Indian biologists say they found the tiny amphibians declining dramatically in number during the 12 years in which they chronicled the species through morphological descriptions and molecular DNA markers. They breed after the yearly monsoon in fast-rushing streams, but their habitat appears to be becoming increasingly dry.
The study listing the new species was published Thursday in the Ceylon Journal of Science. It now lists the number of known Indian dancing frog species to 24. They're found exclusively in the Western Ghats, a lush mountain range that stretches 1,600 kilometers (990 miles) from the western state of Maharashtra down to the country's southern tip. There are other dancing frogs in Central America and Southeast Asia, but the Indian family, known by the scientific name Micrixalidae, evolved separately about 85 million years ago.
Their mating rituals are quite interesting. Only the males "dance", which is actually a unique breeding behavior called foot-flagging. They stretch, extend and whip their legs out to the side to draw the attention of females who might have trouble hearing mating croaks over the sound of water flowing through perennial hill streams. They bigger the frog, the more they dance. They also use those leg extensions to smack away other males - an important feature considering the sex ratio for the amphibians is usually around 100 males to one female. These are tiny, delicate frogs and can easily be swept away in a gushing mountain stream. So breeding happens only once the level of a stream levels drops to the point where the water babbles over boulders and stones. If streams hold less water or dry out too early, the frogs get caught without the right conditions to breed.
The Western Ghats, older than the Himalayas, is among the world's most biologically diverse regions, holding at least a quarter of all Indian species. Yet in recent decades, the region has faced constant threats of iron and bauxite mining, water pollution, unregulated farming and loss of habitat to human settlements. A 2010 report by India's Environment Ministry also said the Ghats were likely to be hard-hit by changing rainfall patterns due to climate change, and more recent scientific studies have also suggested monsoon patterns will grow increasingly erratic.
India's government has been working to establish a vast environmental protection zone across the Ghats to limit polluting industrial activities and human encroachment, but it put the latest proposal on hold earlier this year. Meanwhile, as India's population has grown to a staggering 1.2 billion, at least 25% of the forests have vanished from the Ghats, which is now home to more than 325 of the world's threatened species of plants, birds, amphibians, reptiles and fish.
Photo Credit: Phys.Org