Out of Africa: did plants disperse via the Gomphotherium land bridge?

During the Miocene a land connection between Africa and Eurasia was established as a consequence of the collision of the Afro-Arabian and Eurasian plates. This so-called Gomphotherium land bridge provided an important corridor for mammal migration in the early and middle Miocene, allowing among others various large elephant-like animals to migrate from Africa into Anatolia and the Eastern Mediterranean region and Central Europe. Despite the rich vertebrate fossil records witnessing this large scale migration between Africa and Eurasia there is currently no convincing contemporaneous plant fossil evidence for such a biogeographic pattern. In view of the absence of a broad desert belt (Sahara) in the Miocene and a physical connection between Africa and western Eurasia the working hypotheses of this project is that dispersal of African floral elements into Anatolia and Central Europe should be expected at that time. This project aims to assess whether plants migrated from Africa into western Eurasia via the famed Gomphotherium land bridge. To achieve this, key fossil palynofloras and macrofloras across the early to late Miocene in Anatolia, Greece and Central Europe will be investigated and scrutinized for African floral elements. To accomplish this, evidence from previously studied macrofloras (leaves, fruits, and seeds) will be combined with high taxonomic resolution palynological data from a combined light microscopy and scanning electron microscopy approach used for this project. The combined plant macrofossil records and the palynofloras will make it possible to reconstruct terrestrial environments (vegetation) in Anatolia, Greece and Central Europe that are known to have been inhabited by mammals of African origin during the Miocene. The studied Eurasian floras will also be compared to well-documented late Oligocene to middle Miocene floras in Africa north of the equator to evaluate whether or not African mammals arriving in Anatolia and Europe during the Miocene thrived in habitats (vegetation) different from their original environments.

Out of Africa: did plants disperse via the Gomphotherium land bridge? About 20 to 17 million years ago large African mammals were able to migrate into Europe. This is witnessed by countless vertebrate fossils discovered along their route that ran through the Middle East Mediterranean coastline, via Asia Minor, and into Central and Western Europe. The descendants of these animals then survived in Europe for millions of years. Now an international team of scientists, led by researchers from the University of Vienna, have discovered that even though large African mammals were able to migrate into Europe at that time the same did not apply for typical African floral elements. Paleobotanical evidence show little relation between South African and Northeastern African floras at that time and no correlation was observed between fossil floras in Northeastern Africa and those in Asia Minor or Central Europe. For some reason, probably related to humidity, the plants reached a barrier and were not able to disperse northwards from Africa into Europe during that time. Therefore, when the herbivorous animals arrived in Europe, and in the time that followed, they had to adjust to new feeding grounds and vegetation types. This is evident from the scar marks that were formed during feeding and can now be observed on their fossilized teeth. In the time that followed, from about 14 million years ago and until the last ice age began, continued climate change affected the vegetation of Europe. The lush forests that had previously covered most of the area gradually decreased, the warmth loving floral elements were replaced by more cold tolerant plants, open environments became more prominent, and seasonality increased. This is not only evident from the plant fossil record. The mammalian fossil record shows that even though the species that first arrived from Africa went extinct, their lineages survived in Europe and new species evolved concurrent to the climate and vegetation changes. Their descendants then roamed across Europe until the beginning of the last ice age.