Radiolarians

Recent studies by the Museo cantonale di storia naturale, Lugano, have focused on even the tiniest organisms that formed marine plankton, especially radiolarians (unicellular protozoans with siliceous shells a few tenths of a millimetre long), because they are excellent index fossils that can be used for precisely dating the age of the rocks.

The investigations have so far recorded 73 species and led to the discovery of 7 new species assigned to the genera Sepsagon, Novamuria, Eptingium, Parentactinosphaera and Pessagnollum. The new discoveries allow us to understand the evolution of these organisms in a period of time that was crucial for their differentiation and which is well documented at Monte San Giorgio.

Sespsagon ticinensis, San Giorgio Dolomite, 0.3 mm, © MCSN, photo R. Stockar