Myotis petax

Myotis minuscule. Forearm length 35-40mm. The facial hair color is grayish-brown, the back hair and the belly hair are grayish-brown and grayish-white respectively, the hair is short and soft, and the middle belly hair is about 5.5mm. The ears are long and narrow, with 3-5 horizontal edges and a slightly rounded tip that folds forward slightly beyond the snout tip. The tragus is narrow and long, tapering and tapering from the base, about one-fifth as wide as the length, and about half as long as the ear. The alar membrane is light brown and begins in the middle of the metatarsal bone and the caudal membrane begins at the base of the tibia. The tibia and caudal membrane are hairless, the distance is slightly equal to 1/3 of the margin of the caudal membrane, and the length of the hind foot is more than half of the length of the tibia.

It is distributed in Beijing, northern Xinjiang, Jilin and Liaoning provinces in China. It is distributed abroad in Russia, Japan and Kazakhstan.

East Asian water myoets often live in groups in caves, fly in forest glades, and also fly above water, suggesting that they may trawl the water to hunt fish. The echolocation sound wave is typical frequency modulation, accompanied by 1-2 harmonics. They come out at dusk to hunt nocturnal insects. This species was considered a subspecies of the Water Myotis daubentonii (Myotis Daubentonii) until 2005 and is now a separate species.