Fossil taxon means and standard errors for body mass, distal segment lengths, elongation ratios, and residuals.

1Behavior codes based on the literature (see methods): Abbreviations: VCL, vertical clinging & leaping; L, specialized/frequent leaper and/or grasp-leaper; AQ, arboreal quadruped with unspecialized/infrequent leaping; SC, slow climber (virtually no leaping); T, terrestrial; SUS, suspensory; NA, not applicable (extinct taxon). SC/T/SUS, taxon is characterized by one or more of the three indicated categories.2Natural log of body mass (BM) estimated from cuboid facet size using the following equation: ln[BM] = 1.3274*ln[CW*CD]+3.0238 (see Table S1 in File S1 for data).3Natural log of the ratio of calcaneal distal length (DL) to calcaneal total length (TL).4Res, Residual Elongation from lines calculated in caper using “All Euprimates” with n = 100 species (average from trees 1–4) (Fig. 8)]. Res A: ln[DL/TL] = −0.068(SE ±0.011)*ln[BM]+ −0.39(SE ±0.08); Res B (based on regression of absolute distal calcaneal length versus body mass): ln[DL] = 0.25(SE ±0.022)*ln[BM]+0.36(SE ±0.17).Other abbreviations: est, estimate; ln, natural logarithm; n, sample size; SE = standard error.