During research on the area in 2015, the senior archaeologist Luca Natali made a startling discovery on the cliffs above Due Sorelle Beach: namely, a series of 11 impressions of about 8-15 cm in length and 15-25 cm in width were discovered.

Following subsequent studies performed together with a research team from the University of Camerino, it was agreed that such ichnofossils were imprinted about 110 million years ago by the fore-paddles of a Lower Cretaceous unidentified marine tetrapod.

Thanks to this finding of exceptional value, Monte Conero has become one of the three worldwide sites featuring emerged ichnofossils of a marine reptile.

The author of the footprints was named “Siro” in honor of Sirolo – and soon became its mascot.