Watase line
A biogeographic boundary between the Palearctic and Oriental realms, named after the Japanese zoologist Watase Shozaburo. Used in biology and ecology.
The Watase line is a biogeographic boundary drawn between Yakushima and Amami Oshima.
Named after the Japanese zoologist Watase Shozaburo (渡瀬庄三郎), who proposed the line in the early 20th century. The term combines his surname 渡瀬 with 線 (line).