In the photo: Traces of an unknown animal and their outlines.
The oldest four-legged footprints have been found in Poland - they are 397 million years old. They not only aged terrestrial vertebrates by 18 million years, but also made scientists wonder where these animals came from
About 397 million years ago, four-legged creatures 2.5 m long roamed the territory of modern Poland. Swedish and Polish scientists argue that these giants should be considered the most ancient terrestrial vertebrates.
Wonder Yudo whale fish
Unusual footprints were found between 2002 and 2007 in the southeast of the country in the abandoned Zachelmi quarry in the highlands. Having established the age of the prints, the employees of the University of Warsaw were amazed - the owners of the paws should have lived at least 18 million years earlier than the oldest tetrapods known to science at that time.
Most of the tracks are about 15 cm wide, some are 18 cm. "They clearly show where the hind legs are, where the front ones are," the researchers are amazed.
Due to a lack of information, a scientific name has not yet been assigned to the animal.
"The discovery of footprints at Zachelmi is changing the context for future research into the origins of tetrapods," said a team of scientists who published their findings in the journal Nature.
Unusual development
If Polish and Swedish experts were not mistaken with the dating and the fact that we are really talking about traces of a living creature, and not holes in rocks, it turns out that these large tetrapods lived before not only the fish-like Tiktaalik roseae, who lived 375 million years ago and was able to slightly raise the body above the ground, but also a much more primitive genus Elpistostegids, in which one of the first flippers and fins began to transform into limbs.
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The problem of coexistence of
fish with tetrapods is similar to the situation around dinosaurs and birds. It is incorrect to believe that dinosaurs turned into birds, because feathered and winged lizards coexisted for a long time with the first birds that appeared about 150 million years ago.
One of the leaders of the study, Per Ahlberg of Uppsala University, is confident that the Polish individual lived on the muddy seashore. This disproves the long-held belief that the first tetrapods emerged from rivers or diminishing bodies of water.
In addition to the fact that it is not clear where exactly the first land forces came from, scientists are racking their brains as to why they did it. Prior to the discovery at Zachelmi, paleontologists were inclined to believe that fish began to leave the water due to a decrease in the oxygen content in it. However, the owner of the fore and hind legs was walking on land long before the process of changing the composition of the water began, according to a press release on the website of the Swedish university. If we proceed from the version of predators, it is not clear what made the aquatic inhabitants at a certain point in the Devonian begin to fear for their offspring and go to an unknown land in search of a place for laying.
The work of scientists is complicated by the fact that next to the mysterious traces, neither the bones of this animal, nor the remains of any other animals or plants were found that could shed light on the life of the Devonian lagoon at the dawn of the appearance of tetrapods.
