Scientists rediscovered a forgotten continent from 40 million years ago, and it may have served as a bridge allowing Asian mammals to inhabit southern Europe.
The newly-discovered land passage likely altered the course for countless ancient species, a press release reveals. Many Asian mammals will have thrived, while native species were stamped out of existence.
The continent, called "Balkanatolia", was located between Europe, Africa, and Asia, in a vast area now submerged under the Mediterranean Sea. The researchers behind the (re)discovery believe the continent might help to explain how the first wave of Asian mammals came to colonize south-eastern Europe.
Around 34 million years ago, at the end of the Eocene epoch, a mass extinction event known as the Grande Coupure occurred that saw large numbers of native mammals disappear from Western Europe and new Asian mammals take their place. In their study, published in Earth-Science Reviews, palaeogeologist Alexis Licht and colleagues from the French National Centre for Scientific Research say "when and how the first wave of Asian mammals made it to south-eastern Europe remains poorly understood." But they think "Balkanatolia" provides a possible explanation.
The researchers based their investigation on recent fossil findings in the Balkans that suggested the existence of a "peculiar" bioregion that may have enabled Asian mammals to colonize southeastern Europe as much as 10 million years before the Grande Coupure occurred.
After Licht and colleagues re-examined the evidence from all known fossil sites in the area of the Balkans findings, they found that Balkanatolia likely served as a stepping stone for animals to make the passage from Asia into western Europe. This was caused by a combination of falling sea levels, growing Antarctic ice sheets, and tectonic shifts whose effects connected Balkanatolia to the European mainland between 40 to 34 million years ago.
In its paper, the team of researchers does concede that "past connectivity between individual Balkanatolian islands and the existence of this southern dispersal route remain debated", and that the story "is only built on mammalian fossils and a more complete picture of past Balkanatolian biodiversity remains to be drawn". This is because the team is investigating incredibly wide-ranging geological events spanning millions of years, and they present a single team's interpretation of fossil records from a vast region. Still, the new study provides a unique window into a forgotten continent that may have caused a seismic shift that forever changed the animal kingdom.