Data from: Clade-specific evolutionary diversification along ontogenetic major axes in avian limb skeleton

The evolutionary diversification of birds has been facilitated by
specializations for various locomotor modes, with which the proportion of
the limb skeleton is closely associated. However, recent studies have
identified phylogenetic signals in this system, suggesting the presence of
historical factors that have affected its evolutionary variability. In
this study, in order to explore potential roles of ontogenetic integration
in biasing the evolution in the avian limb skeleton, evolutionary
diversification patterns in six avian families (Anatidae, Procellariidae,
Ardeidae, Phalacrocoracidae, Laridae, and Alcidae) were examined and
compared to the postnatal ontogenetic trajectories in those taxa, based on
measurement of 2641 specimens and recently collected ontogenetic series,
supplemented by published data. Morphometric analyses of lengths of six
limb bones (humerus, ulna, carpometacarpus, femur, tibiotarsus, and
tarsometatarsus) demonstrated that: 1) ontogenetic trajectories are
diverse among families; 2) evolutionary diversification is significantly
anisotropic; and, most importantly, 3) major axes of evolutionary
diversification are correlated with clade-specific ontogenetic major axes
in the shape space. These results imply that the evolutionary variability
of the avian limbs has been biased along the clade-specific ontogenetic
trajectories. It may explain peculiar diversification patterns
characteristic to some avian groups, including the long-leggedness in
Ardeidae and tendency for flightlessness in Anatidae.