Data from: A classic key innovation constrains oral jaw functional diversification in fishes

Modifications to the pharyngeal jaws – a prey processing system located
posterior to the mouth cavity – are widely considered a key innovation
that enhanced diversification within several prominent fish clades. Seen
in cichlids, damselfishes, wrasses, and a few other lineages, these
musculoskeletal alterations are believed to increase the evolutionary
independence, and thus the diversification of the oral and pharyngeal jaw
systems. To test this classic hypothesis, we conducted comparative
phylogenetic analyses to assess the effect of the pharyngeal novelty on
the diversification of feeding morphology and kinematics across a
taxonomically diverse sample of spiny-rayed fishes. We quantified
movements of the oral jaws and other craniofacial structures from 689
suction feeding strikes using high speed videos collected from 228 species
with and without the pharyngeal jaw novelty. Contradicting long-held
predictions, we find significantly greater disparity across all traits and
faster rates of oral jaw functional evolution in fishes without the
specialized prey processing system. The modified pharyngeal jaw is
undoubtedly a functional innovation as it enhances the strength of the
prey processing system, facilitating exceptional transition rates to
feeding on hard and tough prey. However, it also restricts the
diversification of the feeding system, revealing that the impact of
pharyngognathy is more nuanced than previously thought. In light of these
and other recent findings, a reinterpretation of the macroevolutionary
consequences of the pharyngeal jaw novelty is needed.