The Japanese wrinkled frog, Glandirana rugosa, (formerly Rana rugosa), is a species of true frog

True frog

The true frogs, family Ranidae, have the widest distribution of any frog family. They are abundant throughout most of the world, occurring on most continents except Antarctica...

 native to Japan

Japan

Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...

 and introduced to Hawaii

Hawaii

Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

 in the late 19th century. It has sometimes been regarded as a single species with the Imienpo Station frog

Imienpo Station frog

The Imienpo Station frog, Glandirana emeljanovi, is a species of frog found in Northeast Asia. It has sometimes been regarded as a subspecies of the Japanese wrinkled frog, Glandirana rugosa, with which it shares many characteristics...

, Glandirana emeljanovi, which is found on the East Asian mainland. The two species are distinguished from others by their rough and uneven skin. It lives and breeds in various freshwater environments, including ponds, streams and wetlands. The IUCN does not consider this species to be faced by any significant threats.