Preservation and Research Center, City of Yokohama amphibians

<scientific name> Rana japonica
It is endemic to the Japanese Islands and inhabits low mountain forests, paddy fields and grasslands from the plains of Honshu, Shikoku, Kyushu and surrounding islands. In Yokohama City, inhabitation has been confirmed in Tando in the northern part of the city. It lays eggs in early spring, and the egg mass is spherical and large onigiri. The body color on the back is reddish-brown or orange rather than red, similar to Montane Brown Frog (Rana ornativentris), but males of this species can be distinguished by the lack of a squirrel (a part that swells greatly when singing) and the pattern of tadpoles. Also, this species seems to sleep in spring after spawning in early spring. In the past, Tokyo-grown Japanese Brown Frog was once regarded asJapanese Brown Frog. On the other hand, the East and West Japan populations in Japanese Brown Frog are said to be reproductively isolated, and the species may be divided into multiple species.

<scientific name> Glandirana reliquia
It is found in various places such as paddy fields and rivers on the Tohoku Pacific Ocean side from Kanto including Yokohama City, and ponds in parks, but it is considered to be a frog that is rarely separated from water sites. In Yokohama city, it is rarely seen in rivers in the northern part of the city.
An analysis of the Wrinkled Frog and morphology and mitochondrial DNA, which is widely inhabited in Honshu, Shikoku, and Kyushu, found that it was separated from the closely related species that were on the continent when it was older than Wrinkled Frog, and was registered as a new species as Mukashi Wrinkled Frog in August 2022.
The spawning season is from April to August, and dozens of eggs are laid on aquatic plants. The back is light brown or ocher, with many warts, and the skin feels rough. The only native frogs in Honshu is known to winter with tadpoles.
In order to prevent the extinction of the Mukashi Wrinkled Frog produced in Yokohama, Preservation and Research Center has been conducting a trial reintroduction of Mukashi Wrinkled Frog, which has been bred under breeding since 2021.
※Reintroduction of Mukashi Wrinkled Frog