Species account

Description
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. P. shangchengensis is the only hynobiid with a karyotype of 2n = 64 (Yang, 1990; Xiong et al., 2007).
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.

Colour of upper parts brownish black, under side lighter. Juveniles with bluish dots.

Total length on average approx. 16-18 cm (Ye et al., 1993; Fei et al., 2006), but captive specimens may grow to a larger size, approx. 19-20 cm in females (Raffaelli, 2007; Pasmans et al., 2008).

Diagnosis
Vomerine teeth arranged in two separated, arched rows. 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.

Eggs and larvae
The female produces two striated egg sacs, with a bluish sheen. Larvae reach metamorphosis after approx. one year, at a length of approx. 9 cm. They stay in water after metamorphosis (Pasmans et al., 2008).

Distribution
This species occurs in the Dabieshan area (Hubei, Henan, and Anhui Provinces) in central China (Stuart et al., 2008; IUCN, 2010).

Habitat
This salamander inhabits slow-flowing hill streams in forested areas at altitudes between 380 and 1,100 m (IUCN, 2010).

Behaviour
The reproductive behaviour has not been observed. This species appears to be largely aquatic.

Threats and conservation
The species is uncommon. Over-collecting for human consumption is a major threat. Habitat destruction and degradation probably also form a threat. 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).

Observations in captivity
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 temp. of 12°C, one female attached a pair of egg sacs to the underside of a stone; the egg sacs contained 32 eggs each. Larvae hatched after 42 days. They did not have balancers (Raffaelli, 2007). Metamorphosis took place after a year.

Comments
Although collecting localities of the imported specimens are not known, the identification of the species is beyond reasonable doubt. It is striking that in the Chinese literature there is no reference to the extreme sexual dimorphism in head shape. Fei et al. (2010) only depict subadult specimens.

Pachyhynobius shangchengensis male
© 2007 Frank Pasmans

Pachyhynobius shangchengensis female
© 2007 Frank Pasmans

 
Range of Pachyhynobius shangchengensis
© 2010 IUCN, Conservation International & NatureServe.