Balkantolia Rediscovering a forgotten continent 40 million years ago

This forgotten continent lies between Europe, Africa and Asia, and became a gateway between Asia and Europe when the sea level fell and a land bridge was formed about 34 million years ago.

Balkantolia is a low-lying continent that existed about 40 million years ago and was home to an exotic animal group that "paved the way" for Asian mammals to settle in southern Europe, a new study finds.

The report , published on Science Alert on February 22, states that this forgotten continent lies between Europe, Africa and Asia, and this continent - which researchers called “Balkantolia” - became a gateway between Asia and Europe when the level of sea ​​surface and the formation of a land bridge about 34 million years ago.

"When and how did the first wave of Asian mammals reach southeastern Europe? It is still not understood," paleogeologist Alex Lecht and colleagues write in their new study, published in the journal Earth-Science Review.

Asian mammals in Europe

But the result was exciting; About 34 million years ago, at the end of the Eocene epoch, large numbers of endemic mammals from Western Europe disappeared with the emergence of new Asian mammals, in a sudden extinction event now known as the Grand Coupure or Eocene-Oligocene extinction .

However, recent fossil discoveries in the Balkans have upended this timeline, pointing to an "alien" biome that appears to have enabled Asian mammals to colonize southeastern Europe 5-10 million years before the occurrence of the Grande Copier.

Balkantolia 40 million years agoThis forgotten continent lies between Europe, Africa and Asia (Lexus Licht - Gregory Matisse - "CNRS")

To verify this, Lecht of the French National Center for Scientific Research and his colleagues re-examined evidence from all known fossil sites in the region, covering the present-day Balkan Peninsula, the Anatolian Plateau, and the westernmost tip of Asia.

The ages of these sites were revised based on current geological data, and the team reconstructed ancient geographic changes that occurred in the area, which has a "complex history of frequent sinking and re-emergence".

The starting point

What they found suggested that Balkantolia served as a springboard for animals to move from Asia to Western Europe, with the transformation of an ancient land mass from a free-standing continent into a land bridge - and the subsequent invasion of Asian mammals - coinciding with some "ancient geographic changes".

About 50 million years ago, Balkantolia was an isolated archipelago, separated from neighboring continents, where a unique group of animals flourished different from those of Europe and East Asia, according to the analysis. Then a combination of lower sea levels, growing Antarctic ice sheets and tectonic shifts linked Balkantolia to Western Europe 40 to 34 million years ago.

The fossil record showed that this allowed Asian mammals including rodents and ungulates (also known as angios or ungulates) to venture westward and invade Balkantolia. In addition to this record, Lakht and colleagues also discovered jawbone fragments belonging to a rhinoceros-like animal at a new fossil site in Turkey, dating from about 38 to 35 million years ago.

The fossil is arguably the oldest analogue of Asian ungulates discovered in Anatolia to date, predating the Grande Copier by at least 1.5 million years, indicating that Asian mammals were on their way to Europe via Balkantolia.

Balkantolia 40 million years ago - todayA group of lower sea levels has linked Balkantolia to Western Europe (Lexus Lecht - Gregory Matisse - CNRS)

south track

Perhaps this southern route to Europe via Balkantolia was more suitable for adventurous animals than crossing routes through Central Asia, which were at that time drier, colder, and desert-steppe, as Lakht and colleagues suggest.

However, they note in their paper that "the previous connection between the Balkantolia Islands and the existence of this southern dispersal route is still debated", and that the story compiled so far is "based only on mammalian fossils, and is the most complete picture of Balkan biodiversity in the past." It still has to be extracted."

Many of the geological changes that led to Balkantolia are not yet fully understood, and it is important to note that this review is just one team's interpretation of the fossil record.

However, the fossil record of mammals and other vertebrates living on islands is usually sparse and incomplete, while the rich fossil record of Balkantolia "provides a unique opportunity to document the evolution and extinction of island organisms in the deep past," the team concludes.