The world’s largest amphibian, the Chinese giant salamander, has up until now been considered a single species, but a new study led by conservation charity ZSL reveals that there are in fact up to nine different species
Published today in Evolutionary Journal of the Linnean Society, the paper shows how the team, working with partners in China, used genetic data to confirm that the world’s largest amphibian, once thought to be a single species found across central and southern China, consists of multiple unique species found in different river systems - with implications for those working to save these ancient animals from the brink of extinction.
The team behind the paper are calling for the findings to be urgently recognised, to ensure that conservation legislation adequately protects these remarkable animals – which diverged from smaller amphibians 170 million years ago.
Professor Samuel Turvey, a researcher at ZSL’s Institute of Zoology and an author of the paper, said: “Chinese giant salamanders are recognised as Critically Endangered, mainly due to overexploitation of wild populations to support a salamander farming industry that stocks China’s luxury food market. All of the species we’ve now identified are thus at high risk of disappearing forever. If we are to avoid losing the world’s largest amphibians, we need to act urgently to ensure that these newly-recognised species are formally recognised and legally protected.”
Samuel added: “The possibility that Chinese giant salamanders may not be a single species has been suggested by researchers for 20 years, but by comparing levels of genetic difference seen across giant salamander populations with differences shown by other known salamander species, we can now confirm this for sure.”
The world’s largest amphibians, Chinese giant salamanders can grow to 1.8m in length. Their baggy skin helps them maximize the amount of oxygen they can absorb directly from the water they live in, and although their tiny eyes mean they have poor eyesight, they are covered in tiny sensors that help them detect the vibrations of the worms, crustaceans, small fish and frogs that they feed on.
Why are Chinese giant salamanders under threat?
Habitat loss and poaching of wild salamanders to stock farms for the luxury food market poses a major threat to these animals, with millions of salamanders estimated to be kept in farms across China. The salamander farming industry developed in the early 2000s and has led to a surge in the number of animals being removed from the wild, causing populations to decline rapidly. A study by ZSL and partners between 2013 and 2016 found giant salamanders at just four out of 97 sites across 16 Chinese provinces, highlighting the dire status of these animals.
Having split from their closest relatives on the evolutionary Tree of Life as far back as the Jurassic period - when dinosaurs such as Stegosaurus still roamed the Earth - these unique animals are recognised as amongst the world’s most Evolutionarily Distinct and Globally Endangered (EDGE) amphibians – meaning that in addition to being key predators in river ecosystems across China, they are also some of the most extraordinary and overlooked species on the planet.
Melissa Marr, lead author of the paper and research fellow at The University of Edinburgh, said: "Chinese giant salamanders have been described as 'living fossils' as their appearance has remained unchanged for millions of years. Our research reveals hidden diversity; while outwardly similar, these amphibians have, in fact, genetically diverged into at least seven distinct species. These are at risk of extinction even before they can be fully named and protected. As a keystone species, preserving Chinese giant salamanders and their genetic diversity is essential for maintaining the health of their ecosystems. Our findings underscore the urgent need to safeguard these unique amphibians before it's too late."
What work is needed to protect Chinese giant salamanders?
Although confirming the existence of multiple different species is a major step in protecting these rare amphibians, further work is needed to locate surviving wild populations, or to find representatives of the different newly-recognised species surviving on salamander farms that could potentially be used for conservation breeding.
The assumption that Chinese giant salamanders were all the same species has led to problems around their conservation, as Samuel explained: “Salamanders are moved between farms across different parts of China, and are housed together at high densities. Well-intentioned releases of salamanders from farms back into rivers, and accidental escapes of salamanders into the wild, have led to animals invading habitats that are not part of their native range. There’s also the risk that different species will hybridise with each other in farms.”
For threatened species to be adequately protected and relevant legislation to be put in place, they must be formally named – however, only four of the newly-recognised Chinese giant salamander species have available names, and it can often take years for national species lists to be updated to incorporate newly-recognised species, during which time these threatened populations may quickly decline.
Samuel added: “We need to focus our attention on describing China’s previously unknown new giant salamander species, finding any surviving animals, and ensuring that they are recognised in conservation legislation. Without these actions, we’re at risk of losing these remarkable animals forever before adequate protection is in place to conserve them.”
A new Chinese Giant Salamander Conservation Action Plan has also recently been published coordinated by the Chinese conservation organisation Green Camel Bell, ZSL researchers and the IUCN Species Survival’s Amphibian Specialist Group. This outlines the key conservation measures that are needed to help save these species, including improved genetic screening of salamanders released from farms, updated IUCN Red List assessments to include all species, and further work to describe unnamed species and locate and monitor their wild populations.
The research and action plan are both part of ZSL’s wider work protecting Chinese giant salamanders - from London Zoo providing a home to giant salamanders rescued by UK Border Forces, to surveying wild populations and working with the IUCN to assess their current status. This work is just a small part of the conservation charity’s work to protect EDGE species and address the illegal wildlife trade, which is worth about $23 billion a year.
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