Scientists have spotted a rare tree frog in north-eastern India for the first time since the 1800s.

Now classified as Frankixalus jerdonii, the frog was first documented by a British naturalist in 1870 and was long thought to be extinct, according to biologist Sathyabhama Das Biju of Dehli University.

But during a 2007 expedition to the jungles of the north-eastern state of Meghalaya, a team led by Biju made the surprising discovery.

"It was night-time when our team heard loud, unusual calls from the trees in the jungle," he said. "When we went to the site the next morning, we found the frogs breeding inside the tree holes filled with rain water."

The frog has an unusual way of providing for its young, added Biju, who is also dubbed the "frogman of India" by the media on account of his passion for the amphibians.

"Due to insufficient food resources in tree holes, the mother exhibits remarkable parental care by laying unfertilized eggs to feed her tadpoles," Biju told dpa.

While the initial "rediscovery" was made a number of years ago, it was first #link:http://dpaq.de/kzcNM:published# Wednesday by the Public Library of Science journal PLOS ONE, after years of painstaking verification including DNA analysis.

Prior to 2007, the only documented specimens were the two caught in the forests of Darjeeling in 1870 by British naturalist TC Jerdon. They are preserved at London's Natural History Museum.

The yellow-brown species is large by tree frog standards, growing up to 45 millimetres long, with large bulging eyes and blunt snouts.