Species account

Description
This description follows the original description by Min et al. (2005). Small salamander, rather robust with moderately broad head. Tail approximately same length as snout-vent length or a little longer. Nasolabial groove in swollen protuberance on upper lip, relatively inconspicuous. Eyes relatively small. Tongue attached at front, but highly protrusible. Snout more or less rounded, nostrils small. Gular fold evident. 14-15 costal grooves. Tail round at the base, slightly laterally compressed towards the posterior, tapering to a sharp point. Limbs and digits short. When adpressed along the body, three to four costal folds are left uncovered. Fifth toe shorter than fourth. Digits have slight basal webbing. Approximately 45-50 maxillary teeth and 15-20 vomerine teeth. A large, paired patch of paravomerine teeth (about 150) present on palate.  Females have a more rounded snout than males.

Colour dark brown along the flanks; frequently a broad dorsal reddish or brownish stripe of varying intensity from tip of snout until tip of tail. Many small silvery dots and flecks on the sides. Venter gray, lighter than flanks, speckled with tiny whitish spots. 

Total length 8-9 cm.

Diagnosis
Small dark-coloured, lungless salamander with short limbs, nasolabial grooves in the male and 14-15 costal grooves.

Eggs and larvae
Data are lacking. It is assumed that eggs are laid on land and develop directly as in other plethodontid salamanders.

Distribution
The species is found at relatively low elevations in southern to Midwestern South Korea, where it has been found at more than 20 sites. Type locality is the area near Daejeon, Chungcheongnam-do, Korea, at 210 m (Min et al., 2005; IUCN, 2010; AmphibiaWeb, 2011).

Habitat
The species occurs in damp, mossy talus slopes and rockslides of limestone in 15-20 year-old forests of hardwoods and mixed hardwood/pine. It has even been found in a city park. Most individuals were found under small rocks or rock flakes scattered among larger boulders on fine-grained soil (IUCN, 2010; AmphibiaWeb, 2011). Probably the species uses its solid skull, in part, in relation to seeking refuge in tight spaces between rocks (Buckley et al., 2010).

Behaviour
The species is thought to be exclusively terrestrial; breeding is presumed to be by direct development (IUCN, 2010).

Threats and conservation
This species is common within its range. Even so, little information is available concerning its general biology or conservation status (AmphibiaWeb, 2011).

Observations in captivity
None to date.

Comments
The spectacular discovery of a plethodontid salamander in Asia has led to new hypotheses concerning the colonization of Eurasia by plethodontids (Vieites et al., 2007).
A specimen of this species was discovered in the collection of the Institute for Amphibian Biology, Hiroshima University, Japan. It was collected in 1971 from Mt Gyeryong by a joint Korean-Japanese team of researchers but had gone unnoticed (Nishikawa, 2009).
The genome size of Karsenia is relatively large (karyotype 2N=28), and resembles that of the geographically closest plethodontids from western North America, especially species of the genus Hydromantes (Sessions et al., 2008).

Karsenia koreana type locality
© 2009 Max Sparreboom

Range of Karsenia koreana
© Kim (2009), W. Beukema & M. Sparreboom