Andrias jiangxiensis

Conservation: Our long-term field monitoring of A. jiangxiensis sp. nov. yielded only a single incident of a breeding, wild population in the protected area at Daqi Mountain, Jing’an County. This protected area has a riverine habitat of only 6.50 km in linear distance and 36.0 km 2 of area. The upstream water runs inconstantly throughout the year, as flash floods occur occasionally in summer and droughts often occur in the winter, which lead to frequent habitat fragmentations. The downstream habitat out of the nature reserve is blocked by a dam and is inhabitable to A. jiangxiensis sp. nov. due to anthropogenic activities. This small, isolated, and sometimes fragmented population is particularly vulnerable to environmental changes, and thus the species faces a great extinction threat. Therefore, following the IUCN criteria B 1 (extent of occurrence less than 100 km 2, known to exist at only a single location, and extreme fluctuation of extent of occurrence) (IUCN, 2012), we recommend to classify A. jiangxiensis sp. nov. as Critically Endangered (CR), and we recommend to list the species as Class II protected in China, and to implement further assessments.

(Figure 4; Supplementary Table S 4)

Description of holotype: Adult male, body size relatively small, SVL 381 mm, TTL 589 mm; tail muscular, thick at base, gradually flattening posteriorly and distally; dorsal fin well developed, ventral fin much reduced, maximum tail height 76.2 mm; tail short, TAL 208 mm, TAL 54.6 % SVL, 35.3 % TTL. Head dorsally compressed, wide, HL 102 % HW; snout truncated, blunt, widen gradually posteriorly, projecting beyond lower jaw in ventral view; jaw muscular, distinctively widen from snout; jaw muscles continuous with two ovoid, convex temporal muscles dorsally posterior to each eye; nostrils small, NL 1.5 mm, anteriorly and laterally positioned, eye – nare distance 27.6 mm. Eyes small, rounded, EL 4.2 mm, 2.8 times NL, protuberant in life, lacking eyelids; dorsolaterally positioned, wide apart, IND 31.6 % IOD, EL 44.2 % SOD. Mouth large, corner almost reaching mid temporal protuberances; supralabial fold distinct; extending from posterior edge of mouth to axillary. Skin of head and lower jaw mostly smooth with small tubercles scattered dorsolaterally on temporal head and neck in life, all distributed irregularly, gradually increasing in numbers posteriorly; tubercles indistinct after preservation. Transverse gular fold present, without distinct glands. Body robust, dorsally compressed but less than head, elongated, AXD 34.1 % TTL; costal grooves in life, less distinct after preservation; vertebral groove distinct on posterior 3 / 4 of body; neck fold strongly developed, from corner of mouth to posterosuperior axillary; lateral body folds strongly developed, anterior end inferior and discontinuous from neck fold at limb insertion point, extending to caudal base; single dorsolateral series of large tubercles just above base of lateral fold on each side of vertebrate from neck to caudal base, more distinct in life, barely visible after preservation; remaining body skin mostly smooth in life. Limbs short, robust, dorsoventrally compressed, with distinct lateral skin folds, more prominent on posterior limbs; hindlimbs relatively longer and stronger than forelimbs, FLL 10 % TTL, PLL 12 % TTL. Hands and feet dorsally compressed, finger and toe tips enlarged, rounded; finger and toe tips and ventral hands and feet covered with dark carotin layer; four fingers, no webbing, length formula II> III> I> IV, lateral skin fringe distinct on finger IV, continuous with lateral limb fold; five toes, with rudimentary webbing, toe length formula III> IV> II> V> I, toe III, IV, and Vwith stronger lateral fringes. Coloration of holotype: In life (Figure 5), dorsum red-brown, with large continuous or discontinuous irregular black patches, gradually decreasing and broken from midbody to head and tail, a few black spots scattered between large patches; ventral surface grayish brown, with black spots scattered along the mandibular margin only; small white spots with tan edge throughout the body; grayish white around eyes, iris gold with black markings. In preservative (Figure 4), bright tints faded, dorsum and abdomen faded to grayish brown and gray, respectively, white spots with tan edge, black patches and spots remain distinct; horny epidermis on tips of fingers and toes as well as palms and soles brown. Variation: No significant differences in morphology and coloration were found among all adult specimens of the type series, or between genders. However, a distinctive ontogenetic shift existed in coloration. Juveniles less than 30 cm long were mostly spotted (Figure 6 A) instead of having larger patches; after exceeding 40 cm, their coloration pattern resembled the type specimens (Figure 6 B).

Diagnosis: Andrias jiangxiensis sp. nov. can be distinguished from its congeners by a combination of the following characters: (1) head length almost equal to width; (2) head and lower jaw relatively smooth, with small tubercles arranged irregularly; (3) lateral neck fold discontinuous with body fold at forelimb insertion; (4) finger III distinctly longer than finger I; and (5) dorsum red-brown or yellow-brown in life, with large, irregular black patches. Comparisons: Andrias jiangxiensis sp. nov. can be distinguished from A. japonicus (Temminck, 1836) by having smoother head with indistinct tubercles (vs. dense, distinct, large tubercles). Considering that no population has been genetically identified as both pure A. davidianus and A. sligoi, and that farm-bred individuals exhibit genetic contamination (Yan et al., 2018), to avoid confusion due to translocated animals or hybrids, morphological comparisons are constrained to holotypes only. Specifically, Andrias jiangxiensis sp. nov. differs from A. davidianus (holotype MNHN-RA- 0.7613, images posted on: http: // coldb. mnhn. fr / catalognumber / mnhn / ra / 0.7613) by having a smooth head and lower jaw with indistinct, small, irregularly arranged tubercles (vs. head and lower jaw rough, with distinct, regularly arranged tubercles); from A. sligoi (holotype BMNH 1945.11.7.1., images in Turvey et al. (2019 )) by having a smooth skin on the snout and around eyes (vs. with numerous distinct tubercles), and a distinct finger length formula (finger III distinctly longer than finger I vs. finger III equal to finger I).

During the field surveys from September 2020 to March 2022, over 291 wild individuals of adults and juveniles were found in medium-sized, pristine mountain streams with 8 – 10 m wide, water depth 0.1 – 1.5 m, and with rocky substrate (Figure 7 A, B). Many natural caves formed by fallen wood, tree roots and cracks among rocks on both sides of streams provide hiding places for the new species. As a nocturnal species, A. jiangxiensis sp. nov. forages at night. Dorsal color patterning makes it blend well with the rocks at the bottom of the stream, making it difficult to find in flowing water. Vomit and excrement analyses of five wild individuals in July 2021 revealed fish, frogs, aquatic insects, and crustaceans in the natural diet. Two breeding caves were found in a backwater bay of the stream in January 2021 (Figure 7 C, D) and January 2022. A large number of larvae gathered at the entrance, emerging most likely two months after hatching (Figure 7 C, D). Larvae sightings peaked in February and exceeded 100 individuals per day. This continued until March, when no more new larvae emerged from the cave, and the larvae outside began to scatter throughout the stream. Combined with a questionnaire to local giant salamander farmers, we speculate that the breeding season of A. jiangxiensis sp. nov. occurs in mid-September.

Local cultural values: Local cultural pride might have contributed positively to the conservation of indigenous species. Interviews near the survey sites found that most people did not often eat CGS, although nine out of 50 persons had eaten CGS one or two times from curiosity. Six of the 50 interviewed people in Jing’an County, including the towns Guanzhuang and Zhongyuan, could distinguish between the indigenous and introduced CGS species by the shape of head and coloration of adults. They proudly said the indigenous species is “ more beautiful ” than others (Supplementary Dataset S 1); one person described the indigenous species as having a smoother head without tubercles. This differed from negative cultural views of CGS reported in Shaanxi (Cunningham et al., 2016), indicating diverse cultural values across China. We interviewed the owners of two small-scale farms adjacent to the field survey sites, which have existed for years (Supplementary Dataset S 1). They did not cease activities following the dramatic slide in CGS prices from 3 000 RMB / kg (US $ 470 / kg) (Cheng & Zhang, 2015; Shu et al., 2021) to 60 RMB / kg ($ 9 / kg) after 2015. They had refused to use outside sources of CGS (Supplementary Dataset S 1), even during the “ salamander rush ” involving large-scale salamander trading. Such small-scale farms in remote montane villages may be more likely to preserve purebred indigenous lineages than large commercial farms that frequently introduce and sell animals of unknown provenance. They can serve as effective targets for genetic screening, and as reservoirs for potential future population augmentation programs which should such be deemed necessary.

Distribution and natural history: Questionnaires with local residents suggest that this species was densely distributed in two towns of Jing’an County before the 1990 s. Due to commercial breeding, some indigenous purebred individuals served as breed stock in some local small farms. According to our field monitoring, the wild population of this species appears to occur only in Jiulingshan National Nature Reserve. This protected area contains intact habitat, including forested mountains and streams without villages and human activities. It also contains a diversity of teleosts, amphibians, non-avian reptiles, birds and a few mammals.

Etymology: The specific epithet “ jiangxiensis ” refers to the type locality of the new species in Jiangxi, China. It denotes the endemicity of the new species to Jiangxi based on our detailed population surveys. We suggest Jiangxi Giant Salamander as its English common name, and Ữ & 大 ª (Pinyin: Jiāng Xī Dà Ní) as its Chinese common name.

Holotype: KIZ 037731, adult male (Figure 4), ex situ from first generation of offspring of the wild-caught parents, which were collected in Guanzhuang Township, Jing’an County, Jiangxi, China. Paratypes: KIZ 037728, 037730 (adult females), KIZ 037729 (adult male), all with the same collection information as the holotype.