Dendrelaphis nigroserratus, Vogel & Rooijen & Hauser, 2012

Vogel, Gernot, Rooijen, Johan Van & Hauser, Sjon, 2012, A new species of Dendrelaphis Boulenger, 1890 (Squamata: Colubridae) from Thailand and Myanmar, Zootaxa 3392 (1), pp. 35-46 : 39-42

publication ID	https://doi.org/ 10.11646/zootaxa.3392.1.2
publication LSID	lsid:zoobank.org:pub:AEA82C7F-CE12-4248-A498-4E540860AAC3
persistent identifier	https://treatment.plazi.org/id/F928143C-51FA-43AE-97DD-F48078795B15
taxon LSID	lsid:zoobank.org:act:F928143C-51FA-43AE-97DD-F48078795B15
treatment provided by	Felipe
scientific name	Dendrelaphis nigroserratus
status	sp. nov.

Treatment

Dendrelaphis nigroserratus sp. nov.

Figs. 1 View FIGURE 1 , 4a View FIGURE 4 , 6 View FIGURE 6 , 7 View FIGURE 7 , 8 View FIGURE 8

Dendrelaphis striatus, Seesook, 2000

Dendrelaphis striatus, Pauwels et al. 2000

Dendrelaphis cyanochloris, Pauwels et al. 2003

Holotype. QSMI 1282 , juvenile road-killed female ( Fig. 4 View FIGURE 4 , 6 View FIGURE 6 ) collected by Sjon Hauser, on 13 October 2011 at Umphang Wildlife Sanctuary , Umphang district , province Tak, Thailand. Found on Highway 1090, at 5.1 km north and uphill from the bridge over the Mae Klong Khi , near the Karen village of Mae Klong Khi, c. 1100 m a.s.l.

Paratypes (2 specimens). – BMNH 1946.1.6.13 (formerly 1925.9.17.16), female, “Mergui, Burma ”, collector F. Wall ; ZFMK 92809 About ZFMK , damaged specimen, sex unknown, probably a female, “ Between Umphang and Mae Sot, Tak Province, Thailand ”, collector: G. Vogel.

Diagnosis. A species of the colubrid genus Dendrelaphis characterized by 1) a black postocular stripe that extends onto the neck where it forms a pronounced saw-tooth pattern that further posteriorly breaks up into broad black oblique bars, 2) ground colour olive, 3) pale ventrolateral line absent, 4) strongly enlarged vertebral scales, 5) 15 smooth dorsal scales at midbody, 6) 197–204 ventral scales, 7) 148–152 paired subcaudal scales, 8) anal shield divided, 9) relative tail-length 0.30–0.31, 10) 9 supralabials, 4 th through 6 th touch the eye, 11) maximum known total length 156 cm.

The new species differs from all other congeners except D. striatus in the yellow colour of the forepart of the body and the oblique stripes in the anterior half of the body. From D. striatus it differs mainly by the number of ventrals (149–167 in D. striatus ), by the number of subcaudals (120–145 in D. striatus ), and the maximum length (up to 1015 mm in D. striatus ). See below and Table 1 for more detailed comparisons with congeners.

Etymology and suggested common name. The specific epithet is based on the Latin niger (black) and serrare (to saw) and refers to the conspicuous black zigzag (saw-toothed) pattern on the neck. For a colloquial English name we propose Saw-tooth-necked Bronzeback.

Description of the holotype. Juvenile female; snout-vent length 293.0 mm; tail length 134.5 mm; eye very large, horizontal diameter 4.0 mm, pupil circular; distance centre eye to posterior edge nostril 4.5 mm; dorsal scales smooth and in 17–15–11 rows; vertebral scales notably large, with concave posterior margin; anal shield divided; 201 ventral scales; 150 paired subcaudal scales; 9 supralabials, 4th–6th touching eye; infralabials 10 (L), 9 (R); 1 loreal; 1 preocular; 2 postoculars; 6 temporal scales, anteriormost two rudimentary (L), 5 temporal scales, anteriormost one rudimentary (R); paired postparietal shields present; ground colour olive-brown; supralabials, throat yellow; venter greenish; black or pale ventrolateral lines absent; black dot on each preocular; black postocular stripe starts behind eye, covers whole temporal region plus anterolateral edges of parietals, extends onto neck as sawtooth pattern, breaks up further posteriorly into broad black oblique bars, these bars progressively less visible, disappearing behind first third of body.

Variation. A summary of morphological and coloration data of the types is given in Table 2. Some information on uncollected specimens is given in Table 3. The longest specimen in the type series is 1425 mm. Ventrals vary between 200 and 204, the subcaudals between 148 and 152. One paratype has 15 dorsal rows one headlength behind the head. There is no notable variation in colouration.

Natural history. The new species is relatively common in the hill evergreen forests of the districts of Phop Phra and Umphang of Tak province, Thailand. Over the past eight years, one of us (SH) has found at least 40 road kills and seen six living specimens along Highway 1090 in these districts. All were seen in forested areas at elevations of 900 –1350 m. Based on these observations, the new species seems to be as common as the sympatric D. cyanochloris in this area. The new species has been relatively often seen near brooks and dense bamboo thickets ( Fig. 8 View FIGURE 8 ). It is absent in areas where the forest has been destroyed for cultivation of cabbages, suggesting a sensitivity to habitat destruction.

All living specimens were spotted during the daytime, especially on sunny days, and no fresh roadkills have been found early in the morning, suggesting that this species is perhaps strictly diurnal. Little is known otherwise about the new species’ behavior. Photographs taken of a bronzeback in Kaeng Krachan National Park, Thailand, show D. nigroserratus eating a Wallace's Flying Frog, Rhacophorus nigropalmatus Boulenger, 1895 (www.ecologyasia.com/verts/snakes/bronzeback_undescribed.htm).

Distribution. The type specimens originate from Tak province, Thailand and from Mergui (Myeik), Burma ( Fig. 9 View FIGURE 9 ). Over several years, one of us (SH) found road-killed as well as live specimens in Umphang and Phop Phra districts in Tak province, Thailand. Road-killed D. cyanochloris were found in the same area. One specimen of D. nigroserratus was photographed in Kaeng Krachan National Park (see above), which covers parts of Phetchaburi and Prachuap Khiri Khan provinces, Thailand. Finally, Pauwels et al. (2000) provided a record from Phetchaburi Province and Pauwels et al. (2003) from Sangkhlaburi District, Kanchanaburi Province, both locations in West Thailand.

Comparison with other species. None of the Southeast Asian congeneric species exhibits the conspicuous neck coloration of D. nigroserratus sp. nov. Thus, it can be unambiguously identified on the basis of this character alone. See Table 1 for a comparison with D. cyanochloris and D. striatus . Furthermore, D. nigroserratus sp. nov. is distinguished from D. pictus Gmelin, 1789 by its higher ventral and subcaudal counts (166–178 and 113–147, respectively in D. pictus ), the absence of a pale ventrolateral line and its greater maximum TL (120 cm in D. pictus ); from D. proarchos ( Wall, 1909) by its higher ventral count (173–198 in D. proarchos with 198 representing an outlier, 185 being the mean), by the absence of a pale ventrolateral line and its maximum TL (121 cm in D. proarchos ); from D. biloreatus Wall 1908 and D. walli Vogel & Van Rooijen, 2011 by the number of dorsal scale rows at midbody (13 in D. biloreatus and D. walli ), relative tail-length (0.33–0.35 and 0.32–0.35 in D. biloreatus and D. walli , respectively) and maximum TL (90.0 and 90.5 in D. biloreatus and D. walli , respectively); from D. formosus Boie, 1827 by the absence of black longitudinal lines on the posterior half of the body; from D. haasi Van Rooijen & Vogel, 2008 by its higher ventral counts (161–173 in D. haasi ), its relatively shorter tail (0.34–0.38 in D. haasi ) and its size (maximum TL 94.5 in D. haasi ); from D. ngansonensis Bourret, 1935 by its higher ventral count (180–191 in D. ngansonensis ) and relative tail-length (0.33–0.34 in D. ngansonensis ); from D. subocularis Boulenger, 1888 by the number of supralabials bordering the eye (1 in D. subocularis ), the number of ventrals and subcaudals (151–174 and 91–109, respectively in D. subocularis ); from D. tristis Daudin, 1803 by its higher subcaudal count (117–136 in D. tristis ), broader vertebral scales (smaller than the dorsals of the first row in D. tristis ), absence of a pale ventrolateral line and absence of an interparietal spot; from D. kopsteini Vogel & Van Rooijen, 2007 by its higher ventral count (167–181 in D. kopsteini ), its relatively shorter tail (0.32–0.35 in D. kopsteini ) and the absence of a red neck coloration. For more detailed information on these species see Van Rooijen & Vogel (2008a, c, 2009, 2010), Vogel & Van Rooijen (2007, 2008, 2011a, b) and Ziegler & Vogel (1999).