Evolution von Belemnitella in Zeiten des Klimawandels

The proposed study addresses the distribution and dates of first and last occurrence of Belemnitella species, extinct squid, in the Northern Hemisphere. Their correct identification will make it possible to detect migratory movements and extinction events when correlated with temperature fluctuations as a result of global climate change. The following questions will be addressed: Was a rise or fall in temperature more difficult for species to survive? Was the migration, evolution or disappearance of species triggered by a cooling or warming trend or even by stable environmental conditions? Did temperature fluctuations preferentially lead to a north-south migration or did local populations adapt to the changing environmental conditions? Was the preferred lifestyle of the species (good vs. bad swimmers) particularly sensitive to climate change? The intention is to collect and measure belemnites from stratigraphic levels that are not well documented, to bring the measurements of different authors on a common basis and to apply the self-organising Kohonen algorithm and a principal component analysis to determine the species. Multidimensional comparative analyses, hierarchical cluster analyses and van Valen metrics will be carried out to shed light on the evolution of belemnites. The proposed project aims to revise the known Belemnitella species by unifying the basis of systematics and developing a new statistical approach. The new approach will allow for the first time a comparison and alignment of Eastern and Western European concepts for the identification of Belemnitella species. Compiling existing stratigraphic data from key sections with a particular focus on Western Europe and linking these results to dates of first and last occurrence of Belemnitella species will, for the first time, allow the evolution and extinction of species as well as their dispersal to be linked to aspects of climate change, sea level fluctuations and further changes in their marine habitat. The project will also provide information for the first time on whether a certain way of life made Belemnitella species more sensitive to changes in their habitat and more susceptible to extinction events. This allows conclusions to be drawn about present-day marine organisms with a lifestyle similar to Belemnitella, such as squid, cuttlefish and bobtail squid, which are of economic importance.