The Horton Plains slender loris has been so elusive for more than 60 years scientists believed the wide-eyed mammal had become extinct.
It had only been seen four times since 1937 but was fleetingly spotted in 2002 by researchers who identified it by the reflection of a light shone in its eyes.
Experts believe the prime reason for its rarity was due to the loss of its natural forest habitat largely destroyed by the drive to create tea plantations.
Now scientists from the Zoological Society of London's (ZSL) edge of existence programme have managed to capture the world's first pictures of the rare animal during research aimed at quantifying how many species remain in the wild.
The picture of the endangered mammal shows an adult male Horton Plains slender loris, characterised by short limbs and long dense fur, sitting on a forest branch.
It was captured after more than 1,000 night time surveys in Sri Lankan forests taken during 200 hours of painstaking work.
The team not only took pictures of the animal but also captured three live specimens long enough to measure them.
"We are thrilled to have captured the first ever photographs and prove its continued existence - especially after its 65-year disappearing act,” said Dr Craig Turner, a ZSL conservation biologist.
Slender lorises, officially known as Loris tardigradus nycticeboides, are small nocturnal primates which are only found in the tropical forests of southern India and Sri Lanka.
They are about 6-10 inches long (15cm-25cm) and have large saucer-like eyes which help their night-time hunting.
Estimates suggest there are just 100 of the endangered creatures left in the wild, putting it among the world's top five most threatened primates.
But researchers admitted that so little was known about them that numbers could in fact be below 60, which would make them one of the rarest breeds in the world.
[source: http://www.telegraph.co.uk/earth/wildlife/7897057/Horton-Plains-Slender-Loris-pictured-for-first-time.html ]
