First fossil mosquito larva in 99-million-year-old amber with a modern type of morphology sheds light on the evolutionary history of mosquitoes (Diptera: Culicidae)

Mosquitoes (Diptera: Culicidae) have been hypothesized to have originated during the Jurassic Period, about 201–145 million years ago, primarily based on fossil evidence from their sister group, Chaoboridae (phantom midges). However, direct evidence for such an early origin of Culicidae is currently absent. The oldest known mosquito fossils, all adults and recovered from Cretaceous amber deposits about 99 million years ago, display morphologies that differ substantially from modern forms and are regarded as representatives of an extinct lineage, Burmaculicinae. Here we report the discovery of a fossil that represents both the first mosquito larva preserved in amber and the first immature mosquito from the Mesozoic Era, named as a new genus and species Cretosabethes primaevus Amaral & Borkent gen. et sp. n. The specimen exhibits typical mosquito larval morphology and can be confidently identified as an ingroup of Sabethini, a lineage with numerous extant representatives. This finding provides strong support for the Jurassic origin of Culicidae and suggests that the larval morphology of mosquitoes has remained relatively conserved for at least the past 99 million years.