- The critically endangered Chinese giant salamander is not just one, but three distinct species, researchers have now confirmed in a new study.
- One of the newly recognized species, the South China giant salamander (Andrias sligoi), could be largest amphibian on the planet, the researchers say.
- The researchers say they hope the recognition of the Chinese giant salamanders as three species will help the amphibians’ conservation by triggering separate management plans for the species.
The Chinese giant salamander, which reaches lengths of more than 5 feet (1.6 meters), enjoys the title of being the world’s largest living species of amphibian. However, the critically endangered salamander is not just one, but three distinct species, researchers have now confirmed in a new study.
One of the newly recognized species, the South China giant salamander (Andrias sligoi), could be largest amphibian on the planet, the researchers say.
“These findings come at a time where urgent interventions are required to save Chinese giant salamanders in the wild,” Melissa Marr, a doctoral researcher at the Natural History Museum, London, and co-author of the study, said in a statement. “Our results indicate that tailored conservation measures should be put in place that preserve the genetic integrity of each distinct species.”
The Chinese giant salamander was once widespread across central, eastern and southern China. But habitat loss, poaching, and illegal collection for farming as luxury food items wiped out most animals, making them incredibly rare in the wild today. Millions of these salamanders live on farms, though.
In a study published last year, Samuel Turvey, a conservation scientist at the Zoological Society of London, and colleagues who spent four years surveying the salamander’s preferred river habitats across 97 counties in China reported finding only 24 wild individuals at four sites. But even those were likely farmed animals, the researchers said, ones that had either escaped or had been released as part of government-sponsored conservation initiatives.
For a long time, all Chinese giant salamanders were considered to be a single species, Andrias davidianus. Some researchers did suspect that the salamander likely comprised more than just the one species, and another study by Turvey and team published last year found just that: analysis of tissue samples from 70 wild-caught and 1,034 farm-bred salamanders showed that the Chinese giant salamander once included least five genetically distinct lineages. Today’s salamanders, however, show extensive hybridization as a consequence of mixing of the species through farming, the researchers said.
These genetic studies, however, relied on samples collected in recent decades, when the salamanders had already been moved extensively for farming, making conclusions about distinct species difficult. In the latest study, Turvey and his colleagues analyzed samples from a series of historical museum specimens of the salamanders to see what the wild local populations of the Chinese giant salamander may have been like before the onset of widespread farming and movement of the animals by humans.
In the end, the team identified three distinct genetic lineages, sufficiently different enough to represent separate species, each associated with a different river drainage system. These include A. davidianus, A. sligoi, and a third, yet-to-be-named species. The different species of Chinese giant salamanders began to diverge 3.1 million years ago, Turvey said, corresponding to a period of mountain formation in China, as the Tibetan Plateau rose rapidly.
Of the three recognized species, the South China giant salamander (A. sligoi) is most likely the largest, reaching 2 meters (6 feet) in length, the researchers say. The third species, which is known only from tissue samples and not any complete specimen, hasn’t yet been formally described.
The researchers say they hope that the recognition of the Chinese giant salamanders as three species will help the amphibians’ conservation by triggering separate management plans for the species. The team also urges that efforts be made to identify and protect sites where wild populations of the three different Chinese giant salamander species may still occur.
“Salamanders are currently moved widely around China, for conservation translocation and to stock farms that cater for China’s luxury food market,” Turvey said. “Conservation plans must now be updated to recognise the existence of multiple giant salamander species, and movement of these animals should be prohibited to reduce the risk of disease transfer, competition, and genetic hybridisation.”
Citation:
Turvey, S. T., Marr, M. M., Barnes, I., Brace, S., Tapley, B., Murphy, R. W., … & Cunningham, A. A. (2019). Historical museum collections clarify the evolutionary history of cryptic species radiation in the world’s largest amphibians. Ecology and Evolution. doi:10.1002/ece3.5257
