Species: São Tomé giant treefrog (Hyperolius thomensis)
Status: Endangered (EN)
Interesting Fact: Like many other Hyperolius species, the São Tomé giant treefrog breeds in standing water, but instead of using ponds, this remarkable amphibian lays its eggs in water-filled holes in trees.
As its name suggests, the beautifully coloured São Tomé giant treefrog is endemic to the island of São Tomé, 255 kilometres off the coast of Gabon, and is the largest member of the genus Hyperolius. This amphibian presents a classic example of ‘island gigantism’, whereby certain colonisers on islands tend to evolve to become larger than their mainland relatives. The upperparts of the São Tomé giant treefrog are a uniform green to blue-green colour, while the underside is much more brightly coloured with a marbled pattern of orange, white and black. Like other similar species, this treefrog has expanded toe pads and long legs which make it an adept climber.
There is little information available on the current threats to the São Tomé giant treefrog, but the loss of its forest habitat is thought to have had a severe impact on this species. Forest clearance began on São Tomé in the late 15th century to make way for the cultivation of sugar cane, and dramatically accelerated in the 1800s as a result of the production of coffee and cocoa. At one stage in the early 20th century, São Tomé was the world’s largest producer of cocoa, with around 42 percent of the island being devoted to its production. Deforestation rates have since slowed considerably, but the São Tomé giant treefrog is now restricted to the remnants of original primary forest on the island at elevations above 800 metres.
There are currently no known specific conservation measures in place for the São Tomé giant treefrog. However, it may receive a certain level of protection as a result of its occurrence in Obo National Park.
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Kathryn Pintus, ARKive Content and Outreach Officer