Rediscovery of Helophorus auriculatus Sharp, 1884 (Coleoptera, Helophoridae) in Saitama Prefecture, Japan, with ecological notes

Abstract

Helophorus auriculatus Sharp, 1884 is an endangered water beetle that inhabits earth ditches and small pools in riverbeds and paddy fields. In Japan, the recent record of H. auriculatus has been limited to the Ibaraki Prefecture in 2019 and Tsushima Island, Nagasaki Prefecture in 2020. We rediscovered this species in the Saitama Prefecture, Japan, after 34 years and compared the habitat and adult morphology of this species among different Japanese regions.