Neue Kieselholz-Funde mit der Käferfraßspur Pectichnus multicylindricus: Entstehung, Holzreaktion und Verbreitung

The feeding trace Pectichnus multicylindricus, known from the wood of Late Paleozoic conifers and caused by the larvae of early beetles, is documented with new finds for three more occurrences of Carboniferous–Permian sedimentary basins in central and southeast Europe. As a result, we can trace the stratigraphic range of its first occurrence to the late Carboniferous (Stephanian, Gzhelian). The results underscore the ecological importance of insects even in very distant terrestrial habitats in Earth’s history. Since both conifers and beetles first appeared in the late Carboniferous and the feeding track seems to be restricted to conifers, the late Carboniferous is probably close to the highest age of their appearance in Earth’s history. Furthermore, the new finds extend the palaeogeographic distribution from Rhineland-Palatinate over central Germany, Northern Bohemia, Southern Poland, and Eastern Ukraine to the Northwest of China. The recognition value of the typical feeding track gives reason to hope for further evidence in fossil wood collections of other geological periods and regions. The conifers living during the formation of the boreholes show multiple reactions, such as the formation of callus tissue from the vascular cambium or from the medullary rays, which can lead to the partial or complete closure of the wound and the individual boreholes. Furthermore, the tracheids adjacent to the borer ducts show intense swelling and lumen reductions, which indicate fungal infestation with successive selective delignification.