Psammophis turpanensis, Chen & Liu & Cai & Li & Wu & Guo, 2021

Chen, Minli, Liu, Jinlong, Cai, Bo, Li, Jun, Wu, Na & Guo, Xianguang, 2021, A new species of Psammophis (Serpentes: Psammophiidae) from the Turpan Basin in northwest China, Zootaxa 4974 (1), pp. 116-134 : 123-126

Psammophis turpanensis sp. nov.

Holotype. CIB 118224 , adult female, field number GXG1504 ( Fig. 3 ), was collected by Jinlong Liu, Minli Chen, and Na Wu on 25 September 2020 near Aydingkol Lake located in the Turpan Basin, Xinjiang Uygur Autonomous Region, China (42.70894°N, 89.25705°E, elevation 151 meters below sea level) ( Fig. 4 ).

Diagnosis. Psammophis turpanensis sp. nov. can be distinguished from the recognized congeners by a combination of the following characters: 1) dorsal scale 17 rows at midbody, rostral visible from upper side; 2) anal divided, subcaudals paired; 3) 9 supralabials, of which the 4 th to 6 th are touching the eyes; 4) head subtriangular, and body slightly compressed; 5) 209 ventrals (including one preventral) in the single female; 6) dorsum with five stripes, three median stripes from parietals posteriorly to the tip of the tail anteriorly, one pair of stripes from the nostrils to the posterior of the tail; 7) temporal scale arrangement 2+2 on both sides; 8) nasal scale divided, nostril situated between two nasals, anterior nasal touching 2 nd supralabial.

Etymology. This name turpanensis is taken from the type locality—Aydingkol Lake, located in the Turpan Basin. To the best of our knowledge, this is the first reported species from the lowest elevation of the type locality in terrestrial animals. We recommend “Turpan Sand Snake” as its English common name and “Tu Lu Fan Hua Tiao She (吐ỡffiẆ条ẘ)” as its Chinese common name.

Description of holotype. An adult female specimen preserved in 75% alcohol was measured: TL 960 mm (tail incomplete), SVL 861 mm, HL 23.15 mm, HW 12.84 mm, HD 9.02 mm, midbody width 15.51 mm, ED 3.82 mm, inter-narial distance 5.01 mm, frontal scale length (FL) 6.23 mm, frontal-rostral distance (FRD) 5.48 mm, frontal width at midline (FWM) 1.59 mm, frontal width at anterior end (FWA) 3.31 mm. Measurements of other Psammophis species are listed in Table 3 .

Head scalation. Body slender, wide and lightly compressed rather than cylindrical, head subtriangular and distinct from neck ( Fig. 3 ). Eye large, pupil rounded; nostril shaped like ‘>’, pierced between 2 nasals. Tail incomplete in length and therefore the number of subcaudals. Rostral visible from above, protruding, with a distinct cleft underneath. Mental scale smaller than rostral, subtriangular. Internasals paired, lightly subtrapezoidal. Prefrontals paired, subpentagonal from frontal view. Frontal anteriorly twice as wide as at midline, with tear-drop silhouette. Supraoculars subrectangular, length 4.74 mm, width 3.12 mm, 1.5× longer than wide. Supraoculars shorter than frontal. Parietals paired, left is subtriangular and right is subtrapezoidal when viewed from above; right is shorter than the left. Loreal scale partially divided, subrectangular, touching 2+3 supralabials. Nasal scale divided, anterior portion of nasal touching 2 nd supralabial on both sides and larger than posterior nasal. Preocular separates from frontal scale, and postocular touches parietals. Supralabials 9/9, 1 st smallest then gradually increasing in size until the 8 th; the 9 th is smaller than 8 th. Supralabials 1 st –2 nd contacting nasal, 2 nd –3 rd contacting loreal, 4 th –6 th entering orbit, 4 th and 6 th in partial contact with orbit, 5 th in complete contact with orbit; 8 th supralabial is the largest. Infralabials 10/10, first are in contact with each other behind mental; infralabials 1 st –5 th in contact with anterior chin shields; 1 st infralabial larger than 2 nd infralabial, 6 th infralabial is the largest, and subsequent infralabials gradually decrease in size until the last one. Chin shields subrectangular and symmetrical; anterior chin shields (length 5.75 mm of right one) slightly longer than posterior chin shields (length 5.63 mm of right one), and anterior chin shields wider than posterior. Temporals 2+2 on both sides.

Body scalation. Dorsal scale rows, 17 rows around body at one head length behind the head, 17 rows at midbody, and dorsal row at one head length anterior to the vent cannot count number due to the damaged skin. All dorsal scales imbricate, smooth, and the outermost coastal scale rows are slightly larger than the rest; vertebral scale rows not larger than the rest. Ventrals smooth, ventral-lateral border with dorsal scales forming an acute angle; 209 ventral shields (including one preventral); cloacal divided, and subcaudals paired.

Coloration and pattern. After preservation in 75% ethanol for two months, dorsum uniform black-brown throughout entire body. Dorsum with three black-brown stripes that extend from parietal extremity to the tail end, each stripe consisting of a series of black dots (surrounded by four dorsal scales) and brown dots. Laterally, the outermost part of ventral and the first two dorsal scale rows form dorsolateral stripes that derive from the anterior nasal scale. Ventral-lateral white, pale yellow in the middle; each ventral with a black dash on each side forming a ventro-lateral stippled line. Top of the head with longitudinal and irregular dark brown stripes, one stripe as long as the frontal which forks in parietal and combines with two stripes from supraocular and extends to parietal posterior; orange and black spots on labia, chin and the scale rows of neck.

Distribution and habitat. Psammophis turpanensis sp. nov. is currently known from the type locality near Aydingkol Lake ( Fig. 4A, 4B ) and from eastern parts of the town of Xia, Tuokesun county ( Fig. 4C, 4D ), in the Turpan Basin, Xinjiang, China. As shown in Fig. 4 , both sides of the road at Aydingkol Lake have saline-alkaline soil with a rigid and hardening surface. The habitat on one side of the road is mostly dominated by dense vegetation of phragmites extending to vast territories, while Tamarix spp. are also sparsely interspersed in the vicinity of the road ( Fig. 4A ). The vegetation on the other side of the road is mainly large tracts of low and sparse saline plants (mainly Halocnemum spp. , Halostachys spp. and Kalidium spp. ), with many withered vegetation ( Fig. 4B ). At the town of Xia, about two kilometers northwest from the Tugedun village in Tuokesun county, the habitat is characterized by large clusters of Alhagi spp. and Karelinia spp. and soil with texture that is similar to that at the type locality ( Fig. 4C, 4D ). In addition to the sand snakes, the Turpan Racerunner ( Eremias roborowskii ), the Turpan Wonder Gecko ( Teratoscincus roborowskii ), and the Dadun Thin-toed Gecko ( Tenuidactylus dadunensis ) are also present.

Morphological comparison. Detailed comparisons between P. turpanensis sp. nov. and P. condanarus and P. lineolatus are given in Table 3 . Based on the following characters, P. turpanensis sp. nov. is compared with five Asian sand snakes and the Afro-Asian Sand Snake, P. schokari . Psammophis turpanensis sp. nov. is distinct from P. lineolatus by the following differences: larger number of ventrals (209 vs. 181−192 in seven specimens); anterior portion of nasal touching 2 nd supralabial (vs. reaching first supralabial); greater and subtriangular head (HL/HW/ HD: 23.15/12.84/9.02 vs. maximum 18.23/9.05/6.03, subrectangular); dorsum with three black-brown stripes starting from parietal termination and two dorsolateral stripes deriving from anterior nasal scale (vs. dorsum with two stripes tracing to supraoculars and two lateral stripes originating from behind the nostrils); no middle stripe on the head (vs. head with a dark median streak from the interorbital region to the occiput) ( Boulenger, 1896).

Psammophis turpanensis sp. nov. differs from P. condanarus ( Ganesh et al., 2017; Haidar et al., 2020), P. indochinensis ( Hartmann et al., 2011) , P. schokari ( Amr & Disi, 2011; Kark et al., 1993), P. longifrons ( Boulenger, 1896; Vyas & Patel, 2013) and P. leithii ( Boulenger, 1896; Khan, 2002) by the following characters: nasal scale divided (vs. only partially divided in P. condanarus ); frontal anteriorly twice as wide as at the midline (vs. frontal anteriorly not twice as wide as at the midline in P. condanarus ); body black-brown vertebral stripe in a row that is three scales wide (vs. coffee-brown vertebral stripe five scales wide in P. condanarus , vertebral stripe lighter/absent or variable in P. indochinensis , 4 or uniformly dark with vertebral stripe light in P. schokari ); higher number of ventrals (209 vs. 165−179 in P. condanarus , 156−173 in P. indochinensis , 162−194 in P. schokari , 161−167 in P. longifrons , 164−187 in P. leithii ); 4 th to 6 th supralabials in contact with eyes (vs. 4 th, 5 th in P. condanarus , P. longifrons , P. leithii ; and 5 th, 6 th in P. schokari ); preocular not in contact with frontal (vs. reaching in P. condanarus and P. leithii ); anal scale divided (vs. anal entire in P. leithii ); nostril pierced between 2 nasals, anterior nasal touching 2 nd supralabial (vs. nostril pierced between one anterior and two superposed posterior nasals in P. longifrons ). In addition, the other five species except for P. lineolatus are not distributed in China, with non-overlapping geographic distribution between them and P. turpanensis sp. nov.

Figures

FIGURE 3. Photographs of the preserved specimen P. turpanensis sp. nov. (CIB 118224, from Aydingkol Lake, Turpan city, Xinjiang), showing: (A) dorsal view of the whole body, (B) ventral view of the whole body, (C) dorsal view of the head, (D) ventral view of the head, (E) lateral view of the head on the right side, (F) lateral view of the head on the left side, (G) dorsal view of part of the body, (H) lateral view of part of the body, and (I) ventral view of part of the body. Photos by Jinlong Ren, with permission.

FIGURE 4. Habitat of P. turpanensis sp. nov. at two localities: Aydingkol Lake shown by A (on the left side of the road) and B (on the right side of the road). Photos by Jinlong Liu. The Tuokesun county shown by C and D. Photos by Bo Cai.