A team of scientists from Delhi University, Bombay Natural History, Zoological Survey of India, and Brussels' Vrije University discovered frog species that belong to the night frog group and rediscovered three frog species which were thought to be extinct.

The discovery was announced in Zootaxa, the international journal for zoologists.

This discovery will help gain the focus of the study toward amphibians present in India, which are essential for the maintenance of our environment in a healthy manner.

The frogs were spotted in a region known as the Western Ghats, which is a mountain range that runs along the western coast of India and has been identified as one of the ten hottest biodiversity hotspots in the world. Considering the fact that they occupy a small area, at least six of the new species are sensitive to habitat loss and will require immediate steps toward conservation.

Frogs are extremely important indicators not just of climate change, but also pollutants in the environment, said the project's lead scientist, biologist, Sathyabhama Das Biju, from Delhi University.

Many environmental scientists believe that amphibians, including frogs, are excellent biological indicators of a broader ecosystem because of their intermediate position in food webs, permeable skins and typically biphasic life.

Frog populations have declined dramatically since the 1950s; more than one third of the species are believed to be threatened with extinction and more than 120 species are suspected to be extinct since the 1980s.

The findings included the rediscovery of three frog species which were not seen for more than 75 years since their original descriptions by C.R. Narayana Rao in the 1920s and 1930s.

The 12 species of frogs belong to the genus or scientific classification Nyctibatrachus which is formed as Nycti from the Greek word for night and batrachus, the Greek word for frog. Night frogs are a group endemic to India and require either fast-moving rivers or moist forest floor for breeding. The Coorg Night Frog hadn't been seen for 91 years. The Kempholey and Forest Night Frogs had been missing for 75 years.

The study has reported that half of the newly discovered species reproduce without any physical contact between the sexes, with the female depositing her eggs on a leaf and the males later fertilizing them.

Frogs are used in cloning research and other branches of embryology because frogs are among the closest living relatives of man to lack egg shells characteristic of most other vertebrates, and, therefore, facilitate observations of early development.