Pseudis

Pseudis is a genus of South American frogs (swimming frogs) in the family Hylidae. They are often common and frequently heard, but easily overlooked because of their camouflage and lifestyle, living in lakes, ponds, marshes and similar waters with extensive aquatic vegetation, often sitting at the surface among plants or on floating plants, but rapidly diving if disturbed. Whereas the adults are medium-sized frogs, their tadpoles are large; in some species the world's longest.