The discovery of an ancient platypus-like fossil could provide clues to the evolution of monotremes. This specimen is found in Argentina, not Australia, which presents an odd development.
Platypus-Like Fossil Changes History of Monotremes
This 70-million-year-old platypus lived in the ancient lake a long time ago. It was found in south America, far off from where these mammals are found, reported Live Science.
The Patagorhynchus pascuali is the oldest fossil of this ancient egg-laying mammal in that part of the world. It is a clue to how these odd early mammals evolved, including the Platypus and Short Beaked Echidna and others found in Australia and near islands.
The supercontinent Gondwana existed millions of years ago when it was formed from Australia, South America, and Antarctica, which included sections of Asia and Africa then. Next came the landmass beginning to break up 180 million years ago in the Jurassic period, about 66 million years, and it broke off at the end of the Cretaceous period, noted Yahoo.
More discoveries of ancestors of egg-laying mammals in places located in South America has scientist getting their guess about how it happened. One is that they were already down under but passed a land bridge to reach South America, but finding the Argentinian platypus does make a puzzle.
One of these implies that egg-laying mammals are more widespread than assumed because of getting found in some sections of southern Gondwana, said study co-author Fernando Novas. He is a paleontologist from Bernardino Rivadavia Natural Science Museum, Argentina, in Buenos Aires, according to Research Gate.
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Present-Day Platypus Similar to Discovered Fossil
It was examined according to the journal Communications Biology last February 16, identified by a fragment of the lower jaw with a molar tooth. Robin Beck said a molar gives a lot of clues to the development. Beck is an evolutionary biologist not involved in giving his take on the evidence.
He adds that a modern platypus has no teeth though its extinct relative Obdurodon (30 million years old) had teeth in its jaws. P. pascuali molar was the same as it, even with teeth which a modern baby platypus has in the start.
Sources say that P. pascuali, with its teeth and environment, would not have a different diet consisting of small aquatic invertebrates and larvae of insects and snails. The fossil found in Argentina does support these conclusions based on where it was seen. Sediment around it had these organisms in it with some interesting extras too.
More ancient remains were identified as early mammals, turtles, frogs, snakes, water plants, and dinosaurs with the specimen. This find shows a link to the past of egg-laying mammals and their evolutionary path due to gaps in the fossil record that present a divide yet to be understood.
Not finding these fossils in Antarctica with how close it used to be to Australia and South America, there might be ancient platypuses under the tundra. Nova stated that the Australian Ornithorhynchus may have descended from an Argentinian grandfather.
Finding Platypus-like fossils in the cretaceous changes, the history of monotremes not only down under but adds more questions.
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