A new species of Gonyosoma Wagler, 1828 (Serpentes, Colubridae), previously confused with G. prasinum (Blyth, 1854) Author Liu, Shuo Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650223, China Author Hou, Mian College of Continuing (Online) Education, Sichuan Normal University, Chengdu, 610066, China Author Lwin, Ye Htet https://orcid.org/0000-0002-7812-1377 Southeast Asia Biodiversity Research Institute, Chinese Academy of Sciences, Nay Pyi Taw, 05282, Myanmar Author Wang, Qiaoyan Research Institute of Xishuangbanna National Nature Reserve, Jinghong, 666100, China Author Rao, Dingqi Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, 650201, China raodq@mail.kiz.ac.cn text Evolutionary Systematics 2021 2021-06-22 5 1 129 139 http://dx.doi.org/10.3897/evolsyst.5.66574 journal article http://dx.doi.org/10.3897/evolsyst.5.66574 2535-0730-1-129 03620F93FD7A4396B158554FD9866350 2ECF0203159E56BCBC920189956612EF Gonyosoma coeruleum sp. nov. Figs 2 , 3 , 4A, C, E , 5A, B , 7B Holotype. KIZ2019028, adult female, Mengla County, Xishuangbanna Autonomous Prefecture, Yunnan Province, China, 29 April 2019, 21°32'12"N , 101°32'51" E, 900 m a.s.l. Paratypes. KIZ2019025, one adult female and KIZ2019026-KIZ2019027, two adult males, Mengla County, Xishuangbanna Autonomous Prefecture, Yunnan Province, China, 4 May 2019, 21°55'9"N , 101°32'12"E , 890 m, a.s.l. KIZ20200729, adult female, collected from Zhenyuan County, Puer City, Yunnan Province, China, 29 July 2020, 24°3'37"N , 101°3'43"E , 1,240 m a.s.l. KIZ20200904, one juvenile, collected from Menglian County, Puer City, Yunnan Province, China, 3 September 2020, 22°10'16"N , 99°18'31"E ,1,200 m a.s.l. Etymology. The specific epithet " Gonyosoma coeruleum " is the neutral gender of the Latin adjective coeruleus (a, um) meaning "blue" , and is given in reference to the coloration of the iris of this species. Diagnosis. Body size medium (SVL 656-833mm in adults); body slender, head elongated and distinct from neck; large eyes with round pupil; tail long (23-28% of total length) and slender; dorsal scales in 19-19-15 rows, 7-11 rows of mid-dorsal scales keeled; single preocular; two postoculars; one or two anterior temporals and two or three posterior temporals; 189-202 ventral scales; 89-106 paired subcaudals; precloacal plate divided. Dorsal surface bright green with brownish-yellow tip of tail, iris blue, inside of mouth greyish white; tongue brownish yellow with black tips. Figure 2. Type series of Gonyosoma coeruleum sp. nov. in preservative. A dorsal view B ventral view. Description of the holotype. Head elongate, distinct from the neck, flattened, longer than wide, narrowed anteriorly; nostril lateral; eye large, pupils round; rostral triangular, broader than high, visible from above; nasal divided into two scales; two internasals, wider than high, bordered by two large prefrontals posteriorly; frontal single, enlarged, pentagonal, narrowed posteriorly; parietals longer than wide, in contact with each other; supralabials 8/9, first and second in contact with the prenasal and postnasal, third and fourth entering orbit on left side, fourth and sixth entering orbit on right side, eighth 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, second pair meeting in midline; preocular 1/1; postoculars 2/2, lower ones smaller, bordering anterior temporals; anterior temporals 2/2, posterior temporals 2/2. SVL 814 mm; TaL 245 mm; TaL/TL 0.23; DSR 19-19-15, nine rows keeled in the vertebral region, otherwise smooth; ventrals 202 with a lateral keel; subcaudals 89, paired; precloacal plate divided. Figure 3. Head views of the holotype (KIZ2019028) of Gonyosoma coeruleum sp. nov. in preservative. A dorsal B ventral C right D left. Color of holotype in life. Dorsal surface bright green with brownish-yellow tip of tail, reticulate pattern consisting of yellow, black, and white on the interstitial skin; upper lips yellowish-green; anterior ventral surface greenish-white and posterior ventral surface light green; tip of tail brownish-yellow on its ventral surface; ventrals outside the lateral keel usually yellowish-white; iris blue; pale grey inside of mouth; tongue brownish-yellow with black tips. Figure 4. Comparisons of the colors of iris, the colors of inside of mouth, and the precloacal plates. A, C , and E the holotype (KIZ2019028) of Gonyosoma coeruleum sp. nov. B, D , and F the specimen (SEABRI2019120043) of G. prasinum . Variations. The paratypes resemble the holotype in most aspects except that the rows of mid-dorsal scales keeled vary from seven to eleven, anterior temporals vary from one to two, and posterior temporals vary from two to three in paratypes; moreover, the male paratype KIZ2019027 has a relatively longer tail (TaL/TL 0.28). Figure 5. The specimens of Gonyosoma coeruleum sp. nov. and G. prasinum in life. A the female paratype (KIZ20200729) of Gonyosoma coeruleum sp. nov. B the juvenile paratype (KIZ20200904) of Gonyosoma coeruleum sp. nov. C the specimen (SEABRI2019120043) of G. prasinum from Myanmar D the specimen (SEABRI2019120075) of G. prasinum from Myanmar. Distribution. Gonyosoma coeruleum sp. nov. is currently known from Xishuangbanna Autonomous Prefecture and Puer City, Yunnan Province, China (Fig. 6 ), it is probably also distributed in other parts of Yunnan Province and Sichuan, Guizhou, and Hainan Province, China, as well as Southern Myanmar, Thailand, Laos, and Vietnam. Figure 6. Map showing the type locality of Gonyosoma coeruleum sp. nov. (blue star) in Mengla County, Yunnan Province, China; the other collection sites of Gonyosoma coeruleum sp. nov. in Zhenyuan County (blue pentagon) and Menglian County (blue triangle), Yunnan Province, China; the type locality (green square) of G. prasinum in Assam, India; and the new collection site (green dot) of G. prasinum in Htamanthi wildlife sanctuary, Sagaing, Myanmar. Natural history. The specimens from Mengla County were collected on big trees bordering rivers, the specimen from Zhenyuan County was collected on a big tree on the side of a small road in forest, and the specimen from Menglian County was collected on a small tree bordering a stream. All specimens were found at night while they were asleep on tree branches, what shows that this species is diurnal. Through direct observation, we found that they like to feed on small rodents, and whether they also prey on other animals is unknown. Comparisons. Gonyosoma coeruleum sp. nov. can be distinguished from G. boulengeri in lacking a nasal appendage (vs. rostral distinct from the nasal appendage), and no dark stripe behind the eye (vs. an indistinct dark stripe behind the eye) ( Mocquard 1897 ; Smith 1943 ). Gonyosoma coeruleum sp. nov. is distinguishable from G. frenatum based on its single, distinct loreal (vs. loreal united with the prefrontal), and no black streak along the side of the head (vs. a black streak along the side of the head above the supralabials) ( Gray 1853 ; Boulenger 1894 ; Smith 1943 ). Gonyosoma coeruleum sp. nov. can be separated from G. jansenii by having 19 midbody dorsal scale rows (vs. 23-25), and dorsal surface uniform bright green with brownish-yellow tip of tail (vs. olive or yellowish-brown, entirely black posteriorly and on the tail) ( Bleeker 1859 ; Boulenger 1894 ). From Gonyosoma margaritatum , Gonyosoma coeruleum sp. nov. can be differentiated by its dorsal surface uniform bright green with brownish-yellow tip of tail (vs. black, each scale with a yellowish green spot, or green with black borders to the scales, hinder part of body and tail with bright orange rings), and no black streak on each side of the head (vs. a black streak on each side of the head behind the eye) ( Peters 1871 ; Boulenger 1894 ). Figure 7. A habitat at the type locality of Gonyosoma coeruleum sp. nov. B Gonyosoma coeruleum sp. nov. asleep on a tree at night. From Gonyosoma oxycephalum , Gonyosoma coeruleum sp. nov. can be differentiated by the different colors of tail (green with brownish-yellow tip vs. the whole tail light chestnut or buff-red or yellowish brown), no blackish stripe along the side of the head (vs. an indistinct blackish stripe along the side of the head immediately above the supralabials), and the number of midbody dorsal scale, 19 rows (vs. 23-27 rows) (Boie 1827; Boulenger 1894 ; Smith 1943 ). Gonyosoma coeruleum sp. nov. closely resembles G. prasinum , but the colorations of their iris in life are obviously different, the iris of Gonyosoma coeruleum sp. nov. is blue (Fig. 4A ) while the iris of G. prasinum is greenish-yellow (Fig. 4B ; Khandekar et al. 2021 ). The colours of the inside of mouth are slightly different, the inside of mouth of Gonyosoma coeruleum sp. nov. is pale grey (Fig. 4C ) while it is pink (Fig. 4D ) in G. prasinum . In addition, the precloacal plate of Gonyosoma coeruleum sp. nov. is divided (Fig. 4E ) while it is single (Fig. 4F ; Das 2013 ) in G. prasinum .