Beddome (1862) described this species from the Anaimalai and Palani hills. The uniqueness of this species resulted in its being assigned to its own genus Peltopelor in a subsequent treatment by Günther (1864). Later, Smith (1943) subsumed this genus into Trimeresurus. Malhotra and Thorpe (2004) suggested a revised taxonomy for all Trimeresurus (sensu lato) groups and assigned them to different genera, reinstating Peltopelor as a valid genus (also see Wallach et al. 2014).

Lectotype, NHMUK 1946.1.18.72 (formerly BMNH 1861.12.30.80), a male (R.H. Beddome, 1857–1862), designated by Toriba in Golay et al. (1993: 101).

Specimen series: Lectotype – NHMUK 1946.1.17.72 from “Anamallay Mountains, at 6000 feet” collected in 1857–62 by R. H. Beddome; CESS014, CESS015 from Vellimala, Periyar and CESS190 from Rajamalai, Kerala, collected in 2011, by Ashok Kumar Mallik; CESS170 from Uppupara, Goodrickal Range-west, Kerala, CESS256 from Devarmala, Tamil Nadu, collected in 2011, by Saunak P. Pal; BNHS2543 from Shenbaganur, Tamil Nadu and BNHS2545 from Paralai, Valparai collected in 1909, by Maj. Frank Wall.

“Anamallay Mountains; at 6,000 feet elevation” [= Anaimalai Hills, Western Ghats India, ca. 10°22’N; 77°08’E] by lectotype designation (Wallach et al. 2014). The mentioned in the description is “Anamallay mountains at 6000 ft and Pulney Hills at 4000 ft” which is the current day Anamalais, south of the Palghat gap and the Palani hills further east. Here we restrict the nomen Trimeresurus macrolepis to the population distributed in mountain ranges north of the Shencottah gap.

Within the C. macrolepis complex, C. macrolepiss. str. (L6) can be distinguished as follows: in having higher dorsal scale rows: 13–19 (vs. 10–14 in L7); lower ventral count 133–140 (vs. 150 in L7). Craspedocpehalus macrolepis (L6) is allopatric with its sister taxon (L7), from which it has a shallow genetic divergence (3.7% at cyt b and 0.7–1.0% at 16S rRNA). The low level of genetic divergence is the lowest genetic break between any the lineages inferred here (See Supplementary File 5: Table S4). This shallow genetic break coincides with a physical barrier (Shencottah gap) for these lineages.

A medium sized pit viper (recorded till 920mm by Ganesh et al. 2008) with a prehensile tail of length up to 136 mm; a distinct triangular head with large shield-like scales, with 1–3 cephalic scales between the undivided supraoculars with five scales surrounding the supraoculars, up to two scales between the internasal scales and the tip of the rostral scale visible from above; nasal scale entire, sub-rectangular and encompasses the nostril completely with 2–3 scales between the internasals; 1–2 scales between the nasal and the anterior part of the loreal pit; 8 supralabials and 9–12 infralabials on both sides; 6-8 scales including the last infralabial from the first ventral scale; three preocular scales of which the second and third scale from above constitute to form the posterior shields of the loreal pit; one or two post oculars; temporals smooth; 14–17 NSR (dorsal scale rows at neck), 13–19 MSR (dorsal scale rows at midbody), and 10 PSR (dorsal scale rows before vent), all keeled; Last row of scales on both sides bordered with a slightly larger row of scales, separating the ventral scales from the body; Ventrals 133–140, Anal scale undivided, followed by divided subcaudals 50–57.

Specimens in life are in a uniform dark green throughout the dorsal surface, often with a black post ocular stripe that extends to 2 scale rows; the postocular stripe continues to a white to creamy white lateral stripe that stops at the vent; uniform creamy to light green ventrals with hints of light blue, that continues to the mandibular portion that is either yellow, light green, light blue or creamy white in colour; tail after the vent continues with dark green, feeble blue bands at the end of the tail, the terminal scale black or greyish with feeble white bands.

Specimens in preservative show a range of variation in colour depending on the preservative; range from dark to light green on the head and dorsum with hints of or blue black bordering the scales; tail tip banded with grey and white bands, tail darker blue bands with bluish green.

A typically arboreal (rarely terrestrial) species (Ganesh et al. 2010) that is found in high elevation shola forests (tropical montane stunted rainforests) and forests bordering high elevation grasslands. Due to anthropogenic changes to the landscape, this species is also sometimes found in cultivated landscapes such as tea estates and cardamom plantations, found at elevations from about 1100 m asl to 2600 m asl.

Endemic to the southern Western Ghats. The revised distribution restricts this species to the high elevation landscapes of its range, the northern most limit being south of the Palghat gap, in the Nelliampathi hills, Anaimalai, with Palni hills being the eastern-most end of its distribution, extending southwards across High Wavy’s or Meghamalai, Kottaimalai Ranges in the Srivilliputhur-Periyar landscape, to the Sivagiri-Devarmalai range, ending north of the Shencottah gap.

Specimen series: Holotype (BNHS 3593) from Chemunji, Peppara, Agasthyamalai, 08°40.7’N; 77°11.55’E, collected in 2010, by Saunak P. Pal & S.P. Vijayakumar. — Paratype (BNHS 2950) from Tirunelveli Hills (Agasthyamalai), collected in 1976 by Romulus Whitaker.

Chemmunji, in Peppara Wildlife Sanctuary, a part of Agastyamalai Hill Complex, Southern Western Ghats.

Named after Günther’s erstwhile generic nomen that alludes to the shield-like, large scales (peltē: shield/scale, pelor (o)-: a term meaning monstrous [or literally huge], in Greek).

A lineage belongs to the C. macrolepis complex. Differs from C. macrolepis in having lower dorsal scale rows 10–14 (vs. 13–19); higher ventral scale counts 150 (vs. 133–143). The new species is geographically separated from C. macrolepis by the Shencottah gap in the Southern Western Ghats. Craspedocephalus peltopelor sp. nov. (L7) has a shallow genetic divergence (3.7% at cyt b and 0.7–1.0% at 16S) from C. macrolepis (L6).

Holotype in good condition, dissected, with a slender, cylindrical body of snout to vent length (SVL) 263mm and a prehensile tail of length (TL) 57 mm; dorsal scales keeled with anterior dorsal scale rows (DSR) 17, mid body scale rows (MSR) 15 and posterior scale rows (PSR) 10; head prominent, of length 20.5mm, clearly distinguished from the neck with large, smooth dorsal shields on the head; rostral scale triangular with the upper side roughly half the size of the lower side with the tip visible from above; supraoculars of length 5.46 mm and frontal separated by pair of scales on both sides and nasal scales separated by three scales from above; five scales other than the pre and post ocular scales bordering the supraoculars on both sides, with three scales between the posterior edge of the supraoculars; canthus rostralis distinct with 3/3 canthal scale; three preoculars, a postocular and a thin elongated crescent shaped subocular, in contact with a small scale, encompassed by the third and fourth supralabial scale; eye with a distinct elliptical pupil, vertical diameter of the eye 2.94 mm and horizontal diameter 3.52mm; temporal scales smooth; aperture of the nostril completely covered by the nasal scale, undivided and subrectangular; nasal scale bordering the first supralabial; loreal pit present in contact with the second supralabial with two scales between the nasal and the second supralabial; eight supralabials and 12 infralabials, with six scales between the last supralabial, including the last supralabial till the start of the ventral scales; 1^st, 2^nd and 3^rd infralabial scale in contact with the first pair of genials; a gap of four scales including the posterior genials followed by 150 ventrals, laterally separated from the dorsal scale rows by a slightly broader row of dorsal scales; anal scale undivided, followed by 59 divided subcaudals scales; terminal scale on the tail larger than the previous scale, blunt at the tip.

The paratype, of SVL 504mm and TL 145mm, is discoloured with a uniform dark greenish to black colour throughout the specimen in its current preservation state. It differs from the holotype with respect to pholidosis by having 14 DSR, 14 MSR, 11 PSR, 150 ventrals and 64 subcaudals; a distinct head of length 27.5 mm with supraoculars that are separated by one scale from above; two canthal scales on the canthus rostralis, and 3 cephalic scales from above; 11 infralabials on both sides.

Dark to verdant green on the dorsal surface of the head that fades into a lighter green throughout the body dorsally up to the tail and along the lateral sides of the body including the head; a prominent, 2-scale wide, white lateral stripe runs from the creamy white mandibular region; small hints and patches of blue visible on the head and dorsal scales, with the tail tip banded with dark blue or sometimes fully covered with dark blue or black; the last 11 scale rows of the tail banded with black to dark blue and white to yellow; creamy white to yellow mentum fades into a light creamy green throughout the ventrals, sometimes separated by the white ventral stripe from the lateral part of the body.

Greyish green on the head dorsum that fades into a bluish green shade throughout the body; lateral parts of the head light green to bluish green; mentum creamy yellow that blends with creamy green ventrals, separated by the white lateral stripe; tail tip with grey and white bands, tail bluish green with darker blue bands.

A typically arboreal (rarely semi-terrestrial) species (Ishwar et al. 2001, Seshadri, 2012) that is found in high elevation shola forests (tropical montane stunted rainforests) bordering the high elevation grasslands. Due to anthropogenic changes to the landscape, this species is also sometimes found in cultivated landscapes such as tea estates and coffee plantations. Found at elevations from about 1200 m asl to 1868 m asl.

Endemic to the southern Western Ghats, south of the Shencottah gap. Geographically separated from its sister species, C. macrolepis that inhabits the ranges to the north of the Shencottah gap. Found throughout the high elevations of the Agasthyamalai hills.

Jerdon (1854) originally described this species as Trigonocephalus (Cophias) malabaricus and the type locality of this species was mentioned as the “West Coast of Peninsular India”, restricted to the Western Ghats. The types of this species are currently untraceable (Goley et al. 1993, Gumprecht et al. 2004, Wallach et al. 2014). Other subsequently described nomina of C. malabaricus, that are currently recognized as synonyms include Trigonocephalus (Cophias) wardiiJerdon 1854, Trimeresurus anamallensis Günther, 1864 (now a valid species; see below) and Lachesis coorgensis Rao, 1917. Jerdon (1854) in his original descriptions of Trimeresurus malabaricus and Tri. wardii did not mention any locality names or geographic province. Our perusal of historical collection catalogues (Boulenger, 1896; Das et al. 1998; Sclater, 1891; Theobald, 1868, 1876) in two potential repositories associated with Jerdon’s herpetological specimens (the Natural History Museum London and the Zoological Survey of India Kolkata) all reveal that only three precisely-named places have ever been associated with these nomina: Anamalais, Nilgiris and Wayanad (also see Beddome, 1862; Boulenger, 1890).

The specific epithets, mostly toponyms, also suggest the same: C. malabaricus: from ‘Malabar’ i.e. north Kerala and Coimbatore / Nilgiris, in the Western Ghats; C. anamallensis: from Anamalai hills of the Southern Western Ghats; Lachesis coorgensis: from ‘Coorg’ (=Kodagu) a part of Malnad region in Central Western Ghats. The only remaining nomen in its synonymy is Tri. wardii of Jerdon, 1854. Our perusal of historical literature reveal that this eponym could only be named after Samuel Neville Ward (18^th June 1813 – 31^st January 1897). Samuel M. Ward was with the Madras Civil Service (1832–63) and had a final appointment as Judge of Koyambatur (=Coimbatore). He had reportedly been corresponding with naturalists such as Charles Darwin, Edward Blyth, as well as T. C. Jerdon, who described Tri. wardii. Ward had been reported to have visited Sirsi, in North Canara for his work on Indian wildlife, mostly butterflies and birds (Pittie, 2016 and references therein). Beddome (1862) explicitly stated that Tri. wardii is from the Nilgiris. The earliest reference of this group from Agasthyamalai is that of Ferguson (1895), who used Günther’s name (C. anamallensis) to refer to it. Thus historical collections prior to typifications (till Rao, 1917) of the C. malabaricus complex apparently happened only from Anaimalai, Nilgiris and Wayanad.

Syntypes lost (after Smith, 1943; also see Wallach et al. (2014:188), ‘Holotype’ lost (after Das et al. 1998). Hence, as per Art. 75.3 of the Code (ICZN 1999) since we are revising the taxonomy of this group, we designate as neotype the holotype of its junior synonym Lachesis coorgensis Rao, 1917. The selected neotype (read below) is chosen to clarify the identity of this nominal taxon, a well-preserved adult originating from a precise locality, in conformity with the original description of the conferred nomen and housed in a permanent national repository/museum. Thus Craspedocephalus malabaricus and Lachesis coorgensis are now objective synonyms.

Specimen series: Neotype: ZSI-18161 from Coorg, Karnataka, 12°24.82’N; 75°43.85’E by C.R. Narayan Rao in 1917, the holotype of Lachesis coorgensis Rao, 1917. — Other referred material: BNHS 2609-778 from Kotagiri, Tamil Nadu and BNHS 2069–781 from Coonoor, Tamil Nadu by A. M. Kinloch in 1907. Additional comparative material collected for this study - CESS053, CESS055 from Amboli, Maharashtra; CESS063, CESS065 from Saklespura Karnataka; CESS273 from Coorg, Karnataka; CESS086 from Thirunelli, Kerala by Ashok Kumar Mallik between 2009-11 and CESS141 from Silent valley by Saunak Pal and Mrugank Prabhu in 2010; BNHS 2609A from Kotagiri and BNHS 2609B from Coonor, Nilgiris, Tamil Nadu by A.P Kinloch in 1907; BNHS 2596 from Sirsi, Karnataka by Charles McCann in 1938; BNHS 2599 from Mahabaleshwar, Maharashtra by H. Abdulali in 1953; BNHS 2601 from Castle Rock, Karnataka by Mrs. H. Pearson in 1907.

Originally given as “West Coast, Peninsula of India”. Here restricted to Coorg (12°24.82’N; 75°43.85’E) in Central Western Ghats, by neotype designation.

The specific epithet malabaricus is a toponym, alluding to its type locality - the Malabar region of the Western Ghats.

A lineage of the C. malabaricus complex, C. malabaricuss. str. (L5) is here restricted only to populations north of the Palghat Gap. This nominotypical population is 8.3–9% and 1.2–2.2% divergent at cyt b and 16S respectively, from those south of the Palghat Gap (L3 & L4), recognised here as two nominate taxa: C. anamallensis (Günther, 1864) and Craspedocephalus travancoricus sp. nov. (see below). These taxa are allopatric with respect to each other and C. malabaricus.

Neotype in good condition, small lesion near the nape, possibly caused while collecting and euthanizing the individual; specimen with a slender, cylindrical body of snout to vent length (SVL) 481 mm and a prehensile tail of length (TL) 73 mm; dorsal scales keeled with anterior dorsal scale rows (DSR) 21, mid body scale rows (MSR) 21 and posterior scale rows (PSR) 13; head prominent, of length 24.3 mm, clearly distinguished from the neck with small, mildly keeled scales on the head; rostral scale trapezoid, with the lower side roughly more than twice the size of the upper side with the tip visible from above; supraoculars divided, separated by eight cephalic scales between both supraoculars at its posterior border; seven scales bordering each supraocular. Canthus rostralis distinct with four canthal scales; three preoculars, two postoculars and a thin elongated crescent shaped subocular; eye with a distinct elliptical pupil, vertical diameter of the eye 3.31 mm and horizontal diameter 3.68 mm; strongly keeled temporal scales and cephalic scales in the posterior sides above the mandibular joint; aperture of the nostril completely covered by the nasal scale, undivided and sub-pentagonal shaped, in contact with the first two canthal scales and the 1^st and 2^nd supralabial; loreal pit present in contact with the second supralabial and the 2^nd and 3^rd preoculars; nine supralabials and 12 infralabials, with eight scales between the last supralabial, including the last supralabial up to the start of the ventral scales; 1^st, 2^nd and 3^rd infralabial scale in contact with the first pair of genials; a gap of four scales including the posterior genials followed by 148 ventrals, laterally separated from the dorsal scale rows by a slightly broader row of dorsal scales; anal scale undivided, followed by 38 divided subcaudals scales; Terminal scale on the tail larger than the previous scale, blunt at the tip.

The referred materials are of SVL up to 670 mm and TL up to 126 mm with colours varying from dark brownish red to light green throughout the specimens in its current preservation state, differs from the holotype with respect to pholidosis by having 19 to 22 DSR, 19 to 23 MSR, 13 to15 PSR, 145–149 ventrals and 52–54 subcaudals; head distinct with supralabials ranging between 8–10 and infralabials ranging between 10–13; one to three preocular scales, one to two scales (some specimens showing an absence of these scales) between the 3^rd supralabial scale and the suboculars, seven to nine cephalic scales and seven to eight scales surrounding the supraoculars from the dorsum.

A highly variable and polymorphic species, with respect to colour, specimens can be found in a variety of colour morphs - greenish blue-cyan, bright yellow, green, rufous brown, bright orange and red coloured specimens have been encountered during this study; head characterized with a thick dark brown to black postocular stripe till the nape, labials sometimes marked with blotches and a highly variable pattern above the head, sometimes fully dark, some individuals with no markings at all, body with alternating zig-zag saddle shaped markings with the last rows of scales on the tail banded with different colour; these markings vary from brick reddish, dark brown to black, sometimes intermixed with spots of other colours such as green, yellow and blue; the base colour of the body varies from light brown in juveniles, light cream, orange, yellow, brick red, bluish green and sometimes morphs mottled with all or some of the aforementioned colours; ventrals sometimes vary from the colour of the dorsum, complementing the variety of vibrant dorsal colours, but often are coloured similar to the dorsum; colour change is also observed to be seasonal (Kanagavel et al. 2012); juveniles brown with dark brown to black markings, neonates and younger juveniles possess a tail ‘lure’ that is often different from the body’s colouration. Mandibular region and the ventrals in alternating light green, blue, yellow to creamy yellow with speckles, separated from the dorsal scales with a longitudinal lighter irregular stripe, two prominent, labial stripes from the eye and the loreal pit, up to the edge of the lower end of the supralabial region.

Fairly faded specimen with a light brown dorsum, ventrals and tail; scales bordered with dark brown; temporal stripe visible on the right side of the specimen in dark brown, left side with no visible temporal stripe; body with barely distinguishable dark brown saddle shaped markings throughout the body; tail with dark brown stripes from the vent up to the tip.

An arboreal species, commonly found on bushes and in undergrowth in forests and near streams in evergreen forests to moist deciduous and lowland riparian forests. Due to anthropogenic changes to the landscape, this species is also abundantly found in agricultural landscapes such as coffee plantations, from 100-1800m MSL.

Restricted to the central and northern Western Ghats from Mahabaleshwar – Koyna in Maharashtra to the Nilgiris and Elivalmalai hills, north of the Palghat Gap. Known to occur sympatrically with C. occidentalis comb. nov. in Nilgiris and Coorg, with C. gramineus in Amboli and may have some overlap with C. strigatus in the mid to high elevations of the western slopes of the Nilgiris (at the upper limit of its altitudinal distribution).

Günther (1864) described this species as Trimeresurus anamallensis based on type specimens from the Anamalai hills collected by Col. R.H. Beddome. Subsequently, Boulenger (1896) transferred this species to the genus Lachesis, now attributable to New World crotalids (bushmasters), untill Wall (1924) corrected the generic taxonomy. This nomen (C. anamallensis) was in prevailing usage for this entire species complex (e.g. see Wall, 1924), untill Smith (1943) rightly reinstated Jerdon’s senior nomen C. malabaricus.

Lectotype (here designated): NHMUK 1946.1.19.93 from Anamallay hills (=Anamalai hills) collected by R.H. Beddome. — Paralectotypes: NHMUK 1946.1.18.73–74, NHMUK 1946.1.19.82, NHMUK 1946.1.19.89, NHMUK 1946.1.19.94–95, and NHMUK 1946.1.20.3, from Anamallay hills (=Anamalai hills) collected by R.H. Beddome. — Other specimens: CESS178 from Topslip, Anamalai Tiger Reserve, Tamil Nadu, by Ashok Kumar Mallik, 2011; CESS181, Orukomban Range, Parambikulam, Kerala by Ashok Kumar Mallik in 2011; CESS166 from Goodrickal Range, Kakki, Periyar Tiger Reserve, Kerala, by Saunak P. Pal, 2011.

Anamalai hills, Southern Western Ghats, Tamil Nadu, India; same type locality for the type series of C. anamallensis.

The specific epithet anamallensis is a toponym, alluding to its type locality - the Anamalai hills of the Southern Western Ghats.

A cryptic lineage belonging to the C. malabaricus complex, this lineage (L3) is genetically divergent from C. malabaricus (L5) by 8.3% & 1.2%, and from C. travancoricussp. nov. (L4) by 7.1% and 1.5% at cyt b and 16S respectively. This lineage is geographically isolated from C. malabaricus to the North (separated by Palghat Gap) and to the south the boundary broadly lies in the Periyar Plateau, between Gudrikal range (its southern limit) and Devarmalai (northern limit of its sister lineage C. travancoricussp. nov.).

Lectotype in a generally good condition, entire with a cylindrical body of SVL 505mm and a prehensile tail of TL 87mm; dorsal scales mildly keeled with DSR 21, MSR 21 and PSR 15; head of length 29mm prominent and clearly distinguished from the neck with strongly imbricate small scales; tip of the rostral scale visible from above, with the upper end roughly half the size as the lower; divided supraoculars with nine cephalic scales between both the supraoculars; nine scales surrounding each divided pair of supraoculars on both the sides with nine scales between the posterior border of the supraoculars; distinct canthus rostralis with four scales on the canthal ridge; two preoculars and two postoculars, an elongated cresent shapend subocular; strongly keeled temporals and keels continue to be present in other head scales behind the oculars except the supralabials towards the posterior; eye with a distinct elliptical pupil of vertical diameter 3.3 mm and a horizontal diameter of 3.98 mm; nostril aperture completely covered by the nasal scale, undivided and pentagonal-sub rectangular in shape, in contact with the first three canthal scales, first and second supralabial; nine supralabials and eleven infralabials, with eight scales between the edge of the mouth and the first ventral scale; 1^st, 2^nd and 3^rd infralabial scale in contact with the first pair of genials; a gap of six scales in between the first genial and ventrals; 157 ventrals separated laterally from the body scales by a row of slightly broader dorsal scales; anal scale undivided followed by 55 divided caudals; terminal scale rounded and blunt at the tip, slightly larger than the previous scale.

The following characters vary within the specimens of the examined type series. Variations in pholidosis between the specimens were: supralabials 9–10 and infralabials 11–13, preoculars 2–3, ventrals 144–145 and subcaudals 50–62, about 8–12 scales between the edge of the mouth and the ventral scales; 21–22 scale rows around the neck; the post ocular stripe sometimes extends to 2 rows of scales.

Black dorsal head scales with the anterior scales with hints of light green and posterior head scales bordered with yellow, up to the postocular eye stripe, that extends untill the nape; light bluish green on the lateral parts of the head that fades into a creamy yellow to white underside, from the mandibular region up to the ventrals; ventral scales creamy yellow scales alternating with light greenish yellow scales, consecutively larger gaps between the lighter scales filled with the greenish yellow scales towards the tail - these correspond to the alternating between creamy yellow and green scales in the column that separates the ventrals and dorsal scales; caudal scales yellow, bordered and often blotched with black scales; black blotches throughout the dorsum with a gap of 3–4 scale rows.

Head dorsum almost completely covered black to dark brown and scales bordered with light faded green; black/ dark brown postocular stripe about 2 scales wide, a preocular/ temporal stripe that continues to the loreal pit and ends at the supralabials below; black markings on the labials below the suboculars; body in light faded green with black saddle shaped markings, the markings centered with faded brown marbled markings; the row dorsal of scales that meet the ventrals alternate between the dorsal light faded green and dark brown/ black markings with a gap of two to three scales in between them; ventrals plain light creamish yellow; subcaudals in black with yellow blotches.

Similar to C. malabaricus, an arboreal species, commonly found on bushes and in the undergrowth in forests and near streams in moist evergreen forests to deciduous and lowland riparian forests. Due to anthropogenic changes to the landscape, this species is also often found in cultivated landscapes such as coffee plantations, from 100–1800 m asl.

Endemic to the southern Western Ghats, south of the Palghat Gap and north of the Shencottah Gap. We recorded this species in the Nelliamapthy, Anamalai and Palni hills, Cardamom hills, and northern sections of the Periyar plateau. Craspedocephalus anamallensis has been recorded to be sympatric with C. macrolepis at the highest limit of its elevational range (see Malhotra & Davis, 1991).

Holotype: BNHS 3595 (CESS074) from Bonnakard, Peppara, Kerala by Saunak Pal and S. P. Vijayakumar in 2010; BNHS 2607 from Thiruvananthapuram, collector and year unknown. — Paratype: BNHS 3594 (CESS257) from Devarmalai, Tamil Nadu by Saunak Pal and Mrugank Prabhu in 2011.

Peppara (8°39.7167’N; 77°10.7167’E), Kerala, a part of the Agasthyamalai Hill complex of the Southern Western Ghats.

Toponym, named after its distribution in the far south of the Western Ghats, in the southern parts of the ‘Travancore’ hill ranges.

As previously elaborated and clarified (see C. malabaricus account), historical collections and typifications (both prevailing and previously synonymized treatments) did not involve the population circumscribed here as a distinct lineage. Therefore, this innominate population, previously cited (see Inger et al. 1984; Ishwar et al. 2001) under the chresonymy of C. malabaricuss. lat. is here named anew.

A cryptic lineage belonging to the C. malabaricus complex, this lineage (L4) is genetically divergent from C. malabaricus (L5) by 9% & 2.2% and from C. anamallensis (L3) by 7.1 & 1.5% at cyt b and 16S respectively. This lineage is also allopatric with its related taxa C. malabaricus occurring north of the Palghat Gap and is immediately allopatric with C. anamallensis distributed just north of its distribution range, north of the Shencottah Gap.

Holotype in good condition, dissected, with a slender, cylindrical body of snout to vent length (SVL) 345 mm and a prehensile tail of length (TL) 61 mm; dorsal scales keeled with anterior dorsal scale rows (DSR) 21, mid body scale rows (MSR) 23 and posterior scale rows (PSR) 14-15; head prominent, of length 20.28 mm, clearly distinguished from the neck with small, juxtaposed dorsal scales on the head; rostral scale sub triangular with the upper side roughly half the size of the lower side with the tip visible from above supraoculars of length 3.64 mm and width 1.0 mm, separated by seven scales, between the posterior edge of the supraocular scales; canthus rostralis distinct with four canthal scales on the ridge; three preoculars, two postoculars and a thin elongated crescent shaped subocular, in contact with a small scale, encompassed by the third and fourth supralabial scale; eye with a distinct elliptical pupil, vertical diameter of the eye 2.6 mm and horizontal diameter 3.4 mm.; temporal scales mildly keeled; aperture of the nostril completely covered by the nasal scale, undivided and subrectangular; nasal scale bordering the first supralabial; loreal pit present in contact with the second supralabial with two scales between the nasal and the second supralabial: nine supralabials and 11 infralabials, with nine scales between the last supralabial, including the last supralabial till the start of the ventral scales; 1^st, 2^nd and 3^rd infralabial scale in contact with the first pair of genials; a gap of three scales including the posterior genials followed by 147 ventrals, laterally separated from the dorsal scale rows by a slightly broader row of dorsal scales; anal scale undivided, followed by 55 to 56 divided subcaudals scales; terminal scale on the tail larger than the previous scale, blunt at the tip.

The paratypes have SVL upto 282 mm and TL 65 mm, and differ from the holotype with respect to pholidosis by having 20 to 21 DSR, 21 MSR, 14 to 15 PSR, 157 ventrals and 55 subcaudals; three to four canthal scales on the canthus rostralis, and seven to nine cephalic scales from above; 10 to 12 infralabials on both sides.

Head dorsum almost covered with dark brown to purplish brown colour with scales bordered with light yellowish green; postocular and preocular stripe almost indistinguishable from the head dorsum colour, separated with a faded yellowish green stripe; dark brown postocular stripe about 3 scales wide, a preocular/ temporal stripe that continues to the loreal pit and ends at the supralabials below; black border markings on the labials below the suboculars and anterior supralabials; body in light faded green and brown marbled scales with 28 brown saddle shaped markings, the markings centered with faded brown marbled markings; the row dorsal of scales that meet the ventrals alternate between the dorsal marked with faded yellow and dark brown with a gap of two to three scales in between them; ventrals plain light creamish yellow; subcaudals in black with yellow blotches; tail with 13 yellowish green bands on dark brown to black; eyes silverish with a tinge of yellow, rufous red blotches throughout the eye, concentrated towards the middle, perpendicular to the pupil, almost forming a cross.

Similar to colouration in life with brighter colours faded dull and yellows throughout the body bleached to a creamish white colour; pupils bluish white, dilated.

Similar to other members of the C. malabaricus group, an arboreal species, commonly found on bushes and in the undergrowth in forests and near streams in moist evergreen forests to deciduous and lowland riparian forests, from 100–1800 m asl.

Recorded mostly from Agasthyamalai with a single isolated record from Devarmalai hills, across the Shencottah gap. This species may occur sympatrically with C. peltopelorsp. nov. in the highest elevations of Agasthyamalai.

Russell (1796) described ‘Boodroo Pam’ based on a specimen from Vizagapatam (now Vishakhapatnam, Andhra Pradesh state, India) in the northern Eastern Ghats. Shaw (1802) provided a nominate description of that taxon as Coluber gramineus, based on the specimen depicted by Russell (1796). Bechestein (1802) erected the nomen Coluber viridis and Daudin (1803) erected the nomen Vipera viridis based on the same specimen depicted in Russell (1796). These nomina are connected by an objective synonymy and therefore share the same type specimen (see Russell, 1796) and type locality, Vizagapatam. Notwithstanding these, Lacépède (1804) described an Indonesian species as Trimeresurus viridis. This nomen Trimeresurus viridis Lacépède, 1804 has now been superseded by its junior subjective synonym Trimeresurus insularis Kramer, 1977 that is now in prevailing usage (see David et al. 2011). Three unavailable nomina Trigonocephalus fario Jan, 1859, Bothrops viridis fario Jan, 1863 and Bothrops viridis genei Jan, 1863 are present.

Jerdon (1854) discusses this taxon under the nomen Trigonocephalus (Cophias) viridis and miscredits it to Merrem. Beddome (1862) discusses this taxon in part (specimen from Condipalli hills) under the nomen Trimeresurus viridis (see below). Günther (1864) discusses unrelated East Asian species from Penang, Mergui, Laos, Khasya, Sikkim, Ladakh and Ningpo. Günther (1864) questioned if Andaman and Nicobar populations are conspecific with Tri. gramineus s. auct. but concludes that it could not be ascertained based on Blyth’s (1846) brief notes. Theobald (1876) also followed a similar view and refers populations from Sylhet, Burma and Malacca under this name. Subsequently, he maintained the same stance when he mentioned specimens from Sikkim, Khasi hills, Assam, Pegu, Andamans, Bengal and Nepal (Theobald, 1876).

Later Boulenger (1890), perhaps prompted by earlier works (e.g. Theobald), lumped together several S.E. Asian nomina such as Trimeresurus viridis Lacépède, 1804 (see David et al. 2011 for its proper explanation), Trigonocephalus erythrurus Cantor, 1839, Trimeresurus albolabris Gray, 1842, Trimeresurus elegans Gray, 1853 and even a non-green taxon Trimeresurus mutabilis Stoliczka, 1870 (see Vogel et al. 2014 for its current status). Stejneger (1907) also followed Boulenger (1890). This diluted and over-circumscribed concept of ‘Tri. gramineus’ (sic) encompassing almost all green Trimeresurus species, gave rise to the false notion that it is a very widespread and variable species.

Coluber viridis Bechestein, 1802 and Vipera viridis Daudin, 1803 are both objective junior synonyms of Coluber viridis Shaw, 1802, all being described on the basis of the very same type specimen described and illustrated by Russell (1796) as “Boodroo Pam”. Trimeresurus viridis Lacépède, 1804 is a nomen oblitum superseded by Trimeresurus insularis Kramer, 1977 that is now in prevailing usage for this Indonesian species (Wallach et al. 2014). Two female paratype specimens from the Eastern Ghats and one male specimen from Matheran, northern Western Ghats of a former subjective junior synonym (fide Wallach et al. 2014) Trimeresurus occidentalis Pope & Pope, 1933 is herein referred to Tri. gramineus (Shaw, 1802) with respect to its phylogenetic and morphological affinities.

Holotype (iconotype), a 762 mm specimen described and illustrated in Russell (1796: 13–14, pl. 9, titled “Boodroo Pam”).

“hills in the vicinity of Vizagapatam, coast of Coromandel, India” [= Vishakhapatnam, Andhra Pradesh, India, 17°41’N; 83°13’E].

gramineus, ‘grassy’ in Latin, alluding to its grass-green dorsal colouration.

NHMUK 1946.1.19.87 from Cuddapa Hills, Andhra Pradesh, by R.H. Beddome paratype of Trimeresurus occidentalis Pope & Pope, 1933; CESS033 from Gandagan, Orissa by Ashok Kumar Mallik; CESS100, CESS101, CESS102 from Naneghat, Maharashtra by Ashok Kumar Mallik in 2010; AFS96.13 from Masinagudi, and AFS96.14 Gingee, Tamil Nadu by Anita Malhotra in 1997; BNHS 2627 from Khandala, Maharashtra by Charles Mc Cann in 1941, BNHS 2764 from Ahwa, Dangs, Gujarat by Dr. E.M. Shull in 1963 and BNHS 3275 from Sirumalai hills, Tamil Nadu by S.P. Vijayakumar, 2001; CESS526 from Shevroys, Tamil Nadu by Achyuthan Srikanthan and M.V. Shreeram in 2019.

A cryptic lineage (L1) belonging to the C. gramineus complex, it is distinguished from C. occidentalis (L2) as follows: lower ventral scale count 158–179 (vs.142–154). It is genetically divergent from C. occidentalis by 8.1 % and 1.0 % at cyt b and 16S respectively. This lineage is far more widespread than its parapatric sister taxon C. occidentalis, occuring almost throughout peninsular India from Odisha in the east, southern Gujarat to the north-west and as far south as the Srivilliputhur hills.

A species with a slender, cylindrical body of snout to vent length (SVL) up to 679 mm and a prehensile tail; dorsal scales keeled with anterior dorsal scale rows (DSR) 19–21, mid body scale rows (MSR) 19–21 and posterior scale rows (PSR) 15; head prominent, clearly distinguished from the neck with small, juxtaposed scales on the head; rostral scale sub triangular with the upper side roughly one fourth the size of the lower side with the tip visible from above; supraoculars separated by 8–11 scales, between the posterior edge of the supraocular scales; canthus rostralis distinct with three to four canthal scales on the ridge; two to three preoculars, two to three postoculars and a thin elongated crescent shaped subocular; eye with a distinct elliptical pupil; temporal scales mildly keeled; aperture of the nostril completely covered by the nasal scale, undivided and subrectangular; nasal scale bordering the first supralabial; loreal pit present in contact with the second supralabial with two scales between the nasal and the second supralabial; 10–12 supralabials and 11–13 infralabials, with 9–13 scales between the last supralabial, including the last supralabial up to the start of the ventral scales; ventrals 158–179, laterally separated from the dorsal scale rows by a slightly broader row of dorsal scales anal scale undivided, divided subcaudals 54–67; terminal scale on the tail larger than the previous scale, blunt at the tip.

Head and dorsum colour from verdant green to leaf green, sometimes bluish green with black, alternating saddle shaped markings on the dorsum; preocular/ temporal stripe in black, sometimes green fading into black; ventrals with bright yellow, creamish yellow to a dirty white colour; the region where the ventrals meet the dorsum alternating with the ventral colour once every 2–3 scales.

A highly arboreal species found in dry scrub, dry deciduous, semi evergreen and lowland riparian forests from 100-1600 m asl.

Endemic to Peninsular India. Found in the Eastern Ghats (Simlipal hills, Chota Nagpur plateau southwards upto Sirumalai hills) and hills of Central India (Pachmahri, Seoni hill ranges) as well as the Western Ghats from Surat Dangs, southwards till the Shencottah gap.

Pope & Pope (1933), in an effort to fix the status of Southeast Asian taxa of superficially similar green Trimeresurus species, worked out the systematics of the Indian group. Unfortunately, they were mistaken in allocating the nomen Coluber gramineus Shaw, 1802 to the East Asian species (see David et al. 2011). Therefore, thinking that the western population inhabiting India required a new nomen, they thus erected Trimeresurus occidentalis. This taxon was described based on a series of specimens (holotype and paratypes) inhabiting both the Western Ghats and the Eastern Ghats.

Among the four paratypes attributed to this taxon in its original description (Pope & Pope, 1933), one male from Brahmagiri, Western Ghats is currently attributable to this species based on the phylogenetic position of topotypical samples. The distribution of C. occidentalis, as defined here, encompasses the provenance of the holotype (Mudumalai, Wayanad, and the Nilgiri hills in general). We refer three other paratypes, two females originating from the Cuddapa hills and the Shevaroys in the Eastern Ghats and one male from Matheran to C. gramineus (Shaw, 1802) based on the phylogenetic placements of topotypical samples. However, as paratypes have no name-bearing function and status, the nomen Craspedocephalus occidentalis is available in toto for being conferred to this Western Ghats population. Beddome (1862) discusses a specimen from Anamalais under the name Trimeresurus viridis and also miscredits the nomen to Gray, instead of Bechestein or Daudin (see Wallach et al. 2014).

Holotype, NHMUK 1982.8.26.40, an immature male, collected by R.H. Beddome.

Mudumallay, near Wayanad [i.e., Mudumalai hills, in Nilgiris dt., Tamil Nadu, India] in the Western Ghats (fide Pope & Pope 1933).

Latin, for ‘western’, in allusion to its western distribution range, compared to S.E. Asia.

Holotype, NHMUK 1982.8.26.40 from Wayanad, Tamil Nadu by R.H. Beddome; CESS040 from Brahmagiri, Karnataka by S.P. Vijayakumar in 2009; CESS272 from Tadiendamol, Karnataka by Ashok Kumar Mallik in 2011.

A cryptic lineage (L2) belonging to the C. gramineus complex, it can be distinguished from C. gramineuss. str. (L1) as follows: lower ventral scale count 142–154 (vs. 158–179). L2 is genetically divergent from C. gramineuss. str. (L1) by 8.1 % at Cyt b and 1.0 % at16S. This lineage is possibly parapatric with respect to its far more widespread sister taxon C. gramineus, and is endemic to the Wyanad-Bramagiri-Coorg hill complex of the central Western Ghats, at higher elevations (> 1000 m MSL).

Holotype in good condition, entire, with a slender, cylindrical body of snout to vent length (SVL) 400 mm and a prehensile tail of length (TL) 97 mm; dorsal scales keeled with anterior dorsal scale rows (DSR) 23, mid body scale rows (MSR) 21 and posterior scale rows (PSR) 15; head prominent, of length 21.5 mm, clearly distinguished from the neck with small, juxtaposed dorsal scales on the head; rostral scale sub triangular with the upper side roughly one fourth the size of the lower side with the tip visible from above; supraoculars of length 1.85 mm and width 4.15 mm, separated by eight scales, between the posterior edge of the supraocular scales; canthus rostralis distinct with four canthal scales on the ridge; two preoculars, two postoculars and a thin elongated crescent shaped subocular, in contact with a pair of scales scales that are in contact with the third and fourth supralabial scale; eye with a distinct elliptical pupil, vertical diameter of the eye 2.23 mm and horizontal diameter 2.44 mm; temporal scales mildly keeled; aperture of the nostril completely covered by the nasal scale, undivided and subrectangular; nasal scale bordering the first supralabial; loreal pit present in contact with the second supralabial with two scales between the nasal and the second supralabial; nine supralabials and 10 infralabials, with seven scales between the last supralabial, including the last supralabial up to the start of the first ventral scale; 1^stand 2^nd infralabial scale in contact with the first pair of genials; a gap of six scales including the posterior genials followed by 155 ventrals, laterally separated from the dorsal scale rows by a slightly broader row of dorsal scales; anal scale undivided, followed by 60 divided subcaudals scales; terminal scale on the tail larger than the previous scale, blunt at the tip.

Head and dorsum colour varies from bright green to faded dull green, with no markings on the dorsum; preocular/ temporal stripe absent; ventrals in creamish yellow to dirty white colour; the region where the ventrals meet the dorsum alternating with the ventral colour once every 2–3 scales; the colour of the dorsum and ventrals divides exactly at the pre/postocular stripe area, with an absence of a dark stripe (as opposed to C. gramineus).

Head and dorsum in light faded green; ventrals creamish to dirty white in colour; some of the dorsum scales with a black interscalar colour, more evident in the front half of the body; the colour of the dorsum and ventrals divides exactly at the pre/postocular stripe area, with an absence of a dark stripe (as opposed to Tri. gramineus).

A highly arboreal species found in moist evergreen forests from 1000–1900m MSL, sympatric with C. malabaricus throughout parts of its range.

Endemic to the central Western Ghats, distributed in the Wayanad, Brahmagiri, Coorg hills, at higher elevations (> 1000 m asl).

Originally in error, mentioned as “Cape of Good Hope?” and “Madras” subsequently emended to Madras Presidency (=Tamil Nadu) by Boulenger (1896) (see Wallach et al. 2014).

Latinized from its stem word ‘strigate’ alluding to the pattern streaked with colourful, alternate, transverse bars.

Syntypes NHMUK 1946.1.18.79 and NHMUK 1946.1.18.78 from Nilgiris, Tamil Nadu by T.C. Jerdon in 1850.

Syntypes NHMUK 1946.1.18.79 and NHMUK 1946.1.18.78 from Nilgiris, Tamil Nadu by T.C. Jerdon in 1850; CESS142 from Silent Valley, Kerala by Saunak Pal and Mrugank Prabhu in 2010; BNHS 2617 and BNHS 2618 from Coonor by C.Gray in 1917; BNHS 2619 from Coonor by Maj. Frank Wall in 1911; BNHS 2621 from Ooty by Maj. Frank Wall in 1912.

A species of Craspedocephalus (L8) endemic to the Western Ghats, characterized by having the following combination of characters: 2^nd supralabial (usually) not bordering the anterior margin of loreal pit (vs. always bordering in the C. malabaricus, C. gramineus complexes); lacking a prehensile tail and green dorsum (vs. having prehensile tail and green dorsum in the C. gramineus, C. macrolepis complexes); having an undivided supraocular (vs. divided or with indented margins in the C. malabaricus complex).

Relatively stout species with a cylindrical body of snout to vent length (SVL) up to 391 mm and a tail of length (TL) up to 64 mm; dorsal scales keeled with anterior dorsal scale rows (DSR) 20 to 22, mid body scale rows (MSR) 19 to 21 and posterior scale rows (PSR) 15 to 17; head prominent, clearly distinguished from the neck with small juxtaposed scales on the dorsal surface of the head; rostral scale sub triangular with the upper side roughly half the size of the lower side with the tip visible from above; supraoculars separated by 9 to 11 scales on the posterior end; canthus rostralis distinct with three canthal scales; two to three preoculars, two to three postocular and a thin elongated crescent shaped subocular; eye with a distinct elliptical pupil; temporal scales smooth; aperture of the nostril completely covered by the nasal scale, undivided and subrectangular; nasal scale bordering the first supralabial; loreal pit present in contact with the second supralabial with two scales between the nasal and the second supralabial; nine to 10 supralabials and 10 to 12 infralabials, with six to eight scales between the last supralabial, including the last supralabial till the start of the ventral scales; 1^st, 2^nd and 3^rd infralabial scale in contact with the first pair of genials; a gap of three scales including the posterior genials followed by 134 to 142 ventrals, laterally separated from the dorsal scale rows by a slightly broader row of dorsal scales; anal scale undivided, followed by 38 to 44 divided subcaudals scales; terminal scale on the tail larger than the previous scale, blunt at the tip.

Bronze to light brown dorsum blotched with a stark, continuous alternating saddle-shaped pattern in dark brown to black, strikingly similar to the markings on Vipera berus or Gloydius himalayanus; preocular/temporal stripe in dark brown; post ocular stripe in dirty brown continuing towards the loreal pit and the infralabials; another stripe below the subocular stripe fades into the infralabials followed by another blotch towards the end of the infralabials; base colour of the infralabials and ventrals being light creamish to white in colour, often dotted with rufous spots in the supralabials the region where the dorsal scales meet the ventrals in altenating dark brown colour and light brown/bronze colour scales; dorsal bronze scales are dotted with darker brown; the nape is characterized with a prominent horse shoe shaped marking hence earning its common name; in juveniles, the bronze colour is replaced with light brown.

Brown and cream markings dorsally and laterally, occasionally interrupted with silvery/grey scales, tail mostly brown and cream coloured with lighter more vivid cream coloured scales making triangular markings vertically along it (four in total); tip of tail fading to a light cream colour.

A highly terrestrial species found in montane evergreen, moist evergreen and high elevation grasslands.

Endemic to the Nilgiri Massif north of the Palghat Gap, distributed in very high elevations (1700–2600 m asl) (also see Wall, 1919; Bhupathy & Nixon, 2011). This species has the smallest geographic range of all Craspedocephalus in Peninsular India (Ganesh & Chandramouli, 2018).