Trimeresurus caudornatus, Chen & Yu & Vogel & Shi & Song & Tang & Yang & Ding & Chen, 2020

Chen, Zening, Yu, Jianping, Vogel, Gernot, Shi, Shengchao, Song, Zhaobin, Tang, Yezhong, Yang, Jia, Ding, Li & Chen, Cangsong, 2020, A new pit viper of the genus Trimeresurus (Lacépède, 1804) (Squamata: Viperidae) from Southwest China, Zootaxa 4768 (1), pp. 112-128 : 116-124

publication ID	https://doi.org/ 10.11646/zootaxa.4768.1.7
publication LSID	urn:lsid:zoobank.org:pub:D0EA26A4-54F4-47A8-AC8E-0C04605F2AA7
DOI	https://doi.org/10.5281/zenodo.3795446
persistent identifier	https://treatment.plazi.org/id/039487B5-1374-FFA1-85C1-4F77FDF8FF66
treatment provided by	Plazi
scientific name	Trimeresurus caudornatus
status	sp. nov.

Treatment

Trimeresurus caudornatus sp. nov. Chen, Ding, Vogel & Shi

( Figs. 3 View FIGURE 3 , 4 View FIGURE 4 )

Holotype. ZMNH AR1238 View Materials , adult male, collected from Nabang Town , Yingjiang County, Yunnan Province (24.6973°N, 97.5805° E, and 389 m A.S. L.), China by L. Ding and Z. Chen on 17 September 2018 ( Fig. 2A View FIGURE 2 ). GoogleMaps

Paratype. ZMNH AR1239, adult female, same collecting data as the holotype ( Fig. 2B View FIGURE 2 ).

Etymology. The specific name of the new species was made up of the Latin word “ caud ” (tail) and “ ornatus ” (ornamental), indicating a red stripe on the subcaudal scales. As common name we suggest “Ornamental tailed pitviper” in English and “Shì Wěi Zhú Yè Qîng (ṄAEĤďû)” in Chinese.

Diagnosis. (1) Head and body generally dark green, postocular stripes absent in both genders, upper labials light green; (2) ventrolateral stripe faint green yellow, present on the first row of DSR in both genders; (3) iris golden yellow in both genders; (4) dorsal tail mostly dark red, lateral and ventral green; an orange red stripe along the ventral part of the tail; (5) DSR 21/22 –21–15 (n=2), VEN 161–163, SC 52–72; (6) Cep 10, first upper labial partially fused to the nasal; (7) hemipenes elongated, bilobed at 6 th plate, tips reaching SC 37–38, small spines present posterior to the bifurcation, sulcus spermaticus shallow, visible, divides at the base of the organ.

Description of holotype. Body elongated; head triangular, length 1.5 times as long as width, distinct from neck; snout moderate, counting for 33% of HL, 2.3 times of ED, eyes large, VED/DEL ratio 1.0, pupil vertical in life.

SVL: 537 mm; TaL: 122 mm; TL: 659 mm; Tal/TL: 0.185.

VEN: 163; SC: 72, all paired; anal shield entire.

DSR: 21–21–15 scales, rhomboid, weakly keeled, first two rows smooth.

Rostral trapezoidal when viewed from the front, width of base twice as width of top and about 1.5 times of height, front edge obtusely visible from lateral view. Nasal large, sub-rectangular, undivided, half-separated from the first upper labial by a suture behind the nostril. Internasals broad, trapezoidal, broadly in contact, each edged with 4 other head plates, separated from supraoculars by three scales on both sides. Three canthal scales bordering the canthus rostralis between the internasal and corresponding supraoculars, not larger than adjacent snout scales. One loreal on each side. Two elongated preoculars above the loreal pit, elongated and in contact with the loreal, one lower preocular forming lower margin of loreal pit. One postocular on each side. One entire, long and elongated supraocular on each side, about 3 times as long as wide, and 1.1 times as wide as internasals, indented on their inner margin by the upper head scales. Scales on upper snout surface smooth, juxtaposed, irregular in shape, with 5 scales on a line between the internasals and a line connecting the anterior margins of eyes. Cephalic scales small, irregular, smooth, 10 Cep arranged in a line between supraoculars. Occipital scales flat and feebly keeled. Temporals small, subequal, 2 or 3 lower rows of temporals smooth. One thin, elongated, subocular crescent-like, surrounded by 9/9 scales. SL 10/10. 1 st SL triangular, short, separated from corresponding nasal in the posterior part. 2 nd SL high, forming the anterior border of loreal pit, and in contact with nasal at upper part. 3 rd SL much larger than other labials, pentagonal, high and long, 1.3 times as long as high, in contact with subocular. 4 th SL as high as 3 rd but shorter, in contact with the subocular. 5 th SL much smaller than 4th one and separated from the subocular by a smaller scale. The other SL in contact with first row of temporals. IL 13/12, the first pair of infralabials in contact with each other and the first three pairs in contact with the chin shields.

In life, dorsal body dark green, with faint dark crossbands on skin (about 1 to 3 scales broad, not visible when covered by dorsal scales) Lateral body green above and gradually green yellow below. A faint greenish yellow ventrolateral stripe hardly visible on the first row of DSR extending from the neck to above cloaca, color not contrasting with the nearby vent. Ventral body greenish yellow, paler in anterior part, light green in posterior part. Dorsal part of the tail dark red, about 2 dorsal scale rows wide and not mottled. Lateral and ventral part of the tail green. A thin orange red stripe extends on the ventral part of the tail, formed by the inner margins of the SC, extending from the 9 th SC to the tip of tail. Tail tip (posterior 20% of the tail) uniformly red. Iris golden yellow.

Dorsal part of the head dark green. Iris golden yellow. Scales under the lower margin of eyes lawn green. Lower edge of SL and upper edge of infralabials (IL) bordered light sky blue. Chins and nearby ventral head scales yellow green molted with sky blue.

In preservation. Dorsal body olive, with faint black cross bands, width about 1 to 3 dorsal scales. Lateral body green yellow. Ventral body uniformly greenish yellow. A faint green yellow ventrolateral stripe (on first row of DSR) extending from the neck to cloaca. Dorsal tail dark red (inner 2 row of dorsal scales) and not mottled, eternally yellow green, ventrally green yellow with an orange red line starting at the 10 th SC and continuing to tip of tail. Tip of tail (about 1/4 of tail) very dark red. The head dorsally olive; without postocular streak, but a clear boundary below the eyes, olive above and grass green below. The chin and throat are white.

Hemipenes ( Fig. 4F View FIGURE 4 ). Very elongated, tips of hemipenes reaching SC 37 or 38, bifurcate at 6 th plate. About 12 rows of small spines presented posterior to the bifurcation and slightly leaned towards the cloaca, corresponding to SC 7 to 14, this area about 1/5 length of the hemipenes. The remaining hemipenes is calyculate. The shallow sulcus spermaticus divides at the base of the organ.

Comparison. Trimeresurus caudornatus sp. nov. is referred to subgenus Trimeresurus by the “Long papillose” hemipenis ( Malhotra & Thorpe 2004 as Crypelytrops). Main characters separating it from T. albolabris and T. septentrionalis are presented in Tables 5 and 6.

We compared the type series of T. caudornatus sp. nov. with 46 specimens of T. albolabris (see Appendix I). These specimens originated from various localities in China, Vietnam, Thailand and Indonesia. Specimens from India and Myanmar were not included as they differ morphologically from T. albolabris from and near type locality, additionally systematic work further confirm these specimens should not be allocated to T. albolabris . T. caudorna- tus sp. nov. is distinct from T. albolabris by: (1) hemipenes relatively longer, reaching 37 or 38 th SC vs extending to the 15 th SC (Guo & Zhang 2000); (2) an orange red stripe presented on the ventral part of the tail vs absent in the latter species; (3) ventrolateral stripe very faint, green yellow vs lateral stripe yellow or white; and (4) upper labials light green vs usually yellow or white.

T. caudornatus sp. nov. is distinct from T. septentrionalis by: (1) dorsal tail dark red, ventral tail with an orange red stripe vs “tail above bright red, belly light yellowish-green” (examined topotypes, Sharma et al. 2013). (2) fewer ventrals in males and females (163 for the male, 161 for the female) vs 164–170 in males and 166–171 in females. (3) fewer subcaudals (72 in the male, 52 in the female) vs 74–80 in males and 56–66 in females. (4) upper labials light green vs usually yellow or white. (5) ventrolateral stripe faint green yellow in both gender vs white in males.

T. caudornatus sp. nov. is distinct from T. insularis by: (1) The hemipenes forked at 6 th plate with about 12 rows of small spines presented posterior to the bifurcation, tips reaching the 37–38 th SC vs forked opposite 3 rd plate with spongy structure to the end and reaching the 23 th SC (examined type specimens, Kramer 1977). (2) An orange red stripe presented on the ventral part of the tail vs no stripe on the ventral part of the tail. (3) DSR weakly keeled expect the first two rows vs strongly keeled except the first row. (4) Tail relatively shorter, TaL/TL in the male 0.185 vs 0.214 –0.224. (5) Usually more supralabials 10 (11) vs 11–13. (6) Upper labials light green vs usually yellow or white.

T. caudornatus sp. nov. is distinct from T. erythrurus by: (1) lesser dorsal scales, 21 rows at mid-body vs usually 23–25 rows. (2) Head scales not or weakly keeled vs strongly keeled. (3) More subcaudals in males (72 vs 49–71). (4) An orange red stripe presented on the ventral part of the tail vs no stripe on the ventral part of the tail. (5) A very faint green yellow ventrolateral stripe vs a thin white line present in males and in most females.

T. caudornatus sp. nov. is distinct from T. purpureomaculatus by: (1) first upper labials partially fused to the nasal vs “almost completely united with first upper labial”. (2) The hemipenes forked at 6 th plate with about 12 rows of small spines presented after the bifurcation and reaching the 37–38 SC vs forked opposite 3 rd plate entirely devoid of spines and reaching the 20 th SC. (3) Scales in 21 longitudinal rows at mid-body and with lesser DSR vs 25–27 (29). (4) Head scales not or weakly keeled vs strongly keeled. (5) Basic color green vs usually not green (except some specimens from Sumatra). (6) Upper labials light green vs usually not lighter than body but in some populations yellow. (7) Lower number of Cep, 10 vs 13–18 (11).

T. caudornatus sp. nov. is distinct from T. macrops , T. rubeus and T. cardamomensis by: (1) No postocular streak in both gender vs prominent in males. (2) ventrolateral stripe very faint, green yellow vs prominent, white in males. (3) an orange red stripe presented on the ventral part of the tail vs no stripe on the ventral part of the tail. (4) Head more elongated. (5) The supraoculars are narrower. T. caudornatus sp. nov. further differs from T. rubeus by iris golden yellow vs deep red.

T. caudornatus sp. nov. is distinct from T. cantori : (1) Fewer DSR (21 vs 25–29), (2) Fewer SL (10 vs 11–13, only very exceptionally 11. (3) Fewer Cep (10 vs 13–17). (4) Fewer ventrals (161–163 vs 170–182). (5) the new species much slender than T. cantori ( Vijayakumar & David 2006) . Only one of three-color morphs of T. cantori is uniformly green.

T. caudornatus sp. nov. is distinct from T. fasciatus : (1) Dorsal body dark green with faint dark crossbands on the skin vs brownish-grey with olivaceous brown or dark brown crossbands on the back (examined topotypes David et al. 2003). (2) Venter pale green yellow and dorsal tail dark red vs “venter pale greyish brown or brown, heavily speckled with dark brown, anterior part and tip of ventrals nearly totally dark brown”. (3) tail relatively shorter in both gender, TaL/TL in the male/female 0.185 / 0.153 vs 0.202–0.210/0.183-0.198. (4) Internasals broad trapezoidal, broadly in contact vs “separated from each other by one scale” ( David et al. 2003; examined specimens, Appendix I). Additionally, T. fasciatus is endemic to Tanahjampea Island.

T. caudornatus sp. nov. is distinct from T. andersoni : (1) Body uniform dark green vs color above and below variable, usually brown, buff or blackish. (2) Fewer DSR at midbody (21 vs 23 to 25, rarely 21). (3) Fewer ventrals (161–163 vs 171–183) ( Gumprecht et al. 2004). Additionally, T. andersoni is endemic to the Andaman and Nicobar Islands.

T. caudornatus sp. nov. is distinct from T. labialis , Trimeresurus honsonensis , T. venustus and T. kanburiensis by the body color and pattern. The body uniform dark green and with a faint dark crossbands on skin in T. caudornatus sp. nov. while brown in T. labialis ( Vogel et al. 2014) , green patterned with spotted brownish speckles in T. honsonensis , T. venustus ( Vogel 1991) and T. kanburiensis ( David et al. 2004) .

Distribution. The new species is currently only known from the area around Nabang Town, Yingjiang Country, Yunnan Province, China. There is a large distance between the typical location of T. caudornatus and the typical location of T. septentrionalis ( Fig. 5 View FIGURE 5 ).