Data from: Multifaceted impacts of an innovation on dental diversity in an adaptive radiation of cichlid fishes

Evolutionary innovations bring species into new ecological zones by
opening ecological opportunity. However, innovations can have varied
effects on morphology, which is determined by both intrinsic properties of
the innovation and extrinsic properties of the adaptive zone. Here, we
show that the evolution of complex teeth with multiple cusps, a vertebrate
innovation, has mixed effects on the trajectory of dental evolution in an
adaptive radiation of cichlid fishes. Complex teeth first evolved outside
Lake Tanganyika and facilitated a secondary incursion of riverine lineages
into the lake through herbivorous niches. Complex dentitions are more
restricted and segregate along multiple axes of dental diversity. This
dental novelty generated by the evolution of complex teeth was likely
spurred by adaptive evolution pulling traits towards distinct optima. By
accelerating the diversification of tooth cusps, complex teeth unlocked a
new axis of dental diversity, leading to diversification within but not
between ecological niches. These patterns are likely driven by the
functional demands of herbivory. Our results show that innovations can
shape the tempo and mode of morphological change through both intrinsic
and extrinsic effects. Because the consequence of innovation is often
varied, our results highlight the need to jointly consider these effects
to better understand the macroevolutionary diversity of innovations and
their outcomes.