Paleocene of Menat Formation, France, reveals an extraordinary diversity of orthopterans and the last known survivor of a Mesozoic Elcanidae

摘要

The orthopteran fauna of the Paleocene of Menat Formation (France) is revised. It comprises at least 12 species in the following Glades: Grylloidea (an undescribed species, Menatgryllus longixiphus gen. et sp. nov.); Tettigoniidae (Prophasgonura lineatocollis); Elcanidae (Cenoelcanus menatensis gen. et sp. nov.); two Eumastacoidea (Paleochina duvergeri gen. et sp. nov. and Paleochina minuta sp. nov., tentatively placed in the extant family Chorotypidae). These two last taxa are compared to the other described fossil Eumastacoidea. As all these Eumastacoidea are represented by tegmina or hindwings, their previous attributions to the Eumastacidae sensu stricto are questionable. All previously described fossil Caelifera from Menat are considered of uncertain position. Those that were previously considered as Acridoidea are excluded from this Glade. In consequence, the oldest described Acridoidea are Oligocene, at the time of diversification of the grasses on which these insects predominantly live, in accordance with the most recent molecular dating of the Acrididae. Cenoelcanus menatensis is the youngest and first Cenozoic representative of the Mesozoic Elcanidae, showing that this family survived the Cretaceous-Paleocene extinction and became extinct during the Paleogene.