The reptile-type creature, known as Diadectes, lived in what is now the Sudetes region, a mountain range that runs through what is today Poland, the Czech Republic and Germany.
The discovery is significant because it suggests that scales, which helped animals live on land, evolved earlier than previously thought.
“This is historically the first evidence of the occurrence of horny scales in amphibians closely related to amniotes [organisms in which fetal membranes appear during embryonic development],” said Dr. Izabela Ploch from the Department of Regional and Deposit Geology of the Polish Geological Institute.
“The tail of the Diadectes was not naked like in today’s amphibians but covered with rows of scales, such as those seen in many reptiles. It turns out that animals still resembling amphibians in terms of their skeleton were most likely very well adapted to functioning permanently out of water as adults,” Ploch said.
This “creates a wide field for new interpretations of their ecological role in the history of the Earth,” Ploch added.
She explained that water-impermeable skin is one of the key features that paved the way for the first amniotes to fully colonize land, enabling the future success of reptiles, birds, and mammals.
“This feature is provided by a continuous horny layer, made of densely cross-linked proteins. The evolutionary development and timing of this feature is very difficult to trace because skin impressions are extremely rare fossils,” Ploch said.
“Our important discovery suggests that the beginnings of vertebrates' complete independence from water may be much earlier than previously thought," the geologist added.
The footprints of an amphibian's paws and tail from almost 300 million years ago were found during work in the active Piaskowiec Czerwony quarry near Nowa Ruda in Lower Silesia, southern Poland.
The prints were preserved on the surface of a sandstone bed. They were found at the Intra-Sudetic Basin, located in the central part of the Sudetes, on the Polish-Czech Republic border.
