The oldest traces of amphibians and reptiles in what is now Lombardy go back to the end of the Palaeozoic when Permian taxa (290-250 million years ago) left tracks in muds that are now transformed in stones. The extraordinary wealth and diversity of Mesozoic remains found in the Alpine area in Lombardy is such that this area has been the source of most of the information we have on marine vertebrates from the mid- Triassic (about 240-230 million years ago). Over the last two centuries, palaeontologists have discovered abundant remains of both marine and terrestrial reptiles in the Mesozoic fossil deposits.
In contrast, fossils of contemporary amphibian and reptile species and their direct ancestors are scarce in Lombardy. This is probably because there are few Cainozoic deposits in Lombardy, especially from the Neogene and the Quaternary (approximately the last 23 million years). In this period, the area presently corresponding to the Po Plain was for a long time occupied by a sea of varying depth which only in the mid-late Pleistocene, gave way to environments suitable for terrestrial vertebrates. There are only 12 deposits in Lombardy containing fossils of contemporary reptiles and amphibians; and the entire Neogene-Quaternary record consists of 15 taxon/locality data, less than 2% of the records in Italy for this period. Nearly all the data testify the presence of Emys orbicularis.