Large cicada fossil (Cicadidae, Cicadinae, Tacuini) from the Middle Pleistocene Shiobara Group, Nasushiobara, Tochigi, Japan

抄録

In this study, we report a cicada fossil from the Middle Pleistocene (Chibanian) of the Shiobara Group in Nasushiobara, Tochigi, Japan. The specimen, preserving both wings and the body, represents a large individual with an estimated total length of 62 mm (head to forewing apex). Its body size, operculum morphology, and wing venation most closely resemble the extant Auritibicen flammatus (Distant, 1892). However, it differs from that species in its elongated wings and absence of forewing infuscation. Therefore, we tentatively identified the fossil as Auritibicen cf. flammatus (Distant, 1892). Morphological differences between a fossil and extant species may indicate that the fossil represents either an extinct species or an ancestral form of the extant species. Cicada fossils are extremely rare, with only 45 species described to date, all from the Cenozoic. Most are fragments of wings, with few specimens preserving the entire body. The specimen reported here is relatively well-preserved among cicada fossils and is the largest known specimen with the entire body intact. A detailed description of this fossil provides important insights into cicada evolution and speciation. Being from the Middle Pleistocene, it is also the youngest occurrence of a fossil cicada.