We describe the male courtship song of the newly-discovered species Drosophila santomea, endemic to the island of Saõ Tomé and the sister species of the widely distributed D. yakuba, which also inhabits the island. The song of D. santomea resembles that of D. yakuba in lacking a "sine" song, but the interpulse interval (IPI) in the "pulse" song is about 67 ms for the former species and 110 ms for the latter. This is the largest difference in IPI observed between any two sister species in the D. melanogaster subgroup, and may play a role in the strong sexual isolation between these two species.