Sample of several 3D reconstruction of macronarian hind limbs used in this study. (a) Oceanotitan dantasi; (b) Ligabuesarusu leanzai; (c) Lohuecotitan pandafilandi; (d) Saltasaurus loricatus. All taxa in anterior and posterior views.

Specimen sample used in this study. Proximodistal hind limb length measured in mm.

PCA results over GPA aligned coordinates. Variance explained by each shape PC.

Kruskal-Wallis test on shape PCA variables between the most inclusive subclades analysed.

Phylogenetic ANOVA test on shape PCA variables between the most inclusive subclades studied.

RMA models of the shape PCs against log-transformed Centroid size. CI – confidence interval.

PCA results on the GPA aligned landmark and semilandmark curves of the hind limb. (a) PC1-PC2 biplot. (b) PC1-PC2 phylomorphospace with projected phylogenetic tree. (c) Representation of the shape change along PC1, blue are negative scores, red are positive scores. Percentage of variance of each PC in brackets under corresponding axis. Ae – Aeolosaurus, Amp – Ampelosaurus, An – Antarctosaurus, Bo – Bonatitan, Bon – Bonitasaura, Dre – Dreadnoughuts, Eu – Euhelopus, Ja – Jainosaurus, Li – Lirainosaurus, Lig – Ligabuesaurus, Lo – Lohuecotitan, Ma – Magyarosaurus, Me – Mendozasaurus, Mu – Muyelensaurus, Ne – Neuquensaurus, Sa – Saltasaurus.

PCA results for the GPA aligned landmark and semilandmark curves of the hind limbs. (a) PC2-PC3 biplot. (b) PC2-PC3 phylomorphospace with projected phylogenetic tree. (c) Representation of the shape change along PC2, blue are negative scores, red are positive scores. Percentage of variance of each PC in brackets under corresponding axis. Ae – Aeolosaurus, Amp – Ampelosaurus, An – Antarctosaurus, Bo – Bonatitan, Bon – Bonitasaura, Dre – Dreadnoughuts, Eu – Euhelopus, Ja – Jainosaurus, Li – Lirainosaurus, Lig – Ligabuesaurus, Lo – Lohuecotitan, Ma – Magyarosaurus, Me – Mendozasaurus, Mu – Muyelensaurus, Ne – Neuquensaurus, Sa – Saltasaurus.

PCA results for the GPA aligned landmark and semilandmark curves of the hind limbs. (a) PC1-PC3 biplot. (b) PC1-PC3 phylomorphospace with projected phylogenetic tree. (c) Representation of the shape change along PC3, blue are negative scores, red are positive scores. Percentage of variance of each PC in brackets under corresponding axis. Ae – Aeolosaurus, Amp – Ampelosaurus, An – Antarctosaurus, Bo – Bonatitan, Bon – Bonitasaura, Dre – Dreadnoughuts, Eu – Euhelopus, Ja – Jainosaurus, Li – Lirainosaurus, Lig – Ligabuesaurus, Lo – Lohuecotitan, Ma – Magyarosaurus, Me – Mendozasaurus, Mu – Muyelensaurus, Ne – Neuquensaurus, Sa – Saltasaurus.

Time calibrated supertree with PC1-PC2 results and hind limb centroid size for each sauropod.

RMA results of the first three shape PCs against the logarithm of the hind limb centroid size. (a) PC1 against log-Centroid size, all taxa RMA in dark red: intercept = 0.221, slope = −0.102, r2 = 0.105, p = 0.204; Titanosauria only partial RMA in dashed green: intercept = 0.203, slope = −0.092, r2 = 0.118, p = 0.229; Lithostrotia only partial RMA in dotted orange: intercept = 0.246, slope = −0.120, r2 = 0.319, p = 0.07; (b) PC2 against log-Centroid size, all taxa RMA in dark red: intercept = 0.155, slope = −0.072, r2 = 0.054, p = 0.371; Titanosauria only partial RMA in dashed green: intercept = 0.158, slope = −0.075, r2 = 0.117, p = 0.232; Lithostrotia only partial RMA in dotted orange: intercept = −0.127, slope = 0.066, r2 = 0, p = 0.952; (c) PC3 against log-Centroid size (Csize), all taxa RMA in dark red: intercept = 0.137, slope = −0.064, r2 = 0.055, p = 0.363; Titanosauria only partial RMA in dashed green: intercept = 0.110, slope = −0.055, r2 = 0.236, p = 0.078; Lithostrotia only partial RMA in dotted orange: intercept = 0.140, slope = −0.073, r2 = 0.313, p = 0.074. Ae – Aeolosaurus, Amp – Ampelosaurus, An – Antarctosaurus, Bo – Bonatitan, Bon – Bonitasaura, Dre – Dreadnoughuts, Eu – Euhelopus, Ja – Jainosaurus, Li – Lirainosaurus, Lig – Ligabuesaurus, Lo – Lohuecotitan, Ma – Magyarosaurus, Me – Mendozasaurus, Mu – Muyelensaurus, Ne – Neuquensaurus, Sa – Saltasaurus.

Estimated phylogenetic signal via Pagel’s lambda. p value of log-likelihood ratio test after 1000 simulations. * Indicates significant relationships for an alpha of 0.05. log-Csize – Log-transformed hind limb centroid size.

Evolution of log-transformed hind limb centroid size, shape PC1 and PC3 according to our sample and time-calibrated supertree topology. Ba – Barremian, Be – Berriasian, Ce – Cenomanian, Co – Conacian, H – Hauterivian, J – Jurassic, Late-K – Late Cretaceous, Ti – Tithonian, Tu – Turonian, Va – Valanginian. my – million years from present, sc – subclade Colossosauria + Bonitasaura.

Results of pairwise ancestor-descendant comparisons for log-transformed centroid size in macronarian sauropods in our time-calibrated supertree (17 terminal taxa). n = ingroup internal nodes + terminal taxa. *= accepted as significant with alpha <0.05. °= Lithostrotia + Antarctosaurus.

Results of ancestor-descendant pairwise comparisons for shape PC1 in macronarian sauropods in our time-calibrated supertree (17 terminal taxa). n = ingroup internal nodes + terminal taxa. *= accepted as significant with alpha <0.05. °= Lithostrotia + Antarctosaurus.

Results of ancestor-descendant pairwise comparisons for shape PC3 in macronarian sauropods in our time-calibrated supertree (17 terminal taxa). n = ingroup internal nodes + terminal taxa. *= accepted s significant with alpha <0.05. °= Lithostrotia + Antarctosaurus.