The term ‘amber fossils’ is largely associated with inclusions of insects, spiders and plant remnants. However, bacteria, fungi, algae and protozoans may also be preserved in fossil resins. Frequently these soft-bodied microorganisms are lacking otherwise in the fossil record. Because of the sometimes excellent mode of preservation of cells and cell organelles they become of increasing interest in palaeontology. This is especially because they give new insights into higher-level phylogeny.

In our research group amber of several geological epochs is investigated for microinclusions. Rare fossils, for example fungi, are not only preserved in the ca 40 million-year-old Baltic amber. Numerous microbes are also found in ca 100 million-year-old Cretaceous resins. The oldest available amber fossils come from the Carnian stage of the Triassic period and are about 220 million years old. Many of the algae, fungi, ciliates and testate amoebae are morphologically indistinguishable from extant species. Others, however, are archaic representatives which are not known from modern ecosystems. The microorganisms preserved in amber lived at wet tree bark and in small aquatic habitats at the resin-bearing trees or in wet forest soil. They became preserved as the liquid resin entered their microhabitats. Often several species are associated in a single piece of amber. Conclusions regarding the ancient biocoenoses of the amber forests are therefore possible. The consideration of microinclusions in amber research therefore allows a holistic research on the biota of Mesozoic and Cenozoic forests.