The neglected continent that sheds gentle on the evolution of mammals — ScienceDaily

A crew of French, American and Turkish palaeontologists and geologists led by CNRS scientists1 has discovered the existence of a neglected continent they have dubbed Balkanatolia, which nowadays handles the present-day Balkans and Anatolia. Formerly inhabited by a extremely unique fauna, they believe that that it enabled mammals from Asia to colonise Europe 34 million yrs in the past. Their findings are published in the March 2022 quantity of Earth Science Reviews.

For thousands and thousands of many years for the duration of the Eocene Epoch (55 to 34 million many years ago), Western Europe and Eastern Asia shaped two unique land masses with pretty distinct mammalian faunas: European forests were household to endemic fauna these kinds of as Palaeotheres (an extinct team distantly related to existing-day horses, but a lot more like today’s tapirs), whereas Asia was populated by a more assorted fauna together with the mammal families found these days on both continents.

We know that, about 34 million several years in the past, Western Europe was colonised by Asian species, major to a main renewal of vertebrate fauna and the extinction of its endemic mammals, a unexpected event termed the ‘Grande Coupure’. Shockingly, fossils identified in the Balkans place to the presence of Asian mammals in southern Europe very long ahead of the Grande Coupure, suggesting earlier colonisation.

Now, a crew led by CNRS researchers has appear up with an clarification for this paradox. To do this, they reviewed previously palaeontological discoveries, some of which day back to the 19th century, from time to time reassessing their dating in the mild of present-day geological details. The evaluate exposed that, for a great deal of the Eocene, the location corresponding to the current-working day Balkans and Anatolia was household to a terrestrial fauna that was homogeneous, but distinctive from people of Europe and jap Asia. This exotic fauna involved, for case in point, marsupials of South American affinity and Embrithopoda (substantial herbivorous mammals resembling hippopotamuses) previously found in Africa. The location need to as a result have built up a single land mass, divided from the neighbouring continents.

The group also found out a new fossil deposit in Turkey (Büyükteflek) courting from 38 to 35 million several years ago, which yielded mammals whose affinity was clearly Asian, and are the earliest uncovered in Anatolia until eventually now. They located jaw fragments belonging to Brontotheres, animals resembling huge rhinoceroses that died out at the conclusion of the Eocene.

All this info enabled the staff to define the record of this 3rd Eurasian continent, wedged among Europe, Africa and Asia, which they dubbed Balkanatolia. The continent, already in existence 50 million a long time back2 and residence to a one of a kind fauna, was colonised 40 million yrs back by Asian mammals as a end result of geographical alterations that have nonetheless to be completely comprehended. It would seem most likely that a big glaciation 34 million a long time ago, major to the development of the Antarctic ice sheet and decreasing sea levels, linked Balkanatolia to Western Europe, offering rise to the ‘Grande Coupure’.

Notes

1 Functioning at the Centre for Investigation and Instructing in Environmental Geoscience (CNRS/Aix-Marseille Université/IRD/INRAE) and at the Centre for Investigate on Palaeontology — Paris (CNRS/Museum national d’Histoire naturelle/Sorbonne Université). A different French laboratory, Geosciences Rennes (CNRS/Université Rennes 1) also contributed to this study, alongside with Kütahya Dumlupınar and Eskişehir Osmangazi Universities (Turkey) and the universities of Washington, Connecticut, Kansas and Chicago (Usa).

2 Balkanatolia might be a relic of Higher Adria, an additional of the Mediterranean region’s ‘forgotten continents’, shaped above 200 million many years in the past, and brought to mild by reconstructions of the location of tectonic plates carried out by Douwe van Hinsbergen et al. and printed in a 2019 paper.

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