Fourteen new species of tiny “dancing frogs” have been discovered in the jungles of western India, scientists report.
The spectacular haul more than doubles the number of Indian dancing frogs, a family named for the bizarre courtship displays of their foot-waving males, to 24 species. (Also see “Pictures: Meowing Night Frog, Other New Species Found.”)One of the new dancing frogs, Micrixalus kottigeharensis. Photograph by S. D. Biju, Systematics Lab
The diminutive amphibians—which measure 13 to 35 millimeters long—were found during a decade-long search across the Western Ghats, a mountain range that extends north-south across India for 990 miles (1,600 kilometers).
The study was led by India’s frog discoverer-in-chief, University of Delhi professor Sathyabhama Das Biju, whose numerous past finds include the extraordinary purple frog. (Related: “Weird Purple Frog Seduces Females From Underground.”)
Identified using both physical features and analysis of molecular DNA markers, the frogs are described by Biju and his team in the latest issue of the Ceylon Journal of Science (Biological Sciences).
Watch a video of dancing frogs.
Their findings reveal that the new frogs belong to an ancient genus named Micrixalus, which has been hopping about since the dinosaur era.
Associated with the falls and splash zones of small, fast-flowing streams, dancing frogs’ small size—the tiniest new find is no bigger than a bee—and perfect camouflage make them extremely hard to spot, Biju said. (Also see “World’s Smallest Frog Found—Fly-Size Beast Is Tiniest Vertebrate.”)
But following the annual monsoon, when the frogs’ rain forest streams reach the ideal level for breeding, “it is relatively easy to find them,” he said.
Most noticeable were the males, which in the case of at least nine of the newfound species advertised themselves to potential mates with a bizarre display known as foot-flagging.
This involves the frog stretching a hind leg out from its body and waving a fully extended webbed foot. On occasions, the study team noted, the frog’s raised foot also came in handy for pushing rival males out of the way. (See video: “Frogs Shake Booties Before Fights.”)
Female dancing frogs also showed unusual behavior when it came to laying their eggs, Biju said.
“In some species, eggs are laid in a cavity that the female digs with the help of her hind limbs at the bottom of shallow-flowing streams,” he said.
Having made the nest, the female then covers it with sand and gravel—probably to stop the eggs being washed away and to protect them from fish or other predators, Biju explained.
Leg waving or foot-flagging has been recorded in a number of unrelated frogs around the world, from Australia to Brazil, according to Walter Hödl of the Institute of Zoology at the University of Vienna in Austria.
The visual display likely evolved because the noise of rushing streams drowns out the frogs’ mating calls, Hödl said.
As for the females’ nest-digging, “it’s a really striking behavior,” but perhaps not surprising, Hödl added, because “frogs that breed in creeks and streams have to hide their eggs somehow.”
Hödl also agreed with the study team’s view that the new finds mark the Western Ghats as a global biodiversity hot spot for frogs and other amphibians.
“It’s an area which has been underexplored, certainly compared to places like the Amazon and Central America,” he said.
Biju, the so-called frog man of India, is concerned about the impact of habitat loss caused by farming and other human activities on his latest discoveries.
“Over the last 12 years of my field studies on the dancing frogs, I have noticed fewer number of frogs in areas where they used to be abundant,” he said. “Habitats of many species are drastically depleting or being modified.” (See pictures of the world’s vanishing amphibians.)
Several of the new species were recorded only at a single location, Biju noted, while 30 percent of dancing frog species are found only in areas that aren’t protected by the government.
So for some of these unique amphibians, it could be their last dance.