Unraveling the heritage of lost traits

We synthesize ontogenetic work spanning the past century that show evolutionarily lost structures are rarely entirely absent from earlier developmental stages. We discuss morphological and genetic insights from developmental studies reveal about the evolution of trait loss and regain. Credits: Mo Hassan ‐ golden mole; Chris Huh ‐ whale; C. Camilo Julián‐Caballero ‐ beetle; http://creativecommons.org/licenses/by/3.0/ Research highlights By revisiting old and more recent studies, we discuss how trait loss connect ontogeny and phylogeny and enhance our understanding of evolutionary developmental biology.