Insect Fauna of the Late Miocene Locality of Öhningen (Germany) Less Diverse than Reported: An Example of the Hydrophilid Beetles (Coleoptera)

Abstract

The fossils originally assigned to the family Hydrophilidae (Coleoptera, Polyphaga) from the late Miocene locality of Öhningen (southern Germany) are revised. Nine hydrophilid species are recognized, most of them representing the tribe Hydrophilini. Five species are reliably assigned to genera: Hydrochara noachica (Heer, 1847), n. comb. (=Hydrophilus rehmanni Heer, 1847, n. syn.), Hydrobiomorpha braunii (Heer, 1847), n. comb. (=Hydrous escheri Heer, 1862, n. syn.), Hydrobiomorpha heeri n. sp., Hydrophilus spectabilis Heer, 1847 (=Hydrophilus knorrii Heer, 1847, n. syn., =Hydrophilus giganteus Heer, 1862, n. syn.), and Hydrophilus vexatorius Heer, 1847. Two taxa are treated as Hydrophilini incertae sedis: Hydrophilopsis elongata Heer, 1862, and Hydrous ovalis Heer, 1862. Two species represent Hydrophilidae incertae sedis: Escheria ovalis Heer, 1847 and E. bella Heer, 1862. The fossil genus Hydrophilopsis Heer, 1862 likely represents the modern genera Sternolophus Solier, 1834 or Hydrobiomorpha Blackburn, 1888, the fossil genus Escheria Heer, 1847 likely represents some modern genus within the Hydrophilini or Hydrobiusini. Six taxa are excluded from the Hydrophiloidea: Helophorus magnus Heer, 1862, H. exilis Heer, 1862 (possibly belonging to Curculionidae), Hydrobius couloni Heer, 1862 and H. godeti Heer, 1862 (both possibly belonging to Curculionidae: Zygopinae), Hydrophilus braunii var. minor Heer, 1862, and Hydrophilus stenopterus Heer, 1862 (likely a leaf fossil). Our revision revealed a rather high amount of inaccurate family and genus assignments and a moderate amount of species-level synonymy in the original treatment of Öhnigen fauna by O. Heer. The diversity of the hydrophilid beetles in Öhningen is thus lower than previously reported, but still being slightly higher compared to other European Paleogene and Neogene localities.