Pitar (Hysteroconcha) dione, or the elegant Venus clam, formerly known as Venus dione, is a species of bivalve mollusc in the family Veneridae, the Venus clams. The shell is whitish pink, with a row of long curved spines on each valve. The species was named in Systema Naturae in 1758 by the Swedish naturalist Linnaeus. Both there and in his 1771 Fundamenta Testaceologiae, he described the shell in "disquieting[ly]" sexual terms.