Why some taxa are more species-rich than others still represents a major conundrum in biology. Ecological opportunities and evolutionary innovations are considered main factors that drive biodiversity, but are sometimes insufficient to explain current patterns of species richness.
In their viewpoint article, Melzer and Theißen argue that developmental robustness might be an underappreciated factor promoting biodiversity. They hypothesize that only the robust integration of evolutionary innovations enables organisms to seize new ecological opportunities, which may in turn foster the origin of new innovations. Developmental robustness may thus be an important factor for an increase in morphological complexity and biodiversity.