Species account

Small salamander, closely related to Hynobius leechii, originally described from Cheju Island as a subspecies of H. leechii, but recently elevated to species status, on the basis of electrophoretic and morphological analyses (Yang et al., 1997). The following summary description largely follows that of H. leechii. Head a little longer than wide, slightly depressed; snout short and round, big eyes. Vomerine teeth (37-42) in V-shaped pattern. Gular fold present. Body almost cylindrical with 12-14 costal grooves (Kim et al., 2003). Limbs of moderate length, fingers and toes not meeting when fore and hind legs are laid along the body. Base of tail cylindrical, gradually compressed toward the tip and ending in an obtuse tip. During the breeding season the female has a swollen abdomen, the male can be recognized by a higher tail fin, a swollen cloaca, and heavier and broader head (Leeuwen & Vos, 1991; Bouwman, 1995).

Colour olive brown to dark-brown above, mottled with irregular gray-brown spots; tail grayish brown with some dark spotting. Light gray below. Juveniles speckled with small light-coloured spots. 

Total length 10-12 cm.  

Diagnosis
Small olive brown salamander with fine black speckles and slightly flattened tail; usually 12-14 costal grooves. Differs from H. leechii and H. yangi genetically. Morphological differences with H. leechii are subtle and consist mainly of a higher number of vomerine teeth and coccyges in H. quelpaertensis (Yang et al., 1997). H. quelpaertensis is larger than H. yangi (Kim et al., 2003).  

In Cheju Island egg sacs have been found in December, temperatures a few degrees above zero. Matings were observed in captivity from November onward. The animals stayed in the water until early March (Leeuwen & Vos, 1991).

Comments
There is no uniform method of counting costal grooves in the literature on this species and its relatives (see Litvinchuk & Borkin, 2003).