A Maastrichtian insect assemblage from Patagonia sheds light on arthropod diversity previous to the K/Pg event

VERA, E.I.; MONFERRAN, M.D.; MASSAFERRO, J.; SABATER, L.; GALLEGO, O.F.; PEREZ LOINAZE, V.S.; MOYANO-PAZ, D.; AGNOLÍN, F.; MANABE, M.; TSUHIJI, T.; NOVAS, F.E.

Communications Biology

Nature Research

Año: 2023 vol. 6

Insect faunas from the latest Cretaceous are poorly known worldwide. Particularly, in theSouthern Hemisphere, there is a gap regarding insect assemblages in the Campanian-Maastrichtian interval. Here we present an insect assemblage from the MaastrichtianChorrillo Formation, southern Argentina, represented by well-preserved and non-deformed,chitinous microscopic remains including head capsules, wings and scales. Identified cladesinclude Chironomidae dipterans, Coelolepida lepidopterans, and Ephemeroptera. Theassemblage taxonomically resembles those of Cenozoic age, rather than other Mesozoicassemblages, in being composed by diverse chironomids and lepidopterans. To the best ofour knowledge, present discovery constitutes the first insect body fossils for the Maastrichtianin the Southern Hemisphere, thus filling the gap between well-known Early Cretaceousentomofaunas and those of Paleogene age. The presented evidence shows thatmodern clades of chironomids were already dominant and diversified by the end of theCretaceous, in concert with the parallel radiation of aquatic angiosperms which becamedominant in freshwater habitats. This exceptional finding encourages the active search ofmicroscopic remains of fossil arthropods in other geological units, which could provide aunique way of enhancing our knowledge on the past diversity of the clade.