The world's largest amphibian—the Chinese giant salamander (Andrias davidianus, pictured)—should be split into at least five species, all of which are critically endangered in the wild, according to a new study. What's more, say the authors, current conservation practices could be causing these genetically distinct species to crossbreed with one another, effectively fusing them into a single species.
The salamanders, which can grow up to 2 meters in length, were once common in rivers across southeastern China. But today, most are found in commercial farms, which breed the giant amphibians to satisfy growing demand from the luxury food market. In an effort to augment wild populations, the Chinese government encourages the release of farm-raised individuals. But it's not clear whether those individuals are genetically equivalent to wild salamanders.
To figure that out, scientists analyzed DNA from 70 wild-caught salamanders and 1034 farm-raised individuals. The team found that wild individuals could be separated into five highly distinct genetic groups, which split off from one another 5 million to 10 million years ago. In comparison, farm-raised salamanders exhibited extensive genetic mixing, the team reports today in Current Biology. That means that any release of farm-raised salamanders risks muddying the genetic waters, potentially causing a distinct, local salamander species to become extinct through crossbreeding with salamanders carrying the genetics of other species.
It also means that if the wild populations go extinct, the world will not only lose one species of giant salamander, but all five. Many salamanders that remain in farms will be an amalgamation of those species.
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