Antoine P.O. auteur aut IRD De Franceschi D. auteur aut IRD Flynn J.J. auteur aut IRD Nel A. auteur aut IRD Baby Patrice auteur aut IRD Benammi M. auteur aut IRD Calderon Y. auteur aut IRD Espurt Nicolas auteur aut IRD Goswami A. auteur aut IRD Salas Gismondi R. auteur aut IRD text journalArticle eng text/pdf reformatted digital access Tertiary insects and arachnids have been virtually unknown from the vast western Amazonian basin. We report here the discovery of amber from this region containing a diverse fossil arthropod fauna (13 hexapod families and 3 arachnid species) and abundant microfossil inclusions (pollen, spores, algae, and cyanophyceae). This unique fossil assemblage, recovered from middle Miocene deposits of northeastern Peru, greatly increases the known diversity of Cenozoic tropical-equatorial arthropods and microorganisms and provides insights into the biogeography and evolutionary history of modern Neotropical biota. It also strengthens evidence for the presence of more modern, high-diversity tropical rainforest ecosystems during the middle Miocene in western Amazonia. specialized Pebas Formation Peru Hexapoda Arachnida microorganisms 064 103 37 13595-13600 2006 0027-8424 https://www.documentation.ird.fr/hor/fdi:010037607 10.1073/pnas.0605801103 0027-8424 [F A010037607] https://www.documentation.ird.fr/hor/fdi:010037607 https://horizon.documentation.ird.fr/exl-doc/pleins_textes/2025-01/010037607.pdf IRD - Base Horizon / Pleins textes 2006-10-06 2025-01-03 fdi:010037607 fre