The oldest winged insects (Insecta: Pterygota)

Abstract

Introduction: The appearance of wings is considered as the key innovation in insect evolution along with the holometabolous metamorphosis. In spite of considerable scientific effort during the last two centuries the origin of wings remained an unresolved issue of entomology. The oldest fossil records of Pterygota based on fully developed wings are known from close to the transition period between the Mississippian and Pennsylvanian, approximately 323 million years ago. This indicates that the group originated significantly earlier, perhaps in the earliest Carboniferous or, even more likely, in the Late Devonian. Surprisingly, the divergence of Pterygota based on molecular data is estimated to have occurred as early the latest Ordovician to the late Silurian.

Methods: Our application of optical stereomicroscopy together with modern non-invasive techniques like ESEM and micro-CT resulted in a more comprehensive view of external morphology of Carboniferous insects revealing new details in microstructure.

Results: The talk will introduce the earliest pterygote fossils and sum up their significance in regard to their systematical position. On the basis of current discoveries, the postembryonic development with emphasis on the wing growth is newly reconsidered for members of Palaeodictyoptera. Moreover, the rarely preserved wing joints of Palaeozoic members were analyzed to clarify the disparity of the flight apparatus and the relationships between the extinct and the extant winged insects.