Photo/Illutration Masakazu Hayashi of the Hoshizaki Institute for Wildlife Protection stands in a puddle where salamanders breed in Unnan, Shimane Prefecture, in June. (Arata Namima)

MATSUE--Seven new salamander species inhabiting puddles were confirmed in a 40-year research project in western Japan that increased the variety number to 44.

Another type of salamander is also being studied to determine if it is different from the known species.

Five of the eight salamanders were spotted in Shimane Prefecture, likely taking advantage of the humid winters there and other factors.

According to Kanto Nishikawa, an associate professor of systematics at Kyoto University, the clouded salamander was believed to have been the only species to nest in the prefecture. But detailed DNA analyses revealed four other varieties were present.

“Different kinds of salamanders are difficult to distinguish based only on their appearances, and even those from the same species could have drastically different bodily features,” Nishikawa said. “These factors apparently made it impossible for researchers to identify the different species.”

Nishikawa worked with Masafumi Matsui, a professor emeritus of animal systematics at Kyoto University, and others in the still-water research project that ran from the 1970s through February 2019.

Sanin, Iwami, Hiba and Abu salamanders were named after their discovery sites in Shimane Prefecture.

Three additional unknown species were also confirmed outside the prefecture.

The findings have inspired other scientists to aggressively search for new salamanders.

“The discoveries of no less than four species were surprising, and I thought I should study details of their distribution,” said Masakazu Hayashi, head of the survey and research section of the Hoshizaki Institute for Wildlife Protection in Izumo, Shimane Prefecture.

Between March and May last year, Hayashi used tweezers to take DNA samples from larva fins at 28 locations, including water pools by rice paddies, street runoffs and catch basins.

An examination of the samples by a research institute in Fukuoka Prefecture showed that specimens from the cities of Izumo and Unnan in Shimane Prefecture were from a variety related to the Hiba salamander, which is found at high altitudes in the Chugoku mountain range.

It was tentatively named the Izumo type, and its discovery was announced in March. The shapes of its eggs as well as its body attributes will be surveyed to determine if it is a previously unknown species.

Hayashi said so many different salamanders are native to Shimane Prefecture because of the climate and geographical features.

Frequent rainfalls in winter allow the amphibians to secure breeding places during the season, according to Hayashi.

He also believes that the Hiikawa, Gonogawa and Takatsugawa rivers have prevented interbreeding among salamanders inhabiting still waters.

Hayashi’s research found many puddles where salamanders cannot breed because they are trapped in nearby thickets, their habitats, by concrete side ditches and other artificially made objects.

“Multiple varieties turned out to live separately in a limited zone,” Hayashi said. 

“Even small development projects could have great impact on the species’ survival,” he said. “Much more careful preservation measures are required.”

Nishikawa agreed.

“Construction of roads, residences, garbage incineration plants, mega solar farms and other facilities will greatly affect the habitats of salamanders,” Nishikawa said.

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