Other new finds among the 145 new species include a frog that sounds like a cricket and a "sucker fish", which uses its body to stick to rocks in fast flowing waters to move upstream, according to conservation group WWF.
With fangs at the front of each jaw, the "dracula minnow" is one of the more bizarre new species found in 2009 in the Mekong River region, which comprises Cambodia, Laos, Myanmar, Thailand, Vietnam and China's Yunnan Province.
Discovered in a small stream in Myanmar, it is largely translucent and measures up to 1.7 centimetres long.
It is not yet known whether the species is endemic to a single ecosystem within Myanmar, or spread throughout the region as a whole.
Other bizarre discoveries include the Bare-Faced Bulbul bird, which is bereft of feathers on the face and side of the head and has pale blue skin on the rear of the head and around the eyes. It lives in sparse forest on limestone karsts in central Laos.
Among newly recorded plants, the Nepenthes bokorensis plant, found in southern Cambodia, has a climbing length of up to seven metres, with pitchers that trap ants and other insects for food.
"The rate of discovery in the Mekong is almost without equal globally," WWF regional conservation director Stuart Chapman told AFP.
"That's attributed to the enormous geographical and climatic range within the region, going from high altitude to dense tropical forests through to some of the richest freshwater in the world," he said.
"Undoubtedly this region is one of the richest in terms of its biodiversity, but it's also one of the most threatened."
The Greater Mekong region is home to some of the planet's most endangered wild species including tiger, Asian elephant, Mekong dolphin and Mekong giant catfish, said the World Wide Fund For Nature.
WWF has warned the Mekong giant catfish -- one of the world's biggest freshwater fish -- could be driven to extinction if plans to build hydropower dams on Southeast Asia's longest river go ahead, blocking spawning grounds.
"We need to keep one of the treasure troves of the world properly conserved," said Chapman.
