Crouching Scientist, Hidden Salamander (Berkeley Science Review, Fall 2005)

The Korean salamander that shouldn’t be there…or should it?

Lying in an icy grave of frigid industrial water in a black ice bucket, a salamander waits to have its liver taken out—a small but important step in making herpetological history. The salamander is Karsenia koreana, and its recent discovery is a story of surprises, paradoxes, and new insights into the history of salamanders.

This story began in April two years ago in a rocky, forested habitat in the vicinity of Jangtae-san, Daejeon-si, Chungcheongnam-do, Korea, where Stephen Karsen, a high school biology teacher from Illinois who teaches at the Taejon Christian International School in Korea, came across an unusual salamander. “I knew the moment I picked it up that it had to be at least a new record for South Korea – or possibly completely new,” he recounts.

Karsen, unable to identify the salamander, approached amphibian specialists M. S. Min of Seoul National University, S. Y. Yang of Inha University in Incheon, and a former professor, Ronald A. Brandon of Southern Illinois University in Carbondale, who in turn drew it to the attention of David B. Wake, professor emeritus of integrative biology and Curator of Amphibians at UC Berkeley’s Museum of Vertebrate Zoology.

The salamander was clearly different from all known Asian salamanders and was identified as a plethodontid, or lungless salamander. Based on the morphological and molecular data, it was placed in a new genus—Karsenia, named for its original discoverer, Karsen. The common name is Korean crevice salamander, or Ikkee dorongyong in Korean.

Wake, known to some as “Commander Salamander,” and his colleagues published the discovery in Nature last May. They explain that this Asian discovery was initially astonishing because 99% of lungless salamanders are found in the Americas. Prior to the discovery of K. koreana, the only place outside of the Americas that lungless salamanders were found was the western Mediterranean.

But as surprise at this discovery wanes, hindsight is leading researchers to revise their initial assumptions.

“We should have expected to find plethodontid salamanders in Asia. It is actually quite logical,” acknowledges Wake. The fact that the species is found in both the Americas and the Mediterranean strongly suggests that there was a continuous population at some point in the past. This realization has necessitated modifications to the hypotheses of plethodontid historical biogeography.

Another reason the discovery was unexpected was because the amphibian population of Korea was thought to be fully catalogued. Researchers did not expect to discover a new species of any animal in such a seemingly well-understood ecosystem.

How did K. koreana escape notice for so long in such a familiar environment? David Vieites, a post-doctoral fellow in the Wake lab and a co-author of the Nature study, attributes this to the fact that these plethodontids are terrestrial. In Asia and in Europe, there is an understandable bias for exploring aquatic habitats because most salamanders live in water, even as adults. “These are not aquatic at all. So these Korean researchers searched only in aquatic habitats, [which is] one of the reasons why these salamanders are overlooked,” explains Vieites.

Now that researchers know where to look, they are finding that K. koreana is actually very common. Following his group’s initial publication, Vieites traveled to South Korea with two goals in mind: to collect more specimens and tissue samples and to figure out whether there are more plethodontid salamanders in surrounding regions. He spent 10 days in the field hunting for the salamander throughout Taejon, a city near the site of Karsen’s initial discovery, and neighboring areas; in the end, his work paid off, and he reported that K. koreana is relatively prolific.

According to Vieites, this salamander can easily be found in at least three national parks—a fortunate circumstance for researchers interested in studying the new species.

Vieites found around 40 specimens and collected around 80 tissue samples from tail tips. Based on this data he was able to estimate that the salamander has a well-distributed range of 50 by 150 km. Because all of the specimens were morphologically similar, Vieites suspects there is just one species rather than a huge radiation of plethodontid salamanders in Korea, as is the case in the Americas.

Looking forward to future findings of plethodontid salamanders in Asia, Vieites states, “We have plethodontid salamanders in the Americas, the Mediterranean, and now in Korea. Why not in other parts of Asia? China is enormous, huge. If we are lucky, maybe we’ll find more. Why not? We don’t know, but I think it’s worth it to give it a shot in China. It will be fun.”

Last May alone Wake’s group discovered five species of salamanders. Those five species fall into three genera, including Karsenia. In 1985, there were approximately 4,000 species of amphibians and, at last count, there are 5,951 species of amphibians, according to AmphibiaWeb (amphibiaweb.org).

This is especially good news considering that worldwide amphibian populations are in decline. So along with the paradox of being a predictable surprise, the first Asian representative of the plethodontid family presents another welcome paradox: according to Wake, at a time when “amphibians are declining, we are finding new species.”

[pdf version]

~ by Janet Fang on October 15, 2008.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

 
%d bloggers like this: