The record of the fossil representatives of the family Juliidae is updated. The new genus Candinia is proposed, in the subfamily Juliinae, for two fossil species somewhat intermediate between Julia and Berthelinia. The new species Candinia pliocaenica is recorded from the lower Pliocene shallow marine deposits near Siena (Tuscany, Italy). This is the first record of Sacoglossa in the Mediterranean Basin. Based on the very specialized life habits of the Juliidae, it is suggested that subtropical Caulerpa algal prairies inhabited the Mediterranean during the early Pliocene, likely becoming extinct in this basin because of the mid-Pliocene climatic deterioration.