Glossary of "Evolution (4th ed.)" by Futuyma & Kirkpatrick (2017)
- The evolution of a character from a derived state back toward a condition that resembles an earlier state.
Glossary of "Life (9th ed.)" by Sadava et al. (2011)
- The reappearance of an ancestral trait in a group that had previously acquired a derived trait.
- Futuyma, D. J. & Kirkpatrick, M. 2017. Evolution, 4th ed. -xviii + 602 pp. Sinauer Associates, Inc., Sunderland.
- Sadava, D., Hillis, D. M., Heller, H. C. & Berenbaum, M. R. 2011. Life: The Science of Biology, 9th ed. -xliv + 1266 pp. Sinauer Associates, Inc., Sunderland.