2025 Volume 131 Issue 1 Pages 71-76
Despite the recent diversification of Tenthredinid sawflies in Japan, fossil records of this family are notably lacking. Here, we describe specimens belonging to this family from the Chibanian (Middle Pleistocene) lacustrine deposits of the Shiobara Group. These specimens are identified as Tenthredinidae gen. et sp. indet A and B and Nematinae gen. et sp. indet. This study represents the first report of fossil tenthredinids in the Shiobara Group and also an incontrovertible Cenozoic fossil record of this family from Japan.