DOI: 10.5061/dryad.k492m37
title: Data from: Quantifying shape and ecology in avian pedal claws: the relationship between the bony core and keratinous sheath

description: Terrestrial tetrapods use their claws to interact with their environments
 in a plethora of ways. Birds in particular have developed a diversity of
 claw shapes since they are often not bound to terrestrial locomotion and
 have heterogeneous body masses ranging several orders of magnitude.
 Numerous previous studies have hypothesized a connection between pedal
 claw shape and ecological mode in birds, yet have generated conflicting
 results, spanning from clear ecological groupings based on claw shape to a
 complete overlap of ecological modes. The majority of these studies have
 relied on traditional morphometric arc measurements of keratinous sheaths
 and have variably accounted for likely confounding factors such as body
 mass and phylogenetic relatedness. To better address the hypothesized
 relationship between ecology and claw shape in birds, we collected 580
 radiographs allowing visualization of the bony core and keratinous sheath
 shape in 21 avian orders. Geometric morphometrics was used to quantify
 bony core and keratinous sheath shape and was compared to results using
 traditional arc measurements. Neither approach significantly separates
 bird claws into coarse ecological categories after integrating body size
 and phylogenetic relatedness; however, some separation between ecological
 groups is evident and we find a gradual shift from the claw shape of
 ground-dwelling birds to those of predatory birds. Further, the bony claw
 core and keratinous sheath are significantly correlated, and the degree of
 functional integration does not differ across ecological groups.
 Therefore, it is likely possible to compare fossil bony cores with extant
 keratinous sheaths after applying corrections. Finally, traditional
 metrics and geometric morphometric shape are significantly, yet loosely
 correlated. Based on these results, future workers are encouraged to use
 geometric morphometric approaches to study claw geometry and account for
 confounding factors such as body size, phylogeny, and individual variation
 prior to predicting ecology in fossil taxa.
description: Supplemental Tables
 1-4Supplemental Table 1:
 Statistical results for traditional morphometric analyses. Mean, standard
 deviation, and confidence intervals for intraspecific analyses. PGLS of
 log-transformed keratinous sheath arc and log-transformed bony core arc.
 Phylogenetic ANOVAs for traditional morphometrics. T-test comparing bony
 core and keratinous sheath log-transformed arc measurements. Supplemental
 Table 2: Specimen number, species name, family, traditional morphometric
 metrics, and the first 10 PC scores for geometric morphometric data for
 all 580 individuals. Supplemental Table 3: Statistical results for
 geometric morphometric analyses. Tests for allometry and phylogenetic
 signal. Claw shape by group including centroid size as a covariate and
 pairwise comparisons among ecological groups. Disparity, functional
 integration, and modularity analyses. Supplemental Table 4: Specimen
 number, species name, family, centroid size mean, traditional morphometric
 metrics, and the first 10 PC scores for geometric morphometric data for
 species means (n = 145).SupplementalTables
 Revised.xlsxFigure
 S1Figure S1. Tree based on
 Jetz et al. (2012) showing the phylogenetic relationships between the 145
 taxa used in the study. Tips are colored by locomotor mode, showing
 numerous convergences in mode across taxa studied. Blue = predatory, red =
 flying, yellow = ground.FigS1-BirdClawTree.tifTable S2Figure S2. Individual level two-block partial least squares analysis of the bony core landmark configuration and the keratinous sheath landmark configuration using geometric morphometrics. TPS grids show differences in shape along each shape block. Blue = predatory, red = flying, yellow = ground.FigS2-IndividualsIntegration.tifClawJPGs580 radiographs of bird claws. See supplemental tables (Table S2) for additional information.