The Present is the Key to the Past: How Living Fossils in Namibia Share Insights on the Insects of Tertiary European Forests

Abstract

Mantophasmatodean insects have been widely recorded in Cretaceous and Eocene amber. Although rare, Mantophasmatodeans are famous for a quite widespread occurrence in the Baltic area until the Eocene extinction, living in a Tertiary flora commonly associated with forested ecosystems. Close relatives are still alive in southern Africa, like those belonging to the Mantophasma genus, probably one of the most intriguing living fossils in the world. Some nymphs were collected in a Namibian plateau east of the Erongo Complex and carefully cultivated in a laboratory. Our main purpose was to investigate the entire life cycle of these Namibian living fossils to share novel insights in the palaeoclimate of Baltic Eocene. We unravelled the adult morphology and the postembryonic development of these intriguing insects, commonly called heelwalkers, and performed a comparison of the morphometric, ecological and ethological data between our specimens and the living species described so far in literature. Furthermore, we analysed the vibrational male–female communication of these primitive insects. The robust evidence provided here supports some controversial recent palynological assessments of the Eocene and show that the Baltic landscape was much more open than commonly thought.