In Miedary, near Tarnowskie Góry (Upper Silesia), a team of scientists from the Faculty of Biology at the University of Warsaw (UW) and the Institute of Paleobiology of the Polish Academy of Sciences (PAN) made an exceptional discovery. Researchers came across layers containing an unusually large number of animal bones dating back around 240 million years.

“We are conducting excavation work on the site of an abandoned brickyard. The red and green mudstone layers we are exploring are dated to the Middle Triassic. This is a particularly significant moment in the history of life on Earth, as many animal groups, such as mammals, reptiles, and dinosaurs, emerged during this time,” said Dr. Łukasz Czepiński from the Institute of Paleobiology of the Polish Academy of Sciences, a co-author of the study.

“In Miedary, this pivotal moment in the prehistory of our planet is recorded,” he continued.

An article on the results of the work in Miedary was published in the Journal of Vertebrate Paleontology.

The Silesian discovery is an “event on a global scale,” according to Dr. Czepiński. He explains that Middle Triassic sites are very rare, and the nearest places with fossils of a similar age are hundreds of kilometers away from Miedary.

Triassic world

During the Middle Triassic period, Earth looked completely different than it does today. All the continents were connected into one supercontinent, Pangaea. In its eastern part, the Tethys Ocean formed a massive bay. The area being explored by researchers in Miedary was located in its southern part. In this extensive lowland, the sea would flow in and out several times in cycles lasting thousands of years.

“The animals we find in Miedary are buried in sediments of marine origin,” clarifies Wojciech Pawlak from the Faculty of Biology at the University of Warsaw, one of the authors of the publication.

Among the organisms whose remains were discovered in Silesia are four species of small sharks. Researchers also found fossils of bony fish in the mudstones. At the site, they identified the presence of bones resembling a crocodile-like amphibian called Mastodonsaurus, measuring 6 meters in length, as well as the fish-eating reptile Tanystropheus, of similar size, with an exceptionally long neck consisting of 13 vertebrae. Its remains are accumulated in Miedary in an amount unprecedented anywhere else in the world.

“Based on the species composition of this assemblage, it seems to us that we are dealing with a very special environment, rarely identified in the fossil record. The bay did not have salinity typical of either freshwater bodies or salty ones,” explains Wojciech Pawlak.

In total, scientists from the UW and PAN discovered the fossils of 24 species of fish, amphibians, and reptiles. One of the most valuable findings from Miedary is the bones of a mysterious, armored relative of dinosaurs and crocodiles.

“We are still collecting fossils of this animal; many indications suggest that these are scattered bones of one individual. We hope that in the coming years, we will find more specific remains, such as the skull. However, we already know that this is a new type of reptile, the presence of which has not been confirmed anywhere else in the world,” says Dr. Czepiński.