The remains of a crocodile in the “Bełchatów” mine. Unusual discovery

The discoveries that were described in the magazine “Acta Palaeontologica Polonica” were made by scientists from the Faculty of Geology and the Faculty of Biology at the University of Warsaw, the Institute of Paleobiology of the Polish Academy of Sciences and the Polish Academy of Sciences Museum of the Earth and the Moravian Earth Museum (Czech Republic). They found the remains in the lake deposits of the fields of “Szczerców” in the “Bełchatów” brown coal mine. – We were looking for vertebrates and it was the only fragment that we were able to find then. At first he resembled a regular piece of bones. It was only when we stretched him out and watched his other, very characteristic side that there was no doubt that this was a crocodile skin tile, or osteoderm – said the co -captivator, Dr. Marcin Górka from the Faculty of Geology of the University of Warsaw.

Source analysis showed that the northernmost remains of a crocodile from the period of 23 million years. At that time – from Miocene to the Quaternary – there was no crocodile position on north. Older, because chalk crocodiles are known from Sweden. The remains found in the “Bełchatów” mine come from the Miocene era (23 million to 5.3 million years ago), the last really warm and moist in the history of the Earth. – Because the climate was about 3-4 degrees warmer than today, at least it is estimated, therefore the humidity was greater. This meant that all vegetation developed very lush under these conditions, from the remains of which brown coal deposits were formed. The climate also favored the occurrence of various species of sea and land animals. The remains of the latter are particularly in large numbers in karst and lake sediments – described the researcher. Miocene was also characterized by significant tectonic activity marked mainly in southern and central Poland. In many places there were tectonic sinkholes, often filled with water. – Tanks created in this way, lakes, swamps were conducive to the development of vegetation, but it was also a kind of trap for all plant and animal matter that fell into them, and which we can discover today – said Górka.

Among animals, crocodiles deserve special attention – typical for subtropical and tropical areas. In early and central Miocene, Central Europe was a habitat of two different types of crocodiles: Gavialosuchus and Diplocinodon. The first one was a sea type, and its total body length exceeded six meters. The second was an endemic type, usually freshwater, and reached 1.5 to three meters. – The tile we find does not have 100 % features that could indicate which type we are dealing with. However, it was probably extinct already Diplocinodon – A relative of modern alligators. We think so, because, like modern alligators, he had more tolerance to the cold, i.e. it could occur more north – explained the researcher.

Finding a tiny, because measuring about 30 millimeters, a fragment on such a spacious excavation was not easy.

– It's almost like mushrooming. So what if someone walks in the woods, if there is no luck? So you have to be lucky. But you also need to know what you are looking for so as not to throw yourself at everything; That this eye would be a bit sensitive – he admitted. He added that work in the mine requires high mindfulness.

– Visits to the mine are always associated with the threat. We are aware that we are a burden for employees and management. They have to take care of our safety, and at the same time we take them away from their duties. So we are extremely grateful for enabling us this work – emphasized the geologist from the University of Warsaw.

The work published by the Polish-Czech team of researchers presents several previous finds of remains of crocodile from the Czech Republic and Poland. The material described also includes the archival find of a crocodile tooth from platelet sea deposits from Pińczów. This tooth was discovered by prof. Andrzej Radwański in the 1960s-70s. 20th century. Another of the remains presented is a tooth from the Czech Židlochovic, about 14 million years ago. It comes from the collection of prof. Anton Rzehak, but he was never mentioned in any of his work, despite the fact that on a hand -made label the researcher correctly identified him as a crocodile tooth …