Lycodon banksi, Luu & Bonkowski & Nguyen & Le & Calame & Ziegler, 2018

Luu, Vinh Quang, Bonkowski, Michael, Nguyen, Truong Quang, Le, Minh Duc, Calame, Thomas & Ziegler, Thomas, 2018, A new species of Lycodon Boie, 1826 (Serpentes: Colubridae) from central Laos, Revue suisse de Zoologie 125 (2), pp. 263-276 : 266-271

Lycodon banksi sp. nov.

Figs 2-5 , Table 3

Holotype: VNUF R.2015.20 (field number: TK 20.15), adult male, collected on 4 April 2015 by Vinh Quang Luu and Thomas Calame in the karst forest, at the mouth of a cave, Phou Hin Poun NPA, Hinboun District, Khammouane Province, central Laos, at an elevation of 167 m a.s.l.

Diagnosis: Lycodon banksi sp. nov is characterized by the following morphological characters: (1) dorsal scales in 17-17-15 rows, dorsal scales on the anterior 2/3 of the body length smooth, the six central dorsal scale rows of the posterior 1/3 of the body length feebly keeled; (2) supralabials 8; (3) infralabials 10; (4) loreal entering orbit; (5) cloacal single; (6) ventral scales 241; (7) dorsal surface of body with 87 greyish yellow blotches; (8) ventral surface of body and tail uniformly grey cream.

Description of the holotype: Head elongate (HL 15.3 mm), moderately distinct from the neck, longer than wide (HW/HL ratio 0.71), depressed (HH/HL ratio 0.40), narrow anteriorly (IN/IO ratio 0.65); snout elongate (SnL/HL ratio 0.39); nostril lateral, oval shaped, located in the middle of the nasal; eye large (ED/HL ratio 0.17), 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 square internasals, as wide as long, bordered by two large, subpentagonal prefrontals posteriorly; frontal single, enlarged, pentagonal, 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; loreal 1/1, elongate, 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 first pair of chin shields; first and second pairs of chin shields elongate, of the same size and shape, separated by a medial groove, first pair larger than the second; preocular 1/1; postoculars 2/2, of the same size, bordering anterior temporals; anterior temporals 2/2, posterior temporals 3/3, upper ones smaller than lower ones.

Body elongate, SVL 415 mm; TaL> 50 mm (tail tip lost); preventrals 2, ventrals 241; subcaudals 26 (tail tip lost), divided, weakly notched laterally; cloacal single; DSR 17-17-15; dorsal scales on the anterior 2/3 of the body length smooth, the six central dorsal scale rows of the posterior 1/3 of the body length feebly keeled; the vertebral scales not enlarged.

Colouration in life: Head dark grey, without vertical light nuchal band; dorsal surface of body dark greyyellow with 87 greyish yellow irregular dorsal blotches; first body blotch starting at ventral scale 13, a half vertebral scale covered by this blotch; two yellow stripes on each side, from behind the neck to vent, indistinct posteriorly; ventral scales grey cream; dorsal surface of tail with at least eleven greyish yellow tail blotches, ventral surface of tail grey cream.

Hemipenis: The left hemipenis is only in part everted but shows a spinose ornamentation.

Additional specimen: One specimen which was not collected but detected and photographed on 22 July 2016 by an arachnology team consisting of Peter Jaeger, Aloke Sahu and Jonas Ewert , in Khammouane Province, in ca. 12.4 km distance from the type locality. The color pattern of this specimen resembles closely that of the holotype .

Comparisons: In our phylogenetic analysis, Lycodon banksi sp. nov. is nested in a clade containing L. rufozonatus , L. semicarinatus (Cope) , ‘ L. flavozonatus’, L. futsingensis and L. meridionalis . The new species differs from the similar L. meridionalis by having loreal entering the orbit (versus separated from the orbit), dorsal scales on the anterior 2/3 of the body length smooth, the six central dorsal scale rows on the posterior body third feebly keeled (versus distinctly keeled), dorsal head pattern uniform dark grey (versus with yellow-black marbling in L. meridionalis ), and ventral surface grey cream (versus yellow with dark spots posteriorly) (see Bourret, 1935; Orlov & Ryabov, 2004); from L. rufozonatus by having loreal entering the orbit (versus usually separated), a distinctly higher ventral scale count (241 versus 185-204), dorsal scales feebly keeled in the posterior body part (versus all smooth), dorsal head pattern uniform dark grey (versus dark brown with yellow borders), and body pattern blotched (versus banded) ( Boulenger 1893); from L. semicarinatus by having loreal touching the orbit (versus separated), a higher ventral scale count (241 versus 211-234), dorsal scale rows keeled along posterior 1/3 (versus keeled along anterior half), belly pattern uniform grey cream (versus yellow), and body pattern blotched (versus banded) ( Boulenger 1893); from L. flavozonatus by having loreal in contact with the orbit (versus separated), cloacal single (versus divided), six dorsal scale rows on the posterior third of the body feebly keeled (versus 10-12 keeled dorsal scale rows at midbody), dorsal head dark grey (versus black with light markings), and belly pattern uniform grey cream (versus yellow with large black spots); from L. futsingensis by having loreal entering the orbit (versus separated), a higher ventral scale count (241 versus 193-203 in males), dorsal scales feebly keeled in the posterior body part (versus all smooth), and body pattern blotched (versus banded) ( Vogel et al., 2012; Neang et al., 2014) ( Table 4 ).

The new species has a loreal entering the orbit and thus differs from the following species and subspecies of the Lycodon ruhstrati group which have the loreal separated from the orbit: L. cardamomensis Daltry & Wüster, 2002 , L. davidi , L. multifasciatus ( Maki, 1931) , L. ophiophagus Vogel, David, Pauwels, Sumontha, Norval, Hendrix, Vu & Ziegler, 2009 , L. paucifasciatus Rendahl in Smith, 1943, L. ruhstrati ruhstrati ( Fischer, 1886) , and Lycodon ruhstrati abditus ( Vogel et al., 2009) . In addition, the new species differs from L. cardamomensis by having more ventral scales (241 versus 215), and in body pattern (87 blotches versus 12 bands); from L. davidi by having more ventral scales (241 versus 224), six dorsal scale rows on the posterior third of the body feebly keeled (versus dorsal scale rows at midbody slightly keeled, outermost rows entirely smooth throughout body), and belly pattern uniform grey cream (versus anterior third whitishcream, posterior part heavily speckled with dark dots); from L. multifasciatus by having more ventral scales (241 versus maximum 237), and dorsal pattern blotched (versus banded); from L. ophiophagus by having more ventral scales (241 versus 211), and dorsal pattern (87 blotches versus 21-22 bands); from L. paucifasciatus by having fewer dorsal scale rows at neck (17 versus 19), more ventral scale rows (241 versus 221-222), six dorsal scale rows on the posterior third of the body feebly keeled (versus two upper rows plus vertebral row distinctly keeled), and dorsal pattern blotched (versus banded) ( Neang et al., 2014); from L. r. ruhstrati and Lycodon ruhstrati abditus by having more ventral scales (241 versus 211-228; 241 versus 206-224, respectively), and dorsal pattern blotched (versus banded in the latter) ( Vogel et al., 2012); from L. synaptor by having much more ventral scale rows (241 versus 201-203), dorsal pattern with 87 blotches (versus 30-31 bands), and belly pattern uniform grey cream (versus banded) ( Vogel & David 2010); from L. zoosvictoriae by having more ventral scales (241 versus 213), dorsal pattern consisting of 87 blotches (versus 31), and having six dorsal scale rows on the posterior third of the body feebly keeled (versus all weakly keeled) ( Neang et al., 2014).

From the remaining species occurring in Laos, the new species can be distinguished as follows: from L. capucinus by having more ventrals (241 versus 182-211), fewer supralabials (8/8 versus 9-10), cloacal single (versus divided), dorsal blotches 87 (versus reticulated), and greyish yellow blotched body pattern (versus reticulated); from L. fasciatus by having more ventral scale rows (241 versus 182-225), dorsal pattern consisting of 87 blotches (versus 19-49 bands), and belly pattern uniform grey cream (versus white with dark blotches) ( Neang et al., 2014); from L. laoensis by having loreal in contact with the orbit (versus separated), more ventrals (241 versus 169-192), and dorsal scales feebly keeled in the posterior body part (versus all smooth) ( Neang et al., 2014); from L. septentrionalis by having more infralabials (10 versus 7-8), more ventral scales (241 versus 202-217), and dorsal pattern blotched (versus banded), as well as belly pattern uniform grey cream (versus white) ( Neang et al., 2014); from L. subcinctus by the presence of preocular scale (versus absent), having cloacal scale single (versus divided), dorsal pattern blotched (versus banded in anterior part), and more ventral scale rows (241 versus 129-230) ( Neang et al., 2014).

From the remaining species in the fasciatus group, the new species differs as follows: from L. butleri Boulenger by having more ventral scale rows (241 versus 220-227), dorsal pattern blotched (versus banded), and belly pattern uniform grey cream (versus banded & spotted) ( Grismer et al., 2014); from L. cavernicolus by having dorsal head uniformly dark grey (versus light brown), fewer supralabials (8 versus 9 or 10), more dorsal blotches (87 versus 36-45 bands), dorsal scales on the anterior 2/3 of the body length smooth, the six central dorsal scale rows of the posterior 1/3 of the body length feebly keeled (versus all keeled), and greyish yellow blotched pattern on the body (versus white bands); from L. gongshan by having six dorsal scale rows on the posterior third of the body feebly keeled (versus upper and vertebral dorsal rows keeled), more ventral scale rows (241 versus 210- 216), and dorsal pattern with 87 blotches (versus 32- 40 bands) ( Vogel & Luo, 2011); from L. liuchengchaoi by having cloacal scale single (versus divided), dorsal pattern consisting of 87 irregular greyish yellow dorsal blotches (versus 40 well-defined yellow rings), and more ventral scales (241 versus 204) ( Zhang et al., 2011).

Distribution: Lycodon banksi sp. nov. is currently known only from the type locality in the Phou Hin Poun NPA, Khammouane Province, central Laos ( Fig. 6 ).

Etymology: The name of the species is dedicated to our friend and colleague Chris Banks, International Coordinator, Philippine Crocodile National Recovery Team, Zoos Victoria, Australia, for his outstanding contributions towards amphibian and reptile conservation, in particular of the Philippine Crocodile. We propose the following common names: Banks’ Wolf Snake (English), Banks Wolfszahnnatter (German).

Natural history: The holotype was found at 20:39 h, crawling on a limestone outcrop in the karst forest, approximately 0.3 m above the forest floor, at an elevation of 167 m a.s.l. The humidity at the time of collection was approximately 85% and the air temperature ranged from 23 to 26 oC ( Fig. 7 ). Another specimen was observed 12.4 km away from the type locality, active on the ground at 23:30 h, near a limestone cliff in the secondary forest.

Figures

Fig. 2. Adult male holotype of Lycodon banksi sp. nov. (VNUF R.2015.20) in life. (A) dorsolateral view. (B) Head in dorsolateral view. (C) Head in dorsal view. Photos: V. Q. Luu.

Fig. 3. Different head views of the adult male holotype of Lycodon banksi sp. nov. (VNUF R.2015.20). Photos V. Q. Luu.

Fig. 4. Lateral head view of the adult male holotype of Lycodon banksi sp. nov. (VNUF R.2015.20). Drawing by T. Ziegler.

Fig. 5. Additional record of Lycodon banksi sp. nov. in life: (A- B) dorsolateral views. (C) Head in dorsal view. Photos A-C A. Sahu. (D) Dorsal view. Photo P. Jaeger.

Fig. 6. Map showing the type locality of Lycodon banksi sp. nov. in Khammouane Province (black dots) and other records of the genus Lycodon occurring in Laos (after Deuve, 1970; Vogel et al., 2012; Siler et al., 2013; Luu et al., 2013; Teynié et al., 2014).

Fig. 7. Habitat of Lycodon banksi sp. nov. at the type locality. Photo V. Q. Luu.