Photos by renan_ozturk / I was part of National Geographic's Lost World Expedition, which completed a transect of the Upper Paikwa River Basin, near Guyana’s northwestern border with Brazil and Venezuela, to look for new species of amphibians and reptiles in one of the world’s richest and least explored hotspots of biodiversity. Here's a snapshot from writer m_synnott on the journey's end: We set off around 9 a.m., bushwhacking our way through a Seussian forest of twisted, moss-covered trees and dense thickets of saw grass, reeds, and vines. In some places the vegetation was so thick that the only way forward was to crawl on our hands and knees in tunnels wreathed in spider webs heavy with dew. Through openings in the shrubbery, we caught occasional views across the valley toward Mount Roraima. It had rained overnight, and the tepui was ornamented with a dozen or so massive cascades, including the legendary Diamond Waterfall, which burst from a hole in the side of the cliff. After ...