Supplementary Online Material (SOM): Comparative anatomy of the carotid canal in the Miocene small-bodied catarrhine Pliobates cataloniae Florian Bouchet , Alessandro Urciuoli a, Amélie Beaudet a, * b, c, d, a , Marta Pina e, a , Salvador Moyà-Solà a, f, g, David M. Alba a, * a Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, c/ Columnes s/n, Campus de la UAB, 08193 Cerdanyola del Vallès, Barcelona, Spain b Department of Archaeology, University of Cambridge, The Old Schools, Trinity Lane, Cambridge CB2 1TN, UK c School of Geography, Archaeology and Environmental Studies, University of the Witwatersrand, 1 Jan Smuts Avenue, Braamfontein 2000, Johannesburg, South Africa d Department of Anatomy, University of Pretoria, Lynnwood Road, Hatfield 0002, Pretoria, South Africa e Department of Earth and Environmental Sciences, University of Manchester, Williamson Building, Oxford Road, Manchester M13 9PL, UK f Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig de Lluís Companys 23, 08010 Barcelona, Spain g Unitat d’Antropologia (Dept. BABVE), Universitat Autònoma de Barcelona, Edifici C, Facultat de Biociències, Campus de la UAB, 08193 Cerdanyola del Vallès, Barcelona, Spain * Corresponding authors. E-mail addresses: florian.bouchet@icp.cat (F. Bouchet); david.alba@icp.cat (D.M. Alba). 1 SOM S1 Extended methodology 3D carotid canal surfaces For each specimen, the carotid canal was virtually extracted through semiautomatic threshold-based segmentation in Avizo v. 7.0 (Visualization Sciences Group, Bordeaux). The right carotid canal was segmented for most specimens; when this was not possible, the left canal was segmented and mirrored. We devised a protocol to identify the two ends (anterior and posterior) of the carotid canal and cut them at homologous points (Fig. 1; SOM Fig. S1), to obtain 3D canal surfaces comparable among specimens. For the posterior end of the canal, we placed landmarks on its external aperture (carotid foramen; SOM Fig. S1a, b), computed the best-fit plane to these landmarks, translated it to be located at the centroid of the landmark set, and finally cut the canal (Fig. 1a). The centroid of the landmarks on the carotid foramen was taken as the posterior endpoint of the canal (Fig. 1l). The methodology employed to cut the anterior part of the carotid canal was more complex, because its opening on the endocranial surface of the petrosal is irregular and displays a variable outline among individuals. Furthermore, it was not completely preserved in fossil specimens we included here. We started by defining a landmark located posteriorly to the canal opening, and used it to determine the anterior limit at which we could later cut the anterior part of the canal. We defined a landmark termed ‘intersection ridge–groove’ (IRG) that corresponds to the intersection between the anterior pyramidal ridge and the groove of the greater superficial petrosal nerve (SOM Fig. S1c, d; Table 2). Based on IRG, we applied a semiautomatic protocol coded on R v. 3.6.3 (R Core Team, 2020; see script in SOM File S1) to find the plane orthogonal to the 3D carotid canal surface passing through IRG. In particular, the 3D canal surface is first generated and smoothed in Avizo (using a constrained smoothing and a smoothing extent of 3) and then imported as a cloud of points in R (Fig. 1b); the orthogonal projection of IRG onto the canal (IRG’) is calculated (Fig. 1c). These two points (IRG and IRG’) define a main axis, around which infinity of points can be generated, further enabling the creation of infinity of planes. Indeed, a plane can be defined by three points expressed as two vectors, and the axis defined by IRG and IRG’ corresponds to one of the two vectors necessary to compute the orthogonal plane to the canal (passing through IRG), because IRG’ is the orthogonal projection of IRG onto the canal. However, to obtain the second vector, a third point is required, which cannot be defined a priori. We decided to 2 define the cutting plane as the one that is orthogonal to the 3D canal surface (and therefore to the canal streamline) and thus that minimizes the cross-sectional area resulting from the cut. The protocol generates multiple cutting planes—defined on IRG, IRG’, and multiple possible third points—and calculates the cut area for each of them. In particular, we created 360 equally distributed points (differing in 1° of orientation) around the IRG–IRG’ axis (Fig. 1d) and computed the cutting cross-sectional area for all the 360 possible cutting planes (Fig. 1e, f). For each plane possibility, among the cloud of points representing the canal, the points that are closest to the plane (i.e., those having an orthogonal distance to the plane equal or shorter than the distance between two adjacent points of the cloud) are identified (Fig. 1g). Among them, only the most external ones are kept and used to form a convex hull approximating the contour of the canal cross-section (Fig. 1h). The area subtended by the convex hull is then subdivided in n-2 triangles, where n is the number of points that form the hull, using one of the points as the shared vertex (the most acute one) for all the triangles; the area of the triangles is computed and their sum is used as an approximation of the total area of the cross-section (Fig. 1i). The plane for which the resulting cross-sectional area is the smallest is kept and used as reference for cutting the canal at its anterior end (Fig. 1i, j). The centroid of the cross-section obtained by cutting with this orthogonal plane (Fig. 2h–i) is calculated and used as the anterior endpoint of the canal (Fig. 1l). Carotid canal orientation We quantified the orientation of the carotid canal within the petrosal by computing a 3D vector representing the canal direction and decomposing it into two 2D angles relative to standard anatomical planes: one angle represents the canal superior orientation (2DYZA) along the (para)sagittal plane, and the other represents its medial orientation (2DXYA) along a transverse plane—respectively corresponding to canal ‘orientation’ and ‘direction’ sensu Alba et al. (2015: Tables S5 and S6). The 3D vector representing the canal was computed as a single direction, from the posterior to the anterior endpoints of the canal. All the specimens were first put in the same coordinate system by performing a generalized Procrustes analysis (GPA; Rohlf and Slice, 1990; Bookstein, 1991) using the R package ‘Geomorph’ v. 3.3.1 (Adams et al., 2019) based on nine petrosal/tympanic landmarks (Fig. 2; Table 2). This allowed us to scale, orient, and locate the petrosals in a standardized way within a common Cartesian coordinate system. The translation-scaling-rotation parameters resulting from this 3 alignment were then extracted and applied to the two endpoints of the canal vector. Performing the alignment on the petrosal, instead of the canal endpoints or both structures simultaneously, enables the retention of the canal position, orientation and shape inside the petrosal, for each specimen. The coordinates of the posterior and anterior endpoints after the petrosal/tympanic-based alignment were used to compute the 3D vector representing the 3D canal direction. As the specimens were prealigned, we were able to use a single reference vector to calculate the two 2D angles. Despite some variation among the sample, there is an overall correspondence (with no extreme deviations) between spatial axes of the common Cartesian coordinate system and canal directions after alignment: the X-axis corresponds to the anteromedial–posterolateral direction of the canal, the Y-axis corresponds to its inferomedial–superolateral direction, and the Z-axis corresponds to its anterolateral– posteromedial direction. Considering these correspondences, 2DYZA was calculated as the 2D angle between the YZ coordinates of the canal vector and a reference vector with coordinates (1, -1) corresponding to the cranial anteroposterior axis (from posterior to anterior). In turn, 2DXYA was calculated as the 2D angle between the XY coordinates of the canal vector and a reference vector with coordinates (-0.2, 1) also corresponding to the cranial anteroposterior axis (from posterior to anterior). While in anthropoids the canal runs from a posterolateral location to an anteromedial location, after alignment some specimens display a canal running almost anteroposteriorly or slightly (postero)medio(antero)laterally. To take into account those exceptions the 2DXYA angle was calculated so that positive values correspond to medially oriented canals and negative values identify canals (only a few) slightly laterally oriented. Because the alignment is based on petrosal/tympanic landmarks, one should consider the possibility that two specimens possessing similar angles relative to the petrosal may display different angles if computed relative to the whole cranium, depending on the orientation and position of the petrosal inside the cranium. However, based on Spoor’s (1993) data, differences of superior petrosal surface orientations in the sagittal plane and superior and inferior petrosal surface orientations in the transverse plane are not significant among the main crown anthropoid clades. Furthermore, relying on petrosal/tympanic landmarks for scaling-translating-orienting carotid canal specimens, instead of landmarks from the cranium as a whole, has several advantages besides enabling the analysis of fragmentary fossil 4 remains. In particular, this procedure may prevent alignment problems related to striking shape differences between extant lineages (such as the elongated muzzle of some papionins, the much more globulous neurocranium of some hominoids, the longer parietal of platyrrhines, etc.), because the variation in petrosal shape seems less marked. Carotid canal proportions After cutting the two ends of the carotid canal, the 3D canal surfaces were generated again without smoothing in Avizo, and the volume (V, in mm3) of the closed 3D surfaces was computed using the module ‘Surface Area Volume’. The 3D surfaces were then reimported in R and, for each specimen, we calculated canal length (L, in mm). To do so, we computed nine semilandmarks corresponding to the centroids of the canal cross-sections obtained by means of nine equidistant slices generated along the two canal endpoints (i.e., type III landmarks; Bookstein, 1991). The resulting 11 streampoints (2 endpoints + 9 centroids in between) were used to generate 8 equidistant streampoints between the 2 endpoints using the ‘digit.curve’ function of ‘Geomorph’ v. 3.3.1—the sliding process embedded in this function requiring to set a number of final points smaller than the original number of points. Based on these 10 equidistant streampoints representing the canal streamline we computed nine segments (distances), whose sum was taken as canal length. Carotid canal course within the petrosal To assess the course of the carotid canal within the petrosal we used a similar approach to that employed for computing L. We took the 10 equidistant streampoints previously computed during the calculation of L. As mentioned above, these 10 streampoints follow the streamline of the canal, i.e., de facto they represent the canal course. Then we applied the translation-scaling-rotation parameters resulting from the alignment of the petrosals described above to the 10 streampoints. As for the canal orientation, this procedure allowed us retaining the information on the variation of position, orientation and shape of the canal inside the petrosal. The configuration of the 10 canal streampoints obtained after alignment therefore represents the course of the carotid canal within the petrosal. Phylogenetic tree 5 To compute PGLS regressions and quantify phylogenetic signal we used a time-calibrated tree representing the phylogenetic relationships among the extant taxa included in the comparative sample. The tree was derived from the 10kTrees website (Arnold et al., 2010), with some modifications to account for not included species in the 10kTrees website: (1) Simias concolor was added as the sister taxon of Nasalis larvatus with a divergence time at 2.16 Ma (Springer et al., 2012); (2) Presbytis rubicunda was replaced by data on Presbytis melalophos, which is its closest species (Meyer et al., 2011; Springer et al., 2012); (3) Pithecia monachus was added as the sister taxon of Pithecia pithecia, with a divergence time between both taxa set at 3.46 Ma (Springer et al., 2012); (4) Chiropotes chiropotes was added as the sister taxon of Pithecia spp., with a divergence time set at 13.27 Ma (Springer et al., 2012); (5) Plecturocebus cupreus was added as the sister taxon of the Chiropotes- Pithecia clade, with a divergence time set at 19.84 Ma (Springer et al., 2012). We further used two different hypotheses for the phylogenetic relationships among the investigated fossil genera and extant catarrhines, with the exception of Victoriapithecus, considered a stem cercopithecoid in both instances. The tips of the fossil taxa were set based on their geological age: Victoriapithecus at 15 Ma (Benefit, 1999); Epipliopithecus at 14.15 Ma (as estimated from the midpoint of MN6 in Europe based on van der Meulen et al., 2011); Pliobates at 11.62 Ma (Alba et al. 2017); and Ekembo at 17.8 Ma (as the midpoint of the maximum-minimum range of the Kulu Formation in Rusinga Island, where E. heseloni has been found; Drake et al., 1988; Peppe et al., 2009; Harrison, 2010). The divergence between Victoriapithecus and crown cercopithecoids was set 1 Myr older than the cercopithecine- colobine divergence (21.41 Ma). Under hypothesis 1 (SOM Fig. S2a), Epipliopithecus, Ekembo, and Pliobates are considered successive stem hominoids, following the results of Alba et al.’s (2015) cladistic analysis. Their divergence from crown hominoids was set 3, 2 and 1 Myr before the hominid-hylobatid divergence date (19.61 Ma), respectively. In contrast, under hypothesis 2 (SOM Fig. S2b) only Ekembo is considered a stem hominoid, while both Pliobates and Epipliopithecus are considered stem catarrhines within a pliopithecoid clade, following the results of other cladistic analyses (Nengo et al., 2017; Gilbert et al., 2020). The divergence between Epipliopithecus and Pliobates was set 1 Myr older than the oldest occurrence of either of them (1 Myr older than Epipliopithecus, i.e., 15.15 Ma), while the divergence between pliopithecoids and crown catarrhines was set 1 Myr older than the divergence between cercopithecoids and hominoids (30 Ma), as this is 6 older than the oldest documented occurrence of pliopithecoids in the fossil record (18–17 Ma; Harrison, 2013, 2017; Begun, 2017). 7 SOM Figure S1. Landmarks used for delimiting the extremities of the carotid canal as exemplified in a Macaca fascicularis individual. The 3D canal surface (in red; a) is posteriorly defined by putting landmarks on the rim of the carotid foramen (b). The anterior limit of the canal (in red; c) is identified by placing a landmark (IRG) at the intersection between the anterior pyramidal ridge and the groove for the greater superficial petrosal nerve (d). Abbreviations: APR = anterior pyramidal ridge; FSG = fossa for the semilunar ganglion; GgsPn = groove of the greater superficial petrosal nerve; IRG = intersection ridge–groove. 8 SOM Figure S2. Time-calibrated phylogenetic trees of extant anthropoids and selected extinct catarrhines (denoted by a dagger) used in this paper to compute phylogenetic generalized least-squares regressions (excluding fossils), phylogenetic signal (excluding fossils), and phylomorphospaces. The trees are based on molecular data and derived from the 10kTrees website v. 3 (Arnold et al., 2010) with some modifications based on Meyer et al. (2011) and Springer et al. (2012). Extinct taxa were added a posteriori according to the two phylogenetic hypotheses considered in this paper: a) Epipliopithecus, Ekembo and Pliobates are considered successive stem hominoids following Alba et al. (2015: Fig. 8); b) Epipliopithecus and Pliobates are considered sister taxa within a stem catarrhine pliopithecoid clade and Ekembo is considered a stem hominoid, following Nengo et al. (2017: Fig. 5) and Gilbert et al. (2020: Fig. 4). Victoriapithecus is considered a stem cercopithecoid under both hypotheses. The point estimates for extinct taxa correspond to their occurrence in the fossil record (Drake et al., 1988; Benefit, 1999; Peppe et al., 2009; van der Meulen et al., 2011; Alba et al., 2017). See SOM S1 for further details. 9 SOM Figure S3. Results of the cross-validated between-group principal component analysis (CV-bgPCA) using main extant anthropoid clades as the grouping factor, as depicted by a bivariate plot of bgPC2 vs. bgPC1. Convex hulls correspond to: platyrrhines (blue), cercopithecids (red), hylobatids (green), and hominids (gray). Abbreviation: CV-bgPC = cross- validated between-group principal component. 10 SOM Figure S4. Configurations of the carotid canal course in Pliobates compared with fossil and extant anthropoids in superior view: a) Pliobates (IPS58443.1); b) Epipliopithecus (NHMW 1970/1397/0003); c) Ekembo (KNM-RU 2036al); d) Victoriapithecus (KNM-MB 29100); e) Alouatta; f) Aotus; g) Cebus; h) Mico; i) Plecturocebus; j) Cercopithecus; k) Colobus; l) Mandrillus; m) Presbytis; n) Hylobates; o) Hoolock; p) Nomascus; q) 11 Symphalangus; r) Gorilla; s) Pan; t) Pongo. The mean configuration computed for the whole anthropoid sample is represented by black dots while configurations for specimens are represented in beige. For a better understanding of the canal course variation in space the anthropoid mean configuration was used as a reference for visualizing all the configurations at the same relative scale. 12 SOM Figure S5. Configurations of the carotid canal course in Pliobates compared with fossil and extant anthropoids in lateral view: a) Pliobates (IPS58443.1); b) Epipliopithecus (NHMW 1970/1397/0003); c) Ekembo (KNM-RU 2036al); d) Victoriapithecus (KNM-MB 29100); e) Alouatta; f) Aotus; g) Cebus; h) Mico; i) Plecturocebus; j) Cercopithecus; k) Colobus; l) Mandrillus; m) Presbytis; n) Hylobates; o) Hoolock; p) Nomascus; q) Symphalangus; r) Gorilla; 13 s) Pan; t) Pongo. The mean configuration computed for the whole anthropoid sample is represented by black dots while configurations for specimens are represented in beige. For a better understanding of the canal course variation in space the anthropoid mean configuration was used as a reference for visualizing all the configurations at the same relative scale. 14 SOM Figure S6. Configurations of the carotid canal course in Pliobates compared with fossil and extant anthropoids in anterior view: a) Pliobates (IPS58443.1); b) Epipliopithecus (NHMW 1970/1397/0003); c) Ekembo (KNM-RU 2036al); d) Victoriapithecus (KNM-MB 29100); e) Alouatta; f) Aotus; g) Cebus; h) Mico; i) Plecturocebus; j) Cercopithecus; k) Colobus; l) Mandrillus; m) Presbytis; n) Hylobates; o) Hoolock; p) Nomascus; q) 15 Symphalangus; r) Gorilla; s) Pan; t) Pongo. The mean configuration computed for the whole anthropoid sample is represented by black dots while configurations for specimens are represented in beige. For a better understanding of the canal course variation in space the anthropoid mean configuration was used as a reference for visualizing all the configurations at the same relative scale. 16 SOM Figure S7. Results of the between-group principal component analysis (bgPCA) based on carotid canal course variation among the catarrhine subsample, as depicted by a bivariate plot of bgPC2 vs. bgPC1. Convex hulls correspond to: cercopithecids (red), hylobatids (green), and hominids (gray). Abbreviation: bgPC = between-group principal component. 17 SOM Figure S8. Phylomorphospace of carotid canal course variation in extant anthropoids and extinct Miocene catarrhines including Pliobates. Epipliopithecus, Ekembo and Pliobates are considered successive stem hominoids following Alba et al. (2015: Fig. 8), while Victoriapithecus is considered a stem cercopithecoid. See SOM Figure S2a for a representation of this phylogenetic hypothesis. Ancestral nodes: 1 = crown platyrrhines; 2 = crown catarrhines; 3 = crown cercopithecoids; 4 = crown hominoids; 5 = crown hominids; 6, crown hylobatids. 18 SOM Figure S9. Configurations of the carotid canal course in Pliobates compared with other Miocene catarrhines and with the reconstructed carotid canal course for the last common ancestors (LCAs) of various anthropoid clades: a) Pliobates (IPS58443.1); b) Epipliopithecus (NHMW 1970/1397/0003); c) Ekembo (KNM-RU 2036al); d) Victoriapithecus (KNM-MB 29100); e) crown platyrrhines; f) crown catarrhines; g) crown cercopithecoids; h) crown 19 hominoids; i) crown hylobatids; j) crown hominids. The canal courses of the LCAs have been inferred based on the phylomorphospace displayed in SOM Figure S8. For each specimen/LCA, the configurations are displayed in superior (left), lateral (middle), and anterior (right) views. The mean configuration computed for the whole anthropoid sample is represented by black dots, while configurations for Miocene catarrhines and LCAs are represented in beige. The anthropoid mean configuration was used as a reference for visualizing all the configurations at the same relative scale. 20 SOM Table S1 List of extant anthropoid specimens included in this work. µCT scans were mainly downloaded from MorphoSource (https://www.morphosource.org, Duke University) or provided by Sergio Almécija (used in Urciuoli et al., 2020; µCT scans stored at the AMNH, New York, USA) and the Institut Català de Paleontologia Miquel Crusafont (ICP; Sabadell, Spain). Species ID Source Voxel size (mm) Sex DOI/Ark identifier/Occurrence ID MorphoSource ID Alouatta palliata DUEALP 04 Morphosource 0.061 M — S1924 Alouatta palliata DUEALP 06 Morphosource 0.067 M — S78 Alouatta palliata DUEALP 13 Morphosource 0.052 F — S1108 Alouatta palliata DUEALP 14 Morphosource 0.055 F — S1925 Alouatta palliata DUEALP 16 Morphosource 0.058 F — S80 Aotus griseimembra USNM 281551 Morphosource 0.036 M http://n2t.net/ark:/65665/31db1d5a6-9879-459b-b08e-89e55015542e S3994 Aotus griseimembra USNM 281552 Morphosource 0.034 F http://n2t.net/ark:/65665/3b29a3a53-e84f-4f04-9e48-bc203f45765c S3980 Aotus griseimembra USNM 284776 Morphosource 0.035 F http://n2t.net/ark:/65665/34fb1e7f4-ed5d-4d36-9f36-e7741dcd02bd S3996 Aotus griseimembra USNM 284777 Morphosource 0.035 M http://n2t.net/ark:/65665/30fe89705-6148-4207-9b9c-f5435c669587 S3997 Aotus griseimembra USNM 284779 Morphosource 0.038 F http://n2t.net/ark:/65665/354427a46-c645-4785-90d2-b08310d3110d S3979 Ateles geoffroyi AMNH-M 26593 Morphosource 0.062 F urn:catalog:AMNH:Mammals:M-26593 S5312 Ateles geoffroyi MCZ 10138 Morphosource 0.063 F http://dx.doi.org/10.17602/M2/M2917 S971 Ateles geoffroyi MCZ 29628 Morphosource 0.063 F http://dx.doi.org/10.17602/M2/M2919 S973 Cebus imitator MCZ 10135 Morphosource 0.080 F http://dx.doi.org/10.17602/M2/M5151 S1676 Cebus imitator MCZ 34326 Morphosource 0.080 F http://dx.doi.org/10.17602/M2/M5148 S1673 Cebus imitator MCZ 34353 Morphosource 0.080 F http://dx.doi.org/10.17602/M2/M5147 S1672 Cercocebus galeritus AMNH-M 52641 Morphosource 0.068 M urn:catalog:AMNH:Mammals:M-52641 S1513 Cercocebus torquatus AMNH-M 70063 Morphosource 0.118 M urn:catalog:AMNH:Mammals:M-70063 S4046 Cercocebus torquatus MCZ 32625 Morphosource 0.091 M http://dx.doi.org/10.17602/M2/M2589 S777 Cercopithecus mitis MCZ 25022 Morphosource 0.080 F http://dx.doi.org/10.17602/M2/M2929 S983 Cercopithecus mitis MCZ 26832 Morphosource 0.080 F http://dx.doi.org/10.17602/M2/M2930 S984 21 Cercopithecus mitis MCZ 7088 Morphosource 0.080 F http://dx.doi.org/10.17602/M2/M2927 S981 Chiropotes chiropotes USNM 388161 Morphosource 0.047 F http://n2t.net/ark:/65665/3bd51f984-2926-4bd6-a368-1c2be2fb4a87 S3926 Chiropotes chiropotes USNM 388163 Morphosource 0.047 F http://n2t.net/ark:/65665/3007743ab-5f8c-4542-a384-bc68d16bd910 S3928 Chiropotes chiropotes USNM 388165 Morphosource 0.049 M http://n2t.net/ark:/65665/3b5260e90-e411-4638-9257-f4e65440a1ea S3935 Chlorocebus pygerythrus SIU 4799 Morphosource 0.050 F — S4045 Chlorocebus pygerythrus SIU 4800 Morphosource 0.046 F — S4047 Chlorocebus pygerythrus SIU 4801 Morphosource 0.055 M — S4048 Colobus guereza AMNH-M 52211 Morphosource 0.073 M urn:catalog:AMNH:Mammals:M-52211 S1143 Colobus guereza AMNH-M 52213 Morphosource 0.066 F urn:catalog:AMNH:Mammals:M-52213 S3768 Colobus guereza AMNH-M 52238 Morphosource 0.068 F urn:catalog:AMNH:Mammals:M-52238 S1215 Erythrocebus patas MCZ 47015 Morphosource 0.083 M http://dx.doi.org/10.17602/M2/M2923 S977 Erythrocebus patas MCZ 47016 Morphosource 0.083 M http://dx.doi.org/10.17602/M2/M2924 S978 Erythrocebus patas MCZ 47018 Morphosource 0.083 F http://dx.doi.org/10.17602/M2/M2926 S980 Gorilla gorilla AMNH-A 999686 Morphosource 0.131 M — S5189 Gorilla gorilla AMNH-M 54356 Morphosource 0.106 F urn:catalog:AMNH:Mammals:M-54356 S5125 Gorilla gorilla MCZ 17684 Morphosource 0.126 F http://dx.doi.org/10.17602/M2/M2943 S644 Gorilla gorilla MCZ 26850 Morphosource 0.123 F http://dx.doi.org/10.17602/M2/M2947 S995 Gorilla gorilla MCZ 37264 Morphosource 0.126 F http://dx.doi.org/10.17602/M2/M2949 S997 Gorilla gorilla MCZ 46325 Morphosource 0.126 F http://dx.doi.org/10.17602/M2/M2955 S1001 Hoolock hoolock AMNH-M 112720 Morphosource 0.052 M urn:catalog:AMNH:Mammals:M-112720 S1206 Hoolock hoolock AMNH-M 201743 Morphosource 0.064 F urn:catalog:AMNH:Mammals:M-201743 S12604 Hoolock hoolock AMNH-M 83425 AMNH 0.084 F urn:catalog:AMNH:Mammals:M-83425 S1209 Hylobates agilis IPS3773 CENIEH 0.052 ? — Hylobates lar MCZ 41412 Morphosource 0.067 F http://dx.doi.org/10.17602/M2/M2961 S1005 Hylobates lar MCZ 41418 Morphosource 0.067 F http://dx.doi.org/10.17602/M2/M2967 S1008 Hylobates lar MCZ 41421 Morphosource 0.067 F http://dx.doi.org/10.17602/M2/M2969 S1009 Hylobates lar MCZ 41424 Morphosource 0.067 F http://dx.doi.org/10.17602/M2/M3007 S1017 22 Lagothrix lagotricha USNM 269839 Morphosource 0.058 F http://n2t.net/ark:/65665/3d05a410d-2384-4415-a7cb-9d53b2d58726 S3004 Lagothrix lagotricha USNM 461930 Morphosource 0.060 F http://n2t.net/ark:/65665/35d3a334f-9bc6-48e9-864d-6fe2cf11beba S3006 Lagothrix lagotricha USNM 545879 Morphosource 0.058 M http://n2t.net/ark:/65665/30f0814b2-a584-4c20-96c2-fbcb4e5778e2 S283 Lophocebus albigena MCZ 14725 Morphosource 0.090 F http://dx.doi.org/10.17602/M2/M2626 S794 Lophocebus albigena MCZ 18614 Morphosource 0.090 M http://dx.doi.org/10.17602/M2/M2622 S790 Lophocebus albigena MCZ 22737 Morphosource 0.090 F http://dx.doi.org/10.17602/M2/M2621 S789 Macaca fascicularis MCZ 12758 Morphosource 0.062 F http://dx.doi.org/10.17602/M2/M3028 S1032 Macaca fascicularis MCZ 22277 Morphosource 0.062 F http://dx.doi.org/10.17602/M2/M3029 S1033 Macaca fascicularis MCZ 23812 Morphosource 0.062 M http://dx.doi.org/10.17602/M2/M3030 S1034 Macaca fascicularis MCZ 35765 Morphosource 0.062 F http://dx.doi.org/10.17602/M2/M3033 S1037 Macaca fascicularis MCZ 41167 Morphosource 0.091 M http://dx.doi.org/10.17602/M2/M3038 S1042 Mandrillus sphinx AMNH-A 9912049 Morphosource 0.075 M — S5815 Mandrillus sphinx AMNH-M 89367 Morphosource 0.080 F urn:catalog:AMNH:Mammals:M-89367 S4599 Mandrillus sphinx MCZ 34089 Morphosource 0.126 M http://dx.doi.org/10.17602/M2/M5096 S1571 Mico argentatus MCZ 30579 Morphosource 0.041 M http://dx.doi.org/10.17602/M2/M5192 S1708 Mico argentatus MCZ 30580 Morphosource 0.041 M http://dx.doi.org/10.17602/M2/M5193 S1709 Mico argentatus MCZ 32164 Morphosource 0.041 F http://dx.doi.org/10.17602/M2/M5196 S1712 Miopithecus talapoin MCZ 23196 Morphosource 0.050 M http://dx.doi.org/10.17602/M2/M5094 S1665 Miopithecus talapoin MCZ 23197 Morphosource 0.050 M http://dx.doi.org/10.17602/M2/M5093 S1664 Miopithecus talapoin MCZ 5547 Morphosource 0.050 M http://dx.doi.org/10.17602/M2/M5087 S1659 Nasalis larvatus MCZ 37341 Morphosource 0.071 F http://dx.doi.org/10.17602/M2/M5082 S1655 Nasalis larvatus MCZ 41560 Morphosource 0.071 F http://dx.doi.org/10.17602/M2/M5056 S1642 Nasalis larvatus MCZ 41562 Morphosource 0.071 F http://dx.doi.org/10.17602/M2/M5055 S1641 Nomascus leucogenys AMNH-M 87251 Morphosource 0.105 M urn:catalog:AMNH:Mammals:M-87251 S5127 Pan paniscus AMNH-M 86857 AMNH 0.116 F urn:catalog:AMNH:Mammals:M-86857 S1590 Pan paniscus IPS9033 CENIEH 0.066 F — Pan paniscus MCZ 38018 Morphosource 0.094 M http://dx.doi.org/10.17602/M2/M4399 S1333 23 Pan paniscus MCZ 38019 Morphosource 0.092 F http://dx.doi.org/10.17602/M2/M4398 S1332 Pan paniscus MCZ 38020 Morphosource 0.099 ? http://dx.doi.org/10.17602/M2/M4397 S1331 Pan troglodytes AMNH-M 167342 Morphosource 0.089 M urn:catalog:AMNH:Mammals:M-167342 S5129 Pan troglodytes AMNH-M 167344 Morphosource 0.111 M urn:catalog:AMNH:Mammals:M-167344 S5313 Pan troglodytes IPS5698 CENIEH 0.077 M — Pan troglodytes MCZ 17702 Morphosource 0.102 F http://dx.doi.org/10.17602/M2/M4395 S1330 Pan troglodytes MCZ 23167 Morphosource 0.106 F http://dx.doi.org/10.17602/M2/M4390 S1326 Pan troglodytes MCZ 26849 Morphosource 0.106 F http://dx.doi.org/10.17602/M2/M4388 S1324 Papio anubis MCZ 17342 Morphosource 0.108 M http://dx.doi.org/10.17602/M2/M4885 S1615 Papio anubis MCZ 21160 Morphosource 0.118 M http://dx.doi.org/10.17602/M2/M4881 S1613 Papio anubis MCZ BOM 8304 Morphosource 0.118 M http://dx.doi.org/10.17602/M2/M4887 S1616 Piliocolobus badius MCZ 24080 Morphosource 0.080 M http://dx.doi.org/10.17602/M2/M2892 S947 Piliocolobus badius MCZ 24775 Morphosource 0.090 M http://dx.doi.org/10.17602/M2/M2893 S948 Piliocolobus badius MCZ 24793 Morphosource 0.080 F http://dx.doi.org/10.17602/M2/M2894 S949 Pithecia monachus MCZ 27124 Morphosource 0.050 ? http://dx.doi.org/10.17602/M2/M4708 S1496 Pithecia pithecia MCZ 30718 Morphosource 0.050 M http://dx.doi.org/10.17602/M2/M4707 S1495 Pithecia pithecia MCZ 30719 Morphosource 0.0501 F http://dx.doi.org/10.17602/M2/M4706 S1494 Plecturocebus cupreus AMNH-M 72141 Morphosource 0.049 F urn:catalog:AMNH:Mammals:M-72141 S5132 Plecturocebus cupreus AMNH-M 72143 Morphosource 0.049 M urn:catalog:AMNH:Mammals:M-72143 S5133 Plecturocebus cupreus AMNH-M 75987 Morphosource 0.051 M urn:catalog:AMNH:Mammals:M-75987 S5134 Plecturocebus cupreus AMNH-M 75988 Morphosource 0.049 F urn:catalog:AMNH:Mammals:M-75988 S5135 Plecturocebus cupreus MCZ 37828 Morphosource 0.047 M http://dx.doi.org/10.17602/M2/M5171 S1692 Pongo sp. IPS10647 CENIEH 0.077 F — Pongo sp. IPS10651 CENIEH 0.077 F — Pongo sp. IPS9031 CENIEH 0.077 F — Pongo sp. IPSSN CENIEH 0.077 F — Pongo sp. MCZ 37518 Morphosource 0.126 F http://dx.doi.org/10.17602/M2/M4613 S1458 24 Pongo sp. MCZ 35719 Morphosource 0.103 F http://dx.doi.org/10.17602/M2/M4615 S1459 Presbytis rubicunda MCZ 35704 Morphosource 0.080 F http://dx.doi.org/10.17602/M2/M4552 S1419 Presbytis rubicunda MCZ 35705 Morphosource 0.080 F http://dx.doi.org/10.17602/M2/M4551 S1418 Presbytis rubicunda MCZ 36820 Morphosource 0.080 M http://dx.doi.org/10.17602/M2/M4554 S1420 Procolobus verus AMNH-M 89438 Morphosource 0.076 F urn:catalog:AMNH:Mammals:M-89438 S4627 Procolobus verus AMNH-M 89439 Morphosource 0.080 M urn:catalog:AMNH:Mammals:M-89439 S4628 Saguinus fuscicollis AMNH-M 74051 Morphosource 0.027 F urn:catalog:AMNH:Mammals:M-74051 S4404 Saguinus midas MCZ 30597 Morphosource 0.041 M http://dx.doi.org/10.17602/M2/M4498 S1385 Saguinus midas MCZ 30601 Morphosource 0.041 M http://dx.doi.org/10.17602/M2/M4497 S1384 Saimiri sciureus MCZ 20187 Morphosource 0.047 ? http://dx.doi.org/10.17602/M2/M4486 S1373 Saimiri sciureus MCZ 30568 Morphosource 0.047 F http://dx.doi.org/10.17602/M2/M4483 S1370 Saimiri sciureus MCZ 30569 Morphosource 0.047 M http://dx.doi.org/10.17602/M2/M4447 S1362 Semnopithecus entellus AMNH-A 9912285 Morphosource 0.060 M — S4396 Semnopithecus entellus AMNH-A 9912286 Morphosource 0.108 M — S3764 Semnopithecus entellus AMNH-M 90328 Morphosource 0.052 F urn:catalog:AMNH:Mammals:M-90328 S4193 Simias concolor AMNH-M 103369 Morphosource 0.056 M urn:catalog:AMNH:Mammals:M-103369 S3558 Simias concolor AMNH-M 103371 Morphosource 0.056 F urn:catalog:AMNH:Mammals:M-103371 S3965 Symphalangus syndactylus AMNH-M 102724 Morphosource 0.062 F — S5810 Symphalangus syndactylus AMNH-M 106583 AMNH 0.079 F urn:catalog:AMNH:Mammals:M-106583 S533 Theropithecus gelada AMNH-M 238034 Morphosource 0.120 F urn:catalog:AMNH:Mammals:M-238034 S4889 Theropithecus gelada AMNH-M 60568 Morphosource 0.085 M urn:catalog:AMNH:Mammals:M-60568 S4042 Theropithecus gelada AMNH-M 80126 Morphosource 0.087 M urn:catalog:AMNH:Mammals:M-80126 S4065 Trachypithecus cristatus MCZ 35567 Morphosource 0.050 F http://dx.doi.org/10.17602/M2/M4439 S1355 Trachypithecus cristatus MCZ 35584 Morphosource 0.051 F http://dx.doi.org/10.17602/M2/M4436 S1353 Trachypithecus cristatus MCZ 35586 Morphosource 0.050 F http://dx.doi.org/10.17602/M2/M4435 S1352 Abbreviations: F = female; M = male; ? = unknown sex; AMNH = American Museum of Natural History, New York, USA; AMNH-A = American Museum of Natural History, Anthropology Collection, New York, USA; AMNH-M = American Museum of Natural History, Mammal collection, 25 New York, USA; DUEA = Duke University, Evolutionary Anthropology, Durham, USA; ICP = acronym of the collections of the Institut Català de Paleontologia Miquel Crusafont, Sabadell, Spain; MCZ = Museum of Comparative Zoology, Harvard University, Cambridge, USA; MCZ-BOM = Museum of Comparative Zoology, Bones of Mammals collection, Harvard University, Cambridge, USA; SIU = Southern Illinois University, Carbondale, USA; USNM = Smithsonian National Museum of Natural History, Washington, D.C., USA. 26 SOM Table S2 Raw data of the variables describing the orientation, proportions and course of the carotid canal in extant anthropoid specimens. Species ID 2DYZA 2DXYA L/V(1/3) bgPC1 bgPC2 Alouatta palliata DUEALP 04 66.73 30.17 3.06 -0.36 0.15 Alouatta palliata DUEALP 06 61.00 44.25 3.56 -0.40 0.17 Alouatta palliata DUEALP 13 70.71 29.86 3.17 -0.40 0.11 Alouatta palliata DUEALP 14 68.50 26.13 2.90 -0.34 0.09 Alouatta palliata DUEALP 16 64.95 38.50 3.50 -0.41 0.12 Aotus griseimembra USNM 281551 60.21 20.69 4.29 -0.41 -0.09 Aotus griseimembra USNM 281552 57.58 16.89 3.60 -0.41 -0.13 Aotus griseimembra USNM 284776 55.28 19.84 3.37 -0.24 -0.12 Aotus griseimembra USNM 284777 55.09 23.71 3.90 -0.43 -0.10 Aotus griseimembra USNM 284779 52.21 8.25 3.39 -0.27 -0.12 Ateles geoffroyi AMNH-M 26593 59.21 32.81 3.53 -0.48 0.11 Ateles geoffroyi MCZ 10138 50.66 38.21 3.69 -0.40 0.16 Ateles geoffroyi MCZ 29628 57.38 39.33 4.05 -0.32 0.11 Cebus imitator MCZ 10135 64.39 23.90 3.38 -0.41 0.02 Cebus imitator MCZ 34326 72.30 37.16 4.01 -0.48 -0.02 Cebus imitator MCZ 34353 64.19 26.39 4.14 -0.41 0.05 Cercocebus galeritus AMNH-M 52641 57.39 11.66 2.40 0.24 0.04 Cercocebus torquatus AMNH-M 70063 79.78 14.60 2.28 0.25 -0.02 Cercocebus torquatus MCZ 32625 73.83 19.02 2.91 0.22 0.10 Cercopithecus mitis MCZ 25022 57.20 -0.89 2.77 0.25 -0.06 Cercopithecus mitis MCZ 26832 58.20 1.59 2.78 0.24 -0.03 Cercopithecus mitis MCZ 7088 57.59 14.39 3.19 0.19 -0.05 Chiropotes chiropotes USNM 388161 71.59 26.41 3.23 -0.41 0.01 Chiropotes chiropotes USNM 388163 67.98 39.14 3.73 -0.43 0.06 Chiropotes chiropotes USNM 388165 63.98 34.79 3.33 -0.43 0.06 Chlorocebus pygerythrus SIU 4799 66.70 12.29 2.74 0.22 -0.10 Chlorocebus pygerythrus SIU 4800 80.13 19.28 2.84 0.16 -0.14 Chlorocebus pygerythrus SIU 4801 65.77 26.59 2.79 0.22 -0.02 Colobus guereza AMNH-M 52211 71.43 26.52 2.88 0.06 0.03 Colobus guereza AMNH-M 52213 58.93 10.06 3.13 0.10 -0.04 Colobus guereza AMNH-M 52238 76.34 18.85 2.44 0.11 0.01 Erythrocebus patas MCZ 47015 72.58 28.49 2.65 0.20 0.09 Erythrocebus patas MCZ 47016 58.13 31.28 2.86 0.11 0.14 27 Erythrocebus patas MCZ 47018 57.22 20.98 2.70 0.21 -0.02 Gorilla gorilla AMNH-A 999686 56.92 10.14 3.10 0.17 0.13 Gorilla gorilla AMNH-M 54356 50.82 6.84 2.99 0.20 0.05 Gorilla gorilla MCZ 17684 61.71 18.12 2.85 0.19 0.17 Gorilla gorilla MCZ 26850 55.54 3.89 3.28 0.17 0.12 Gorilla gorilla MCZ 37264 55.97 16.40 3.24 0.18 0.07 Gorilla gorilla MCZ 46325 56.37 12.71 3.51 0.06 0.08 Hoolock hoolock AMNH-M 112720 52.89 4.59 2.26 0.09 -0.25 Hoolock hoolock AMNH-M 201743 57.65 15.22 2.53 0.22 -0.10 Hoolock hoolock AMNH-M 83425 52.54 11.33 2.57 0.22 -0.06 Hylobates agilis IPS3773 44.51 1.00 3.19 0.20 -0.06 Hylobates lar MCZ 41412 59.84 11.48 2.63 0.16 0.04 Hylobates lar MCZ 41418 50.05 1.19 2.65 0.21 0.01 Hylobates lar MCZ 41421 78.27 2.48 1.97 0.29 0.06 Hylobates lar MCZ 41424 74.17 12.69 2.08 0.14 -0.10 Lagothrix lagotricha USNM 269839 52.40 38.35 3.78 -0.47 0.09 Lagothrix lagotricha USNM 461930 61.55 31.61 3.36 -0.32 0.11 Lagothrix lagotricha USNM 545879 59.62 34.10 4.18 -0.37 0.13 Lophocebus albigena MCZ 14725 76.19 30.79 2.53 0.06 0.00 Lophocebus albigena MCZ 18614 69.57 7.34 3.03 0.11 -0.10 Lophocebus albigena MCZ 22737 61.40 18.58 2.40 0.22 0.01 Macaca fascicularis MCZ 12758 73.31 31.62 3.84 0.09 -0.06 Macaca fascicularis MCZ 22277 70.90 13.51 2.73 0.17 -0.14 Macaca fascicularis MCZ 23812 74.49 22.03 3.07 0.09 -0.20 Macaca fascicularis MCZ 35765 73.79 26.47 2.21 0.25 -0.17 Macaca fascicularis MCZ 41167 70.90 5.01 2.77 0.27 0.03 Mandrillus sphinx AMNH-A 9912049 78.47 24.83 3.87 0.21 0.05 Mandrillus sphinx AMNH-M 89367 69.43 13.60 2.44 0.34 -0.02 Mandrillus sphinx MCZ 34089 70.52 2.25 2.37 0.32 0.12 Mico argentatus MCZ 30579 79.36 33.38 4.16 -0.07 -0.14 Mico argentatus MCZ 30580 70.89 37.76 3.40 -0.09 -0.18 Mico argentatus MCZ 32164 71.40 36.16 3.86 -0.10 -0.16 Miopithecus talapoin MCZ 23196 75.86 -3.12 3.74 0.10 -0.18 Miopithecus talapoin MCZ 23197 84.14 -3.55 3.18 0.18 -0.19 Miopithecus talapoin MCZ 5547 76.48 6.76 3.41 0.18 -0.07 Nasalis larvatus MCZ 37341 68.96 8.49 2.94 0.17 -0.10 Nasalis larvatus MCZ 41560 68.07 8.32 3.28 0.11 -0.12 Nasalis larvatus MCZ 41562 69.62 2.58 2.90 0.13 -0.29 28 Nomascus leucogenys AMNH-M 87251 46.95 10.01 2.88 0.32 -0.08 Pan paniscus AMNH-M 86857 51.61 10.73 3.15 0.11 0.15 Pan paniscus IPS9033 58.88 7.58 3.31 0.12 0.13 Pan paniscus MCZ 38018 52.37 2.45 3.53 0.20 0.18 Pan paniscus MCZ 38019 37.27 -0.82 3.35 0.12 0.14 Pan paniscus MCZ 38020 44.76 10.08 3.12 0.17 0.19 Pan troglodytes AMNH-M 167342 57.40 27.78 3.52 0.13 0.17 Pan troglodytes AMNH-M 167344 40.91 17.19 3.42 0.08 0.13 Pan troglodytes IPS5698 68.86 14.32 3.15 0.17 0.09 Pan troglodytes MCZ 17702 58.80 8.02 3.44 0.13 0.13 Pan troglodytes MCZ 23167 69.11 15.22 2.55 0.12 0.11 Pan troglodytes MCZ 26849 65.72 19.18 3.82 0.06 0.14 Papio anubis MCZ 17342 71.02 12.95 3.00 0.25 0.06 Papio anubis MCZ 21160 77.92 12.01 3.06 0.23 0.04 Papio anubis MCZ BOM 8304 84.99 13.10 2.89 0.23 0.07 Piliocolobus badius MCZ 24080 72.37 13.36 1.80 0.23 -0.11 Piliocolobus badius MCZ 24775 63.44 25.62 2.73 0.15 0.01 Piliocolobus badius MCZ 24793 70.48 26.93 1.40 0.27 -0.14 Pithecia monachus MCZ 27124 61.35 31.85 3.95 -0.35 0.09 Pithecia pithecia MCZ 30718 65.29 33.95 4.17 -0.32 0.03 Pithecia pithecia MCZ 30719 64.58 24.78 3.91 -0.28 0.02 Plecturocebus cupreus AMNH-M 72141 60.37 36.47 3.82 -0.50 -0.05 Plecturocebus cupreus AMNH-M 72143 58.98 35.27 4.03 -0.41 -0.02 Plecturocebus cupreus AMNH-M 75987 54.55 29.05 3.95 -0.47 0.05 Plecturocebus cupreus AMNH-M 75988 67.10 39.93 3.84 -0.45 -0.08 Plecturocebus cupreus MCZ 37828 59.76 34.57 4.42 -0.45 0.03 Pongo sp. IPS10647 35.58 26.47 3.08 -0.10 0.12 Pongo sp. IPS10651 57.41 14.44 3.41 0.00 0.08 Pongo sp. IPS9031 45.95 23.54 2.81 -0.03 0.09 Pongo sp. IPSSN 51.04 12.11 3.22 0.19 0.20 Pongo sp. MCZ 35719 55.71 21.61 2.61 0.14 -0.01 Pongo sp. MCZ 37518 55.44 18.00 2.57 0.17 0.07 Presbytis rubicunda MCZ 35704 73.37 9.72 3.28 0.05 -0.03 Presbytis rubicunda MCZ 35705 59.19 10.94 3.26 0.07 0.02 Presbytis rubicunda MCZ 36820 79.70 20.06 3.31 0.01 -0.05 Procolobus verus AMNH-M 89438 72.35 13.25 3.05 0.19 -0.12 Procolobus verus AMNH-M 89439 76.59 3.64 2.67 0.23 -0.13 Saguinus fuscicollis AMNH-M 74051 74.69 29.71 4.08 -0.29 -0.13 29 Saguinus midas MCZ 30597 79.05 43.03 3.18 -0.30 -0.26 Saguinus midas MCZ 30601 75.43 34.46 3.27 -0.22 -0.17 Saimiri sciureus MCZ 20187 68.68 38.36 2.91 -0.49 -0.09 Saimiri sciureus MCZ 30568 67.23 27.31 3.44 -0.36 -0.09 Saimiri sciureus MCZ 30569 70.14 38.60 3.48 -0.37 -0.10 Semnopithecus entellus AMNH-A 9912285 66.06 28.37 2.52 0.12 0.05 Semnopithecus entellus AMNH-A 9912286 64.95 33.39 3.01 0.16 0.05 Semnopithecus entellus AMNH-M 90328 62.09 25.82 3.17 0.12 0.01 Simias concolor AMNH-M 103369 73.52 29.07 3.13 0.08 -0.12 Simias concolor AMNH-M 103371 71.86 33.87 3.40 -0.11 -0.10 Symphalangus syndactylus AMNH-M 102724 38.27 19.77 3.37 0.08 0.12 Symphalangus syndactylus AMNH-M 106583 44.54 23.27 3.32 0.06 0.00 Theropithecus gelada AMNH-M 238034 66.58 7.26 2.87 0.28 0.05 Theropithecus gelada AMNH-M 60568 68.61 20.77 3.02 0.27 0.06 Theropithecus gelada AMNH-M 80126 65.87 24.69 3.11 0.21 0.08 Trachypithecus cristatus MCZ 35567 58.10 27.71 3.38 0.13 -0.07 Trachypithecus cristatus MCZ 35584 80.20 17.07 3.23 0.26 -0.12 Trachypithecus cristatus MCZ 35586 61.67 21.44 3.35 0.22 -0.02 Abbreviations: 2DYZA = 2D angle in the YZ plane (canal superior orientation; in degrees); 2DXYA = 2D angle in the XY plane (canal medial orientation; in degrees); L = length (in mm); V = volume (in mm3); bgPC = between-group principal component; AMNH = American Museum of Natural History, New York, USA; AMNH-A = American Museum of Natural History, Anthropology Collection, New York, USA; AMNH-M = American Museum of Natural History, Mammal collection, New York, USA; DUEA = Duke University, Evolutionary Anthropology, Durham, USA; ICP = acronym of the collections of the Institut Català de Paleontologia Miquel Crusafont, Sabadell, Spain; MCZ = Museum of Comparative Zoology, Harvard University, Cambridge, USA; MCZ-BOM = Museum of Comparative Zoology, Bones of Mammals collection, Harvard University, Cambridge, USA; SIU = Southern Illinois University, Carbondale, USA; USNM = Smithsonian National Museum of Natural History, Washington, D.C., USA. 30 SOM Table S3 Results of the Kruskal-Wallis comparisons for the indices and bgPCs describing the orientation, proportions and course of the carotid canal in the main extant anthropoid clades. H p 2DYZA 45.74 <0.001 2DXYA 58.57 <0.001 L/V(1/3) 63.73 <0.001 bgPC1 83.36 <0.001 bgPC2 39.31 <0.001 Abbreviations: 2DYZA = 2D angle in the YZ plane (canal superior orientation; in degrees); 2DXYA = 2D angle in the XY plane (canal medial orientation; in degrees); L = length (in mm); V = volume (in mm3); bgPC = between-group principal component; H = Kruskal-Wallis statistic. 31 SOM Table S4 Results of the Bonferroni-corrected Mann-Whitney post hoc pairwise comparisons for the indices and bgPCs describing the orientation, proportions and course of the carotid canal in the main extant anthropoid clades. Platyrrhini Cercopithecidae Hominidae Hylobatidae 2DYZA Platyrrhini — <0.01 <0.001 0.035 Cercopithecidae <0.01 — <0.001 <0.01 Hominidae <0.001 <0.001 — 1 Hylobatidae 0.035 <0.01 1 — 2DXYA Platyrrhini — <0.001 <0.001 <0.001 Cercopithecidae <0.001 — 1 0.240 Hominidae <0.001 1 — 1 Hylobatidae <0.001 0.240 1 — L/V(1/3) Platyrrhini — <0.001 <0.001 <0.001 Cercopithecidae <0.001 — <0.01 1 Hominidae <0.001 <0.01 — 0.016 Hylobatidae <0.001 1 0.016 — bgPC1 Platyrrhini — <0.001 <0.001 <0.001 Cercopithecidae <0.001 — 0.068 1 Hominidae <0.001 0.068 — 0.390 Hylobatidae <0.001 1 0.390 — bgPC2 Platyrrhini — 0.760 <0.001 1 Cercopithecidae 0.760 — <0.001 1 Hominidae <0.001 <0.001 — <0.001 Hylobatidae 1 1 <0.001 — 32 Abbreviations: 2DYZA = 2D angle in the YZ plane (canal superior orientation; in degrees); 2DXYA = 2D angle in the XY plane (canal medial orientation; in degrees); L = length (in mm); V = volume (in mm3); bgPC = between-group principal component. 33 SOM Table S5 Results of the permutational analysis of variance based on the Euclidean distances between group means. Groups correspond to the main extant anthropoid clades (i.e., platyrrhines, cercopithecids, hylobatids, and hominids) used in the bgPCA and further analyses (see the main text). The tests have been computed with the streampoint configurations (i.e., full space) and with the bgPC scores with and without cross-validation (i.e., bgPCA spaces). While p is the significance of group mean differences, the coefficient of determination (R2) denotes the variance explained by the grouping structure. p R2 Full space 0.001 0.67 bgPCA space without CV 0.001 0.77 bgPCA space with CV 0.001 0.77 Abbreviations: bgPCA = between-group principal component analysis; CV = cross-validation. 34 SOM File S1. R script used to import the 3D carotid canal surface and iteratively find the orthogonal plane to the canal passing through IRG (intersection ridge–groove) among several cutting plane possibilities. (Provided as a separate R file.) 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