7 new species of golden-backed frogs found
(Large golden-backed frog - Hylarana magna)
For a long time golden-backed frogs that occur in India and Sri Lanka were mistakenly considered as belonging to the same species but an Indo-Sri Lankan research team led by S D Biju, amphibian researcher and professor at University of Delhi, has ended the identity crisis by conclusively showing that frogs on the Indian side and Sri Lankan side are distinctly different species.
The research team has discovered seven new species of Golden-backed frogs (Genus Hylarana) from the Western Ghats-Sri Lanka Global Biodiversity Hotspot. The results of the study were published in the latest issue of Contributions to Zoology, an international journal published from Netherlands.
"Before this discovery, it was widely accepted that some of the Golden-backed frogs that occurred in India and Sri Lanka belonged to the same species. Using integrated methodologies, the research team has conclusively shown that the frogs on the Indian side and Sri Lankan side are distinctly different species. After more than a century of misidentification, the frogs have finally received taxonomic justice!" a press release said.
The researchers surveyed the Western Ghats-Sri Lanka biodiversity hotspot for over ten years. The study used DNA techniques and morphological evidence as tools to identify species and understand their distribution ranges. The yield from their study was handsome - 14 distinct Golden-backed frogs, with seven new species.
"When I started fieldwork for this group of animals there were only four valid species of Golden-backed frogs in the Western Ghats-Sri Lanka biodiversity hotspot. The more I saw, the more I realized that scientists had been confused in their evaluation of the diversity of Golden-backed frogs of this region for over a century," Prof Biju stated in the release.
Globally, Golden-backed frogs are one of the most widely distributed group of frogs and their distribution extends across three continents (Africa, Asia and Australia). This taxonomically complex group has puzzled the scientists for a long time.
One could walk from India across to Sri Lanka 500,000 years ago since the two landmasses were connected. Now they are separated by 30 kilometers of ocean, but unsurprisingly are strikingly similar in their geology, climate and evolutionary history. The ancient land that bridged the present day subcontinent of India and the island of Sri Lanka, served as a corridor for dispersal of flora and fauna. Therefore, the very natural assumption that two Golden-backed frog species (Hylarana aurantiaca and Hylarana temporalis) were common in both countries is not surprising, the release said while explaining the reasons behind the mistaken assumption.
The study has concluded that these two regions do not have commonly shared species. Golden-backed frogs in India are endemic to India and the ones in Sri Lanka are endemic to Sri Lanka. The conservation strategies for Golden-backed frogs of these two regions need to be considered separately.
Golden-backed frogs are major components of tropical forest ecosystems and are of great importance in river systems. "Golden Backed Frogs, like many forest frogs, are excellent indicators for the health of tropical forest water systems," said Prof. Biju, the lead author of this study. However, these frogs are facing the threat of extinction owing to extreme anthropogenic activities, mainly habitat destruction.
Out of the seven new species discovered, six were found in the Western Ghat states of India (four from Kerala, and one each from Karnataka and Maharashtra) and one from Sri Lanka. "One of the newly named species remained unnoticed despite its occurrence in urban areas," says Sonali Garg, co-researcher and student from University of Delhi. Urban Golden-backed frog (Hylarana urbis), named urbis due to its occurrence in urban areas, is one of the seven new species discovered in this study.
The Western Ghats are a global amphibian hotspot and one of the most important centers of extraordinary amphibian diversity. Our knowledge of its real diversity is still incomplete, the release said. Currently there are nearly 200 amphibian species known from the Western Ghats and about 100 of these were discovered only in the last 15 years. Biju and his colleagues described about 70 of them.