Called ‘Balkanatolia’, it formed a land bridge over which Asian mammals colonized southern Europe
The Earth is a geologically living planet and the continents that we can see today are far from those that were observed millions of years ago. Now, paleontologist Alexis Licht and his team have found evidence that a lost continent emerged some 40 million years ago over what is now the Mediterranean Sea, serving as a bridge between Europe, Africa, and Asia that some Asian mammals used to colonize the south of our continent. The results have just been published in the journal ‘ Earth-Science Reviews ‘.
“When and how the first wave of Asian mammals arrived in southeastern Europe is still not well understood,” write the authors, who have dubbed this rediscovered continent ‘ Balkanatolia ‘.
What is known was the dramatic result of this mysterious arrival: it is documented that around 34 million years ago, at the end of the Eocene epoch, large numbers of European mammals suddenly disappeared. This phenomenon has been known as the Grande Coupure mass extinction.
However, recent fossil finds in the Balkans have altered that timeline, pointing to a ‘peculiar’ bioregion that appears to have allowed Asian mammals to colonize southeastern Europe 5 to 10 million years before this event occurred. mass extinction.
To investigate, Licht, of the French National Center for Scientific Research, and colleagues re-examined evidence from all known fossil beds on today’s Balkan Peninsula and Anatolia, the westernmost peninsula in Asia. By reviewing the age of these places, the team observed a convulsive history of lands that sank and then rose again. And, at that time, that piece of land was converted from an independent continent to a land bridge that some animals took advantage of to move from Asia to Western Europe, coinciding with the aforementioned “dramatic paleogeographic changes”.
About 50 million years ago, Balkanatolia was an isolated archipelago, cut off from neighboring continents, the researchers found. A unique ecosystem thrived there, with fauna unlike that of Europe and East Asia. But some ten to fifteen million later, the combination of falling sea levels, plus rising Antarctic ice sheets and tectonic shifts caused this continent to become connected to Western Europe. This allowed Asian mammals, including rodents and ungulates (four-legged mammals), to venture west and invade Balkanatolia, the fossil record shows.
Following the path of fossils
In addition to that record, Licht and his colleagues also discovered jaw fragments belonging to a rhinoceros-like animal at a new site in Turkey, which they dated to around 38 to 35 million years ago. The fossil is of an ungulate resembling the oldest Asian specimen discovered in Anatolia to date, and predates the Grande Coupure by at least 1.5 million years, suggesting that Asian mammals were ‘on their way to Europe through Balkanatolia.
This southern passage into Europe through Balkanatolia was perhaps more favorable for ‘adventurous animals’ than traversing higher latitude routes through central Asia, which at the time were drier and cooler desert steppes. However, they note in their article that “the past connectivity between the individual Balkanatolian islands and the existence of this southern dispersal route remains debated,” and that the history reconstructed so far “is only based on mammalian fossils and a picture The most complete of the past biodiversity of the Balkans remains to be drawn.
Many of the geological changes that gave rise to Balkanatolia remain to be fully understood, and it is important to note that this review is only one team’s interpretation of the fossil record. That said, the fossil record of mammals and other vertebrates living on the islands is often sparse and fragmented, while Balkanatolia’s rich terrestrial fossil record “provides a unique opportunity to document the evolution and demise of island biotas.” in deep time,” the team concludes.