The find comes from the Diadectidae family, a group of early amphibians closely related to amniotes—organisms that develop inside an amniotic sac, such as reptiles, birds and mammals.
Izabela Ploch, a geologist at the Warsaw-based Polish Geological Institute (PIG-PIB) and co-author of the study published in Biology Letters, said that the presence of horn-like scales on the amphibian's tail is a first in scientific records.
"Unlike modern amphibians, whose tails are typically bare, the diadectid's tail had rows of scales, akin to those seen in many reptiles," said Ploch.
"This suggests these creatures were well-adapted to live on land full-time as adults," she added.
The fossil was discovered during excavations at the Red Sandstone quarry near Nowa Ruda, in Poland's southwestern Lower Silesia region. The area, part of the intra-Sudetic basin, was a sedimentary basin during the early Permian period and fossil traces, including footprints and skin impressions, have been preserved in a layer of sandstone dating back to this era.
"These aren't just skeletal remains but also traces left by these creatures," Ploch remarked, describing the discovery as a result of successful collaboration with quarry workers and local government officials.
She also said that the imprints of the creature's limbs are the size of a human hand, and the detailed tail skin imprint lies next to a hind limb print, indicating the direction the animal was moving.
Ploch pointed out that the impermeable nature of the skin, a trait critical for amniotes' conquest of land, appears to have evolved earlier than previously thought.
"This property is provided by a continuous horny layer built from densely networked proteins," she explained. "Tracing the evolutionary development and timing of this trait is challenging, as skin impressions are extremely rare fossils."
This discovery not only contributes to understanding the evolutionary transition from aquatic to terrestrial life but also suggests that the diversification into fully terrestrial species may have occurred much earlier.
The study involved a collaborative effort from scientists across several institutions, including the University of Warsaw and the University of Wrocław in Poland, the Moravian Museum and Masaryk University in the Czech Republic, and the Geoskop Prehistoric World Museum and the Natural History Museum in Germany.
(rt/gs)
Source: naukawpolsce.pl