The islands were key laboratories for the advancement of evolutionary theory from the pioneering work of Charles Darwin and Alfred Russell Wallace in the 19th century.
Now there is a new paper PLOS ONE from an international group of investigators describes two new fossil relatives of handbags that reveal how a unique island ecosystem developed in ecocene about 43 million years ago.
"Development in many respects is easier to study in an island context than on a large continent such as North America because it is a simpler ecosystem," said co-author K. Christopher Beard, a professor of ecology and evolutionary biology at the University of Kansas curator with the Institute for Biotechnology diversity of the KU and the Museum of Natural Sciences. "Evolutionary biologists have focused on the islands since Darwin and Wallace independently formulated their ideas of evolution based on their observations of plants and animals living on the Galapagos Islands and the Malay Archipelago, which is modern Indonesia."
Beard, however, said that the bad nerves of animals living on islands through a "deep period of time" or over a milliolet-year period hindered our understanding of exactly how island ecosystems are. The new document describes two new fossil species that have been identified from their teeth, which settled the Pontide region of modern north-central Turkey.
During the eocene period, the Pontide Island is a larger version of the modern Mediterranean sea called Tethys. At that time, Africa and Eurasia were not connected, as they are today in the Middle East, but Africa, due to the tectonic plutonium, swam towards the north and eventually slid several times with Eurasia. The Pontide area was bounced between these convergent continents. Because of this geological situation, the Pontida region is similar to the island of Sulawesi in the Indonesian archipelago, which is similarly sown between the convergent continents of Asia and Australia.
"No other ecosystem on the face of the planet from any period of time matches what we found in Turkey's eocene – it's a completely unique mammal ecosystem, similar to Madagascar today," he said. "But how this island has evolved over time? You will need fossils and time depths to see this. Here we can study in detail how this old island developed – from where different animals came, how they came in, and when they are when they arrived there, some of these mammals, including one of the new pieces of pieces that we discovered, could diversify on the island. It seems that most of the Eocene mammals on the island of Pontida came there by swimming or rafting in split the sea in Tethys, instead of piercing the island when he separated himself from the neighboring parts of Eurasia. "
Beard's researchers were Grégoire Métais from National d 'Histoire naturelle in Paris, John R. Kappelman from the University of Texas, Alexis Licht of the University of Washington, Faruk Ocakoglu from Eskis University? Ehir Osmangazi in Turkey, and KU Pauline MC Coster and Michael H. Taylor.
In Pontide marsupial fossils – which do not have living offspring – the team found evidence that the typical forms of life that develop on islands are generally at risk if they have enough time.
"One thing we definitely know is that the incredibly interesting and unique ezic biota that happened on this island in today's Turkey is completely eliminated," Beard said. "When the island was re-affiliated with continental Europe, it was eradicated and more physiological animals could have accessed it for the first time, driving the strange sharpness of biota to extinction. A message for conservation biology today is that island ecosystems by nature the unique conservation biologists today are concerned about the many threatened taxa on the islands. The ugly truth that paleontology guarantees is that most of the island's favors are condemned to extinction in due course. They are the developmental dimension of evolution – although they are wonderful places to study processes evolution. "
Brada said that the newly-described fossil basket – Galatiadelphys minor in Orhaniyeia nauta – lived near the top of the food chain at Ponta eocene, because mammals were unable to reach a small island.
"One of the strangest things about Pontida's island fauna is that there are no real carnivorous mammals," he said. "There was nothing to do with cats, dogs, bears or suburbs – without the modern mammals mammals. They could not get to the Pontide terrain because it was an island. So, these riders are ecologically occupying their place on the top of the food chain."
According to the KU researcher, newly discovered fossils proved that the geological context has a major impact on how ecosystems are made on any island.
"The current ideas on the evolution of the island are based on some rather simplified but rather effective models," Beard said. "These models suggest that colonies are colonized by the islands based on two main factors – how large is the island and how far from the nearby landlocked islands? The larger island makes a greater goal and hosts a greater diversity of habitats, facilitating colonizing the island, and when they get there, they have better livelihoods and perhaps even diversification. "
According to the findings of his Pontida team, Beard said that the geological context is at least as important as the size of the island or the distance from the original territory of colonizing animals.
"All men may have been created the same, but not all islands. The geological context of the island – here in the area of active tectonic convergence – we think that these other factors, the size and the distance to the continent are overwhelmed," he said. "The most strange thing about the Pontida mammals is that it contains a unique blend of animals coming from Europe, Africa and Asia. Also, our two new baskets show different evolutionary roots in the north and south, as they were planted between Eurasia and Africa, animals but they come from a number of directions. It is interesting to compare with the modern island of Sulawesi in Indonesia, which, like Pontide terrain, is also a mixed animal. It mainly hosts animals, such as tarseras that are clearly associated with Asian species, but you also have on the Sulawesi species that are clearly associated with mammals from New Guinea. If today you look at the tectonic plates, Sulawesi is simplified between Australia and Asia in a similar way to Pontide because he was in Egocene between Africa and Asia. "
Brada recently returned from Turkey, where she and her team carried out several field activities. This research was funded from several sources, including large donations from the US National Science Foundation.