Craspedocephalus occidentalis (Pope & Pope, 1933) Mallik & Srikanthan & Ganesh & Vijayakumar & Campbell & Malhotra & Shanker, 2021

Mallik, Ashok Kumar, Srikanthan, Achyuthan Needamangalam, Ganesh, Sumaithangi Rajagopalan, Vijayakumar, Seenapuram Palaniswamy, Campbell, Patrick D., Malhotra, Anita & Shanker, Kartik, 2021, Resolving pitfalls in pit viper systematics - A multi-criteria approach to species delimitation in pit vipers (Reptilia, Viperidae, Craspedocephalus) of Peninsular India reveals cryptic diversity, Vertebrate Zoology 71, pp. 577-619 : 577

Craspedocephalus occidentalis (Pope & Pope, 1933) comb. nov.

Figures 20 , 21 , 22

Trimeresurus occidentalis Pope & Pope, 1933

Trimeresurus viridis (nec Coluber viridis Bechestein, 1802) - Beddome, 1862 part

Lachesis graminea - Wall, 1919 part

Craspedocephalus occidentalis (Pope & Pope, 1933)

Taxonomic History.

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.

Remarks.

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).

Type.

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

Type locality.

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

Etymology.

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

Material examined.

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.

Lineage diagnosis.

A cryptic lineage (L2) belonging to the C. gramineus complex, it can be distinguished from C. gramineus s. str. (L1) as follows: lower ventral scale count 142-154 (vs. 158-179). L2 is genetically divergent from C. gramineus s. 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).

Redescription (also see Pope & Pope 1933).

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; 1stand 2nd 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.

Colour in life.

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 ).

Colour in preservative.

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 ).

Habitat.

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

Distribution.

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

Figures

Figure 20. Craspedocephalus occidentalis comb. nov. in life, showing: (A) entire dorsal view, (B) head dorsal view, (C) head lateral view, (D) entire lateral view; Coorg, Karnataka.

Figure 21. Craspedocephalus occidentalis comb. nov. holotype (NHMUK 1982.8.26.40), in preservation, showing: (A) head lateral left view, (B) head dorsal view, (C) head ventral view, (D) head lateral right view.

Figure 22. Craspedocephalus occidentalis comb. nov. holotype (NHMUK 1982.8.26.40), in preservation, showing: (A) entire dorsal view, (B) entire ventral view.