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Separately, a peculiar trace found in Australia’s 356 million years of rock panels indicates that reptile relatives appeared from 35 to 40 million years earlier than they thought before.
The tracks also push the origin of Amniots, the groups that cover reptiles, birds and mammals, and provide new evidence of how animals have passed from existing at sea only on land.
Amniots are an essential part of the transition from water to land life because they were the only tetrapodes or four ends of creatures that developed on land.
Previously, the oldest body fossils and traces associated with amniotics were dated to 318 million years in Canada.
However, new conclusions published on 14 May. In Nature magazine, it is challenging such long -term assumptions and signaling that the redevelopment of tetrapods living in the water on Earth is probably much faster than scientists thought.
“I’m stunned,” said Erik Ahlberg, a professor of evolution and development biology at Uppsala University. “One track with a plate that one person can lift, question everything we thought, what we knew, when modern tetrapods developed.”
The discovery point indicates that Australia, once a central ancient southern supercontinent in Gondwana, which also included today’s Africa, South America, Arabia, Madagascar, Antarctica and India, can be an ideal place to look for more amniotics and reptile fossils-and where they originated.
The research team compared tracks to many animals, including a modern Iguana foot. – Traci clarenbeek
Rewriting of evolutionary history
The rock plate found by amateur paleontologists and researched co -author Craig Ei and John Eason in the Snowy Plains formation in Victoria, Australia, seem to show two sets of the same animal, which reflect the earliest traces they have ever discovered.
The shape of the feet is similar to a modern water monitor and, although the exact size of the animal is unknown, it may have been similar to a small Goann -like being, about 80 centimeters (31 inch), said John Long, the main author of study, strategic professor at Paleontology at Flinders University. Asian water monitors are large lizards from Southeast and Southeast Asia, and Goannos are large lizards, mostly found in Australia.
The nail, the main feature of the reptiles, could give the primitive tetrapod dig and climb into the trees.
Researchers analyzed the sets of the tracks on the stone to determine what animal they were made. – Long and others
Ahlberg said the animal that made traces is the oldest known reptile and the oldest known amniot. And it helps scientists break the code, how tetrapods develop.
“Our new find means that the two main evolutionary lines leading to modern tetrapodes – one, the line to modern amphibians and two – a line leading to reptiles, mammals and birds – were different from each other much earlier than before, probably in the Devon period about 380 million years ago.”
Until this conclusion, the Devon period was believed to be the time of primitive fish -like tetrapods and “fishpodes” such as the Tyliniik, which contained the features of fish and early tetrapods, and began to explore the shoreline in limited ways.
However, the new study reveals the variety of large and small tetrapods, some water and others mostly or completely land, most likely lived at the same time.
“One of the consequences of our research is that Tetrapod’s diversity was currently greater and has covered more advanced forms than was thought,” Ahlberg wrote in an email.
It is very important to understand when life has moved from completely water to land as it is one of the greatest steps in the evolution of life, Long said. This transition has shown that the animals were no longer dependent on or near life water.
Dr. Aaron Cameens, Dr. John Long and Dr. Alice Clement analyzes a copy of the fossil tracks near the reptile model. – Traci clarenbeek
The transition was partly due to the evidence of the amniotics to reproduction with hard, not soft eggs.
“The movement of vertebrates to dryness was an important part, and the most important step was the evolution of amniotic egg in the nearest normal ancestors of reptiles and mammals,” Ahlberg said. “So these events form the main episode in our ancestors and the history of the planet.”
The new study promotes the origin of amniotics much deeper into the carbon period, 299 million years ago. Up to $ 359 million The Sumida, which wrote an attached article to run with the study, did not participate in new research.
Search for Amniote Origins
Long investigated ancient fish fossils from the Mansfield district, where the plate was found, since 1980.
“The Mansfield area produced many famous fossils, starting with spectacular fossil fish found 120 years ago, and ancient sharks. But the holy Grail we’ve always searched for was evidence of terrestrial animals or tetrapods, as well as early amphibians. He.
Researchers are looking for fossils along the broken river near Mansfield. – John Long
The fossils of Mansfield district explained how the sexual organs could first develop in ancient armored fish.
Now the researchers want to know who else lived in Gondwana along with the ancient reptile they found.
The findings led to investigators to expand the search for the earliest amniotic fossils and their relatives on the southern continents, Sumida said.
“Most of the earliest amniotic discovery are known from the continents derived from the northern components of Pangea,” The letter stated in Sumida. “There, the discoveries suggested that Amnote Origins could be in those regions. Now it seems clear to me that we now have to expand our early carbon dioxide searches in areas of Australia, South America and Africa. “
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