Species account

Description
Small salamander, related to Hynobius leechii and H. quelpaertensis. Identified earlier as a taxon different from H. leechii (Yang et al., 1997), but only recently described as a separate species on the basis of genetic and morphological analyses (Kim et al., 2003). The following summary description is derived from Kim et al., (2003). Head longer than broad, longer in males than in females. Females with relatively longer trunk than males. 12-14 costal grooves. Limbs short, and when laid against the body, mostly do not overlap. Separation between toes and fingers is greater in females than in males. Males have longer and higher tails than females. 

Colour olive light brown above, usually without dark speckles. Underside of body lighter.

Total length 10-12 cm.

Diagnosis
Most similar to H. leechii, but distinguished from it by longer and higher tail, greater separation of adpressed limbs, slightly deeper vomerine teeth series, egg sacs coiled, a light brown dorsum, and distinct genetic differences. It has a smaller snout-vent length, relatively longer head, higher tail, and shorter trunk, and more costal grooves than H. quelpaertensis from Cheju. From H. quelpaertensis  from peripheral islands, H. yangi can be differentiated by a relatively longer and higher tail and wider head, and by having more costal grooves and narrower separation of limbs (Kim et al., 2003). 

Eggs and larvae
The female produces a pair of egg sacs, taking on a spiraled shape, attached to water plants or branches in standing water; clutch size of one female was 86 eggs. Mean diameter of the egg 2.7-2.8 mm (Kim et al., 2003).

Distribution
Localities are clustered round the type locality Hyoam-ri and nearby Gilcheon-ri, both in Jangan-eup, Busan-shi in southeastern South Korea (Kim et al., 2003; Kim, 2009).

Habitat

Behaviour
Breeding occurs from late February to late March (Kim et al., 2003). There are no published data on the behaviour of Hynobius yangi, but on-going work at Kangwon National University suggests that in its general pattern, reproductive ecology and mating behaviour is similar to that of H. leechii and H. quelpaertensis (cf Park et al., 1996).

Threats and conservation
Given the limited range and isolated occurrence, this species is vulnerable to habitat destruction (Kim et al., 2003).

Observations in captivity
No data available.

Comments

Hynobius yangi, male, living holotype,  Kori,  South Korea  
© Jong-Bum Kim, Mi-Sook Min & Masafumi Matsui

Range of Hynobius yangi (Kim, 2009), map by W. Beukema & M. Sparreboom.