noun
Japanese brown frog; Rana japonica
A species of frog native to Japan; scientific name Rana japonica. Often referred to by its katakana name.
See also: アカガエル
ニホンアカガエルは春先に産卵する。
The Japanese brown frog spawns in early spring.
アカガエル is a broader term for brown frogs (genus Rana), while ニホンアカガエル specifically refers to the Japanese species Rana japonica.
Compound of 日本 (Nihon, 'Japan') + 赤蛙 (akagaeru, 'brown frog'). The katakana spelling is standard for biological species names.