Description
Karsenia koreana is a relatively small salamander, with male snout vent lengths being 37.2 - 45.4 mm and female snout-vent lengths being 41.4 - 50.8 mm (Song et al. 2017), that superficially resembles members of the North American genus Plethodon. It is moderately robust with a well-defined, moderately broad head. The relatively rounded snout is prominent, and the nostrils are small. The nasolabial groove is relatively inconspicuous but lies in a swollen protuberance on the upper lip. The eyes are relatively small but protuberant. The tongue is attached at front but in an anesthetized specimen it is highly protuberant. The tongue pad is rounded and lacks posterior flaps. The teeth are small, undifferentiated and weakly bicuspid. There are roughly 43 - 50 maxillary teeth and 13 - 21 vomerine teeth in males, 40 - 56 maxillary teeth and 12 - 20 vomerine teeth in females. A large, paired patch of paravomerine teeth (total about 150) is present on the palate. There are 14 to 15 costal grooves. The tail is about the same length as the snout-vent length or slightly longer. The tail is round basally but may be slightly laterally compressed towards the posterior end where it tapers to a sharp point. The limbs and digits are relatively short. When the limbs are appressed along the trunk, three to four costal folds are left uncovered. The digits are relatively short and have rounded tips. The fifth toe is noticeably shorter than the fourth. The digits have slight basal webbing (Min et al. 2005).

Karsenia koreana is a plethodontid salamander, all of which do not have lungs or a pterygoid bone, but have many paravomerine teeth and a nasolabial groove. Practically, K. koreana can be differentiated from other plethodontids because it is the only member of the family found in Asia. Morphologically, the genus Plethodon diverges from other plethodontid genera in ankle morphology. The genera Aneides and Chiropterotriton have a relatively larger 5th distal tarsal that articulates with the centrale while the 4th distal tarsal is small and separated from the fibulare by d5. Karsenia differs from both genera with its paired premaxillaries, small hands and feet, short digits, a tongue attached to the front of the mouth, and epibranchials shorter than the ceratobranchials. Karsenia koreana resembles species of Plethodon, especially ones from western North America, but is smaller and shorter-bodied. It has less prominent jaw muscles compared to species from northwestern California and southwestern Oregon, while its hands and feet are highly similar. The paired premaxillae and skull roof are similar to the western Plethodon while its tarsus and vomer resemble Aneides; however, it has less swollen jaw muscles and shorter toes (Min et al. 2005).

In life, the general coloration is dark, especially along the flanks, but with a dorsal reddish or brownish stripe that extends from the tip of the snout and all along the body and tail. The stripe is most vivid in the pelvic and tail base region. The venter is gray, lighter than the flanks (Min et al. 2005).

According to Song et al. (2017), the snout-vent length, an aspect of sexual dimorphism, was smaller on average for males than for females. Also, differences in body size result from maturity of males at a younger age and shorter longevity. In other words, males are sexually mature at smaller sizes than females.

Distribution and Habitat

Country distribution from AmphibiaWeb's database: Korea, Republic of

	View distribution map in BerkeleyMapper.
	View Bd and Bsal data (2 records).

The species is described from a rocky region near Jangtae-san, Daejeon-si, Chungcheongnam-do in South Korea. There was an observed increase in potential suitable range for K. koreana along western Korea and northeast regions of Pyeongchang (Borzée et al. 2019). It is known from a number of localities in that region, specifically in relatively young forests (ca. 50 years) of hardwoods and pines. The species is widely distributed and the range may be larger than presently known. Individual salamanders have been found under small rocks and pieces of limestone, and among rocky substrate on a generally fine-grained soil base (Min et al. 2005, Borzée et al. 2019).

Life History, Abundance, Activity, and Special Behaviors
This species is thought to be exclusively terrestrial and it occurs in damp woodland habitats away from streams and ponds. More specifically it can be found on damp, mossy slopes and in rock slides, and is associated with limestone. They need heavy rainfall during the dry winter months to survive (Borzée et al. 2019).

The species appears to be relatively abundant, locally (Song et al. 2017). And a large population of K. koreana was found along the west border of Daejeon (Borzée et al. 2019).

Researchers have not yet observed courtship behavior or the development processes – thus, its life history is only presumed by looking into closely related species, including Hydromantes, Atylodes, Speleomantes, and Aneides (Song et al. 2017).

Males mature more rapidly, causing their adult form to be smaller in size than that of females (Song et al. 2017).

Larva
As a plethodontid, K. koreana is presumed to be a direct developer with no larval stage.

Trends and Threats
According to models of Karsenia distribution, an increase of potential suitable range was observed in western Korea as well as the northeast of Pyeongchang. Despite this large range, the threats toward K. koreana should not be dismissed. Researchers have determined that changes in precipitation due to climate change is a factor that could influence the range of the species, as they require plentiful rainfall during the dry winter season in order to thrive. The species is also threatened by habitat fragmentation and in the future, the population may have to be translocated to areas such as the Baekdudaegan Mountains Reserve (Borzée et al. 2019).

Possible reasons for amphibian decline

General habitat alteration and loss
Climate change, increased UVB or increased sensitivity to it, etc.

Comments
Discovery of this plethodontid salamander in Korea was a great surprise. It is the only Asian plethodontid known. Although it resembles members of the genus Plethodon in general morphology, its internal anatomy and sequences of nuclear genes (RAG-1) show that it is distinct and not a particularly close relative of Plethodon. In the morphology of its ankle it resembles Aneides, and in its DNA sequence it is shown to be a sister taxon of a clade including Aneides and the desmognathine pletodontids. At present little information is available concerning its general biology or conservation status (Min et al. 2005).

Bayesian Inference and Maximum Likelihood analyses of RAG-1 nDNA show strong support for Karsenia to be sister to the Aneides, Desmognathus and Phaeognathus genera (Min et al. 2005).

This species was discovered 34 years before its description; a specimen has been found in the collection of the Institute for Amphibian Biology, Hiroshima University, Japan, that was collected in 1971 from Mt. Gyeryong by a joint Korean-Japanese team (Nishikawa 2009).

Karyotype is 2N=28, with all 14 chromosomes bi-armed and no heteromorphic sex chromosomes. C-banding shows that heterochromatin is concentrated mainly at the centromeres. The genome is large; around 53.5 pg (Sessions et al. 2008).

References

Borzée, A, Andersen, D, Groffen, J, Kim, H-T, Bae, Y, Jang, Y (2019). "climate change-based models predict range shifts in the distribution of the only Asian plethodontid salamander: Karsenia koreana." Scientific Reports , 9, 11838. [link]

Min, M.S., Yang, S.Y., Bonett, R.M., Vieites, D.R., Brandon, R.A., and Wake, D.B. (2005). ''Discovery of the first Asian plethodontid salamander.'' Nature, 435, 87-90.

Nishikawa, K. (28). ''The first specimen of Karsenia koreana (Caudata: Plethodontidae) collected 34 years before its descript.'' Current Herpetology, (27-28).

Sessions, S. K., Stöck, M., Vieites, D. R., Quarles, R., Min, M.-S., and Wake, D. B. (2008). ''Cytogenetic analysis of the Asian plethodontid salamander, Karsenia koreana: evidence for karyotypic conservation, chromosome repatterning, and genome size evolution.'' Chromosome Research, 16, 563-574.

Song, J-Y, Matsui, M, Matsuki, T, Nishikawa, K, Koo, K-S, Oh, H-S (2017). "Life History of a Unique Asian Plethodontid Salamander, Karsenia koreana." Zoological Science , 34(2), 122-128. [link]

Species Account Citation: AmphibiaWeb 2023 Karsenia koreana: Korean Crevice Salamander <https://amphibiaweb.org/species/6429> University of California, Berkeley, CA, USA. Accessed Jan 25, 2025.

Citation: AmphibiaWeb. 2025. <https://amphibiaweb.org> University of California, Berkeley, CA, USA. Accessed 25 Jan 2025.

AmphibiaWeb's policy on data use.