Rhabdophis guangdongensis, Zhu, Guang-Xiang, Wang, Ying-Yong, Takeuchi, Hirohiko & Zhao, Er-Mi, 2014

Zhu, Guang-Xiang, Wang, Ying-Yong, Takeuchi, Hirohiko & Zhao, Er-Mi, 2014, A new species of the genus Rhabdophis Fitzinger, 1843 (Squamata: Colubridae) from Guangdong Province, southern China, Zootaxa 3765 (5), pp. 469-480 : 473-478

Rhabdophis guangdongensis sp. nov.

Holotype. Adult female, SYS r000018, collected by Ying-Yong Wang from Aizhai Village (24°56′16.58″ N, 113°39′57.82″ E; 132 m a.s.l., datum = WGS84), Renhua County, Guangdong Province, China, on May 26, 2008 ( Figure 2 , Figure 3 : A and B).

Diagnosis. Rhabdophis guangdongensis sp. nov. can be diagnosed by the combination of the following characters: 1) head distinct from the neck; 2) the presence of a nuchal groove, with enlarged and paired scales on each side; 3) maxillary teeth 20, the posterior-most three teeth abruptly enlarged, not grooved, and not separated by diastemata from the rest of the series; 4) nostril large and lateral, in a completely divided nasal; 5) supralabials six, the third and fourth touching the eye; 6) seven infralabials, the first four contact with anterior chin-shields; 7) dorsal scales in 15 rows throughout, feebly keeled, the outer row smooth; 8) ventrals 126; 9) anal divided; 10) subcaudals 39, paired; (11) the presence of a final spine at tip of tail; 12) top of head, occiput and nape before black collar grey; 13) a broad black collar, posteriorly bordering a reverse V-shaped orange mark on the nape; 14) dorsal surface of body and tail brown-grey, with narrow black cross-bars; 15) body and tail with two dorsolateral longitudinal brownish-red lines, respectively with a series of white spots in cross-bars.; 16) lips with two conspicuous black oblique bands; 17) ventral surface of head and neck cream with black spots, posteriorly gradually becoming entirely black.

Comparisons. Comparative data of R. guangdongensis sp. nov. with 20 known species of the genus Rhabdophis were obtained from the literature ( Günther 1858, 1864; Boulenger 1893, 1900; Bourret 1935; Smith 1943; Tweedie 1957; Leviton 1970; Zhao & Jiang 1981; Zhao & Adler 1993; Zhao 1997; Zhao, et al. 1998; Stuebing & Lian 2002; Lang & Vogel 2006; Das 2010, David & Vogel 2010) and are shown in Table 2 . Examined specimens of R. adleri , R. callichroma , R. chrysargoides , R. himalayanus , R. leonardi , R. lineatus , R. nigrocinctus , R. nuchalis , R. pentasupralabialis , R. spilogaster , R. subminiatus , R. swinhonis , and R. tigrinus are listed in Appendix 1.

R. guangdongensis sp. nov., R. swinhonis , R. angeli (Bourret, 1934) , R. pentasupralabialis , and R. nuchalis have the minimal number of dorsal scale rows (DSR) in this genus, equal to 15 rows throughout. The new species is most similar to R. swinhonis , from which it differs by having 39 subcaudals vs. 44–74 in R. swinhonis ; the posterior-most three maxillary teeth strongly enlarged, not separated by diastemata from the rest of the series vs. posterior-most two or three maxillary teeth strongly enlarged, separated by diastemata in R. swinhonis ; top of head, occiput and nape before black collar grey vs. top of head brown, occiput and nape before black collar reddish, nuchal groove usually black and forming a longitudinal continuous or intermittent black line before black collar in R. swinhonis ; orange V-shape zone behind black collar vs. reddish zone (i.e., occiput and nape reddish) before black collar in R. swinhonis ; ventral surface of head and neck cream with black spots, posteriorly gradually becoming entirely black vs. yellowish, powdered with brown on the sides in R. swinhonis ; having dorsolateral black cross-bars on body and tail vs. absent in R. swinhonis ; and having two dorsolateral longitudinal brownish-red parallel lines with white spots in cross-bars vs. absent in R. swinhonis . The new species differs from R. angeli by having 20 maxillary teeth, the posterior-most three maxillary teeth strongly enlarged, not separated by diastemata from the rest of the series vs. 22 to 23 maxillary teeth, the posterior-most two strongly enlarged, separated by diastemata in R. angeli ; top of head grey vs. brown in R. angeli ; dorsal surface of body and tail brown-grey vs. brownish in R. angeli ; body and tail with two dorsolateral longitudinal brownish-red parallel lines vs. absent in R. angeli ; the presence of two series of white spots vs. a dorsolateral series of small reddish spots in R. angeli ; lips light grey vs. light brown in R. angeli ; ventral surface of head and neck cream with black spots, posteriorly gradually becoming entirely black vs. anteriorly pale orange, speckled with brown, hinder parts entirely brown in R. angeli . The new species differs from R. pentasupralabialis by having 20 maxillary teeth, the posterior-most three maxillary teeth strongly enlarged, not separated by diastemata from the rest of the series vs. 18 maxillary teeth, the posterior-most two strongly enlarged, separated by diastemata in R. pentasupralabialis ; top of head grey vs. olive in R. pentasupralabialis ; a broad black collar posteriorly bordering a reverse V -shaped orange zone on the nape vs. absent in R. pentasupralabialis ; lips with two conspicuous black oblique bands vs. absent in R. pentasupralabialis ; ventral surface of head and neck cream with black spots, posteriorly gradually becoming entirely black vs. grey-white or grey-green in R. pentasupralabialis ; body and tail with two dorsolateral longitudinal brownish-red parallel lines vs. absent in R. pentasupralabialis . The new species differs from R. nuchalis by having the posterior-most three maxillary teeth strongly enlarged, not separated by diastemata from the rest of the series vs. the posterior-most two maxillary teeth strongly enlarged, separated by diastemata in R. nuchalis ; top of head grey vs. olive in R. nuchalis ; a broad black collar posteriorly bordering a reverse V -shaped orange zone on the nape vs. absent in R. nuchalis ; lips with two conspicuous black oblique bands vs. absent in R. nuchalis ; ventral surface of head and neck cream with black spots, posteriorly gradually becoming entirely black vs. uniform black, or black in the middle and olive on the sides in R. nuchalis ; body and tail with two dorsolateral longitudinal brownish-red parallel lines vs. absent in R. nuchalis .

From the remaining 16 members of the genus Rhabdophis , the new species can be readily distinguished by its dorsal scales in 15 rows throughout, ventrals (VEN) 126, subcaudals (SC) 39 vs. 19 DSR at midbody, VEN 142, SC 66 in R. lineatus (Peters, 1861) ; DSR 18(17)–17–15, VEN 149–159, SC 43–62 in R. leonardi ; DSR 17–17–15, VEN 143–162, 71–93 SC in R. auriculata ( Günther, 1858) ; DSR 19–19–17, VEN 150–164, SC 73–88 in R. adleri ; DSR 19–19–17, VEN 165–171, SC 82–88 in R. himalayanus ; DSR 19–19–17, VEN 150–170, SC 80–97 in R. nigrocinctus ; DSR 19–19–17, VEN 144–184, SC 56–97 in R. subminiatus ; DSR 19–19–17 (15), VEN 144–188, SC 38–74 in R. tigrinus ; DSR 19–19–15 (17), VEN 176–185, SC 63–97 in R. murudensis (Smith, 1925) ; 19 DSR at midbody, VEN 148–156, SC 75–92 in R. barbouri (Taylor, 1922) ; 19 DSR at midbody, VEN 152–159, SC 79– 86 in R. callichroma (Bourret, 1934) ; 19 DSR at midbody, VEN 138–147, SC 40–53 in R. conspicillatus (Günther, 1872) ; 19 DSR at midbody, VEN 143–175, SC 60–93 in R. chrysargos (Schlegel, 1837) ; 19 DSR at midbody, VEN 148–156, SC 75–92 in R. spilogaster (Boie, 1827) ; 21 DSR at midbody, VEN 156, SC 76 in R. callistus (Günther, 1873) ; 21 DSR at midbody, VEN 154–161, SC 64–79 in R. chrysargoides ( Günther, 1858) ; furthermore, by outer dorsal scale row smooth vs. keeled in R. adleri , R. barbouri , R. auriculata , R. callichroma , R. callistus , R. chrysargoides , R. chrysargos , R. himalayanus , R. lineatus , R. murudensis , R. spilogaster ; by having maxillary teeth 20 vs. more than 25 in R. auriculata , R. himalayanus , R. nigrocinctus , R. callichroma , R. chrysargos , and R. adleri .

*: total number of maxillary teeth (the number of maxillary teeth before the diastemata + the number of maxillary teeth behind the diastemata).

R. guangdongensis sp. nov. is sympatric with R. subminiatus , it further differs from the latter by having two dorsolateral longitudinal brownish-red parallel lines, respectively with a series of white spots vs. absent in R. subminiatus ; by having a broad black collar, posteriorly bordering a V-shaped orange zone on the nape vs. neck tinged with vermilion, without broad black collar in adult R. subminiatus ; the presence of a jet-black cross-bar or triangular mark, posteriorly bordering yellow mark on the nape in young R. subminiatus .

Description of holotype. Body elongated, cylindrical; head moderately long, 3.8% of total length; tail moderate, 16.4% of the total length; head length (HL) 1.73 times head width (HW), and significantly broader than the neck; snout moderately long (29.7% of HL); rostral much broader than deep, just visible from above; internasals slightly shorter than prefrontals; prefrontals wide, bending to the loreal region; frontal slightly longer than broad, as long as the distance from the rostral to frontal; parietals longer than the frontal, barely twice as broad in front as behind; nostril large and lateral, in a completely divided nasal; loreal single, longer than deep; eye large (17.8% of HL), pupil rounded; supraocular single; preocular single; two postoculars; subocular absent; six supralabials, the third and fourth touching the eye, the fifth largest; seven infralabials, the first one in contact with each other behind the mental, first four infralabials in contact with the anterior chin-shields, the seventh significantly extended; anterior temporal single; posterior temporal single; 20 maxillary teeth gradually posteriorly enlarged in a continuous series, the posterior-most three teeth abruptly strongly enlarged, not grooved, and not separated by diastemata from the rest of the series; the presence of a nuchal groove, eleven scales on each side of groove more or less distinctly enlarged and paired; dorsal scales in 15 rows throughout, feebly keeled, the outer most ones smooth; ventrals 126; anal divided; subcaudals 39, paired; the presence of final spine at tip of tail.

Measurements of holotype (in mm). TL 537; SVL 449; TaL 88; HL 20.2; HW 11.7; SL 6.0; ED 3.6; EN 3.2.

Coloration of holotype in life. Brownish-grey above; top of head, occiput and nape grey; a broad black collar in width of five scale rows, posteriorly bordering a reverse V-shaped orange zone in width of four scale rows on the nape; 44 pairs of narrow dorsolateral black cross-bars on body and 15 pairs on tail; body and tail with a longitudinal brownish-red line parallel to contralateral line, respectively with a series of white spots in cross-bars; lips light-grey with two conspicuous black oblique bands, one below the eye, another behind the eye between the fifth and sixth supralabials; ventral surface of head and neck cream with black spots, posteriorly gradually becoming entirely black ( Figure 3 : A and B).

Coloration of holotype in preservative. Grey-brown fades to gray; orange fades to yellowish-white ( Figure 2 )

Distribution, habitat and behaviour. Currently, R. guangdongensis sp. nov. is only known from the type locality, Aizhai Village, Renhua County, Guangdong Province, China. On August 15, 2011, my colleague encountered another individual of this species at Mount Diefushan (22°36′26.22″ N, 114°24′50.14″ E, 56 m a.s.l., datum = WGS84), Shenzhen City, Guangdong Province, China, but no sample and measurements were taken after it was photographed ( Figure 3 : C). In addition, in the last three years, two individuals of this species were photographed by tourists in submontane forest in Mount Wutong, Shenzhen City, Guangdong Province, China; one of which was swallowing an earthworm.

Therefore, we tentatively consider that the new species is a terrestrial species distributed from the Renhua County, northern Guangdong Province to the coastal city of Shenzhen, southern Guangdong Province, China ( Figure 4 ). It preys on earthworms and inhabits lowland evergreen forests and submontane forest at 56–138 m above sea level ( Figure 5 ).

Etymology. The specific epithet “ guangdongensis ” is in reference to the known distributed localities, Guangdong Province, China. We propose the vernacular English name “Guangdong Keelback”.

Remark. The species is considered to be locally rare. Since May 2008 to date, only the holotype of R. guangdongensis sp. nov. was found during our extensive field surveys in southern China, including the areas from the type locality to Shenzhen City. Only three individuals of this species were found by others. The lowland and submontane forests are threatened by deforestation, changing land use, alien invasive plants, and ecological degradation. Therefore, the species should be classified as a rare and endangered species in the relevant legal provisions.

Figures

FIGURE 2. Dorsal (A) and ventral (B) view of the holotype SYS r 000018 of Rhabdophis guangdongensis sp. nov. in preservative. Photo by Ying-Yong Wang.

FIGURE 3. The holotype SYS r 000018 of Rhabdophis guangdongensis sp. nov. A: Dorsal view of head and neck in life. B: Lateral view of head and neck in life (photo by Ying-Yong Wang); C: Dorsolateral view (Photo by Shi-Shi Lin, on Mount Diefushan, taken on August 15, 2011).

FIGURE 4. Map showing the localities of Rhabdophis guangdongensis sp. nov. in Guangdong Province, southern China: (1) type locality, Aizhai Village, Renhua County, Shaoguan City. (2) Mount Diefushan, Shenzhen City. (3) Mount Wutong, Shenzhen City. (Map from http: // ditu. google. cn / maps? hl = zh-CN & tab = wl, January 10, 2013)

FIGURE 5. Habitat of Rhabdophis guangdongensis sp. nov. at the type locality, Aizhai Village, Renhua County, Shaoguan City, Guangdong Province. Photo by Ying-Yong Wang taken on May 26, 2008.

Tables

TABLE 2. Significant characters of R. guangdongensis sp. nov. and the other known 20 species of the genus Rhabdophis See Material and methods section for the data sources.

Species DSR	Outer dorsal scale row	VEN	SC	PRO	PTO	MT*
R. guangdongensis 15–15–15 sp. nov.	smooth	126	39	1	2	20
R. angeli 16(15)–15–15	smooth	117–126	39–46	1	3	22–23
R. swinhonis 15–15–15	weakly keeled or smooth	124–165	44–74	1	2–3	19–23(17– 21+2–3)*
R. nuchalis 15–15–15	smooth	144–169	35–65	1	3	18–22
R. pentasupralabialis 15–15–15	smooth	135–162	43–64	1	2–3	18
R. lineatus 19 at midbody	strongly keeled	132–142	66–71	2	3	18(16+2)
R. leonardi 18(17)–17–15	smooth	149–159	43–62	1	2–3	19(17+2)
R. auriculata 17–17–15	strongly keeled	143–162	71–93	1–2	3	27–32
R. adleri 19–19–17	feebly keeled	150–164	73–88	1–2	3–4	27(25+2)
R. himalayanus 19–19–17	feebly keeled	165–171	82–88	2	3	26(24+2)
R. nigrocinctus 19–19–17	keeled or smooth	150–170	80–97	1	3–4	28(26+2)
R. subminiatus 19–19–17	keeled or smooth	144–184	56–97	1	3–4	23-26(21–24+2)
R. tigrinus 19–19–17(15)	keeled or smooth	144–188	38–74	1–2	2–4	22-23(20–21+2)
R. barbouri 19 at midbody	strongly keeled	148–156	75–92	2	3	no data
R. callichroma 19 at midbody	keeled	152–159	79–86	1–2	3	27–35
R. murudensis 19–19–15(17)	feebly keeled	176–185	63–97	1	3	23(21+2)
R. conspicillatus 19 at midbody	keeled or smooth	138–147	40–53	1	3	no data
R. chrysargos 19 at midbody	strongly keeled	143–175	60–93	1–2	3	27–35
R. spilogaster 19 at midbody	feebly keeled	148–156	75–92	1–2	3–4	15
R. callistus 21 at midbody	strongly keeled	156	76	1	4	no data
R. chrysargoides 21 at midbody	strongly keeled	154–161	64–79	1	3	24(22+2)