Lycodon pictus, Janssen, Helen Y., Pham, Cuong T., Ngo, Hanh Thi, Le, Minh Duc, Nguyen, Truong Q. & Ziegler, Thomas, 2019

Janssen, Helen Y., Pham, Cuong T., Ngo, Hanh Thi, Le, Minh Duc, Nguyen, Truong Q. & Ziegler, Thomas, 2019, A new species of Lycodon Boie, 1826 (Serpentes, Colubridae) from northern Vietnam, ZooKeys 875, pp. 1-29 : 1

Lycodon pictus sp. nov. Figs 2 , 3 , 4 , 5 , 6

Holotype.

IEBR 4166 (field number CB 2012.97), adult male, collected on 18 April 2012 by TQN et al. (altitude 701 m a.s.l.), Trung Khanh District, Cao Bang Province.

Paratypes.

ZFMK 93747, juvenile, collected on 15 October 2011 by TQN et al. (altitude 588 m a.s.l.), Ha Lang District, Cao Bang Province; ZFMK 93746, adult female, collected on 10 April 2012 by TQN et al., Ha Lang District, Cao Bang Province.

Diagnosis.

Lycodon pictus sp. nov. can be differentiated from its congeners by the following morphological characters: dorsal scales in 17 –17– 15 rows, all smooth; supralabials usually eight (rarely nine); infralabials ten; one elongated loreal on each side, in contact with the eye; precloacal plate single; ventral scales 212-218 (plus one or two preventral scales); subcaudals 90 or 91; a total length of 597+ mm in males and 543 mm in females; tail / total length ratio 0.211-0.215; maxillary teeth 13 or 14; dorsal surface of body with 28 or 29 light body bands; dorsal surface of tail with 13 cream bands forming a distinct blotch in the vertebral region; ventral surface of body and tail mostly cream with the dark body bands in part extending towards the venter, sometimes forming complete dark bands around the body.

Description of the holotype.

Head elongate, moderately distinct from the neck, rather flattened, longer than wide, narrow anteriorly; nostril lateral, located in the middle of the nasal; eye large, pupils vertically elliptic; rostral triangular, much broader than high, hardly visible from above; nasal divided into two scales by a vertical ridge along posterior edge of nostril; two internasals, anteriorly rounded, slightly wider than high, bordered by two large, pentagonal prefrontals posteriorly; frontal single, enlarged, pentagonal to hexagonal, narrowed posteriorly; parietals longer than wide, in contact with each other medially, with upper anterior and posterior temporals, paraparietal laterally and four nuchal scales posteriorly; paraparietals elongated, anterior part widened; loreal 1/1, elongate, not entering orbit; supralabials 8/8, first and second in contact with nasal, third to fifth entering orbit, sixth largest; infralabials 10/10, first pair in broad contact with each other, first to fifth in contact with anterior pair of chin shields; anterior and posterior pairs of chin shields elongate, of the same size and shape, second pair not meeting in midline; preocular 1/1; postoculars 2/2, lowermost smaller, bordering anterior temporals; anterior temporals 2/2, posterior temporals 3/3, upper ones thinner than lower ones. Left maxilla arched, with an angular apex, distinctly bent inwards anteriorly. A total of 13 maxillary teeth or teeth alveola, with the following formula: five small anterior teeth, with the last two ones being somewhat enlarged + two strongly enlarged teeth, thick, and not much curved + a wide gap, somewhat wider than the length of the largest teeth + four small teeth + a small gap + two enlarged posterior teeth.

Body elongate, SVL 488 mm; TaL> 109 mm (tail tip lost); preventral 1, ventrals 212, from behind neck region distinctly notched laterally; subcaudals> 54 (tail tip lost), paired; precloacal plate single; DSR 17-17-15, all smooth; the vertebral scales not enlarged; DSR reduction from 17 to 15 at the position of ventral 150.

Coloration in preservative.

Head, neck, and dorsal surface of body brownish black; light body bands beginning after 1.5 times the head length behind the head, in total 29 transverse light bands on body and at least nine light bands on tail; the first four body bands yellowish cream, and distinctly widened towards the venter, increased in size posteriorly; a dark mottling in the vertebrate region more prominent posteriorly; the subsequent light body bands with two distinct indentations on each side, fused in the middle in the last third of the body. In dorsal view the light bands forming a distinct blotch in the vertebral region, with a dark centre and a lighter frame; laterally, the middle part of the light bands forming blotches, but wider and with an extended dark centre, fused laterally in the last third part of the body; the lower and widest part of the light body bands with a dark small blotch in the centre in the anterior part of body; the light bands on the tail with a blotch like pattern in the vertebral region, but less pronounced than that on body, and one light blotch at the lateral side of tail, widened towards the venter, with a dark centre; ventral surface of head and neck yellowish cream, belly cream and greyish cream in the last third part of body and on lower tail surface; the dark dorsal bands (28 on body and at least nine on tail) in part extending towards the venter (most prominent in the anterior five dark body bands), not forming complete dark bands around the body, but complete on the tail; lateral side of the head dark above and light below, with the lighter pattern beginning in the supralabial region; tip of lower jaw and infralabial region in part greyish; dorsal surface of the head and upper head sides a bit paler than the remaining head dorsum.

Hemipenis.

Hemipenes elongated, not fully everted, not turgid. Truncus without spines. Spine ornamentation starting at truncus region with somewhat enlarged, medium sized spines. Apex with microspines. Sulcus stretches in the middle to apex. Apex not fully everted, ending somewhat widened with an oblique opening, with microspines inside, pointing to the not fully everted condition of the outer genital organ.

Variations.

In the juvenile ZFMK 93747, the number of supralabials on the left side is nine, with fourth to sixth entering the orbit. The loreal does not touch the eye on the right side. The lower anterior temporal scale is not touching the postocular scale on the left side. In general, the coloration is more intense in the juvenile. The creamy pattern on the posterior third of the body sides is connected by a horizontal cream-colored stripe. It has a yellowish cream band on the head that reaches from SL 5 behind the jaws and distinctly lightens the posterior half of the head but does not touch the frontal. In the juvenile, the banded pattern is more simple, consisting of dark bands which narrow towards the venter and light bands which widen towards the venter and bear a dark pattern and a more or less distinct dark blotch at the lower side (see Fig. 5 ).

In the female ZFMK 93746, the lower anterior temporal scale is not touching the postocular scale on the right side. For measurements and scalation data of the examined specimens see Table 1 .

Dentition.

Female ZFMK 93746 and juvenile ZFMK 93747: Left maxilla arched, with an angular apex, distinctly bent inwards anteriorly. A total of 13 (in female) or 14 (in juvenile) maxillary teeth or teeth alveola, with the following formula: five small anterior teeth, with the last two ones being somewhat enlarged + two strongly enlarged teeth, thick, and not much curved + a wide gap, somewhat wider than the length of the largest teeth + four small teeth + a small gap + two enlarged posterior teeth in the female and three posterior teeth in the juvenile, with the anterior two ones enlarged.

Comparisons.

In our phylogenetic analysis, Lycodon pictus sp. nov. is most closely related to L. liuchengchaoi and L. multizonatus . From L. liuchengchaoi , the new species differs in terms of body scalation (all smooth in the new species vs. feebly keeled in several median rows in L. liuchengchaoi ), head scalation (ten infralabials vs. 7-9) and dentition (13 or 14 maxillary teeth vs. 8 or 9). In addition, the new species differs from the latter in having 28 or 29 cream body bands (vs. 40 yellow rings on the body in L. liuchengchaoi ) ( Zhang et al. 2015).

The new species differs from L. multizonatus by having more maxillary teeth (13 or 14 vs. 10 or 11 in L. multizonatus ), more infralabials (10 vs. 8) and a single precloacal plate (vs. divided). In addition, the new species differs from the latter in terms of body scalation (minimum 212 ventrals and minimum 90 subcaudals vs. 190-195 ventrals and 68-75 subcaudals in L. multizonatus ). Furthermore, L. pictus sp. nov. has fewer light body bands (28 or 29 vs. 55-73 in L. multizonatus ) ( Lei et al. 2014).

From its Vietnamese congeners, the new species can be differentiated as follows: Lycodon pictus sp. nov. differs from L. capucinus in having a single precloacal plate (vs. divided), a loreal touching the eye (vs. not in contact with the eye), in having more ventrals (minimum 212 vs. 182-211) and more subcaudals (90 or 91 vs. 59-74), and in terms of dorsal pattern (banded vs. reticulated) ( Luu et al. 2019).

Lycodon pictus sp. nov. differs from L. cardamomensis in terms of dorsal scalation (17-17-15 smooth DSR vs. 19-17-15 weakly keeled DSR), in having a loreal in contact with the eye (vs. separated) and in having 28 or 29 light body bands (vs. 12-14 pinkish orange body bands) ( Daltry and Wüster 2002, Do et al. 2017).

Lycodon pictus sp. nov. differs from L. davisonii in having 17 midbody dorsal scale rows (vs. 13 midbody dorsal scale rows), fewer ventral scales (maximum 218 vs. 235-265), more infralabials (10 vs. 8) and the absence of preocular (vs. present). In addition, the new species differs from the latter in having a different dorsal pattern (28 or 29 cream bands on body vs. 36 white rings on the body) ( Blanford 1878, Boulenger 1893).

Lycodon pictus sp. nov. differs from L. fasciatus in having smooth dorsal scales (vs. keeled) and more maxillary teeth (13 or 14 vs. 11). Additionally, the colour pattern of Lycodon pictus sp. nov. differs in being dark brownish black with light body bands turning into a marbling posteriorly, whereas L. fasciatus is black or purplish black above with yellowish cross-bars of irregular outline and has a dark median stippling ( Pope 1928, Smith 1943). Werner (1922) described Dinodon yunnanensis from Yunnan Fu, now Kunming, Yunnan Province, southwestern China. This species was synonymized with Lycodon fasciatus by Pope (1935: 188), but according to Vogel and David (2010), this taxon might be a distinct species (see also Vogel and David 2019). Lycodon pictus sp. nov. differs from Dinodon yunnanensis Werner, 1922 in having more ventrals (minimum 212 vs. 193), more subcaudals (90 or 91 vs. 66), more infralabials (10 vs. 9) and more light body bands (28 or 29 vs. 23) ( Werner 1922, Vogel and David 2010, Vogel and David 2019).

Lycodon pictus sp. nov. differs from L. flavozonatus in terms of dorsal scalation (smooth vs. keeled), in having more subcaudals (90 or 91 vs. 80-88), the loreal in contact with the eye in Lycodon pictus sp. nov. (vs. separated in L. flavozonatus ) and in coloration pattern (brownish black with 28 or 29 cream body bands and 9-13 light bands on the tail vs. black with 68 yellow body bands and 21 on the tail) ( Pope 1928, Vogt in Pope 1928).

Lycodon pictus sp. nov. differs from L. futsingensis in having more ventrals (minimum 212 vs. 193-208) and more subcaudals (minimum 90 vs. 72-87). Additionally, the loreal does not enter the orbit in L. futsingensis , whereas it enters the orbit in Lycodon pictus sp. nov. ( Vogel et al. 2009).

Lycodon pictus sp. nov. differs from L. laoensis in having a single precloacal plate (vs. divided), more ventral scales (minimum 212 vs. 163-192), more subcaudal scales (minimum 90 vs. 60-76), an elongated loreal scale in contact with the orbit (vs. separated) and cream body bands (vs. yellow) ( Grismer et al. 2014, Neang et al. 2014).

Lycodon pictus sp. nov. differs from L. meridionalis in having smooth dorsals (vs. feebly keeled in 10-12 median rows), a lower ventral scale count (maximum 218 vs. 227-240) and fewer subcaudals (maximum 91 vs. 96-106). In addition, the new species differs in having cream body bands (vs. yellow thin crossbars) ( Gawor et al. 2016 and examined ZFMK specimens, see Appendix 1).

Lycodon pictus sp. nov. differs from L. namdongensis in having more subcaudals (90 or 91 vs. 85) and the loreal in contact with the eye (vs. separated from the eye in L. namdongensis ). The new species also differs in coloration pattern (brownish black with 28 or 29 light bands on the body vs. grey with 23 cream cross rings on the body in L. namdongensis ), and in having irregular bands turning into a marbling posteriorly (vs. clearly demarcated cross bands on the body) ( Luu et al. 2019).

Lycodon pictus sp. nov. differs from L. paucifasciatus in terms of dorsal scalation (17-17-15 smooth DSR vs. 19-(19-17)-15 DSR, the upper one or two plus vertebral row distinctly keeled) and fewer ventral scales (maximum 218 vs. 219-222). In addition, the new species has a loreal entering the eye (vs. separated) and 28 or 29 light body bands (vs. 14-25 beige or dirty cream body bands) ( Vogel et al. 2009).

Lycodon pictus sp. nov. differs from L. rosozonatus in having 17-17-15 smooth DSR (vs. 19-19- 15(17) keeled DSR), fewer ventral scales (maximum 218 vs. 221-234) and a loreal in contact with the eye (vs. separated). In addition, the new species has cream body bands (vs. pinkish red) ( Hu et al. 1975, Neang et al. 2014).

Lycodon pictus sp. nov. differs from L. rufozonatus in having a loreal in contact with the eye (vs. separated), smooth dorsal scales (vs. feebly keeled in the posterior body part), and in coloration pattern (28 or 29 cream body bands vs. 44-52 light red body bands) ( Zhao 2006, Luu et al 2018).

Lycodon pictus sp. nov. differs from L. ruhstrati abditus in having smooth dorsals (vs. 7-8 dorsal scale (including vertebral) rows keeled), an elongated loreal in contact with the eye (vs. separated), and in having irregular bands turning into a marbling posteriorly (vs. clearly demarcated cross bands on the body) ( Vogel et al. 2009).

Lycodon pictus sp. nov. differs from L. septentrionalis by its smooth dorsal scales (vs. 7-9 median rows feebly keeled), 10 infralabials (vs. 7 or 8), and the loreal entering the orbit (vs. separated in L. septentrionalis ). In addition, the new species differs in having cream irregular bands on a brown body (vs. white narrow bands on a black body forming complete annuli) ( Günther 1875, Boulenger 1893, Neang et al. 2014).

Lycodon pictus sp. nov. differs from L. subcinctus in having 10 infralabials (vs. 8 or 9), one preocular (vs. preocular absent), smooth dorsal scales (vs. feebly keeled) and 28 or 29 cream bands on the body and 9-13 on the tail (vs. 9-15 bands on the body and none on the tail) ( Boulenger 1893, Neang et al. 2014).

Lycodon pictus sp. nov. differs from L. ophiophagus , a species from southern Thailand but with similar scalation, in having a loreal entering the eye (vs. separated) and in dorsal colour pattern (28 or 29 light bands on a brown body vs. 20 or 21 white bands on a dark body) as well as and in having irregular bands turning into a marbling posteriorly (vs. clearly demarcated cross bands on the body) ( Vogel et al 2009).

For additional measurements, dentition, and scalation data see Tables 2 - 8 .

Distribution.

Lycodon pictus sp. nov. is currently known only from Ha Lang and Trung Khanh districts, Cao Bang Province, northern Vietnam ( Fig. 7 ).

Etymology.

The name of the species pictus means painted or decorated in Latin and refers to its unique dorsal colour pattern.

Natural history.

Lycodon pictus sp. nov. seems to be closely associated with karst environment. Specimens were found at night between 19:00 and 23:00, on forest paths or on the ground near cave entrances. The surrounding habitat was secondary karst forest, consisting of medium and small hardwood trees mixed with shrubs and vines. Air temperature was 23.4-29.6°C and humidity was 66-79%. Other reptiles were also found at the site, including Acanthosaura lepidogaster (Cuvier, 1829), Gekko adleri Nguyen, Wang, Yang, Lehmann, Le, Ziegler & Bonkowski, 2013, Goniurosaurus luii Grismer, Viets & Boyle, 1999, Lycodon futsingensis (Pope, 1928), and Protobothrops trungkhanhensis Orlov, Ryabov & Nguyen, 2009 ( Fig. 8 ).

Figures

Figure 2. Holotype of Lycodon pictus sp. nov. (IEBR 4166) in life. Photograph T. Lehmann.

Figure 3. Head views of Lycodon pictus sp. nov. (IEBR 4166) in preservative (scale bar refers to head in dorsal view). Photographs T. Ziegler (upper), C. T. Pham (lower).

Figure 4. Female paratype of Lycodon pictus sp. nov. (ZFMK 93746) in life. Photographs T. Q. Nguyen.

Figure 5. Juvenile paratype of Lycodon pictus sp. nov. (ZFMK 93747) in preservative (upper, dorsal view; lower, ventral view). Photographs T. Ziegler.

Figure 6. Dorsal head and neck pattern of the juvenile paratype of Lycodon pictus sp. nov. (ZFMK 93747) in preservative. Photograph T. Ziegler.

Figure 7. Map showing the type locality of Lycodon pictus sp. nov. in Cao Bang Province.

Figure 8. Habitat of Lycodon pictus sp. nov.: the female paratype (ZFMK 93746) was found in Ha Lang District, Cao Bang Province.