A few days back, biologists found an extraordinary tree frog in India that was thought to have died out more than a century ago. The discovery was made by renowned Indian biologist Sathyabhama Das Biju and a team of scientists, in the jungles of north-eastern India, a BBC report said. 

The golf-ball sized bizarre frog with eyes on top of its head was first collected by a British naturalist in 1870.  

Source: b'Tree Frog | Source: SD Biju'

According to a report in The Christian Science Monitor, the elusive frog is part of an entirely new genus, one level up from a species.

But this is not the first time when a long-thought extinct species has surfaced to life again. 

Here is a look at some species that were thought to be extinct but are very much present in the world:

1. Big-Eared Bat

Last seen in 1890, a team of University of Queensland researchers spotted the strange bat in the forest of Papua New Guinea in 2012. The mammal was listed as "possibly extinct" by the International Union for Conservation of Nature.

Source: The Conversation

According to University of Queensland, the New Guinea big-eared bat and the long-eared bats (also called big-eared bats) are distinguished from all other Papua New Guinea bats by a combination of large ears and a simple nose-leaf located behind their nostrils.

2. Tiny Primate

The 2-ounce (57-gram) carnivorous primate was last seen alive in 1920s until the gremlin-like pygmy tarsier was discovered in the forests of Indonesia in 2008 by two researchers of Texas A&M University. 

Source: Source: National Geographic

The creature has big eyes and was found covered in dense coats of fur to keep warm in the chilly environment of mountaintop of Indonesia's cloud forests. 

3.  Miller's Grizzled Langur

Though it was never claimed that the large grey monkey better known as grizzled langur was extinct, a team of scientists working in the jungles of Indonesia accidentally rediscovered the animal in 2011. Interestingly, the langur was located very much outside the area where his presence had been recorded last. 

Source: b"Miller's grizzled langur | Source:\xc2\xa0Simon Fraser University"

According to a report in The Guardian report, a team of experts from Simon Fraser University in Canada had set up camera traps in the Wehea forest, on the eastern tip of Borneo island for capturing images of clouded leopards, orangutans and other wild animals. But when they saw the footage, they left startled to see a group of monkeys never seen before by them. 

4. Cuban Solenodon

In 2003, a Cuban farmer found the first live specimen of the enigmatic worm-munching creature after scientists claimed that only few of them have been seen since 1980s. 

Source: It's Nature

The curious animal named "Alejandrito" with its long snout and tiny body covered with spiky, brown hair was also known as Solenodon cubanus. With its discovery, scientists who had very little knowledge about the creature, had dubbed the discovery vital for furthering the knowledge about the animal. 

5. Coelacanth

Believed to be hidden or extinct since 65,000 millions years, a 1938 catch by a South African museum curator proved that the creature was still alive.  The species was described by Professor J.L.B. Smith in 1939 and was named after its discoverer, Miss Marjorie Courtenay-Latimer. 

Source: b'Coelacanth or Latimeria chalumnae | Source: Smithsonian National Museum of Natural History'

For many years, living coelacanths were known only from the western Indian Ocean, but in September 1997 and during the following year coelacanths were captured in northern Sulawesi, Indonesia. The Indonesian discovery was made by Mark V. Erdmann, then a doctoral student from UC Berkeley studying coral reef ecology in Indonesia. 

Feature image source: SD Biju