In a roadside puddle in Kerala, India, University of Delhi amphibian researcher Sonali Garg, a Ph.D. candidate, and her research supervisor, SD Biju, discovered a new genus and species of narrow-mouthed frog (family Microhylidae). 

Unlike most new discoveries that have resulted from explorations in secluded forests, the frog was found in one of the most explored and researched areas of the Western Ghats Biodiversity Hotspot. 

“This frog went unnoticed until now probably because it appears for less than four days for breeding activities and lives a secretive lifestyle for the rest of the year,” Garg said.

The new genus is currently known from a single locality despite extensive surveys in the nearby vicinity. Its closest relatives are found more than 2,000 kilometers away, in Southeast Asia.

During routine field surveys as part of her PhD research, Garg collected some unusual tadpoles that could not be confidently identified. Subsequent genetic comparisons were puzzling—the DNA barcodes failed to match any other known frogs from the region. The next two years were spent in vain searching for an adult. 

That changed one day in 2015, after heavy monsoon rains. Large aggregations of more than 200 frogs were observed on grass blades around a temporary rainwater puddle. Breeding activities took place for less than four days. Then the water level decreased, and the frogs disappeared. The team failed to locate even a single individual of the species at any other time of the year, despite three years of repeated surveys at the same location. 

Due to the frog’s extremely short breeding season and its disappearance for the rest of the year, the new genus has earned the common name “mysterious narrow-mouthed frog.”

The discovery of yet another endemic frog genus from the Western Ghats Biodiversity Hotspot further highlights the amphibian diversity and endemism harbored in the region. Unfortunately, the area and its species face myriad threats.

“The only known population of the new genus is found in a wayside area disturbed with vehicular movement, plantation activities and human settlements,” Garg said. “Since little is known about the habitat requirements and the distribution range of the new frog, the specific site needs to be preserved.” 

Garg is currently monitoring the area to gather more information about the conservation requirements of this enigmatic species.   

The findings have been published in the current issue (13 February 2019) of the journal Scientific Reports under the title “New microhylid frog genus from Peninsular India with Southeast Asian affinity suggests multiple Cenozoic biotic exchanges between India and Eurasia.”

The study was in part funded by CEPF, which invested in the Western Ghats Biodiversity Hotspot from 2008 through 2015.