The evolution of the vestibular apparatus in apes and humans
- Universitat Autònoma de Barcelona, Cerdanyola del Vallès, Spain
- Laboratoire PACEA, UMR 5199 CNRS, Université de Bordeaux, France
- University of the Witwatersrand, South Africa
- University of Pretoria, South Africa
- Laboratoire AMIS, UMR 5288 CNRS, Université de Toulouse, France
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Spain
Figures
Figure 1
The vestibular apparatus of extant hominoids, other anthropoids, and some fossil hominoids, in lateral view.
(a) Homo sapiens (EMBR 121); (b) Pan paniscus (MCZ 38019); (c) Pan troglodytes (AMNH.M 51204); (d) Gorilla gorilla (AMNH.M 167338); (e) Pongo pygmaeus (IPS 10647); (f) Hylobates lar (MCZ 41424); (g) Hoolock hoolock (AMNH.M 83425); (h) Symphalangus syndactylus (AMNH.M 106583); (i) Ateles geoffroyi (MCZ 29628); (j) Theropithecus gelada (AMNH.M 60568); (k) Erythrocebus patas (MCZ 47017); (l) Trachypithecus cristatus (MCZ 35597); (m) Piliocolobus badius (MCZ 24793); (n) Oreopithecus bambolii (BAC 208); (o) Australopithecus sp. (StW 573); (p) Australopithecus sp. (StW 578). Scale bars equal 5 mm.
Figure 2 with 1 supplement
Main patterns of vestibular shape variation among the analyzed anthropoid sample as shown by bivariate plots of principal components from the between-group principal components analysis (bgPCA) using a few major clades (i.e., platyrrhines, cercopithecoids, hylobatids and hominids) as grouping factor.
(a) bgPC2 vs. bgPC1. (b) bgPC3 vs. bgPC1. Variance explained by each bgPC is included within parentheses. Color code: dark green, platyrrhines; orange, hominids; red, hylobatids; brown, papionins; green, cercopithecins; blue, colobines. Colored stars correspond to: green, Oreopithecus; black, Australopithecus sp. (StW 573); red Australopithecus sp. (StW 578). Lateral (top/left), superior (middle), and posterior (bottom/right) views of deformation maximum (red) and minimum (blue) conformations for each bgPC are shown along each axis. Hominids are distinguished from hylobatids and cercopithecoids along bgPC1 (positive vs. mostly negative values, respectively), which is mainly driven by the volumetric proportions of the SCs and by their size relative to that of the vestibular recesses. bgPC2, driven by the size of the anterior and posterior SCs relative to the lateral one, distinguishes platyrrhines (more negative values) from catarrhines. Hylobatids (on positive values) differ from all other anthropoids along bgPC3 due to the reduced and posteriorly tilted posterior SC, as well as by the relative orientation among the canals. Oreopithecus does not match the variability of extant anthropoids as its morphology shows a mosaic of primitive and derived features. The two Australopithecus specimens match instead the range of extant hominids, with StW 573 being most similar to Pan, while StW 578 to Homo.
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Figure 2—source data 1
Individual scores for all the principal components (bgPC) yielded by the between-group principal components analysis (bgPCA) of deformation-based 3DGM of vestibular shape for anthropoids, using major taxa (i.e., hominids, hylobatids, cercopithecoids, and platyrrhines) as grouping factor.
The variance explained by each bgPC is reported within parentheses. Table provided as a separate Excel file.
- https://cdn.elifesciences.org/articles/51261/elife-51261-fig2-data1-v1.xlsx
Figure 2—figure supplement 1
Box-and-whisker plots of the principal components (bgPCs) from the between-group principal components analyses (bgPCA) of vestibular shape for the anthropoid sample.
(a) bgPC1; (b) bgPC2; (c) bgPC3. Colored stars correspond to: green, Oreopithecus; black, Australopithecus sp. (StW 573); red Australopithecus sp. (StW 578).
Figure 3
Results of the 3DGM deformation-based analysis superimposed on the vestibular apparatus of hominoids in lateral view.
Cumulative displacement variations are rendered by pseudocolor scale ranging from dark blue (5.1 µm) to dark red (0.42 mm). Black arrows correspond to the vectors identifying the direction and amount of displacement. (a) Homo sapiens (EMBR 121); (b) Pan paniscus (MCZ 38019); (c) Pan troglodytes (AMNH.M 51204); (d) Gorilla gorilla (AMNH.M 167338); (e) Pongo pygmaeus (IPS10647); (f) Hoolock hoolock (AMNH.M 83425); (g) Symphalangus syndactylus (AMNH.M 106583); (h) Hylobates lar (MCZ 41424). Scale bars equal 5 mm. Hominids (a–e) differ from other anthropoids in the stouter semicircular canals and the vertically compressed (more eccentric) anterior semicircular canal, while hylobatids (f–h) possess slender canals more similar to those of cercopithecoids (j–m).
Figure 4
Results of the 3DGM deformation-based analysis superimposed on the vestibular apparatus of hominoids, in superior view.
Cumulative displacement variations are rendered by pseudocolor scale ranging from dark blue (<5.1 µm) to dark red (0.42 mm). Black arrows correspond to the vectors identifying the direction and amount of displacement. (a) Homo sapiens (EMBR 121); (b) Pan paniscus (MCZ 38019); (c) Pan troglodytes (AMNH.M 51204); (d) Gorilla gorilla (AMNH.M 167338); (e) Pongo pygmaeus (IPS10647); (f) Hoolock hoolock (AMNH.M 83425); (g) Symphalangus syndactylus (AMNH.M 106583); (h) Hylobates lar (MCZ 41424). Scale bars equal 5 mm. Hominids (a–e) differ from other anthropoids in the stouter semicircular canals, except for the lateral canal of Ateles. Among great apes, Pongo (e) displays the most inflated canals and a uniquely displaced lateral semicircular canal, Pan (b, c) has the least derived morphology, and Gorilla (e) possesses a laterally protruding lateral canal. Homo (a) combines a slight (variable) reduction of the lateral canal with an enlarged posterior canal. Hylobatids (f–h) show an obtuse angle between the posterior and the anterior SCs.
Figure 5
Results of the 3DGM deformation-based analysis superimposed on the vestibular apparatus of hominoids in posterior view.
Cumulative displacement variations are rendered by pseudocolor scale ranging from dark blue (<5.1 µm) to dark red (0.42 mm). Black arrows correspond to the vectors identifying the direction and amount of displacement. (a) Homo sapiens (EMBR 121); (b) Pan paniscus (MCZ 38019); (c) Pan troglodytes (AMNH.M 51204); (d) Gorilla gorilla (AMNH.M 167338); (e) Pongo pygmaeus (IPS10647); (f) Hoolock hoolock (AMNH.M 83425); (g) Symphalangus syndactylus (AMNH.M 106583); (h) Hylobates lar (MCZ 41424). Scale bars equal 5 mm. Homo (a), together with Gorilla (d), displays a markedly posterolaterally protruding posterior canal. The two species of Pan (b, c) can be distinguished from one another for the orientation of the anterior canal (more medially inclined in P. troglodytes, (c). Hylobatids (f–h) display a small posterior canal relative to the size of the anterior and lateral ones.
Figure 6
Results of the 3DGM deformation-based analysis superimposed on the vestibular apparatus of the fossil specimens included in the present study.
Each vestibule is displayed in lateral (left), superior (middle), and posterior (right) views. Cumulative displacement variations are rendered by pseudocolor scale ranging from dark blue (<5.1 µm) to dark red (0.42 mm). Black arrows correspond to the vectors identifying the direction and amount of displacement. (a) Oreopithecus bambolii (BAC 208); (b) Australopithecus sp. (StW 573); (c) Australopithecus sp. (StW 578). Scale bars equal 5 mm. Oreopithecus (a) displays large vertical canals and a small, flat lateral one that intersect the plane of the posterior SC. The angle between the anterior and posterior SCs is one of the narrowest among the studied sample. StW 573 (b) and StW 578 (c) differ by means of a larger lateral canal in the previous and by the more rounded and developed anterior SC in the latter.
Figure 7
Bivariate regressions between (a) vestibular shape (as represented by bgPC1) and log-transformed cube root of vestibular volume (ln Vol), and (b) semicircular canal log-transformed cube root of volume (ln VolSC) vs.log-transformed length (ln L).
Lines represent OLS best-fit lines for the whole anthropoid sample (black), hominids (red), and other anthropoid taxa (blue). Note that there is a significant correlation between bgPC1 (which captures differences in SC thickness and macular organ size) and vestibular volume, more marked in hominids than in the rest of the sample (see Table 3 for further details). Note as well that hominids and other anthropoids show a similar negatively allometric relationship between the cube root of volume and length of the SCs, but with a marked allometric grade shift—such hominids possess stouter canals than other anthropoid taxa at comparable lengths once size-scaling effects have been taken into account (see Table 3 for further details). Both australopiths fall above the regression line for hominids, while Oreopithecus is slightly below, yet well above the regression line for non-hominid taxa. Color code as in Figure 2.
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Figure 7—source data 1
Linear measurements for the analyzed specimens and used for computing the linear regressions.
Table provided as a separate Excel file.
- https://cdn.elifesciences.org/articles/51261/elife-51261-fig7-data1-v1.xlsx
Figure 8
Tangent space of vestibular shape among the analyzed anthropoid sample as shown by bivariate plots of principal components from the PCA of deformation-based analysis.
Variance explained by each PC is included within parentheses. Convex hulls correspond to: hominids (orange), hylobatids (red), cercopithecoids (blue), platyrrhines (green). Color code: dark green, platyrrhines; orange, hominids; red, hylobatids; brown, papionins; green, cercopithecins; blue, colobines. Hominids are distinguished from hylobatids and other anthropoids along PC1 (mostly negative vs. positive values, respectively), while PC2 tends to distinguish platyrrhines (more negative values) from catarrhines. Even if slightly more overlapping, the groups identified when observing the morphospace obtained with bgPCA are already present in the PCA.
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Figure 8—source data 1
Individual scores for all the principal components (PC) yielded by the principal components analysis (PCA) of deformation-based 3DGM of vestibular shape for anthropoids.
The variance explained by each PC is reported. Table provided as a separate Excel file.
- https://cdn.elifesciences.org/articles/51261/elife-51261-fig8-data1-v1.xlsx
Figure 9
Main patterns of vestibular shape variation among the analyzed anthropoid sample as shown by bivariate plots of principal components from the landmark-based between-group principal components analysis (bgPCA) using major taxa as in Figure 2.
(a) bgPC2 vs. bgPC1. (b) bgPC3 vs. bgPC1. Variance explained by each bgPC is included within parentheses. Lateral (top), superior (middle), and anterior (bottom) views of landmarks and semilandmark maximum (red) and minimum (blue) conformations for (c) bgPC1, (d) bgPC2, and (e) bgPC3. Color code as in Figure 2. Hominoids and cercopithecoids are distinguished along bgPC1 (mostly negative vs. positive values, respectively), which is mainly driven by the vertical compression of the anterior SC, as well as the position of the lateral (more anteriorly connecting with the vestibule) and the posterior (displaced posteromedially) canals. bgPC2, driven by the size of the anterior and posterior SCs relative to the lateral one, tends to distinguish platyrrhines (more negative values) from catarrhines, while bgPC3, driven by the size of the anterior and lateral SCs relative to that of the posterior canal, as well as by the relative orientation among the canals, tends to distinguish most hylobatids (more negative values) from great apes, humans, and cercopithecoids (more positive values). The two Australopithecus specimens fall within the hominid range, flanking that of hylobatids. Similarly to the deformation-based approach, StW 578 is more similar to humans (matching the distribution of Homo), while StW 573 is found within the scatter of points of Pan species. In the landmark-based analysis, Oreopithecus overlaps within cercopithecoids and also falls close to platyrrhines.
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Figure 9—source data 1
Individual scores for all the principal components (bgPC) yielded by the between-group principal components analysis (bgPCA) of landmark-based 3DGM of vestibular shape for anthropoids, using major taxa (i.e., hominids, hylobatids, cercopithecoids, and platyrrhines) as grouping factor.
The variance explained by each bgPC is reported within parentheses. Table provided as a separate Excel file.
- https://cdn.elifesciences.org/articles/51261/elife-51261-fig9-data1-v1.xlsx
Figure 10
Reconstructed evolutionary history of the vestibular apparatus in the sample restricted to hominoids.
The depicted phylomorphospaces are obtained by projecting the phylogeny displayed in Figure 13 on the bivariate plots between principal components: (a) bgPC2 vs. bgPC1 (see Figure 2a); (b) bgPC3 vs. bgPC1 (see Figure 2b). Color code: red, Hylobates lar; orange, Symphalangus syndactylus; light green, Hoolock hoolock; blue, Pongo pygmaeus; dark green, Gorilla gorilla; cyan, Pan troglodytes; purple, Pan paniscus; fuchsia, Homo sapiens; chartreuse, Oreopithecus bambolii; black, Australopithecus sp. Key ancestral morphologies reconstructed using maximum likelihood for the last common ancestor of various clades are depicted as follows: 1, crown hominoids (hylobatids and hominids); 2, crown hylobatids (gibbons and siamangs); 3, crown hominids (great apes and humans); 4, crown hominines (African great apes and humans); 5, Pan-Homo clade; 6 Australopithecus-Homo clade.
Figure 11
Reconstructed vestibular shape for the last common ancestors (LCA) of the main clades of interest as reconstructed using maximum likelihood methods for deformation-based 3DGM analyses applied to the anthropoid sample (Figure 7), in lateral (left), superior (middle), and posterior (right) views.
Cumulative displacement variations are rendered by pseudocolor scale ranging from dark blue (<5.1 µm) to dark red (0.42 mm). Black arrows correspond to the vectors identifying the direction of displacement. The reconstructed LCAs depicted are the following: (a) crown hominoids; (b) crown hylobatids; (c) crown hominids; (d) crown hominines; (e) Pan-Homo clade; (f) Australopithecus-Homo clade.
Figure 12
Illustration of hominoid, hominid and hylobatid synapormophies for the vestibular apparatus.
See Table 8 for further details. character #1: (a) rounded (gray) and compressed (green) anterior canal; character #2: (b–c) non-posteriorly displaced posterior canal (gray), posteriorly displaced posterior canal (green); character #3: (b–c) lateral canal intersecting(dashed line) the posterior one (gray), lateral canal non-intersecting the posterior one (in green); character #4: (d-e) curved (gray) and straight (green) medial portion of the lateral canal; character #5: (f–g) flat (gray) and bent upwards (green) trajectory of the lateral canal ampullar portion; character #6: (h–i) anterior and posterior SCs forming an angle (dotted arc) close to the right angle (gray), anterior and posterior canals forming an obtuse angle (green); character #7: (h–i) posterior canal equal in size to the other SCs and forming a right angle with the lateral canal (gray), small posterior canal relative the other SCs and inclined posteriorly respective to the lateral canal (green); character #8: (j–k) slender SCs (gray), stout canals (green); character #9: (j–k) small vestibular recesses (gray), enlarged vestibular recesses (green).
Figure 13
Time-calibrated molecular phylogeny of extant anthropoids used in the analyses of phylogenetic signal and PGLS regressions as inferred from a species supermatrix.
Fossil taxa have been added a posteriori according to their phylogenetic position and their point estimates correspond to their last occurrence in the fossil record (Rook et al., 2000; Wood and Boyle, 2016). Oreopithecus is here considered as a stem hominoid, predating the split between hominids and hylobatids, while Australopithecus has been added following the first appearance datum for A. africanus based on the Jacovec Cavern specimens. For the phylomorphospace the phylogenetic tree has been pruned to include extant and extinct hominoids only. Branches are color-coded: dark green, platyrrhines; brown, papionins; green, cercopithecins; blue, colobines; orange, hominids; red, hylobatids. Extinct taxa are denoted by a dagger.
Tables
Table 1
Percentage of correctly classified individuals with cross-validation according to the groups (hominids, hylobatids, cercopithecoids, platyrrhines) used in the between-group principal components analysis based on group-centroid distances.
| Cercopithecoidea | Hominidae | Hylobatidae | Platyrrhini | |
|---|---|---|---|---|
| Cercopithecoidea | 96.3% | 3.8% | 0.0% | 0.0% |
| Hominidae | 3.3% | 96.7% | 0.0% | 0.0% |
| Hylobatidae | 5.9% | 0.0% | 94.1% | 0.0% |
| Platyrrhini | 0.0% | 0.0% | 0.0% | 100.0% |
Table 2
Phylogenetic signal results for a between-group principal components analysis (bgPCA) applied to vestibular shape deformation fields in the analyzed sample of extant anthropoids.
| bgPC1 | bgPC2 | bgPC3 | |
|---|---|---|---|
| Variance | 68.79% | 19.60% | 11.61% |
| Eigenvalue | 0.821 | 0.234 | 0.138 |
| Pagel’s λ | 1.000 (p<0.001) | 0.921 (p<0.001) | 1.000 (p<0.001) |
| Blomberg’s K | 1.152 (p<0.001) | 1.514 (p<0.001) | 1.163 (p<0.001) |
Table 3
Posterior probabilities of group membership based on the bgPC scores for fossil specimens in the analysis based on the anthropoid sample.
Note that these are probability estimates of having a particular score given membership in a particular group, not the likelihood of group membership in each of a priori defined groups given a particular score. Highest probability for each specimen in bold.
| Cercopithecoidea | Hominidae | Hylobatidae | Platyrrhini | |
|---|---|---|---|---|
| BAC 208 (Oreopithecus) | p=0.046 | p=0.013 | p<0.001 | p=0.012 |
| StW 573 (Australopithecus) | p=0.005 | p=0.678 | p<0.001 | p<0.001 |
| StW 578 (Australopithecus) | p<0.001 | p=0.190 | p<0.001 | p<0.001 |
Table 4
Posterior probabilities of group membership based on the bgPC scores for fossil specimens in the analysis restricted to hominoid genera.
Note that these are probability estimates of having a particular score given membership in a particular group, not the likelihood of group membership in each of a priori defined groups given a particular score. The highest probability for each specimen in bold.
| Hoolock | Hylobates | Symphalangus | Pongo | Gorilla | Pan | Homo | |
|---|---|---|---|---|---|---|---|
| BAC 208 (Oreopithecus) | p<0.001 | p<0.001 | p<0.001 | p<0.001 | p<0.001 | p=0.002 | p=0.026 |
| StW 573 (Australopithecus) | p<0.001 | p<0.001 | p<0.001 | p=0.019 | p<0.001 | p=0.368 | p=0.264 |
| StW 578 (Australopithecus) | p<0.001 | p<0.001 | p<0.001 | p=0.062 | p=0.077 | p=0.030 | p=0.727 |
Table 5
Bivariate regressions of vestibular shape vs. volume and of semicular canal volume vs. length.
Both ordinary least-square linear regressions (OLS) and phylogenetic generalized least-square regressions (PGLS) are provided for the whole anthropoid sample, as well as hominids and non-hominids separately. Vestibular shape is represented by the first three principal components (bgPC), while vestibular volume (Vol) is represented by its log-transformed cube root. Semicular canal volume (VolSC) and length (L) are represented by the log-transformed cube root and the log-transformed length, respectively, of the three semicircular canals together. For each regression, the coefficient of determination (R2), the significance of the slope (p), and the slope and intercept values with their corresponding standard error (SE) and 95% confidence intervals (CI) are included. Regressions bolded when significant at p<0.05. For bgPCs vs. VOL regressions, a significant correlation denotes allometry, while for VOLSC vs. L regressions there is allometry when the correlation is significant and the 95% CI for the slope excludes unity.
| R2 | p | slope | SE | 95% CI | intercept | SE | 95% CI | |||
|---|---|---|---|---|---|---|---|---|---|---|
| OLS | ||||||||||
| Anthropoids (n = 142) | ||||||||||
| bgPC1 vs. ln Vol | 0.635 | <0.001 | 5.257 | 0.335 | 4.600 | 5.914 | −6.191 | 0.399 | −6.973 | −5.409 |
| bgPC2 vs. ln Vol | 0.008 | 0.146 | 0.453 | 0.309 | −0.154 | 1.060 | −0.533 | 0.368 | −1.254 | 0.188 |
| bgPC3 vs. ln Vol | 0.000 | 0.385 | 0.192 | 0.220 | −0.239 | 0.622 | −0.226 | 0.261 | −0.738 | 0.287 |
| ln VolSC vs. ln L | 0.288 | <0.001 | 0.897 | 0.118 | 0.666 | 1.128 | −2.328 | 0.429 | −3.169 | −1.487 |
| Hominids (n = 30) | ||||||||||
| bgPC1 vs. ln Vol | 0.480 | <0.001 | 6.496 | 1.233 | 4.079 | 8.913 | −7.781 | 1.797 | −11.303 | −4.259 |
| bgPC2 vs. ln Vol | 0.026 | 0.195 | −1.400 | 1.054 | −3.466 | 0.666 | 2.307 | 1.538 | −0.708 | 5.322 |
| bgPC3 vs. ln Vol | 0.039 | 0.153 | −0.720 | 0.490 | −1.681 | 0.240 | 1.036 | 0.714 | −0.365 | 2.436 |
| ln VolSC vs. ln L | 0.251 | 0.003 | 0.621 | 0.190 | 0.249 | 0.992 | −1.084 | 0.705 | −2.465 | 0.297 |
| Non-hominids (n = 112) | ||||||||||
| bgPC1 vs. ln Vol | 0.058 | 0.006 | 1.990 | 0.709 | 0.601 | 3.380 | −2.645 | 0.785 | −4.183 | −1.108 |
| bgPC2 vs. ln Vol | 0.010 | 0.152 | −1.027 | 0.712 | −2.422 | 0.368 | 1.061 | 0.788 | −0.482 | 2.605 |
| bgPC3 vs. ln Vol | 0.046 | 0.013 | 1.332 | 0.529 | 0.295 | 2.368 | −1.466 | 0.585 | −2.613 | −0.319 |
| ln VolSC vs. ln L | 0.219 | <0.001 | 0.454 | 0.080 | 0.297 | 0.611 | −0.783 | 0.291 | −1.352 | −0.213 |
| PGLS | ||||||||||
| Anthropoids (n = 27) | ||||||||||
| bgPC1 vs. ln Vol | 0.261 | 0.004 | 3.401 | 1.065 | 1.314 | 5.488 | −3.719 | 1.376 | −6.416 | −1.022 |
| bgPC2 vs. ln Vol | 0.003 | 0.416 | 0.625 | 0.756 | −0.858 | 2.107 | −1.27 | 0.962 | −3.155 | 0.615 |
| bgPC3 vs. ln Vol | 0.063 | 0.111 | −0.727 | 0.440 | −1.589 | 0.135 | 0.879 | 0.570 | −0.238 | 1.996 |
| ln VolSC vs. ln L | 0.437 | <0.001 | 0.502 | 0.109 | 0.288 | 0.716 | 3.144 | 0.124 | 2.901 | 3.388 |
| Hominids (n = 5) | ||||||||||
| bgPC1 vs. ln Vol | 0.221 | 0.240 | 4.440 | 3.042 | −1.521 | 10.402 | −4.627 | 4.499 | −13.445 | 4.192 |
| bgPC2 vs. ln Vol | 0.036 | 0.760 | −1.144 | 3.421 | −7.850 | 5.561 | 1.892 | 4.990 | −7.888 | 11.672 |
| bgPC3 vs. ln Vol | 0.062 | 0.687 | −0.392 | 0.883 | −2.122 | 1.338 | 0.596 | 1.309 | −1.970 | 3.162 |
| ln VolSC vs. ln L | 0.553 | 0.093 | 0.631 | 0.259 | 0.124 | 1.138 | 2.920 | 0.327 | 2.279 | 3.561 |
| Non-hominids (n = 22) | ||||||||||
| bgPC1 vs. ln Vol | 0.008 | 0.294 | 1.376 | 1.276 | −1.125 | 3.877 | −1.674 | 1.512 | −4.639 | 1.290 |
| bgPC2 vs. ln Vol | 0.030 | 0.445 | 0.763 | 0.978 | −1.154 | 2.679 | −1.444 | 1.152 | −3.701 | 0.814 |
| bgPC3 vs. ln Vol | 0.020 | 0.500 | −0.419 | 0.610 | −1.616 | 0.777 | 0.577 | 0.730 | −0.854 | 2.008 |
| ln VolSC vs. ln L | 0.504 | <0.001 | 0.634 | 0.134 | 0.371 | 0.896 | 3.052 | 0.137 | 2.784 | 3.320 |
Table 6
Probability of correct classification of individuals from the hierarchical clustering analyses of deformation fields according to the groups (hominids, hylobatids, cercopithecoids, platyrrhines) used in the bgPCA.
| Hominidae | Hylobatidae | Cercopithecoidae | Platyrrhini |
|---|---|---|---|
| 90.0% | 23.5% | 65.0% | 66.7% |
Table 7
Phylogenetic signal results for a between-group principal components analysis (bgPCA) applied to vestibular shape procrustes residuals in the analyzed sample of extant anthropoids.
| bgPC1 | bgPC2 | bgPC3 | |
|---|---|---|---|
| Variance | 53.34% | 29.29% | 17.37% |
| Eigenvalue | 2.462 | 1.352 | 0.802 |
| Pagel’s λ | 1.000 (p<0.001) | 0.902 (p<0.001) | 0.932 (p=0.006) |
| Blomberg’s K | 1.226 (p=0.001) | 1.081 (p=0.001) | 0.528 (p=0.01) |
Table 8
Phylogenetically informative discrete characters of vestibular morphology that represent potential synapomorphies of either hominoids or hominids.
| Character # | Character definition | Character statesa | Synapomorphic for |
|---|---|---|---|
| #1 | Anterior SCb | 0 = rounded; 1 = vertically compressed | Hominoidea |
| #2 | Posterior SC | 0 = non posteromedially displaced; 1 = posteromedially displaced | Hominoidea |
| #3 | Insertion of the lateral SC slender portion on the vestibule | 0 = posterior (lateral SC intersecting the posterior SC plane); 1 = anterior (not intersecting) | Hominoidea |
| #4 | Lateral SC medial portion | 0 = curved; 1 = straight | Hominoidea |
| #5 | Trajectory of the lateral SC ampullar portion | 0 = flat; 1 = bent upwards | Hominoidea |
| #6 | Angle between the planes identified by the anterior and posterior SCs | 0 = close to right angle, 1 = obtuse | Hylobatidae |
| #7 | Inclination and size of the posterior SC relative to the size of the anterior and lateral SCs | 0 = forming a right angle and equal or larger in size, 1 = posteriorly tilted and smaller | Hylobatidae |
| #8 | Robusticity of SCs | 0 = slender; 1 = stout | Hominidae |
| #9 | Extension of vestibular recesses relative to that of the SCs | 0 = smaller; 1 = similar in size | Hominidae |
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Abbreviations: SC = semicircular canals.
a Character state 0 represents the primitive condition reconstructed for the last common ancestor of crown catarrhines.
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b Some platyrrhines display a superior eccentricity of the anterior SC that might be apomorphic.
Table 9
Sample of extant anthropoid specimens analyzed in this paper based on µCT image stacks.
See Supplementary file 1 for further details on each specimen.
| Family | Species | n | M | F | ? |
|---|---|---|---|---|---|
| Atelidae | Alouatta palliata | 5 | 3 | 2 | 0 |
| Atelidae | Ateles geoffroyi | 5 | 1 | 4 | 0 |
| Cebidae | Cebus apella | 5 | 3 | 2 | 0 |
| Cercopithecidae | Cercocebus galeritus | 5 | 3 | 2 | 0 |
| Cercopithecidae | Cercopithecus mitis | 5 | 0 | 5 | 0 |
| Cercopithecidae | Chlorocebus pygerythrus | 5 | 2 | 3 | 0 |
| Cercopithecidae | Colobus guereza | 5 | 2 | 3 | 0 |
| Cercopithecidae | Erythrocebus patas | 5 | 3 | 2 | 0 |
| Cercopithecidae | Lophocebus albigena | 5 | 2 | 3 | 0 |
| Cercopithecidae | Macaca fascicularis | 5 | 1 | 4 | 0 |
| Cercopithecidae | Mandrillus sphinx | 5 | 5 | 0 | 0 |
| Cercopithecidae | Miopithecus talapoin | 5 | 3 | 2 | 0 |
| Cercopithecidae | Nasalis larvatus | 5 | 0 | 5 | 0 |
| Cercopithecidae | Papio anubis | 5 | 3 | 2 | 0 |
| Cercopithecidae | Piliocolobus badius | 5 | 4 | 1 | 0 |
| Cercopithecidae | Presbytis hosei | 5 | 1 | 4 | 0 |
| Cercopithecidae | Presbytis rubicunda | 5 | 2 | 3 | 0 |
| Cercopithecidae | Theropithecus gelada | 5 | 4 | 1 | 0 |
| Cercopithecidae | Trachypithecus cristatus | 5 | 0 | 5 | 0 |
| Hylobatidae | Hoolock hoolock | 6 | 2 | 4 | 0 |
| Hylobatidae | Hylobates lar | 7 | 0 | 7 | 0 |
| Hylobatidae | Symphalangus syndactylus | 4 | 2 | 2 | 0 |
| Hominidae | Gorilla gorilla | 7 | 2 | 5 | 0 |
| Hominidae | Homo sapiens | 5 | 2 | 3 | 0 |
| Hominidae | Pan paniscus | 5 | 1 | 4 | 0 |
| Hominidae | Pan troglodytes | 7 | 4 | 3 | 0 |
| Hominidae | Pongo pygmaeus | 6 | 0 | 4 | 2 |
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Abbreviations: n, total number of specimens; M, males; F, females; ?, unknown sex.
Additional files
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Supplementary file 1
List of extant anthropoid specimens analyzed in this paper.
µCT image stacks were downloaded from MorphoSource digital repository at https://www.MorphoSource.org (Duke University, Durham, NC, USA) or scanned at Paul Sabatier University (PSU, Toulouse, France), the American Museum of Natural History (AMNH; New York, NY, USA) and Centro Nacional de Investigación sobre la Evolución Humana (CENIEH; Burgos, Spain).
- https://cdn.elifesciences.org/articles/51261/elife-51261-supp1-v1.xlsx
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Transparent reporting form
- https://cdn.elifesciences.org/articles/51261/elife-51261-transrepform-v1.docx
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