The revision of fossil big-eyed bugs suggests a peculiar evolutionary history of a peculiar true bug family (Heteroptera: Lygaeoidea: Geocoridae)

Abstract

The fossil record of the lygaeoid true bug family, Geocoridae so far consisted of a compression fossil from the Florissant Formation, Geocoris infernorum, and a mould fossil from the Izarra Formation, G. monserrati. Here, we report the third taxon, Protogeocoris arcanus gen. et sp. nov. from Cenomanian Burmese amber along with revision of the two previously mentioned species. The study of the specimens resulted in erecting a new genus, Eocenogeocoris gen. nov. to accommodate G. infernorum [ = Eocenogeocoris infernorum (Sudder, 1890) comb. nov.], because of its unique combination of characters compared to extant geocorine true bugs. Furthermore, the interpretation of the novel morphological data acquired from the study of the fossil geocorids in the context of the knowledge on extant representatives of the family suggests that characteristic groups of the family may have been evolved until the mid-Cretaceous, whilst the species-level diversity of the nominotypical genus, Geocoris Fallén, 1814, and closely allied genera is possibly resulted by quick radiation event after a climatic changes at the Eocene-Oligocene boundary.