The species is uncommon. Over-collecting for human consumption is a major threat (Fei et al., 2006). Habitat destruction and degradation probably also form a threat. Locals sell the species as Tylototriton asperrimus or giant Chinese salamander (Wang et al., 2009). Populations are in decline (Cai, 2001); it is considered vulnerable (Stuart et al., 2008; IUCN, 2010). Its habitats are fragmented and there is a need to protect this species from unmanageable capturing from the wild; protective measures have been proposed (Cai, 2001; Wang et al., 2009; Xiong et al., 2009).
Very stout salamander with short limbs, leaving a distance of four costal grooves between fingers and toes, when limbs are adpressed (Fei et al., 1983, 1985; Xiong et al., 2007). Extremely thick head in adult males. Caudal fin strong. Tail length shorter than snout-vent length. Labial fold present. A distinct feature of the skull: maxillary contacts with pterygoid (Fei et al., 2006).
2n=64, 1M, 2ST, 3T, 4T, 5M, 6T, 7T, 8T, 9T, 10T, 11T, 12ST, m (13–32), from Yang (1992).
M: metacentric; SM: submetacentric; T: telocentric; ST: subtelocentric; m: micro-chromosome
The mitochondrial genome has been sequenced by Zhang et al. (2006).
Pachyhynobius shangchengensis resembles Pachytriton labiatus, a salamandrid species from southern China. They share smooth skin, a stout body shape (pachy- means stout and fat), short limbs that are separated when adpressed, high caudal fins and a brownish black dorsum. And both species inhabit montane streams. But Pachyhynobius shangchengensis differs from Pachytriton labiatus by having a shorter tail (65% of snout-vent length vs. 80% in Pachytriton labiatus) and a uniform grey venter (vs. a blotched venter in Pachytriton labiatus), and a very broad head in the male.
Stout salamander with cylindrical body. 13 costal grooves. Tail cylindrical at base, laterally compressed near tail tip; tail shorter than snout vent length. Limbs short; when adpressed, toes and fingers do not meet. Snout rounded, labial folds present. Gular fold present. Vomerine teeth arranged in two arched series and separated at the midline. Four fingers, five toes, with cornified coverings at tips. Skin smooth. Very conspicuous sexual dimorphism: The adult male develops a thick broad head, not seen to that extent in any other hynobiid. Both sexes have high tailfins. Color of upper parts brownish black, under side lighter. Juveniles with bluish dots.
All measurements are from Fei et al. (1985).
Male (7 specimens). Total length: 150–184 mm; snout-vent length: 91–114.4 mm; Head length: 20.1–27 mm; Head width: 16–21.5 mm; forelimb length: 16.4–19.5 mm; hind-limb length: 20–24.5 mm.
Female (9 specimens). Total length: 157–176 mm; snout-vent length: 95–106 mm; Head length: 20–22.8 mm; Head width: 15–18.9 mm; forelimb length: 15.7–19.9 mm; hind-limb length: 19.5–24.4 mm.
Based on morphological, karyotypic and DNA sequence data, Xiong et al. (2007) and Nishikawa et al. (2001) find that Pachyhynobius shangchengensis is the same species that is later described as Hynobius yunanicus by Chen et al. (2001). The latter species is the juvenile form of the former species. Based on mitogenomic data, Pachyhynobius shangchengensis may be the sister taxon to all other hynobiids except Onychodactylus fischeri (Peng et al., 2010) or the sister taxon to a clade including Batrachuperus, Liua, Pseudohynobius, Salamandrella and Hynobius (Zhang et al., 2006).
This species occurs in the Dabieshan area (Hubei, Henan, and Anhui Provinces) in central China (Stuart et al., 2008; IUCN, 2010).
This salamander inhabits montane streams at elevations from 380–1,100 m (water pH=5.5). It prefers small pools along the stream, where water is clear and slow. Water depth 0.5–1.5 m. Stream substrate includes small rocks and sand. Adult salamanders hide in crevices between rocks. When rocks are flipped, they do not swim away immediately but stay still and blend into the sand (Wang et al., 2009). Pachyhynobius shangchengensis is mostly nocturnal. It feeds on stream shrimps, small fishes, earthworms and insects (Cai, 2001; Wang et al., 2009). Wounded and scarred specimens have been found. Cai (2001) suggested that stream crabs may have inflicted these wounds. Hibernation begins in mid November when water temperature drops below 10 °C and ends in mid March.
This salamander has been imported to Europe via the pet trade. The salamanders can be fiercely aggressive but can be kept in large tanks with flowing water and sufficient hiding places. The species has been bred on a single known occasion. A successful attempt at breeding is recorded by Pasmans et al. (2008). The salamanders were kept in large tanks at temperatures usually remaining below 20 °C, but incidentally rising to 27 °C in summer. Winter temperatures were 2–5 °C. In May 2005, at a water temperature of 12 °C, one female attached a pair of egg sacs to the underside of a stone; the egg sacs contained 32 eggs each. The egg sacs are striated with a bluish sheen. Larvae hatched after 42 days. They did not have balancers (Raffaelli, 2007). Metamorphosis took place after a year at a length of approximately 9 cm. They stay in water after metamorphosis (Pasmans et al., 2008).