Calamaria berezowskii Günther, 1896

Liang, Ya-Ting, Huang, Zi-Dan, Ding, Li, Vogel, Gernot, Ananjeva, Natalia B., Orlov, Nikolai L., Shi, Sheng-Chao, Wu, Zheng-Jun & Chen, Ze-Ning, 2024, Revalidated after having been described more than a century ago: Calamaria berezowskii Günther, 1896 (Squamata, Colubridae) from Sichuan, Southwestern China, Zoosystematics and Evolution 100 (3), pp. 897-911 : 897-911

Calamaria berezowskii Günther, 1896

Figs 3 , 4 , 5 , 6

Calamaria pavimentata — populations in Sichuan of Zhao et al. (1998) and Zhao (2006); Zhao (2003). Synonym.

Description of lectotype ZISP 8823.

Adult male, collected from Lun-ngan-fu (龙安府 Long’an Fu, now 龙安镇 Long’an Town of 平武县 Pingwu County) of Sze-chuen (Sichuan Province of China) ( Günther 1896).

HL: 8.0 mm, 3.0 % of SVL; HW: 5.0 mm, HW / HL: 62.5 %; HH: 4.0 mm, HH / HL: 50.0 %; EyeD: 0.7 mm, larger than eye-mouth distance 1.0 mm; EyeD 8.8 % of HL.

SVL: 271 mm; TaL: 19 mm; TL: 290 mm; Tal / TL: 6.6 %.

DSR: 13–13 – 13 scales; VEN: 155; SC: 22, divided, followed by a shield covering tail tip; anal scale single.

Rostral as broad as high; pupil rounded; preocular 1 / 1 (left / right, hereafter); postocular 1 / 1; supralabials 4 / 4, the second and third supralabials entering orbit, the fourth longest; infralabials 5 / 5. Visible yellowish collar on left and right sides of the neck present. Dorsal color brown, with a faint dark line along each side of the back; ventral surface uniform white. Tail rather obtuse, with a conical end. 2–3 pairs light color spots at the base of the tail.

Description of referred specimen GXNU DLR 195.

Adult female, collected from Mt. Gongga, Moxi Town, Luding County, Ganzi Tibetan Autonomous Prefecture, Sichuan Province, China (29.645105 ° N, 102.111076 ° E, 1736 m a. s. l.) collected by Xu Zhang on 31 August 2018.

Body elongated, cylindrical; head small, not distinct from nape; tail short, similar in form to head; tail not flattened, tapering and bluntly pointed at tip.

HL: 8.3 mm, 2.9 % of SVL; HW: 3.9 mm, HW / HL: 47.0 %; HH: 4.0 mm, HH / HL: 48.2 %; EyeD: 0.7 mm, larger than eye-mouth distance 1.1 mm; EyeD 8.4 % of HL.

SVL: 288 mm; TaL: 17 mm; TL: 305 mm; Tal / TL: 5.6 %. Body thickness about 4.70 to 6.71 mm; base of tail 3.18 mm thick.

VEN: 165 (+ 2 preventrals); SC: 16, all paired; anal shield entire, ventral scales immaculate.

DSR: 13–13 – 13 scales, dorsal scales smooth and immaculate.

Rostral shield width (2.22 mm) is larger than height (1.62 mm), internasals and prefrontals fused 2 scales; prefrontal length (2.28 mm) is less than frontal length (2.61 mm), not entering orbit, and touching first two supralabials; frontal hexagonal, longer (2.61 mm) than wide (2.50 mm); six paraparietals; parietal scales long, tangent to supraocular, postocular scales, supralabials; one preocular present; parietal broadly in contact with the last supralabials; pupil rounded; supralabials 4 / 4, second and third entering orbit, the fourth largest (length 2.34 / 2.32 mm) and tangent to the postoculars; mental not touching anterior chin shields; infralabials 5 / 5, first three touching anterior chin shields; anterior chin shields are slightly longer than posterior chin shields, presence of mental groove; less than 1 / 2 of the posterior chin shield meets in the midline; dorsal scales reduced to 6 rows above last subcaudal at tail; anal scale is complete and single.

Coloration in life. The dorsal color was blackish brown, with a faint dark line along each side of the back which is about 3 scales wide apart; the outermost corners of the ventral scales were brownish, and the ventral surface was lighter; presence of distinct yellowish collar; absence of light ring at the base of the tail.

Coloration in preservative. The specimen was preserved in alcohol. Dorsal body blackish brown, ventral surface light khaki. Dorsal head and neck coincide with the dorsal body, with a pair of light spots on each side of the neck and on the back of head; dorsum without distinct blotches; venter immaculate, without any dark stripes or scattered spots; ventral surface of tail with a dark longitudinal stripe and blotches; ventral scales with dark outermost corners.

Variations for population from Mt. Gongga, Luding County.

Measurements of other specimens are given in Table 4 . Male with relatively longer tail (TaL / TL are distinctly larger in the adult male). Adult female GXNU DLR 194 displays many scattered brown spots on the venter, and with distinct light-yellow blotches on the left and right sides of the neck, but in adult male GXNU DLR 195 the venter is immaculate without any dark spots. The population of Mt. Gongga, Luding County differs slightly from the type specimen in dorsal and ventral coloration (dorsal body blackish brown vs brown, ventral surface light khaki vs white), and differs from the lectotype ZISP 8823 in color spots at the base of the tail (absent vs present) (Figs 3 , 4 , 5 ).

Detailed morphological comparisons.

Detailed morphological comparisons between Calamaria berezowskii and 20 congeners of the genus from China and mainland Southeast Asia are:

Calamaria berezowskii is distinguished from C. albiventer , C. lumbricoidea , C. prakkei , C. schlegeli , and C. concolor by having fewer supralabials (4 vs 5–6), and the 2 nd and 3 rd supralabials shields touching the orbit (vs. 3 rd and 4 th supralabials touching orbit), mental not touching anterior chin shields (vs. touching in C. albiventer , C. lumbricoidea , C. prakkei and C. concolor ).

Calamaria berezowskii is distinguished with C. lovii , C. nebulosa , C. thanhi and C. yunnanensis by having presence of preocular scale (vs. absence of preocular scale), eye diameter less than distance from eye to mouth edge (vs. reverse condition in C. thanhi and C. nebulosa ), fewer ventral scales in males (149–155 vs 161–202 in C. lovii , 149–155 vs 184 in C. thanhi and 149–155 vs 167–184 in C. yunnanensis ), more subcaudal scale in males (22–25 vs 14–20 in C. lovii , 22–25 vs 15–20 in C. yunnanensis ).

Calamaria berezowskii differs from C. sangi , C. gialaiensis and C. buchi by having mental not touching anterior chin shields (vs. touching), dorsal scales reduced to six rows at tail (vs. reduced to four rows), fewer ventral scales (149–167 vs 190 in C. sangi , 149–167 vs 191 in C. gialaiensis , 149–167 vs 221–236 in C. buchi ).

Calamaria berezowskii is distinct from C. arcana and C. jinggangensis by having the eye diameter less than the distance from the eye to mouth edge (vs. reverse condition in C. arcana and C. jinggangensis ), fewer ventral scales (149–167 vs 170–192 in C. arcana and C. jinggangensis ), more subcaudals in females (16 vs 12–14 in C. arcana and C. jinggangensis ), a distinctly different coloration (dark orange or orangish-red in fresh specimens in C. arcana and C. jinggangensis ), presence of dark outermost corners on ventral scales (vs. absence in C. arcana and C. jinggangensis ), a faint dark line along each side of the back present (vs. opposite condition in C. arcana and C. jinggangensis ), a dark longitudinal line or scattered spots on the underside of tail present (vs. absent in C. arcana and C. jinggangensis ).

Calamaria berezowskii differs from C. abramovi by having the rostral wider than high (vs. width equal to high in C. abramovi ), fewer ventral scales in males (149–155 vs 159 in C. abramovi ), dorsal scales reduced to six rows at tail (vs. reduced to four rows in C. abramovi ), tail ends in obtuse point (vs. sharp point in the end of tail in C. abramovi ), and a distinctly different coloration (body black with yellow-orange spots on venter in C. abramovi ).

Calamaria berezowskii differs from C. andersoni by having eye diameter smaller than distance from eye to mouth edge (vs. reverse condition in C. andersoni ), fewer ventral scales in males (149–155 vs 171 in C. andersoni ), dorsal scales reduced to six rows at tail (vs. reduced to four rows in C. andersoni ), light blotches on neck present (vs. absent in C. andersoni ).

Calamaria berezowskii differs from C. septentrionalis by having eye diameter less than distance from eye to mouth edge (vs. reverse condition in C. septentrionalis ), mental separated from anterior chin shields (vs. reverse condition in C. septentrionalis ), not gradually tapering at tip (vs. tail tip broadly rounded in C. septentrionalis ), higher number of subcaudals (22–25 vs 15–19 in males and 16 vs 6–11 in females), absence of black stripe on venter of tail (vs. venter of tail with broad and distinct median black stripe in C. septentrionalis ).

Calamaria berezowskii differs from C. pavimentata by having the rostral shield width larger than high (vs. reverse condition in C. pavimentata ), the eye diameter less than the distance from eye to mouth edge (vs. reverse condition in C. pavimentata ), tail not tapering anteriorly and abruptly pointed at tip (vs. tail tapering gradually to a point in C. pavimentata ), dorsal scales reduced to six rows at tail (vs. reduced to four rows in C. pavimentata ), dorsum of body with two faint dark lines (vs. distinct narrow and dark longitudinal lines on dorsum in C. pavimentata ).

Calamaria berezowskii differs from C. dominici by having eye diameter less than eye-mouth distance (vs. opposite situation in C. dominici ), mental separated from anterior chin shields (vs. mental touching tip of right anterior chin shield in C. dominici ), dorsal scales reduced to six rows at tail (vs. reduced to four rows in C. dominici ), fewer ventral scales in females (153–165 vs 174 in C. dominici ), absence of blotches on dorsum (vs. present irregular yellow blotches on dorsum in C. dominici ), venter immaculate without dark stripes (vs. ventral side dark with yellow blotches and bands).

Calamaria berezowskii differs from C. strigiventris by having posterior chin shields meeting in midline (vs. diverging or meeting only in anteriorly in C. strigiventris ), dorsal scales reduced to six rows at tail (vs. reduced to four rows in C. strigiventris ), lower number of subcaudals (22–25 vs 29–33 in males and 16 vs 20–30 in females in C. strigiventris ), venter immaculate (vs. presence of three interrupted longitudinal black stripes in C. strigiventris ), tail not flattened, tapering and bluntly pointed at tip (vs. slowly tapering anteriorly, then abruptly tapering to a point in C. strigiventris ).

Diagnosis.

Calamaria berezowskii can be distinguished from all other congeneric species by having the following combination of morphological characters: 1) rostral shield width larger than high; 2) prefrontal shorter than frontal, touching the first and second supralabials; 3) frontal hexagonal, length longer than width; 4) mental not touching anterior chin shields; 5) two pairs of chin-shields, the anterior not much longer than the posterior, less than 1 / 2 of the posterior chin shield meets in the midline; 6) eye diameter less than eye-mouth distance; 7) single preocular, single postocular; 8) four supralabials, second and third supralabials entering orbit; 9) five infralabials, first three touching anterior chin shields, first pair of supralabials touching each other; 10) six scales and shields surrounding the paraparietals; 11) dorsal scales smooth, DSR 13–13 – 13 (n = 4); 12) dorsal scales reduced to six rows above last subcaudal at tail; 13) 149 (+ 2 preventrals) – 155 ventrals in the males (n = 2), 153–165 (+ 2 preventrals) in the females (n = 2); 14) 22–25 subcaudals in the males (n = 2), 16 in the females (n = 2), all paired; 15) anal plate single and intact; 16) dorsum of body and tail blackish-brown or brown, with a faint dark line along each side of the back; 17) a more or less distinct yellowish collar; 18) 2–3 pairs of small white spots may be present or absent on the tail; 19) ventral scales of body light khaki or white, with a dark longitudinal line or scattered spots on the underside of tail; 20) two outermost dorsal scale rows light khaki with upper margins partly dark pigmented; 21) tail relatively short (5.6–10.5 % of the total length), not flattened, slowly tapering to obtuse, with a conical end.

Etymology.

Named after collector of type specimen, Russian traveler and zoologist. Michael Berezowski. For common name, we suggest “ 川西两头蛇 ” (Chinese), “ Berezowski’s Reed Snake ” (English).

Distribution and ecology.

Terra typica of Calamaria berezowskii is Lun-ngan-fu (now Long’an Town of Pingwu County) ( Günther 1896). It is known from western Sichuan Province, China, including Pingwu County, Shimian County, Baoxing County, Luding County, Mt. Emei and Pingshan County ( Zhao et al. 1998; Zhao 2003; this study). These localities are all on the eastern edge of the Qinghai-Tibet Plateau bordering Sichuan Basin. In Luding County, it was found at an elevation of 1680–1827 meters, surrounded by mountainous evergreen broad-leaved forest belt and evergreen broad-leaved deciduous broad-leaved mixed forest belt (Fig. 7 ). It has a typical subtropical-based vertical natural belt spectrum, with big altitude differences, and abundant rare plant and animal resources ( Wang et al. 2023).

Figures

Figure 3. Calamaria berezowskii (GNXU DLR 195): A. Dorsal head; B. Ventral head; C. Right view of head; D. Left view of head; E. Dorsal middle body; F. Lateral middle body; G. Dorsal tail; H. Ventral tail; I. Dorsal view; J. Ventral view.

Figure 4. Calamaria berezowskii (GXNU DLR 194) in life.

Figure 5. Lectotype ZISP 8823 of Calamaria berezowskii: A. Right view of head; B. Left view of head; C. Dorsal view; D. Ventral view.

Figure 6. Original description of Calamaria berezowskii Günther, 1896: A. Drawing; B. Description.

Figure 7. Macrohabitat of Calamaria berezowskii in Luding County, Sichuan Province, China.