The oldest Gondwanan non-biting midge (Diptera, Chironomidae, Podonominae) sheds light on the historical biogeography of the clade

Abstract

Podonominae, a group of non-biting midges within the Chironomidae family, serves as an important biogeographical model. For a long time, it was believed that Podonominae originated in Northern Gondwana and later spread to Laurasia. However, because the oldest known fossils of this group come from the Jurassic period in Eurasia more recent interpretations have suggested a Laurasian origin.

We present the oldest record of Podonominae from Gondwana, specifically from the Tithonian age (Jurassic) in Australia. This discovery is also the oldest Chironomidae fossil found in the Southern Hemisphere and suggests that Podonominae likely originated in Gondwana. The new fossil represents a highly specialized form of Podonominae, adapted to living in the littoral zones of large lakes. It has adaptations to this environment that are unique amongst Podonominae, and similar to those found in some modern marine Chironomidae species such as Telmatogetoninae.