Li (1999) described Gloydius shedaoensis qianshanensis based on specimens collected from Qianshan Mountain, Anshan City, and Longtanshan Mountain, Wafangdian City, Liaoning Province. The specimens were preserved in the Snake Island Natural Museum in Lushun. However, the type specimens were lost during the relocation and expansion of the museum, including the holotype SB980563 collected from Qianshan Mountain, Anshan City, and paratypes collected from Longtanshan Mountain, Wafangdian City (interview to Jian-Li Li who described briefly and named this subspecies). Additionally, the original description only listed some numbers of ventral and subcaudal scales, with data on the length and weight of pregnant and juvenile snakes, but lacked detailed morphological descriptions and photos of specimens, which led to disagreements among later authors on the validity of this subspecies.

SYNU900701, adult male (Figs 2, 3), collected at Qianshan Mountain Area, Liaoyang City, Liaoning Province, China (40°53'54"N, 123°17'42"E; 385 m a.s.l.). Collected by Xian-Chun Qiu on 6 July 2020.

Twelve adult and eight juvenile specimens. Males SYNU900702–900704, females SYNU900705–900710, and juvenile SYNU900712 were collected from the same locality as the neotype by Xian-Chun Qiu between July and October 2020. Male SYNU13090001, female SYNU900712, and juveniles 1510184, 1510184, SYNU13090003, SYNU13090004, SYNU13090005, SYNU13090024 and SYNU1309006, collected by Jing-Song Shi during summer and autumn (2013–2015) from Wafangdian City, Liaoning province (39°56'20"N, 122°15'28"E; 450 m a.s.l.). Male SYNU900713, collected by Xian-Chun Qiu in July 2014 from Qianshan Mountain, Anshan City, Liaoning Province, China (40°59'36"N, 123°7'36"E; 406 m a.s.l.).

This subspecies is named after its type locality, i.e., Qianshan Mountain, Liaoning Province, China.

The morphological distinctions between Gloydius shedaoensis qianshanensis and other congeneric species and subspecies are as follows: (1) medium size, TTL up to 730 mm. (2) three palatine teeth. (3) dorsum light gray and covered with dark gray irregular X-shaped pattern; (4) black postorbital stripe with white lower margin; (5) postorbital stripe width smaller than eye diameter but larger than half of the eye diameter; (6) head flat and slender, slightly triangular; (7) mid-body dorsal scales 23; (8) ventral scales 153–170; (9) subcaudals 33–49.

(Figs 4, 5): Gloydius shedaoensis qianshanensis belongs to the G. halys-intermedius group with 3 palatine teeth and 23-mid-body dorsal scale rows, which is different from the G. strauchi group with 21 rows of mid-body dorsal scales, including G. strauchi (Bedriaga, 1912), G. himalayanus (Günther, 1864), G. qinlingensis (Song & Chen, 1985), etc. It is different from the G. blomhoffii group with 4 palatine teeth, including G. blomhoffii (Boie, 1826), G. brevicaudus (Stejneger, 1907), G. ussuriensis (Emelianov, 1929), etc. The external morphology of G. s. qianshanensis is very similar to some taxa of the G. halys-intermedius group, including G. s. shedaoensis, G. intermedius, and G. changdaoensis Li, 1999. The results of PCA indicate that significant differences in head morphology exist between G. s. qianshanensis, G. s. shedaoensis, G. intermedius, and G. changdaoensis (Fig. 6). HL and PSW are the main indexes to distinguish the above species in PCA (Table 3). Furthermore, G. s. qianshanensis can also be distinguished by the following characters (Table 4): (1) light or dark gray dorsum (vs. brownish red or dark brown in G. intermedius and G. changdaoensis); (2) dark gray X-shaped spots appear on the dorsum (vs. dark and light cross striations interspersed in G. intermedius, rounded spots with light central color and dark margins on the lateral body in G. changdaoensis); (3) black postorbital stripe (vs. dark brown or brown in G. intermedius and G. changdaoensis); (4) postorbital stripe width less than the eye diameter but more than half of the eye diameter (vs. less than or approximately equal to half of the eye diameter in G. s. shedaoensis, approximately equal to eye diameter in G. intermedius and G. changdaoensis); (5) wider stripes cover 3–21 or 4–20 rows of mid-body dorsal scales (vs. stripes cover 5–19 rows of mid-body dorsal scales in G. s. shedaoensis).

The skull of Gloydius shedaoensis qianshanensis is quite similar to G. s. shedaoensis but differs in the following characteristics: (1) the postorbital processes of G. s. shedaoensis is more anteroposteriorly elongated than it in G. s. qianshanensis; (2) the anterodorsal edge of the postorbital of G. s. qianshanensis is in contact with the caudolateral edge of the frontal, while the anterodorsal edge of the postorbital is not in contact with the caudolateral edge of the frontal (separated from the frontal by the postorbital process of the parietal); (3) G. s. qianshanensis have less pterygoid teeth (9–10, n = 6) than G. s. shedaoensis (11–12, n = 3); the dentary teeth of G. s. shedaoensis are longer and slenderer relative to G. s. qianshanensis; (4) G. s. shedaoensis has more curved palatine teeth than G. s. qianshanensis; (5) the dorsal edge of choanal process of the palatine in G. s. qianshanensis is significantly vaulted, rendering the palatine triangular shaped in lateral view, while the dorsal edge of choanal process of the palatine in G. s. shedaoensis is less vaulted and smooth (Figs 7, 8).

SYNU900701, adult male, medium size, tail short (TTL 585 mm, TL 80 mm, TL/TTL 0.14). Head slightly triangular in dorsal view, slightly flat and slender, distinct from the neck (HL 27.7 mm, HW 16.5 mm, HD 9.5 mm, HW/HL 59.6%); snout blunt, slightly protruding from the lower jaw; eyes relatively small, pupil vertical (ED 3.4 mm, ED/HL 12.2%).

Nine large scales are intact on the head. Rostral slightly trapezoidal, wide at bottom and narrow at top, the upper margin visible from dorsal view; nasal divided, anterior part larger, posterior margin of nostril tangent to the middle gap of nasal; two loreals, lower one forms the forward margin of pit; preoculars 3/3 (left/right), upper one turns up to dorsal head and extends to prefrontal, lower two slender and smaller, form the posterior margin of pit; postoculars 2/2, upper one small, lower one sickle-shaped and significantly longer, extending around the lower margin of eye to third supralabial; supralabials 8/7, first supralabial in contact with both parts of nasals, second supralabial smallest, third supralabial lagest and extending the bottom of orbit; temporals 2+3/2+3, largest temporal in contact with fourth and fifth supralabial on both sides; infralabials 11/11, first pair extends behind mental and connect, separate mental from chin shields; a pair of chin shields slightly rhombic, forming the mental groove in the middle; dorsal scales texture matte, keeled except for the row connecting with ventral scales; dorsal scale rows 23-23-17; ventral scales 157; anal plate single; subcaudals 41, in pairs.

The background coloration of dorsal head is light gray, a pair of discontinuous black stripes on both sides extending backward from the outside of supraocular and parietal; eye rust red on the upper half while brown on the bottom half, pupil black with rust red margin; a black stripe appears behind eye and extends to the corner of mouth, black stripe slightly wider than half eye diameter, bottom of stripe is wavy with a very thin white margin; temporals, supralabials, and infralabials below black postorbital stripe are light gray and scattered with dark brown tiny blobs; a dark gray pincer shaped pattern with an opening toward the head appears on dorsal neck; dorsum basically light gray with dark gray irregular X-shaped pattern, a light gray crossband composed of 1–2 scales is formed between two X-shaped pattern; a row of dark gray vaporous blobs separated from X-shaped pattern appear on lateral body; the end of tail is dark brown with grey crossbands; ventral surface of head grayish white, and the color gradually darkens from ventral neck to rear, the ventral surface of body from after neck to before tail is rust red, irregular vaporous black blobs appear near the gap of ventral scales; ventral tail gray and covered with dark brown spots.

Morphometric data are summarized in Table 1. The dorsal background coloration of paraneotype SYNU900703 is close to earthy yellow. Postoculars 3/3 in paraneotype SYNU13090001.

Gloydius shedaoensis qianshanensis is distributed in the Liaodong Peninsula mountainous area north to Liaoyang County, east to Xiuyan County, and south to Wafangdian City of Liaoning Province (Fig. 9).

Gloydius shedaoensis qianshanensis dwells in the deciduous broad-leaved forest in mountainous and hilly areas and the microhabitats contain forest edges, shrubs, grass, and gravel hillsides (Li 1999). Adults are easier to find in autumn because at that time they climb up branches to prey on avians, mainly Passerines (Fig. 10). The predation sites are usually selected on twigs above puddles or near the branches bearing berries, and other structures that attract avians. Sometimes two G. s. qianshanensis ambush on the same branch or adjacent branches in highly similar positions. In this study, two adult male G. s. qianshanensis were collected in Wafangdian City in early October 2019. One of them was collected from the ground bushes, and the other was collected from a branch not far away. It was established that both of their excrements had bird feathers that have not been completely digested. The excrements of adult individuals collected in Liaoyang City in October 2022 are mostly bird feathers, and only one sample excrement contains the hair of small mammals. G. s. qianshanensis do not estivate like G. s. shedaoensis on Snake Island. They prey on small mammals such as mice in midsummer. The main activity period of G. s. qianshanensis is from May to October of the year. They begin to hibernate in early November. The distribution of Gloydius shedaoensis qianshanensis is limited to the mountains of the Liaodong Peninsula, which may be related to their avian feeding habits. The East Asian-Australasian Flyway supports the greatest diversity and populations of migratory birds globally (Yong et al. 2015). The Liaodong Peninsula is located in the East Asian-Australasian Flyway and it is the necessary passage for some south-north migratory passerine birds to cross the Bohai Strait to reach the southern part of the Chinese Mainland (Yong et al. 2021).

Mating occurs in spring and autumn, and hatch from late August to mid-September, with 3–16 offspring per adult. The total length of the baby snakes is 192–247 mm and they weigh 4.5–6.8 g (Li 1999). Two juveniles were collected in Wafangdian City in June 2013. One of the samples vomited a centipede, and found centipedes in the stomach of the other sample, indicating that centipedes are an important diet composition for juvenile G. s. qianshanensis. In addition, juveniles do not prey on avians, but on juvenile mice of Mus musculus Linnaeus, 1758 in our captivity observations.