Shigeyasu Tokunaga () (1874âÂÂ1940) was a Japanese zoologist, geologist, and palaeontologist. His family name by birth was and some of his papers were published under this name.
Shigeyasu Tokunaga was born in Atago, Tokyo on 20 August 1874 (Meiji 7). His father was a private secretary to the Shimazu clan, while his paternal grandfather had served the Satsuma Domain in Edo. His maternal grandfather was the pharmacologist , his maternal uncle the chemist .
In 1894, Shigeyasu enrolled as a student in the Department of Zoology at the Imperial University, Tokyo, where he also attended lectures and classes in the Department of Geology. As a graduate student at Tokyo Imperial University, he studied under Bunjirà  Kotà Â, , and , among others.
His 1902 paper coauthored with Jà «zà  Iwasaki () on the fossil skull to which in 1914 they would give the name Desmostylus japonicus was the first description of a Japanese Miocene mammal. He went on to conduct geological surveys of Karafuto, the Ryà «kyà « Islands, Taiwan, Korea, and China, with coal a particular specialism. From 1910 he was professor in the Faculty of Science and Engineering at Waseda University. In 1936 he became chairman of the and in 1937 of the .
Tokunaga was a devotee of Noh: he studied under the sà Âke of the Hà Âshà  school and performed on stage over three hundred times, particularly in plays of the fourth and fifth categories, appearing in later life also in elderly female roles in plays including Sotoba Komachi. His wife edited volumes of tanka, while their eldest son was a specialist in Hungarian literature and professor at Tokyo University of Foreign Studies. Tokunaga died on 8 February 1940 (Shà Âwa 15).