Physa mezzalirai is an extinct fossil species of air-breathing freshwater snail, an aquatic pulmonate gastropod mollusc belonging to the family Physidae. This species is characterized by its small sinistral (left-handed) shell, a common feature in this family. Physa mezzalirai dates back to the Turonian to Santonian-aged Adamantina Formation (Upper Cretaceous Bauru Group), in São Paulo state, Brazil.