The species was described from a pair of complete fruit specimens. The
holotype fossil was recovered from Resner Canyon, location
National Museum of Natural History USNM 11018 in the Toroda Creek Graben of Northeast Washington State. Location USNM 11018 is an outcropping of early Eocene,
Ypresian, The plant community preserved in the Klondike Mountain formation is a mixed confer-broad leaf forest with large pollen elements of
birch and
golden larch, but also having notable traces of
fir,
spruce,
cypress, and
palm. The Allenby formation is similar with the birch and golden larch as strong pollen signals and traces of fir and spruce, however the cypress and palm are not distinct signals.
Acer toradense was described from a pair of
specimens, the holotype, number "USNM 396010 A,B" which is currently preserved in the
paleobotanical collections housed at the
National Museum of Natural History, part of the
Smithsonian Institution in
Washington, D.C. and the paratype, "UBCB 2400", is in the paleobotanical collection of the
University of British Columbia in
Victoria, British Columbia. The specimens were studied by
paleobotanists
Jack A. Wolfe of the
United States Geological Survey, Denver office and Toshimasa Tanai of
Hokkaido University. Wolfe and Tanai published their 1987
type description for
A. toradense in the
Journal of the Faculty of Science, Hokkaido University. The
etymology of the chosen
specific name toradense is in recognition of the type locality in the Toroda Creek Graben.
A. toradense is one of three species assigned to the extinct section
Torada. The three members of the section
A. stonebergae,
A. toradense, and
A. washingtonense were known only from the Republic and Princeton fossil localities when first described. Of the three species, both
A. stonebergae and
A. toradense are only known from the samara fossils, only
A. washingtonense has been described from both leaves and samaras. The three are among a number of
Acer species described from the Republic and Princeton sites by Wolfe and Tanai. ==Description==