IdiocetusIdiocetus is a genus of extinct cetaceans of the family Balaenidae.Discoverys belonging to this genus were first found in Piacenzian strata near Montopoli in [Val d'Arno], a town in Tuscany. The Italian paleontologist Giovanni Capellini described the whale in 1876 and attributed it to a new genus and species, establishing the type species Idiocetus guicciardinii. Some decades later, in 1926, other fossil remains possibly belonging to the genus were discovered from the Tortonian of Japan.