxa 2020 2020-05-20 4779 3 301 332 journal article 22007 10.11646/zootaxa.4779.3.1 712a6136-5d6c-4505-8a8a-3d0556e146c1 1175-5326 3835357 0B6F641C-424E-4042-A9B6-A130C58935AB Boiga ceylonensis ( Günther, 1858 ) ( Tables 3–4 ; Fig. 3 , 9A&B ) Dipsadomorphus ceylonensis Günther, 1858 Dipsas ceylonensis— Boulenger (1890) part Boiga ceylonensis— Smith (1943) part; Hutton (1949) part; Hutton & David (2009) part Boiga ceylonensis ceylonensis — Deraniyagala, 1955 Specimens examined. Males (n=18). Lectotype (designated herein): Sri Lanka . BMNH 54.3 .21.22 from “ Ceylon ” . Paralectotypes : BMNH 46.12 .2, BMNH 53.12 .24.29, BMNH 1946.1 .4.79 all from Ceylon . Additional specimens: Sri Lanka . BMNH 1955.1.9.83–86 Tonaconibe Estate ; USNM 267760 Kandy ; USNM 254753 Sabarugamuwa ; SMF 19676 Ceylon ; SMF 32595 Colombo ; ZMB 8058 Ceylon ; NMW 20225 Deniyaya ; ZMB 7302 Paradenia ; UPZMR007 and UPZMR010b both from Peradeniya , Kandy ; FMNH 121533 Ceylon ; FMNH 120919 Ceylon , Uva : Namunukula , 4000’; FMNH 179248 Namunukula , Tonacombe Estate , 3900’; FMNH 167006 Central Prov : Meda-Maha Nuwara . Females (n=19). Paralectotype : Sri Lanka . BMNH 19.3 .29.10 Ceylon .Additional specimens : BMNH 97.10 .20.3 Neboda ; BMNH 1933.12 .6.16 Diyatalaura , Uva province ; BMNH 1915.5 .3.8 Anuradhapura ; FMNH 142403 Uva : Moneragala , Moneragala Estate , 3000 ’; FMNH 131380 North Central Prov : Manampitiya ; FMNH 167008 Central Prov : Meda-Maha Nuwara ; FMNH 167007 Central Prov : Meda-Maha Nuwara ; FMNH 165053 South Prov : Bundala ; UPZMR010a Peradeniya , Kandy ; UPZMR010c Peradeniya , Kandy ; RMNH 1027 , ZFMK 31782 , ZFMK 36841 , ZFMK 20352 , NMW 25352:3 , SMF 19677, NMW 25470 all from Ceylon without exact locality . Taxonomic history. Günther (1858) described this species as Dipsadomorphus ceylonensis based on a series of seven syntypes (re-registered as BMNH 54.3 .21.22, BMNH 46.12 .2, BMNH 53.12 .24.29, BMNH 1946.1 .4.79, BMNH 19.3.29.10) comprising adults and juveniles as well as male and female specimens all hailing from Ceylon [now Sri Lanka ]. Boulenger (1890) transferred it to the genus Dipsas . Wall (1909) split this complex into five species. Smith (1943) transferred them to the genus Boiga and, following Annandale (1909) , synonymised all of these taxa back again with B. ceylonensis with some reservations. Deraniyagala (1955) split B. ceylonensis from Sri Lanka and from Western Ghats and named them as subspecies Boiga ceylonensis ceylonensis , as the nominotypical form from Sri Lanka , and Boiga ceylonensis dakhunensis as a new subspecies from Indian peninsula (see B. nuchalis account below). This subspecific arrangement was not followed by later authors ( Whitaker & Captain, 2004 ; Somaweera, 2006 ; Wallach et al ., 2014 ). TABLE 3. Diagnostic characters of the members of the Boiga ceylonensis group (including B. barnesii ; * rarely crown with obscure dark wash)

Species	Midbody scalerows	Ventrolateral pattern	Temporals	Crown pattern	Dorsal bars	Subcaudal pairs
B. ceylonensis	19	paired spots	8––17	Yes	Dark brown	<110
B. beddomei	19	paired spots	9––12	No	Black	> 110
B. flaviviridis	19	Unmarked	10–11	No	Black	> 110
B. barnesii	19	White, black blotches	10–11	Yes	Dark grey blotches	<110
B. thackerayi	17–19	White, black blotches	Yes	Black	<110
B. nuchalis	21–23	faint spots	10–18	No*	Dark brown	<110
B. dightoni	21–23	Salmon pink spots 17–19		No	Salmon pink	<110
B. andamanensis	21	none	8	No	Feeble	<or> 110

The type series of Dipsadomoprhus ceylonensis is a mixture of species, with BMNH 1946.1.4.75 belonging to the species B. beddomei sensu lato . Thus we here refine the diagnosis and definition of Dipsadomorphus ceylonensis , by designating a lectotype . Hence, in accordance with Art. 74.7 of the Code (ICZN, 1999), we here designate a well preserved adult male specimen BMNH 54.3.21.22 from “ Ceylon ” as the lectotype of Dipsadomorphus ceylonensis . Etymology. Toponym, for ‘an inhabitant of Ceylon’, now Sri Lanka . TABLE 4. Selected morphological characters of the member in the Boiga ceylonensis group (including B. barnesii )

Taxon	Ventrals	Sub caudals	Temp- orals	Preoc- ulars	Supra & Infra labials	Total length (mm)	Tail length (mm)	Relative tail size %
B. ceylonensis	217–237	95–109	8–17	1	S:7–8 I:10–12	310–979	60–220	21.8–23.9%
B. beddomei	238–252	117 (1 specimen)	9–12	1	S:8–9 I:11	809	185	22.9% (rest cut)
B. flaviviridis	248–259	100–109	10–11	1	S:8–9 I:10–12	828–980	166–178	18–20%
B. barnesii	217–218	96–100	10–11	3	S:8 I:9–10	537–572	123–129	22.6–22.9%
B. thackerayi	211–221	94–102	7	1	S:8 I:10	674–1163	157–293	22.1–26.8%
B. nuchalis	228–255	94–109	10–18	1	S:8–9 I:10–14	381–1142	83–257	18.7–22.5%
B. dightoni	235–248	99–112	17–19	1	S:8 I:11–14	1056–1083	218–225	20.8–24%
B. andamanensis	259–262	102–124	8	1	S:8 I:10–11	1435–1635	295–375	18–26%

FIGURE 3. Lectotype of Boiga ceylonensis BMNH 54.3.21.22 from Ceylon. (A) entire—dorsal, (B) entire—ventral, (C) ventral pattern close-up, (D) head—ventral, (E) head—lateral, (F) head—dorsal views. Diagnosis (redefined herein). A species of Boiga endemic to Sri Lanka , defined by the following combination of characters: 19 midbody scale rows (vs. 21–23 in B. nuchalis , B. dightoni , B. andamanensis ); predominantly brownish dorsum (vs. greenish in B. flaviviridis ; variable in B. andamanensis ); vertebral scales strongly enlarged (vs. feebly enlarged in B. barnesii ); crown patterned with distinct black blotches (vs. crown unpatterned in B. beddomei , B. andamanensis ); subcaudals <110 (vs.> 110 in B. beddomei ); ventrolateral region devoid of large adjacent white and black blotches (vs. blotches present in B. barnesii , B. thackerayi ), but with a series of spots on both the ends of each ventral scale (vs. venter unpatterned in B. andamanensis , B. flaviviridis ). Description of the lectotype . A medium-sized specimen (total length 972 mm ), snout vent length 740 mm , tail length 232 mm ; long tail (relative tail length 23.9%); with slender habitus, thin neck, wide head; 19–19–15 scale rows; rostral visible from above; preocular 1, subequal to loreal; postoculars 2; loreal 1; supralabials 8, 3 rd , 4 th and 5 th ones touching eye; infralabials 11/10, with 1–4 touching chin shields; temporals 10; preventrals 1; ventrals 234, angulate laterally; cloacal 1; subcaudals 108 pairs. Dorsal colour drab brownish-grey, with darker brown to blackish-brown crossbars; crossbars covering 2–4 scales in size, extending either sides up to 3–4 scale rows across, about 61 bars on body, 17 on tail; interspaces often with sparse dark dots; a distinct postocular stripe up to the jaw angle; distinct circular markings on top of head; labials, chin and venter ashy brown; venter finely spotted with darker shade, each ventral scale with two dark dots at both ends, giving a dotted line-like appearance along ventrolateral region. Variation. Our material agrees with the lectotype in most aspects, with the following variation: snout-vent length 502–764 mm , tail length 155–215 mm , relative tail length 21.8–23.9%; midbody scale rows 19 ( 21 in 1 out of 37 cases); supralabials 8 (very rarely 7, i.e. 3 out of 74 cases), 3 rd to 5 th touching eye (very rarely 3 rd and 4 th only); infralabials 10–12, with 1–4 touching chin shields; temporals 9–16; preventrals 1–2; ventrals 217–237; subcaudals 95–109 pairs; dorsum with about 52–76 cross bars on body and 16–36 on tail. Distribution and natural history. This species in endemic to Sri Lanka and occurs in the wet forested parts of the island ( Wall, 1921 ; Samarawickrama et al . 2005 ; Somaweera 2006 ) (Fig. 13). One specimen was found by us in Kanneliya Rain Forest Reserve (Galle, Sri Lanka ) around midnight lying on a bush at about 1 m above the ground, obviously ambushing for prey. It was not moving while being photographed and was not aggressive. Another adult female was found close to Hunasgiriya range near Kandy. It was sighted on a tree branch at 1.5 m height at 21:50 hrs, near tea gardens.