There are two entirely distinct worlds in south-east Venezuela’s small equatorial rainforest. Gigantic, flat-topped sandstone cliffs tower like impervious fortresses above the dense jungle – a reserved, cloud-wrapped ‘Otherworldly place’ encircled by a rackety underworld alive with screeching macaws and Jabbering monkeys. Called ‘Tepuis’ by the Pemon tribe of the region, the sheer-walled peaks were the push for Sir Arthur Conan Doyle’s tale, The Lost World.
Closely 2 billion years ago, when Africa and South America were still a piece of the super-continent Gondwanaland, residue from deteriorating peaks created an expansive bed of sandstone. This was raised by earth movements, and as millenniums passed by merciless scouring by weather and moisture unhurriedly wore away more vulnerable spots.
Now only the elevated table cliffs remain, some 3200ft (980m) lofty and physically secluded from the landmass below. The rainforest’s temperature is around 26C (78F), but at the peak, cloud-shrouded plateau, it is almost 10C (18F) cooler.
Because of their age-long isolation, the flora and fauna, on the tepuis have thrived unmixed with others and almost undisturbed by humankind. This so thrilled Conan Doyle that he envisioned a world of the prehistoric kingdom still surviving.
But scientists researching at the tepuis’ tops have discovered no animal more considerable than a mountain lion. Their chief appeal has been in analysing how plants and animals of the ‘Otherworld’ have evolved in comparison with identical ‘underworld’ species.
Earth’s Pandora includes a warty toad that is hardly 1in (24mm) in length and cannot leap or swim. It limps clumsily, its ebony skin disguising it against Roraima’s blackened rocks.
Each tepui showcases a distinct assortment of plants – of the estimated 12,000 or so species discovered there, at least half are uncommon, including many kinds of bromeliads and some insect-digesting pitcher plans. Because the rain filters through the soil very quick, plants suffer from both nutrient and soil shortages. Bromeliads root in lichens and mosses and on stems, and some 1000 orchid species, many no larger than a root, pin in rock cracks and moss tuffs. There are also unusual fungi that kill insects and plant food by injecting it with venom.