Dendrelaphis kopsteini, Vogel, Gernot & Rooijen, Johan Van, 2007

Vogel, Gernot & Rooijen, Johan Van, 2007, A new species of Dendrelaphis (Serpentes: Colubridae) from Southeast Asia, Zootaxa 1394, pp. 25-45 : 34-43

Dendrelaphis kopsteini sp. nov.

( Figs. 9–14 )

Ahaetulla formosa (non Dendrophis formosus Boie, 1827 ): Taylor (1965: 814).

Dendrelaphis formosus: Flower (1896: 883) ; Tweedy (1983: 63, 154, plate 4); Lim & Lee (1989: 53); Vogel (1990: 10, Abb. 4); Lim & Lim (1992: 64); Manthey & Grossman (1997: 337, Abb. 246); Ziegler & Vogel (1999: 206); Pauwels et al. (2000: 141); Nutphand (2001: 148).

Dendrophis formosa: Frith (1977: 278) ?

Dendrelaphis formosus (non Dendrophis formosus Boie, 1827 ) part.: Flower (1899: 605, 660); Inger & Voris (2001: 889); Iskandar & Colijn (2002: 53).

Dendrelaphis spec. A: Rubeli (1988: 133.)

This chresonymy includes only citations based on specimens definitely identified as Dendrelaphis kopsteini sp. nov.

Holotype. MNHN 1962.1052, adult female (figs. 9–12), from “fleuve Endau, état de Johore”, Endau river, State of Johore, Federation of Malaysia. Collected by Pierre Pfeffer, unknown date.

Paratypes (7 specimens). Thailand. MNHN 1997.6579 (female) “Phang­Nga Province, Wildlife breeding station, Muang District”; QSMI Q 531 (former PSGV 45) (female), “near Thung Song, Nakhon Si Tammarat Province, South Thailand ”. Federation of Malaysia (West Malaysia). MNHN 1962.1051 (male),” fleuve Endau, état de Johore” meaning Endau river, Province of Johore, Federal Republic of Malaysia; ZMH R08445 (former PSGV 269) (male), “way to Cameron Highlands, 620m ”, on the highway to Cameron Highlands, Perak province, 620m; RMNH 40117 (former PSGV 777) (male), “Pet Trade, West Malaysia ”. Singapore. MNHN 1893.147 (male), “ Singapore ”. INDONESIA. Sumatra Island. ZSM 277/1909 (female), “Tanjung Morawa”, located near Medan, Sumatera Utara Province.

Diagnosis. A rather stout species of the Dendrelaphis formosus group, with 15 dorsal scale rows at midbody, 167­181 ventral scales, 140­154 subcaudal scales, 2 supralabials touching the eye and a first sublabial that touches 2 infralabials. The eye is rather large. The vertebral scales are larger than the lowest dorsal row. There is one loreal plate. A black postocular stripe covers only the lower half of the temporal region and ends at the rear of the jaw. Vertebral scales with a broad black posterior margin. It differs from all other species of this genus by the red colour that is visible in life on the skin between the scales of the first part of the body.

Etymology. This species is named after Dr. Felix Kopstein (1893­1939), who contributed so much to our knowledge of the snake fauna of Indonesia. Several of the specimens we used for our studies were collected by him. He was also the first to report delayed fertilisation.

Suggested English name: Kopstein’s Bronzeback.

Description of the holotype (figs. 9­12). Body slender; head long, distinct from the neck, rather broad for a species of this genus, when seen from the side. Eye rather large, 7.1 mm in diameter. Pupil round. Tail long. The reddish tongue is protruded.

SVL 95.0 cm; TAIL 46.0 cm; TL 141.0 cm; ratio TAIL/TL: 0.33; 181 ventrals (+3 preventrals); 147 divided subcaudals (plus 1 terminal scale); anal shield divided; dorsals 15:15:11; dorsal scales disposed obliquely, smooth and without apical pits; vertebral scales enlarged, larger than first row of dorsals, hexagonal in shape and with straight posterior margins; 1 loreal (L+R); 1 preocular (L+R); 2 postoculars (L+R); 1 supraocular (L+R); 8 supralabials (L+R); supralabials 4 and 5 touch the eye (L+R); 10 infralabials (L), 11 infralabials (R); first infralabials touch at the mental groove; infralabials 1 through 5 touch anterior chin shield (L+R); infralabials 5 and 6 touch posterior chinshield (L+R); first sublabial short, touches infralabials 6 and 7 (L+R); temporals 2:2:2 (L+R).

Ground­colour bronze; a black temporal stripe starts before the eye, covers the lower half of the temporal region and ends at the rear of the jaw. The throat is yellowish with the sublabials being partly bluish. The vertebral scales have a very broad black posterior edge. Some vertebral scales lack a white lateral margin, some have a unilateral white margin and some have white margins bilaterally; subcaudals have a black point medially; no lateral black stripes in posterior half of the body; dorsals on the tail have a pronounced black circumference resulting in a reticular black pattern on the tail; no light ventrolateral stripe. Belly dark.

Description of the paratypes. A summary of morphological and coloration data of the paratypes is given in Table 3 . Other important characters agree with features of the holotype.

Description and variation. The maximal total length known is 142.5 cm (SVL 96.5 cm, TAIL 46.0 cm) for a male (MNHN 1893.147 from Singapore). The largest known female is 131.5 cm long (SVL 88.0 cm, TAIL 43.5 cm; MNHN 1997.6579 from Phang­Nga, Thailand). This species reaches a size similar to D. cyanochloris and D. formosus .

Body relatively slender in males and females; head long, distinct from the neck, rather broad for a species of this genus, when seen from the side. Eye rather large, 5.8–7.1 mm in diameter (unadjusted values). Diameter eye / distance (anterior border of) eye to nostril 1.1–1.4 in 3 males, 1.2–1.3 in 4 females. Pupil round. Relative tail length 0.32–0.34. No sexual dimorphism was noted for the relative tail length.

Dorsals smooth, in 15:15:11 rows; 171–179 ventrals (plus 1–3 preventrals) in 4 males, 167–181 ventrals (plus 1–3 preventrals) in 4 females; 141–154 subcaudals in 4 males, 140–147 subcaudals in 3 females, all paired; anal shield divided; 1 preocular; 2 postoculars; 1 loreal; normally 2+2+2 temporals (2+1+2+2, 2+2+1+2, 2+1+2 each in one case); 8­10 supralabials (9/ 10 in 1 specimen, 9/ 9 in 1 specimen, 9/ 8 in 3 specimens, 8/ 8 in 2 specimens, one damaged specimen has 9 on one side); in all cases 2 supralabials touching the eye (4/5 on both sides in 3 specimens, 5/6 on both sides in 2 specimens, 4/5 on one side and 5/6 on the other side in 3 specimens); 10 infralabials, one specimen has 11 infralabials on one side; 2 pairs of gulars between the preventrals and the posterior submaxillaries; 6th and 7th infralabial touched by the first sublabial.

Ground colour bronze, olive or brown, the vertebral scales sometimes lighter with broad black posterior margins. The neck is brick red anterior followed by blue coloration. This coloration is extremely vivid when the snake inflates its neck. This vivid coloration reduces to some blue dots after the first third of the body. The posterior part of the dorsal scales is dark, forming small vaguely defined bands. There are no black lateral stripes and there is no light ventrolateral stripe. The colour of the head corresponds to the ground coloration dorsally. A dark line extends from the nose to the angle of the mouth, covering only the lower temporal region. The upper labials are yellowish as is the underside of the head. The anterior part of the belly is yellowish, darkening towards the rear. The colour of the tail corresponds to the ground colour, dorsally the scales have dark margins. The subcaudals have dark tips forming some kind of a median line. The tongue is red, the eye brown.

In alcohol the red colour vanishes very fast, the blue coloration vanishes after several years. We noted no sexual dimorphism in our sample of 4 males and 4 females.

Range. The examined specimens of D. kopsteini originated from Peninsular Thailand, Peninsular Malaysia, Singapore and Sumatra.

Comparison with other species. Evidently, there are many significant differences between D. kopsteini , D. cyanochloris and D. formosus ( Table 2 ). The most prominent morphological differences are as follows. The eye is very large in D. formosus whereas it is small in D. cyanochloris (see also fig. 15). D. kopsteini takes up an intermediate position. Although this was not quantified and tested, the shape of the head corresponds with the eye­size. In D. formosus , the head bulges behind the snout to accomodate the large eye whereas the head is nearly flat in D. cyanochloris (fig. 15). Again, D. kopsteini takes up an intermediate position. The three species differ in tail­length which is highest in D. kopsteini . The three species differ significantly in ventral count which is highest in D. cyanochloris and lowest in D. kopsteini . D. formosus has a higher subcaudal count than D. cyanochloris . A conspicuous difference lies in the length of the first sublabial. In D. formosus , this shield is very long whereas it is short in both D. kopsteini and D. cyanochloris . Finally, the eye is always touched by two supralabials (4,5 or 5,6) in D. kopsteini whereas in most cases it is touched by three supralabials (mostly 4,5,6 where 4 touches the eye with the posterior corner) in D. formosus and D. cyanochloris . The differences in coloration are pronounced and highly invariable. D. formosus always has three black lateral stripes in the posterior half of the body whereas these stripes never occur in D. cyanochloris or D. kopsteini . The black stripes in D. formosus are a prominent feature and are even explicitly mentioned in Boie’s overly concise description. In D. kopsteini the postocular stripe covers only the lower half of the temporal region and ends at the rear of the jaw. In contrast, the postocular stripe covers the whole temporal region and runs onto the neck in both D. formosus and D. cyanochloris . D. kopsteini has vertebral scales with a very broad black posterior margin in contrast to D. formosus and D. cyanochloris . Finally, in both D. formosus and D. kopsteini the subcaudals often have black tips whereas this is never the case in D. cyanochloris . The differences in eye­size and tail­length between D. kopsteini and D. humayuni were determined separately (see materials and methods) and are not shown in table 2. D. kopsteini differs from D. humayuni in having a much larger eye (5.5­6.2 versus 4.0­5.4 (SVL­adjusted values); p<0.0001) and a longer tail (38.5–41.0 cm versus 32.5–39.0 cm (SVL­adjusted values); p=0.0002). In addition, the postocular stripe ends at the rear of the jaw in D. kopsteini . In D. humayuni , it runs onto the neck in where it breaks up into black spots (based on the description by Tiwari & Biswas, 1973; picture in Vijayakumar & David, 2006 and examination of BMNH 1940.3.4.28). Finally, Dendrelaphis kopsteini differs from all other members of the genus by its brick red nape, which makes it very easy to identify if it is alive or freshly dead.

Apart from the differences, there are some important similarities. All species of this group have strongly enlarged vertebral scales that are larger than the first row of dorsals, 15 dorsals at mid­body and a single loreal scale. Dendrelaphis ­species have either 15 or 13 dorsals at mid­body and Mertens (1934) considered the possession of 15 dorsals to be a primitive character state. Finally, all lack the light ventrolateral stripe which is present in several Dendrelaphis ­species and was considered to be a primitive character state by Mertens (1934). Pending phylogenetic analysis of this genus, we define the D. formosus group on the basis of these similarities. The following species are members of this group: D. kopsteini , D. cyanochloris , D. formosus , D. humayuni , D. cf. cyanochloris (Java) .

Discussion. In order to evaluate the status of D. kopsteini , D. cyanochloris and D. formosus , the distributional ranges of the latter two species need to be revised. The examined specimens of D. cyanochloris originated from Northeast India, Burma and Thailand with the Thai Peninsula being the southernmost record. Another record from the Thai Peninsula, ( Frith, 1977) is trustworthy given the morphological data provided (213 ventrals, 151 subcaudals). A record from Peninsular Malaysia (Chan­Ard et al., 2001) without a doubt is a D. formosus as the shown specimen has black lateral lines and a large eye. The records from Pulau Tioman, West Malaysia (e.g. Hien et al., 2001; Van Rooijen & Van Rooijen, 2002) are questionable. The portrayed specimens appear to be D. formosus although they might even represent an undescribed taxon. Finally, Wall (1921) mentioned the Nicobar islands as part of the range but these records turned out to represent D. humayuni ( Tiwari & Biswas, 1973; Vijayakumar & David, 2006). Indeed, a specimen from the Nicobars examined by us (BMNH 1940.3.4.28) also turned out to be a D. humayuni . The examined specimens of D. formosus originated from Peninsular Thailand, Peninsular Malaysia, Sumatra (including the Mentawei Islands), Java and Borneo. As such, all three species occur sympatrically in Peninsular Thailand. In addition, D. kopsteini occurs sympatrically with D. formosus in Peninsular Malaysia and Sumatra.

D. kopsteini , D. formosus and D. cyanochloris differ from each other with regard to coloration, scalation and body­proportions. The three species are discretely diagnosable on the basis of several characters and there is no indication of hybridization in areas of sympatry. As such, whether the Biological Species Concept or the Evolutionary Species Concept (e.g. Frost & Hillis, 1990) is applied, there is no doubt that these species represent independent lineages. An updated key to the Dendrelaphis ­species of the Sunda­region is provided below. D. humayuni is included as it is a member of the D. formosus group. It is entirely possible that more undescribed species inhabit the Sunda­region. Therefore, the key may not work in all cases.

1 13 dorsal scale rows at mid­body ............................................................................................ caudolineatus

­ 15 dorsal scale rows at mid­body ................................................................................................................ 2

2 a light ventrolateral stripe present ......................................................................................................... pictus

­ no light ventrolateral stripe.......................................................................................................................... 3

3 temporal stripe covers only the lower part of the temporal region.............................................................. 4

­ temporal stripe covers the whole temporal region....................................................................................... 5

4 temporal stripe ends at the rear of the jaw; neck red when inflated; eye large; 2 supralabials touch the eye; first sublabial touches 2 infralabials .................................................................................. kopsteini sp. nov.

­ the temporal stripe runs onto the neck where it breaks up into black bars; neck not red; eye small ............ ........................................................................................................................................................ humayuni

5 neck yellow when inflated; black oblique bars laterally on the body; less than 170 ventrals ........... striatus

­ neck not yellow, more than 170 ventrals ..................................................................................................... 6

6 3 black lateral stripes present on the posterior third of the body; eye very large, head bulges behind the snout to accomodate the large eye; first sublabial touches more than 2 infralabials ....................... formosus

­ 3 black lateral stripes absent; eye small, head nearly flat, more than 180 ventrals....................................... .............................................................. cyanochloris (mainland South­East Asia) / cf. cyanochloris (Java)

Given the number of highly significant differences between D. kopsteini , D. formosus and D. cyanochloris , it is amazing that these species have been confused for such a long time. On the other hand, early confusions have led to mistakes in the literature which have led to subsequent misidentifications. Such vicious circles can only be broken by thorough re­examination of the original material. For example, Boulenger (1894) mentions a ventral range of 179­205 and a subcaudal range of 132­158 for D. formosus . These data have been copied in subsequent major works such as De Rooij (1917), Meise & Henning (1932) and Taylor (1965). The subcaudal minimum of 132 is very low whereas the ventral maximum of 205 is very high compared to our data (table 2). The source of the low subcaudal minimum mentioned by Boulenger (1894) was a specimen originating from “ Afghanistan (??)”. Examination of this specimen ( BMNH 43.7.21.68) showed that it was indeed not a D. formosus , although it could not be identified. The high ventral maximum of 205 mentioned by Boulenger was based on a specimen from Java. The specimen was not examined in this study, but on the basis of the collected data on formosus ­specimens from Java (n=20), the probability to observe a specimen with 205 ventrals was calculated to be lower than 0.00005. Given the low number of specimens examined by Boulenger (n=6), his extremely high maximum ventral count is highly unlikely. Furthermore, the above­mentioned probability was calculated on the basis of a theoretical normal distribution. As biological variables do not follow theoretical normal distributions to the extremes of the distribution, the count provided by Boulenger is probably non­existent in reality. As such, it is evident that the initial ranges in ventral and subcaudal counts as given by Boulenger were not based solely on D. formosus . This idea is strengthened by Boulenger’s statement that black lateral lines may be present in the posterior part of the body of D. formosus . In fact, all specimens examined by us (n=33), from the whole distributional range, possessed black lateral stripes posteriorly. Similar shortcomings held true for the description of D. cyanochloris . Wall (1921) mentioned a ventral count of 175­207 in the original description. However, his description of D. cyanochloris was partly based on specimens of D. humayuni which has a relatively low ventral count (170­178, Vijayakunar & David, 2006). Due to these inaccuracies, the incorrect ventral range of D. formosus (179­205) as given by Boulenger (1894) was nearly identical to the incorrect ventral range of D. cyanochloris (175­207) as given by Wall (1921). In reality, the species differ significantly in ventral count (table 2). In addition, the conspicuous posterior lateral stripes in D. formosus could not be used to differentiate D. formosus from D. cyanochloris as these were incorrectly thought to be variably present in D. formosus .

The fact that such a common snake as D. kopsteini has never been regarded a distinct species must be the result of the longstanding problems surrounding the identities of D. formosus and D. cynochloris : D. kopsteini has simply been hidden from taxonomic herpetology behind a cloud of confusion.

The major landmasses of the Sunda region have been interconnected several times during the geological history of the area ( Inger & Voris, 2001) enabling species to disperse across the Sunda region. The last connections occurred between 10.000 and 17.000 years ago due to northern glaciation. Especially terrestrial and arboreal species have been able to use these connections to migrate and as a result are frequently wide spread ( Inger & Voris, 2001). For example, D. formosus and D. pictus occupy all the major land masses of the Sunda region. D. kopsteini has evidently used those connections to attain its present distribution. However, for some reason, D. kopsteini has not been recorded from Java and Borneo. Java has a relatively small surface area and therefore harbours a relatively low diversity (In Den Bosch, 1985). In addition, its climate is quite different, with a marked dry season throughout much of the island. As such, exclusion of certain species from the Javanese fauna is not surprising. Indeed, two other members of the genus, D. caudolineatus and D. striatus , are absent from the Javanese snake fauna while present in the remainder of the Sunda region which has a wetter or more equatorial climate. More surprising is the absence of D. kopsteini from Borneo. This island has a large surface area and as a result harbours a high biodiversity. Indeed, Borneo is inhabited by all Dendrelaphis species from the Sunda region ( D. caudolineatus , D. formosus , D. pictus , D. striatus ), with the exception of D. kopsteini . Possibly, this otherwise rather common snake is rare on Borneo, and consequently as yet unrecorded from that island.

Specimens examined. Dendrelaphis cyanochloris . North­East India: BMNH 1940.3.4.27, BMNH 1909.3.9.10, BMNH 1940.3.4.26; Burma: BMNH 1946.1.6.13, BMNH 1925.4.2.34; Thailand: PSGV 761b, PSGV 761c small, PSGV 761a large, MNHN 1999.7624, ZMB 58905.

Dendrelaphis cf. cyanochloris . Java: RMNH 6880, RMNH 40100, RMNH 7447 (82).

Dendrelaphis formosus . Java: SMF 32346, SMF 32347, SMF 32348, MNHN 1975.70, SMF 18667, RMNH 877, RMNH 9005 (1), RMNH 9005 (2), RMNH 40098, RMNH 40105, RMNH 40099, MNHN 7307, MNHN 469, RMNH 40102, RMNH 36443, RMNH 36446, RMNH 40101, RMNH 36444, RMNH 36447, RMNH 36445, ZMB 7151; Peninsular Thailand: BMNH 1940.3.4.28; Peninsular Malaysia: PSGV 793a small, PSGV 782, PSGV 793b large; Borneo: RMNH 8208 (59), RMNH 8208 (61), RMNH 8208 (58), RMNH 8249, RMNH 872; Mentawei­Islands, Sumatra: RMNH 5524; Padang, Sumatra?: RMNH 870; Deli, Sumatra: ZMA 9441.

Dendrelaphis humayuni . Nicobars: BMNH 1940.3.4.28.

Dendrelaphis kopsteini sp. nov. Peninsular Malaysia: MNHN 1962.1051, ZMH R08445 (former PSGV 269), RMNH 40117 (former PSGV 777), MNHN 1962.1052; Singapore: MNHN 1893.147; Peninsular Thailand: MNHN 1997.6579, QSMI Q 531 (former PSGV 45); Sumatra: ZSM 277/1909

Figures

FIGURE 9. Dendrelaphis kopsteini sp. nov. Holotype, MNHN 1962.1052. Left side of the head. Photograph by Gernot Vog e l.

FIGURE 10. Dendrelaphis kopsteini sp. nov. Holotype, MNHN 1962.1052. Top of the head. Photograph by Gernot Vog e l.

FIGURE 11. Dendrelaphis kopsteini sp. nov. Holotype, MNHN 1962.1052. Ventral side of the head. Photograph by Gernot Vogel.

FIGURE 12. Dendrelaphis kopsteini sp. nov. Holotype, MNHN 1962.1052. Photograph by Gernot Vogel.

FIGURE 13. Dendrelaphis kopsteini sp. nov. Living specimen from Thailand. Photograph by Gernot Vogel.

FIGURE 14. Dendrelaphis kopsteini sp. nov. Living specimen from Thailand. Photograph by Gernot Vogel.

Tables

TABLE 3. Morphological and coloration characters of the paratypes of Dendrelaphis kopsteini.

	MNHN 1962.1051	MNHN 1893.147	Collection number ZMH R08445 RMNH 40117 MNHN QSMI Q 531 ZSM (former PSGV (former PSGV 1997.6579 (former PSGV 45) 277/1909 269) 777)
Sex SVL(cm)	M 78.5	M 96.5	M M F F F 75.5 81.5 88.0 91.0 81.5
TaL(cm)	39.5	46.0	41.5 41.5 43.5 ­ 43.0
Ventrals	175	179	171 173 177 178 167
Subcaudals	154	149	141 148 140 ­ 146
Dorsal formula Infralabials	15:15:11 10/10	15:15:11 10/10	15:15:11 15:15:11 15:15:11 15:15:11 15:15:11 10/10 10/10 10/10 10/10 10/10
Supralabials	9/10	9/9	9/? 8/9 9/8 8/9 8/8
Supralabials touching the eye	5,6/5,6	5,6/5,6	4,5/4,5 4,5/5,6 5,6/4,5 4,5/5,6 4,5/4,5
Infralabials touched by the first sublabial	6,7/6,7	6,7/6,7	­/6,7 6,7/6,7 6,7/6,7 6,7/6,7 6,7/6,7
Postoculars	2/2	2/2	2/2 2/2 2/2 2/2 2/2