The discovery of new fossil remains in the Bergamo Alps, belonging to Macroplacus raeticusa marine reptile that lived about 200 million years ago. This species, until now, was known only through fossils found in the Bavarian Alps.
The fossil was found by Pio Carlo Brizzi in 2010 in the locality of Oschiolo, in the municipality of Gazzaniga in the province of Bergamo, but has only recently been studied by Stefania Nosotti and Simone Maganuco (Natural History Museum of Milan) and Federico Confortini (Civic Museum of Natural Sciences “Enrico Caffi” of Bergamo). It is a skull approximately 6.3 cm long and 6.1 cm wide, found in a geological formation of the Rhaetian chronostratigraphic plane, the last into which the Upper Triassic is divided, which dates back to between 206 and 199 million years ago. It owes its name to the Rhaetian Alps, between Switzerland, Austria and Italy.
The fossil skull has been attributed to Macroplacus raeticusa turtle-like marine reptile. The attribution was made on the basis of a comparison with the holotype (the model of a biological description) of this species, found in Germany. Macroplacus raeticus it belonged to the order Placodonts, a subdivision of the superorder Sauropterygii. The most famous exponent of this superorder is certainly the Plesiosaur, quite well known in popular culture. Unlike the Plesiosaur, however, the Placodonts did not have a long neck, but were more morphologically similar to turtles: stocky and with strong flattened teeth for splitting the molluscs they fed on.
The skull of Macroplacus raeticus found in the province of Bergamo, it was subjected to a computerized tomography, which made it possible to compare its features with those of the German holotype. In this way it was possible to establish that it was the same species, although at different times of growth: the holotype is twice as large as the Bergamo fossil. Morphologically it is therefore the same species, but the specimen found in Gazzaniga was smaller.
This discovery allows us to improve our knowledge about Triassic marine wrecks and the internal evolution of Placodonts, as well as increasing the number of prehistoric fossils present in Italy.
