The first black fly (Diptera: Simuliidae) from the Lowermost Eocene Oise amber (France)

Simulium (Hellichiella) oisense sp. nov., oldest representative of this subgenus, is described from the Lowermost Eocene amber of Oise (Northern France). It shares with this subgenus the pedicel significantly larger than first flagellomere; radius with hair dorsobasally; scutum unpatterned; sensory vesicle typically occupying about one fourth or less of palpomere II; pedisulcus shallow; claws each with basal thumblike; precoxal bridge complete.

Compared to the fossil species currently attributed to this subgenus, it is characterized by the presence of 10 antennomeres, palpomere IV shorter than palpomeres II+III, and pedisulcus well distinct. The extant species of this subgenus are Holarctic, living in small sandy streams and under rather cold to cool climates, which does correspond to the paleoenvironment but not the warm paleoclimate of the Oise amber deposit.

The subgenus is otherwise known by one species from the Baltic amber and one from the Rovno amber, both Middle Eocene.