Hynobius maoershanensis Zhou, Jiang & Jiang, 2006
No data regarding the conservation status of Hynobius maoershanensis. Currently this species is only known from Mount Maoer, and only three breeding ponds have been discovered (Zhou et al., 2006). Population size could be very small.
A large hynobiid salamander with total length around 15 cm. Interior series of vomerine teeth reaches the posterior margin of eye. 12 costal grooves. Limbs are strong. When fore and hind limbs are adpressed, fingers and toes overlap for a distance of 2.5–3 costal grooves. Dorsum is uniformly black. Egg sac is slightly arched but does not form a helix.
Karyotype:
2n=56, 1M, 2M, 3M, 4SM/ST, 5M/SM, 6M/SM, 7SM, 8SM, 9M, 10SM, 11M, 12ST, 13ST, 14M, 15ST/SM, 16M, 17M, 18M, m (19–28), from Qing (2009).
M: metacentric; SM: submetacentric; T: telocentric; ST: subtelocentric; m: micro-chromosome
Mitochondrial DNA sequence is available in Nishikawa et al. (2010).
Hynobius maoershanensis is similar to the adult form of H. chinensis from Hubei, which was rediscovered recently (Wang et al., 2007). The two species have a similar body size and coloration, 12 costal grooves and inconspicuous tubercles on palms and soles. Hynobius maoershanensis differs from the latter species by having numerous white spots on venter, whereas H. chinensis has dark blotches on its ventral side.
Summarized from Zhou et al. (2006). A large hynobiid. Snout rounded; distance between nares slightly smaller than between eyelids. Labial fold absent. Gular fold prominent and visible in dorsal view. Angle of jaw far exceeds the posterior margin of eye to a distance of 3/4 diameter of the eye. Tongue oval in shape with free lateral margins. Trunk is stout and flat with prominent vertebral groove. 12 costal grooves. Limbs are well-developed. When adpressed fingers and toes overlap for a distance of 2.5–3 costal grooves. Four fingers and five toes. Tubercles on palms and soles are absent or inconspicuous. Base of tail rounded. The posterior part of tail is gradually laterally compressed. Caudal fin inconspicuous. Dorsal color is black in water and turns yellowish green on land. Ventral color is grey with numerous white spots.
All measurements are from Zhou et al. (2006).
Male (5 specimens). Total length: 152.3–160.2 mm; snout-vent length: 81.9–91 mm; Head length: 20–23.1 mm; Head width: 15.5–18.2 mm; forelimb length: 24.3–26.1 mm; hind-limb length: 28–29.5 mm.
Female (3 specimens). Total length: 136.1–155.2 mm; snout-vent length: 76.5–83.6 mm; Head length: 18.2–21 mm; Head width: 15.8–19.5 mm; forelimb length: 27–29.2 mm; hind-limb length: 29–30.5 mm.
Phylogeny derived from mitochondrial DNA data suggests that Hynobius maoershanensis and H. chinensis are sister species and are nested deeply within the continental Chinese hynobiids (Nishikawa et al., 2010). High morphological similarity between these two species also indicates close relationship. Whether they are two species or only one requires further study.
Currently this species is only known from Mount Maoer, Xing’an county, Guangxi.
Hynobius maoershanensis occurs close to montane swamps at an elevation of 2,000 m. The swamps are surrounded by conifers (Tsuga chinensis) and broadleaf-trees. In the breeding season, the salamander is found in lentic ponds with clear water and a thick layer of silt. It is terrestrial outside the breeding season and hard to find. One individual was dug out at a construction site (Zhou et al., 2006).
Breeding season lasts from November to February. A pair of egg sacs is laid by each female. The egg sac is less than 200 mm long, slightly arched but not forming a helix. Both ends of the egg sac attenuate rapidly into slender tubes. Each egg sac contains 37–45 embryos. Males appear to guard the egg sacs (Zhou et al., 2006).