A rainbow snake and Klingon newt are among the whimsical new species discovered in the Greater Mekong region, scientists announced today.

A new report published by World Wildlife Fund unveiled 163 new Mekong species to the world—all of which were found in 2015 alone.

One of the most species-rich spots on Earth, the Mekong and its river encompass parts of Laos, Cambodia, Thailand, Myanmar, and Vietnam. Over the last 20 years, biologists have discovered nearly 2,500 new species in its mountains and rain forests.

"Species discovery isn’t random. A lot of times, people just haven’t looked," says David Blackburn, a herpetologist at the Florida Museum of Natural History who wasn't involved in the WWF report.

Many are very small, making them harder to spot by scientists. Others live only in small patches of habitat in hard-to-reach locations. Still others may be confused with other species.

But finding them is crucial, Blackburn says: A formal classification is the first step in protecting a species.

“A lot of the world’s biodiversity remains to be described,” Blackburn says. “Some of these species are prone to extinction. We can’t protect what we need to protect without data.”