Scientists thought the Sri Lankan Kandyan dwarf toad (Adenomus kandianus) had gone extinct in 1876. Exhaustive surveys of the area they were originally found in had yielded no evidence of the toad.
In 2009, researchers cataloguing the Peak Wilderness Sanctuary in Sri Lanka found four of the small toads on rocks in a fast-moving stream. After identifying the toads as Kandyan dwarf toads, the researchers returned. They have since found that the toad is almost exclusively in a two hundred square meter area. The small habitat range helps explain why they have been so hard to find for 133 years.
The Kandyan dwarf toad is no longer considered extinct, but is still endangered because of its limited range and encroachment on its habitat by humans.
Forest stream in Sri Lanka via Shutterstock