Baltic amber from Northern Europe is an outstanding deposit due to the high diversity of well-preserved inclusions, mostly insects. Although it is one of the richest sources of fossils, science has consistently failed to define its geological age, despite applying various traditional approaches. There are several hypotheses concerning the age of Baltic amber, which is generally dated as Eocene, with an age range between 55 and 34 Ma. Difficulties in the age determination are essentially due to the repeated re-deposition of the amber, the broad range of the ancient forest, and its probable existence for several million years. It limits the scientific value of all Baltic amber fossils in evolutionary divergence time estimation. This is very unfortunate, especially because these fossils would be very important for reconstructing evolutionary events in the Eocene, which was a period of dynamic climate, with several warming and cooling events and is considered as a deep-time analogue of current climatic changes.
The core idea of my project was to apply an innovative approach of precise dating for this very important fossil deposit by using DNA, the morphology of extinct and extant species within the framework of advanced Bayesian statistics. Information contained in DNA sequences together with the morphology of both extinct and extant taxa allowed for estimating phylogenetically the age of fossils from Baltic amber, and thus the amber itself. I used a dataset from my previous project as a basis and expanded it with fossils from Cenozoic deposits worldwide.
The main result of the project is developing a method for estimating the age of fossil deposits using a total-evidence phylogenetic approach. This new approach has been used to establish the age of Baltic amber deposits.
The knowledge of the age of the Baltic amber fossils could be of use in e.g. evolutionary biology, palaeoecology, biogeography, and palaeoclimatology. It gives us an insight into the ecosystems' response to the dynamic climate changes that took place in the Eocene and shaped out the recent biota.
