This is the accepted version of the article: Arias-Martorell, Julia; Almécija, Sergio; Urciuoli, Alessandro; [et al.]. «A proxi- mal radius of Barberapithecus huerzeleri from Castell de Barberà: Implications for locomotor diversity among pliopithecoids». Journal of Human Evolution, Vol. 157 (August 2021), art. 103032. DOI 10.1016/j.jhevol.2021.103032 This version is available at https://ddd.uab.cat/record/248395 under the terms of the license A proximal radius of Barberapithecus huerzeleri from Castell de Barberà: Implications for locomotor diversity among pliopithecoids Julia Arias-Martorell a,b,*, Sergio Almécija c,d,a, Alessandro Urciuoli a, Masato Nakatsukasae, Salvador Moyà-Solà a,f,g, David M. Albaa,* 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 School of Anthropology and Conservation, Marlowe Building University of Kent, Canterbury, UK CT2 7NR, UK c Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA d New York Consortium in Evolutionary Primatology, New York, NY 10024, USA e Laboratory of Physical Anthropology, Graduate School of Science, Kyoto University, 606- 8502 Kyoto, Japan; f Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig de Lluís Companys 23, 08010 Barcelona, Spain g Unitat d’Antropologia Biològica (Departament de Biologia Animal, Biologia Vegetal i Ecologia), Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain * Corresponding authors. E-mail addresses: julia.arias@icp.cat (J. Arias-Martorell); david.alba@icp.cat (D.M. Alba). 1 1 A proximal radius of Barberapithecus huerzeleri from Castell de Barberà: Implications for 2 locomotor diversity among pliopithecoids 3 4 Abstract 5 Pliopithecoids are a diverse group of Miocene catarrhine primates from Eurasia. Their 6 positional behavior is still unknown, and many species are known exclusively from 7 dentognathic remains. Here we describe a proximal radius (IPS66267) from the late Miocene 8 of Castell de Barberà (Vallès-Penedès Basin, NE Iberian Peninsula) that represents the first 9 postcranial specimen of the pliopithecoid Barberapithecus huerzeleri. A body mass estimate 10 based on the radius is compared with dental estimates, and its morphology is compared with 11 that of extant and fossil anthropoids by qualitative means as well as by landmark-based 3D 12 geometric morphometrics. The estimated body mass of ~5 kg for IPS66267 closely matches 13 the dental estimates for the (female) holotype, thereby discounting an alternative attribution to 14 the large-bodied hominoid recorded at Castell de Barberà. In multiple features (oval and 15 moderately tilted head with a pronounced lateral lip and a restricted articular area for the 16 capitulum; proximodistally expanded proximal radioulnar joint; and short, robust and 17 anteroposteriorly compressed neck) the specimen differs from hominoids and resembles 18 instead extant non-ateline monkeys and stem catarrhines. The results of the morphometric 19 analysis further indicate that the Barberapithecus proximal radius shows closer similarities 20 with non-suspensory arboreal cercopithecoids and the dendropithecid Simiolus. From a 21 locomotor viewpoint, the radius of Barberapithecus lacks most of the features functionally 22 related to climbing and/or suspensory behaviors and displays instead a proximal radioulnar 23 joint that would have been particularly stable under pronation. On the other hand, the 24 Barberapithecus radius differs from other stem catarrhines in the less anteroposteriorly 25 compressed and less tilted radial head with a deeper capitular fovea, suggesting a somewhat 26 enhanced mobility at the elbow joint. We conclude that pronograde arboreal quadrupedalism 27 was the main component of the locomotor repertoire of Barberapithecus but that, like other 28 crouzeliids, it might have displayed better climbing abilities than pliopithecids. 29 30 Keywords: Crouzeliidae; Pliopithecidae; Fossil primates; Miocene; Functional morphology; 31 Locomotion. 32 33 1. Introduction 34 Pliopithecoids are a diverse group of early to late Miocene primates that is customarily 35 considered a Eurasian clade of stem catarrhines more derived than propliopithecoids 36 (Andrews et al., 1996; Begun, 2002, 2017; Harrison, 2005, 2013; Urciuoli et al., 2021). 37 Although pliopithecoids must have originated in Africa sometime during the Oligocene, their 38 African forerunners are uncertain (Harrison, 2013; Begun, 2017)—Rossie and MacLatchy 39 (2006) considered that Lomorupithecus from the early Miocene of Uganda is a pliopithecoid, 40 but we concur with Harrison (2010, 2013) that it is more likely a dendropithecid. Undoubted 41 pliopithecoids are not recorded until 18–17 Ma in China (Harrison and Gu, 1999; Begun, 42 2002, 2017; Harrison, 2013), slightly predating the earliest record of Eurasian hominoids 43 (Heizmann and Begun, 2001; Casanovas-Vilar et al., 2011; Roos et al., 2019; Gilbert et al., 44 2020a). Although the internal phylogeny of the group is unclear, we provisionally classify the 45 various pliopithecoid genera (see in particular Harrison and Gu, 1999; Moyà-Solà et al., 2001; 46 Begun, 2002, 2017; Harrison, 2005, 2013; Alba et al., 2010; Alba and Moyà-Solà, 2012; Alba 47 and Berning, 2013; Sankhyan et al., 2017; Harrison et al., 2020) into four different families 48 following Harrison et al. (2020): Dionysopithecidae, Pliopithecidae, Crouzeliidae and 49 Krishnapithecidae. 50 In the Iberian Peninsula, pliopithecoids are restricted to the middle and late Miocene 51 of the Vallès-Penedès Basin (Marigó et al., 2014). They include (for details about the age, see 52 Casanovas-Vilar et al., 2011, 2016a, 2016b; Alba et al., 2017, 2019): Pliopithecoidea indet. 53 from Abocador de Can Mata (ACM) locality ACM/C3-B2 (12.1 Ma; Alba et al., 2012a); 54 “Pliopithecus” sp. from Sant Quirze (~11.9–11.2 Ma; Harrison et al., 2002a); the pliopithecid 55 Pliopithecus canmatensis from several ACM localities from 11.9 to 11.7 Ma (Alba et al., 56 2010; Alba and Moyà-Solà, 2014); Crouzeliidae indet. from Can Feliu (probably <11.2 Ma; 57 Crusafont-Pairó and Golpe-Posse, 1981); the crouzeliid Barberapithecus huerzeleri from 58 Castell de Barberà (~11.2 Ma; Alba and Moyà-Solà, 2012); and the crouzeliid Egarapithecus 59 narcisoi from Torrent de Febulines (9.1 Ma; Moyà-Solà et al., 2001). Both Barberapithecus 60 and Egarapithecus were considered pliopithecids instead of crouzeliids by Begun (2002, 61 2017), but respectively crouzeliine and anapithecine crouzeliids by Harrison et al. (2020), and 62 we concur with the latter view, in agreement with the original descriptions of these genera 63 (Moyà-Solà et al., 2001; Alba and Moyà-Solà, 2012). The Vallès-Penedès pliopithecoids are 64 mostly known from dentognathic material, which hampers making locomotor inferences. 65 Only a few undescribed postcranial remains of P. canmatensis from ACM (three partial 66 phalanges, a partial metatarsal V, a femur and a humerus shaft fragments) were preliminary 67 reported by Alba and Moyà-Solà (2014). This contrasts with the partial skeleton of Pliobates 68 cataloniae, a small-bodied catarrhine from ACM locality ACM/C8-A4 (~11.6 Ma; Alba et al., 69 2015, 2017) that preserves abundant postcranial elements and shows an intriguing mixture of 70 plesiomorphic (stem catarrhine-like) and derived (crown hominoid-like) features. Pliobates 71 was recovered as a stem hominoid by the cladistic analysis performed by Alba et al. (2015), 72 but alternate cladistic analyses have suggested pliopithecoid affinities (Nengo et al., 2017; 73 Gilbert et al., 2020a, 2020b; see also Benefit and McCrossin, 2015). While the hominoid-like 74 features displayed by Pliobates in the elbow and wrist might be convergent, it shows greatest 75 dental similarities with dendropithecids rather than pliopithecoids (Alba et al., 2015). 76 Therefore, we refrain from including Pliobates in the Pliopithecoidea, pending more detailed 77 analyses of its craniodental and postcranial morphology (currently underway). 78 Elsewhere in Eurasia, the postcranial anatomy of pliopithecids is best known based on 79 three partial skeletons (one almost complete) of Epipliopithecus vindobonensis (included in 80 Pliopithecus by some authors; e.g., Harrison et al., 2020) from the middle Miocene of 81 Devínska Nová Ves, Slovakia (Zapfe and Hürzeler, 1957; Zapfe, 1958, 1961). The postcranial 82 evidence for Pliopithecus s.s. is much more limited, including a metacarpal II, a calcaneus 83 and a proximal pedal phalanx of Pliopithecus antiquus from the middle Miocene of Sansan, 84 France (Zapfe and Hürzeler, 1957; Zapfe, 1961; Senut, 2012), and a metacarpal I (Depéret, 85 1887: Pl. XIII Fig. 56; Zapfe and Hürzeler, 1957; Zapfe, 1961) and a proximal humerus 86 (Ginsburg and Mein, 1980; Arias-Martorell et al., 2015) from La Grive-Saint-Alban, France. 87 The postcranial remains of crouzeliids are also scarce and mostly limited to anapithecines, 88 including a manual proximal phalanx of Laccopithecus robustus from the late Miocene of 89 Lufeng, China (Meldrum and Pan, 1988), as well as some phalanges and two femora of 90 Anapithecus hernyaki from the late Miocene of Rudabánya, Hungary (Begun, 1988, 1993, 91 2002; Kordos and Begun, 1999, 2001). The currently known postcranials of crouzeliines only 92 include a talus and a calcaneus of Crouzelia auscitanensis from Sansan (Senut, 2012). The 93 femur of Paidopithex rhenanus from the late Miocene of Eppelsheim, Germany (Kaup, 1861; 94 Pohlig, 1895; Begun, 1992; Köhler et al., 2002) is also considered to belong to a large 95 pliopithecoid of uncertain affinities (Begun, 2002, 2017). 96 Here we describe a fragment of proximal radius (IPS66267) of a small-bodied 97 catarrhine primate from the earliest Vallesian (MN9, late Miocene) site of Castell de Barberà 98 (Vallès-Penedès Basin, NE Iberian Peninsula). The specimen was found among the 99 collections of the Institut Català de Paleontologia Miquel Crusafont (ICP) in February 2012 100 by Lars van den Hoek Ostende while revising the uncatalogued micromammal material from 101 this site. The specimen was mixed with other (non-primate) bone fragments in a box labeled 102 with the name of the site but without associated museum records about the collection date or 103 exact stratigraphic provenance. However, in all probability the specimen was collected by 104 Miquel Crusafont-Pairó’s team during the late 1960s or 1970s, when systematic excavations 105 were performed at the site (Alba et al., 2019). Castell de Barberà is one of the few sites where 106 pliopithecoids and hominoids co-occur (Andrews et al., 1996; Sukselainen et al., 2015; Alba 107 et al., 2019; DeMiguel et al., 2021). In particular, both the crouzeliine B. huerzeleri and a 108 large-bodied dryopithecine (cf. Dryopithecus fontani) have been reported from this site 109 (Crusafont Pairó and Hürzeler, 1969; Crusafont-Pairó and Golpe-Posse, 1981; Moyà-Solà et 110 al., 2005; Almécija et al., 2011, 2012; Alba et al., 2011, 2019; Alba, 2012; Alba and Moyà- 111 Solà, 2012; Marigó et al., 2014). The aim of this paper is threefold: (1) to provide a 112 description of IPS66267; (2) to estimate the body mass of the taxon to which it belongs; and 113 (3) to morphologically compare it, both qualitatively and quantitatively (by means of three- 114 dimensional geometric morphometrics [3DGM]) with extant anthropoids and extinct stem 115 catarrhines, in order to investigate its closer morphometric affinities and draw locomotor 116 inferences. We did not include Pliobates in the comparative analyses because its phylogenetic 117 position is controversial (see above) and also because its complete radius merits a deeper 118 analysis (including both the proximal and the distal epiphyses), which are beyond the scope of 119 this paper and will be provided in a forthcoming paper (Arias-Martorell et al., in prep.). Our 120 results indicate that an assignment of IPS66267 to B. huerzeleri is warranted, thereby 121 representing one of the few postcranial elements (and the first elbow joint element) currently 122 available for crouzeliids. Based on morphofunctional considerations, the implications of 123 IPS66267 for understanding locomotor diversity among the Pliopithecoidea are discussed. 124 125 2. Materials and methods 126 2.1. Studied and comparative sample 127 The proximal radius fragment from Castell de Barberà (IPS66267; Fig. 1) is housed in 128 the ICP. A 3D model of the specimen is available from MorphoSource.org (Supplementary 129 Online Material [SOM] File S1). Its morphology was qualitatively compared with extant and 130 extinct anthropoids based on 3D models, casts housed in the ICP, and the literature. The 131 comparative fossil sample for qualitative comparisons included the following species, 132 selected as representative fossils from their respective groups: 133 (a) Stem catarrhines from Africa (dendropithecids): KNM-MO 63 from Moruorot (Rose et al., 134 1992: Fig. 8; Senut, 1989: Fig. 62; Rossie et al., 2012) and KNM-MO 17022B from Kalodirr 135 locality 751 (Rose et al., 1992: Fig. 9), assigned to Simiolus enjiessi; KNM-RU 2098 from 136 Rusinga Island (Le Gros Clark and Thomas, 1951: Pl. 4 fig. 9, Pl. 5 fig. 11; Senut, 1989: Fig. 137 76, Pl. X), assigned to Dendropithecus macinnesi; 138 (b) Stem catarrhines from Europe (pliopithecoids): The radii of individuals I (catalog No. O. 139 E. 304 PCe) and II (catalog No. NHMW 1970/1397/0003) from Devínska Nová Ves (Zapfe, 140 1958: Pl. 1A, B; Zapfe, 1961: Fig. 54; Senut, 1989: Fig. 95, Pl. XV), assigned to E. 141 vindobonensis; 142 (c) Stem hominoids: KNM-RU 2036AI (left radius; Napier and Davis, 1959: Pl. 6 Fig. 20g, 143 Pl. 7 Figs. 22–24) and 2036CE (right proximal radius; Walker and Pickford, 1983: Fig. 4; 144 Senut, 1989: Fig. 74, Pl. VII) from Rusinga Island, assigned to Ekembo heseloni (see 145 McNulty et al., 2015); KNM-TH 28860-J (proximal right radius; Ward et al., 1999: Fig 2k; 146 Sherwood et al., 2002: Fig. 1f) from locality BPRP122 at Kipsaramon in the Tugen Hills, 147 assigned to Equatorius africanus; and KNM-WK 16950J (proximal left radius; Leakey and 148 Leakey, 1986; Leakey et al., 1988: Fig. 5) from Kalodirr, assigned to Turkanapithecus 149 kalakolensis. 150 (d) Fossil great apes: RUD 66 from Rudabánya (Morbeck, 1983: Fig. 2D), assigned to 151 Rudapithecus hungaricus; AS95.503 from Sinap locality 12 (Kappelman et al., 2003: Fig. 152 4.26), assigned to Ankarapithecus meteai; TNA 0001 (partial proximal right radius; Lin et al, 153 1987: Fig.1; Harrison et al., 2002b) from the Shihuiba site in Lufeng County, Yunnan 154 Province, assigned to Lufengpithecus lufengensis. 155 We also performed quantitative analyses using 3DGM, which include an extant 156 anthropoid sample of 117 3D models from 17 genera (Table 1; SOM Table S1). The 3D 157 models were produced using a NextEngine surface scanner (NextEngine, Inc., California, 158 USA) and two different high-resolution μCT scanners (SOM Table S1): a BIR ACTIS 159 225/300 industrial μCT scanner (Department of Human Evolution, Max Planck Institute for 160 Evolutionary Anthropology, Germany) and a Nikon XT 225 ST μCT scanner (Cambridge 161 Biotomography Centre, Department of Zoology, University of Cambridge, UK). Specimens 162 scanned with the NextEngine scanner were obtained using a resolution of >10,000 points per 163 square inch; 6–12 scans were taken at two or more positions and then merged using 164 ScanStudio HD PRO software v. 1.3.2 (Next Engine, Santa Monica). The isotropic voxel size 165 range for the μCT scans sample is 21.9–51.5 μm. Laser scan-derived 3D models were cleaned 166 (fill holes, irregularities in mesh, etc.) using Geomagic Wrap 2017 (3D Systems, Inc. 167 Morrisville), and μCT scans were processed in AVIZO v. 6.3 (Visualization Sciences Group, 168 Berlin). 3D models obtained using different scanning techniques have been shown to produce 169 reliable and repeatable measurements (Tocheri et al., 2011; Shearer et al., 2017). Therefore, 170 all models were analyzed using the same software and methodology (IDAV Landmark Editor 171 v. 3.6; Wiley et al., 2005) irrespective of digitalization techniques. To assess the reliability of 172 high-quality casts for identifying the features described in the landmark protocol, a high- 173 quality cast of IPS667267 was landmarked and included alongside the original specimen in 174 the 3DGM analyses. Both fall very close to one another in the morphospace (SOM Fig. S1; 175 SOM Table S2), suggesting that the effect of relying on casts instead of original fossil 176 specimens is negligible for the purposes of our study. 177 The fossil sample for 3DGM analyses included a subsample (based on the 3D surfaces 178 available to us) of the extinct taxa included in the qualitative assessment: the small-bodied 179 stem catarrhines S. enjiessi (KNM-MO 63 and KNM-MO 17022B), D. macinnesi (KNM-RU 180 2098), and E. vindobonensis (O. E. 203 PCe); and Ek. heseloni (KNM-RU 2036AI), which 181 was included to adequately calibrate the stem hominoid condition. The Simiolus and 182 Epipliopithecus specimens were scanned from high-quality casts housed at the ICP: KNM- 183 RU 2098 and KNM-RU 2036CE (D. macinnesi and Ek. heseloni, respectively, which are both 184 housed in the National Museums of Kenya in Nairobi, Kenya) and IPS66267 (housed at the 185 ICP), which were scanned from the original specimens. All 3D models of the fossil material 186 were obtained using a NextEngine surface laser scanner using the HD3 macro mode and 187 landmarked alongside the extant sample in Landmark Editor. 188 189 2.2. Body mass estimation 190 Body mass (BM, in kg) was estimated for IPS66267 based on radial head surface area 191 (RHSA, in mm2) using the ‘total sample’ (cercopithecoids + hominoids) allometric equation 192 reported by Ruff (2003: Table 7). Following Ruff (2002: Appendix Table 1), RHSA was 193 computed as 0.785 × RHML × RHAP, where RHML and RHAP are radial head mediolateral 194 and anteroposterior breadths (Ruff, 2002: Appendix Fig. 1). Logarithmic detransformation 195 bias (Smith, 1993) was corrected using the quasimaximum likelihood estimator provided by 196 Ruff (2003: Table 3) and the 95% CI for the prediction was calculated based on the standard 197 error of estimate (SEE) and an inverse Student’s t distribution with the degrees of freedom 198 provided by the same author. 199 BM was also estimated for the (female) holotype of B. huerzeleri (IPS1724) based on 200 the dental measurements. Following Egi et al. (2004), only first and second upper and lower 201 molars were used. These dental BM estimates were derived from Egi et al.’s (2004: Table 2) 202 anthropoid allometric equations based on occlusal area (mm2). The latter was computed as the 203 product between mesiodistal length and buccolingual width as reported by Alba and Moyà- 204 Solà (2012), by averaging left and right antimeres when available. Logarithmic 205 detransformation bias was corrected using the ratio estimator as reported by Egi et al. (2004: 206 Table 2). The 95% CIs for the prediction based on each tooth were computed using the SEE 207 and an inverse Student’s t distribution with the degrees of freedom determined by effective 208 sample size as reported by Egi et al. (2004). An average BM estimate was then computed for 209 IPS1724 based on the mean estimate and the maximum and minimum 95% CIs for the four 210 molars. 211 212 2.3. Geometric morphometric analyses 213 The shape affinities of the proximal radius of IPS66267 were explored using 14 3D 214 surface landmarks (Table 2; Fig. 2) on a sample of extant anthropoid radii including all extant 215 hominoid genera (Table 1; SOM Table S1). The landmark protocol was designed specifically 216 to capture the most informative elements of shape preserved in IPS66267, which is missing 217 part of the posteromedial aspect of the radial head (see Section 3.1. below for a full 218 description of preservation; Fig. 1). Therefore, no landmarks were placed in the posterior and 219 medial aspects of the radial head or the distally extending posteromedial articular surface. 220 Regarding the orientation of the radii for type II and III landmark identification, 221 complete radii (i.e., those included in the extant sample, as well as the fossil specimen of E. 222 vindobonensis) were anatomically oriented in anterior view, which readily allowed the 223 identification of the medial, lateral and posterior aspects of the radial head. The partial fossil 224 specimens were oriented based on the anterior position of the radial tuberosity, which was 225 preserved in all individuals and allowed us to anatomically identify the anterior aspect of the 226 radius. Some of the landmarks had been used in previous studies, such as some of those 227 placed on the deepest point of the fovea and outline of the radial head (Tallman, 2010, 2013). 228 We added additional landmarks that account for the position and size of the fovea relative to 229 the radial head outline, which has direct implications for the discrimination between 230 cercopithecoids and hominoids (Rose 1987; Rose et al., 1992), and landmarks on the distal 231 expansion of the articular surface of the radial head, which clearly separates hominoids from 232 other taxa (Harrison, 1987), and on the radial neck, which is also a known aspect of variation 233 between hominoids, cercopithecoids, platyrrhines and fossil taxa (Rose et al., 1992). The 234 coordinates were translated, rotated and size-scaled to unit centroid size (CS) using a 235 generalized Procrustes analysis (GPA) with the ‘Morpho’ v. 2.8 package (Schlager, 2017) in 236 R v. 3.6.1. (R Core Team, 2019). To identify major patterns of shape variation across the 237 sample, we performed a between-group principal component analysis (bgPCA; Mitteroecker 238 and Bookstein, 2011) on the GPA-transformed coordinates of the extant sample, with major 239 anthropoid clades (platyrrhines, cercopithecines, colobines, hylobatids, and hominids) as the 240 grouping factor. The fossil configurations were projected a posteriori onto the morphospace 241 generated by the bgPCA. To address the criticisms raised on the use of bgPCA on highly- 242 multivariate data sets (as it is the case of 3DGM data; Bookstein, 2019; Cardini et al., 2019; 243 Cardini and Polly, 2020), and to rule out the presence of spurious grouping in the sample, we 244 computed a cross-validated bgPCA and compared the results to those of a standard bgPCA. 245 Group mean differences were tested with a permutational analysis of variance 246 (PERMANOVA; 1000 permutations) based on the Euclidean distances between the means, 247 and we computed the Z-scores and the R2 (i.e., the amount of variance explained) for group 248 differences in the raw shape data, and the scores of both the standard and the cross-validated 249 bgPCAs using the ‘vegan’ v. 2.5 package (Oksanen et al., 2020) in R. We determined the 250 number of between-group principal components (bgPCs) with meaningful direction (i.e., 251 those worth interpreting and keeping for subsequent analyses; Bookstein, 2014) with the 252 ‘getMeaningfulPCs’ function in ‘Morpho’. The correlation between meaningful bgPC scores 253 and log-transformed CS (with natural logarithms, ln CS) was computed by means of a 254 phylogenetic generalized least squares (PGLS) regression (Adams, 2014) using the 255 ‘geomorph’ v. 3.1.1 package (Adams et al., 2020) in R. 256 The phylogenetic signal embedded in proximal radius shape among extant anthropoids 257 was quantified by means of Pagel’s λ (Pagel, 1999) and Blomberg’s K statistics (Blomberg et 258 al., 2003), computed for the meaningful bgPCs using the ‘phytools’ v. 0.6-60 package 259 (Revell, 2012) in R. Both Pagel's λ and Blomberg's K test the null hypothesis of no 260 phylogenetic signal (i.e., closely related species do not resemble each other more than distant 261 relatives) by comparing the observed data distribution to that expected under a Brownian 262 motion model of evolution. Despite the underlying similarities, the two statistics provide 263 different information. Pagel’s λ is a scaling factor quantifying the influence of the taxa 264 phylogenetic relatedness on the covariance matrix of the analyzed trait (Pagel, 1999; 265 Freckleton et al., 2002): λ = 1 implies that trait covariance is exclusively influenced by the 266 phylogeny (i.e., under a Brownian motion model of evolution), λ < 1 suggests that other 267 factors besides phylogeny influence trait evolution, and λ = 0 is obtained when no 268 phylogenetic correlation is found in the data. In turn, Blomberg’s K informs about how well 269 the distribution of the phylogenetic tree tips reflects the patterns of variance-covariance found 270 in the data. Similar to the Pagel’s λ statistics, K = 0 implies a model of evolution that closely 271 resembles that expected under Brownian motion; for K < 1, the variance accumulates within 272 the clades, with closely related taxa resembling each other less than expected, possibly as a 273 consequence of independent evolution (i.e., homoplasy); finally, when K > 1, not closely 274 related taxa are more similar than expected under a Brownian motion model of evolution, thus 275 implying the variance accumulates among clades (as the result of stabilizing selection or 276 architectural constraints). 277 We also used a phylomorphospace approach (Sidlauskas, 2008) to visualize the 278 magnitude and direction of major patterns of shape variation along the phylogeny. This 279 method projects a phylogenetic tree onto a given tangent space (here defined by the first two 280 bgPCs) by estimating ancestral node scores via a maximum likelihood method for continuous 281 characters and by using the centroid scores of the included species as the tips of the tree 282 branches. We relied on a molecular-based time-calibrated phylogenetic tree downloaded from 283 10kTrees website v. 3 (Arnold et al., 2010) for the extant taxa. The extinct taxa were added 284 according to their phylogenetic relationships as inferred by recent cladistic studies (Gilbert et 285 al., 2020b: Fig. 4), i.e., S. enjiessi and D. macinnesi were considered sister taxa preceding the 286 Eurasian stem catarrhine E. vindobonensis, whereas Ek. heseloni was considered a stem 287 hominoid; B. huerzeleri was included as the sister-taxon of E. vindobonensis based on the 288 assumption that pliopithecoids are monophyletic (e.g., Gilbert et al., 2020b). The divergence 289 time of the nodes for extinct taxa was arbitrarily set 1 Myr prior to the divergence between the 290 next derived node (Almécija et al., 2019; Urciuoli et al., 2021). The tip age estimates used for 291 the fossils were the following: E. vindobonensis, 14.15 Ma (average of the maximum and 292 minimum age ranges for MN6 in central Europe; van der Meulen et al., 2011); S. enjiessi, 293 17.2 Ma (average of the ages of Kalodirr [16.7 Ma] and Moruorot [17.7 Ma]; Rose et al., 294 1992); D. macinnesi, 17.8 Ma (age of locality R3a from the Hiwegi Formation of Rusinga 295 Island; Drake et al., 1988; Senut, 1989; Peppe et al., 2009); Ek. heseloni, 17.8 Ma (age of the 296 Kulu Formation of Rusinga Island; Peppe et al., 2009); and B. huerzeleri, 11.2 Ma (age of 297 Castell de Barberà; Alba et al., 2019). 298 299 3. Results 300 3.1. Description 301 IPS66267 is a 1.9 cm-long proximal fragment of a right radius (Figs. 1 and 3a, b), 302 similar in size to those of Simiolus enjiessi (Fig. 3c, d) but clearly smaller than the radius of E. 303 vindobonensis (Fig. 3e, f), and more closely approching in size the radii of the smallest 304 hylobatids (Fig. 3g, h). The shaft is broken close to the proximal limit of the radial tuberosity 305 (Figs. 1a, 3a). The specimen is generally well preserved, except for some abrasion and 306 breakage on the posteromedial border of the radial head (Figs. 1c–e and 3b). Although this 307 abrasion hinders a precise evaluation of the proximal radial outline, the preserved portion 308 clearly shows that the radial head is oval (Figs. 1e and 3b), with its major diameter passing 309 anterolaterally to posterolaterally—assuming that the radial tuberosity is roughly situated 310 anteriorly. 311 The proximal articular surface for the capitulum of the humerus (Figs. 1e and 3b) is 312 restricted, but relatively deep. The fovea is eccentrically situated toward the posteromedial 313 portion of the radial head. The articular surface for the zona conoidea of the humerus is more 314 extensive medially (Fig. 1d) and, especially, laterally (Fig. 1b). There is a pronounced lateral 315 lip (Figs. 1a–c and 3a), and the bevel for articulation with the zona conoidea of the humerus is 316 restricted to the posterolateral side of the radial head (Fig. 1b, c). The head appears to have 317 been more elevated medially than laterally (Figs. 1a, c and 3a), although abrasion on its 318 posteromedial portion makes it difficult to ascertain the presence of a proximally projecting 319 tubercle (Fig. 1c, d). 320 The articular surface corresponding to the proximal radioulnar joint is proximodistally 321 more extensive on the anteromedial than on the posterolateral portion of the radial head. The 322 presence and extent of a flattened posterior region cannot be adequately ascertained due to 323 incomplete preservation. The radial head is tilted anterolaterally relative to the proximodistal 324 long axis of the neck, at an angle of ca. 82º. The neck is relatively wide mediolaterally (i.e., 325 only moderately constricted relative to the head; Figs. 1a, c and 3a), but very compressed 326 anteroposteriorly (Fig. 1b, d). Otherwise, the morphology of the radial neck cannot be 327 properly evaluated, due to incomplete preservation (only until close to the proximal end of the 328 tuberosity). However, the presence of a ridge along the anteromedial portion of the neck (Fig. 329 1a, c)—presumably corresponding to the proximal extension of the biceps muscle insertion on 330 the bicipital tuberosity—suggests that the neck would have been quite short. 331 332 3.2. Body mass estimates 333 The measurements taken on the proximal radius (Table 3) yield a BM estimate of 4.9 334 kg (CI = 4.4–5.3 kg), which closely matches the dental BM estimate of ~5.3 kg (CI = 4.0–6.7) 335 computed for the holotype specimen (see Table 3 for estimates derived for each molar, which 336 largely overlap with one another). 337 338 3.3. Qualitative comparisons 339 The oval proximal outline of the head of IPS66267 (Figs. 1e and 3b) resembles that of 340 extant monkeys such as Colobus and Cebus, as well as extinct stem catarrhines such as 341 Simiolus (Fig. 3d; Rose et al., 1992). Compared with the radial head of Epipliopithecus (Fig. 342 3f; Zapfe, 1958, 1961), IPS66267 is somewhat less broad mediolaterally, although all the 343 above-mentioned taxa differ from the hominoid pattern characterized by roughly circular 344 radial heads (Fig. 3g, h). The restricted and eccentrically situated area for articulation with the 345 humeral capitulum in IPS66267 further resembles the morphology of both extant and extinct 346 non-hominoid anthropoids, although the fovea is somewhat deeper. This morphology suggests 347 for IPS66267 a more globular humeral capitulum than in the above-mentioned non-hominoid 348 taxa (including Dendropithecus, Simiolus and Epipliopithecus), although still smaller than in 349 extant and extinct hominoids. In this respect, stem hominoids such as Ekembo, 350 Turkanapithecus and Equatorius, as well as the fossil hominid Lufengpithecus, already 351 display a more derived pattern (Walker and Pickford, 1983; Leakey et al., 1988; Lin et al., 352 1987; Rose et al., 1992; Rose, 1993a; Ward et al., 1999; Sherwood et al., 2002)— 353 characterized by more circular radial heads, as well as larger and deeper foveae—which more 354 closely resembles that in extant apes and humans. 355 The pronounced lateral lip of IPS66267 also resembles that of extant monkeys, 356 dendropithecids and Epipliopithecus (Rose et al., 1992). In contrast, in extant hominoids the 357 lateral lip is much less developed and more similar in size to the medial one. In this respect, 358 the stem hominoids Ekembo, Turkanapithecus, and Equatorius (Walker and Pickford, 1983; 359 Rose et al., 1992), as well as the fossil great apes Ankarapithecus (Kappelman et al., 2003), 360 Rudapithecus (Morbeck, 1983; Rose et al., 1992) and Lufengpithecus (Lin et al., 1987; Rose, 361 1997) show an intermediate condition (i.e., a moderately developed lateral lip). With regard to 362 the bevel for articulation with the zona conoidea, in IPS66267 it is restricted to the region of 363 the lateral lip, as in non-hominoid anthropoids (Rose et al., 1992), whereas in hominoids it 364 occupies most of the radial head contour and it is visible in side view. Stem hominoids also 365 display an intermediate condition for this feature, with a beveled area that is more extensive in 366 side view than in non-hominoid anthropoids, and which is not restricted to the lateral lip 367 (Walker and Pickford, 1983; Leakey et al., 1988; Rose et al., 1992; Sherwood et al., 2002). 368 Ankarapithecus and Lufengpithecus show a more derived pattern than stem hominoids, with 369 the bevel being well developed both anteriorly and medially (Lin et al., 1987; Rose, 1993a, 370 1997; Kappelman et al., 2003). 371 The medial elevation of the radial head (relative to its lateral portion) in IPS66267 is 372 also displayed to some degree by most anthropoids, being related to the anterolateral 373 angulation of the head relative to the neck. The development of this feature in IPS66267 is 374 intermediate between the condition displayed by non-hominoid anthropoids and that of both 375 hominoids and atelines (i.e., subfamily Atelinae, which includes the woolly and spider 376 monkeys), in which the angulation is less marked. In this respect, the similar degree of tilting 377 of the radial head in Epipliopithecus and Dendropithecus is more pronounced than that of 378 IPS66267, so that the former taxa more closely resemble the condition of most non-hominoid 379 catarrhines (Zapfe, 1961; Rose et al., 1992; Rose, 1993a, 1994). In contrast, the morphology 380 of Ekembo, Equatorius and Turkanapithecus (Walker and Pickford, 1983; Rose et al., 1992; 381 Ward et al. 1999; Sherwood et al., 2002; Leakey et al., 1988), with no medial elevation of the 382 head, resembles the extant hominoid condition much more closely than IPS66267. 383 IPS66267 shows a marked proximodistal extension of the articular surface of the 384 proximal radioulnar joint on the anteromedial portion of the radial head, compared to its 385 posterolateral portion, which is another typical feature of anthropoids—excluding atelines and 386 hominoids. Thus, IPS66267 does not differ from the condition of Epipliopithecus and the 387 dendropithecids Simiolus and Dendropithecus (Rose et al., 1992; Rose, 1993a). Only extinct 388 hominoids (Ekembo, Turkanapithecus, Equatorius, Ankarapithecus and Lufengpithecus) 389 approximate to some degree the extant hominoid condition, with the proximal radioulnar joint 390 occupying part of the radial head periphery (Lin et al., 1987; Leakey et al., 1988; Rose, 1997; 391 Rose et al., 1992; Sherwood et al., 2002; Kappelman et al., 2003). Similarly, the 392 mediolaterally broad but anteroposteriorly quite compressed radial neck of IPS66267 is also 393 characteristic of most anthropoids (except hominoids and atelines), including Epipliopithecus, 394 Simiolus and Dendropithecus (Rose et al., 1992), so that only in Ekembo the neck is less 395 compressed anteroposteriorly—the radial neck of Equatorius and Turkanapithecus appears to 396 be slightly more compressed than in Ekembo (Leakey et al., 1988; Ward et al., 1999; 397 Sherwood et al., 2002). 398 399 3.4. Proximal radial shape analysis 400 The bgPCA (Fig. 4) discriminates among extant hominoids, cercopithecoids and 401 platyrrhines. In particular, the analysis correctly classifies 73% of cases (70% after cross- 402 validation; SOM Fig. S2a, b) in the five groups defined a priori (platyrrhines, cercopithecines, 403 colobines, hylobatids, and hominids). Group differences were significant at p < 0.001 404 irrespective of whether the raw data or bgPCA (either standard or cross-validated) data were 405 analyzed. The Z-scores were similar for the raw data (8.12), standard bgPCA (10.45) and cross- 406 validated bgPCA (10.45), and R2 increased to some extent from the raw data comparisons (0.24) 407 to cross-validated (0.46) and standard (0.46) bgPCA—overall indicating that grouping structure 408 is not spurious but that variance may also be influenced by other factor(s). bgPC3 and bgPC4 409 only accounted for <10% of variance each, were not reported back as meaningful, and yielded 410 no meaningful discrimination; therefore, only the results for bgPC1 and bgPC2 are given below. 411 bgPC1 (69% of variance) is significantly correlated with ln CS (p = 0.001), with great 412 apes and humans displaying the most negative values. However, CS only accounts for a 413 limited amount of shape variation (R2 = 0.35, adjusted R2 = 0.33), as best illustrated by the 414 fact that hylobatids and Ateles considerably overlap with hominids. bgPC1 embeds significant 415 phylogenetic signal (K = 0.42, p = 0.004; λ = 0.73, p = 0.03), but the low value of both K < 1 416 and λ < 1 suggests a considerable amount of homoplasy. Overall, this axis discriminates 417 between hominoids (hominids with negative scores, and hylobatids with slightly negative to 418 intermediate scores) and most monkeys (more positive scores, particularly in colobines and 419 platyrrhines)—with the exception of Ateles, which partly overlaps the hominoid (particularly, 420 hylobatid) range of variation (Fig. 4). With the exception of Ekembo, which occupies 421 intermediate scores, all the other fossils including Barberapithecus fall squarely within the 422 monkey distribution apart from hominoids, with Epipliopithecus having the most positive 423 score among the fossils, closely followed by Dendropithecus (Fig. 4). Shape differences along 424 bgPC1 are driven by the shape of the radial head (Fig. 4a–d). The more positive scores 425 displayed by stem catarrhines and monkeys other than Ateles denote more oval radial heads in 426 proximal view (Fig. 4c) and a marked medial elevation of the head in anterior view (Fig. 4d), 427 which results into an anterolateral angulation of the head. In contrast, hominoids and Ateles, 428 which display negative scores, have a more circular head (Fig. 4a) that is not tilted (Fig. 4b). 429 Furthermore, in the groups with more positive scores the articular surface extends less distally 430 onto the side of the head, particularly laterally and medially, while hominoids and Ateles have 431 a well-developed distal expansion of the articular surface with beveling. 432 bgPC2 (19% of variance), which is not correlated with ln CS (p = 0.83), distinguishes 433 between platyrrhines and cercopithecoids with only a slight overlap between cebids and 434 colobines (Fig. 4). This axis embeds no significant phylogenetic signal (K = 0.18, p = 0.60; λ 435 = 0.27, p = 0.16). Barberapithecus and a Simiolus specimen (KNM-MO 17022B) and Ekembo 436 (albeit, with somewhat more negative values) occupy an intermediate position between 437 colobines and platyrrhines, whereas the other Simiolus specimen (KNM-MO 63), 438 Epipliopithecus and, in particular, Dendropithecus, show very negative scores and more 439 closely align with platyrrhines (other than Ateles). Shape differences along bgPC2 are driven 440 by the size (larger vs. smaller) and position (eccentric vs. centrally located) of the fovea 441 relative to the radial head outline, as well as its relative depth (i.e., shallower vs. deeper). 442 Specimens with positive scores have a larger, deeper, and non-eccentric (i.e., centrally placed) 443 fovea as well as a more rounded head outline (Fig. 4g), whereas specimens with negative 444 scores display a shallower, more eccentric and restricted fovea together with an oval head 445 outline (Fig. 4e). Negative scores further denote a slightly more tilted head (Fig. 4f) as 446 compared with specimens with more positive scores (Fig. 4h). 447 The phylomorphospace approach (Fig. 5) reconstructs the LCAs of crown anthropoids, 448 crown platyrrhines, and crown catarrhines as very similar to one another, being characterized 449 by positive bgPC1 and negative bgPC2 scores, and essentially displaying a non-ateline 450 platyrrhine-like morphology most similar to that of Alouatta. The LCA reconstructed for the 451 two analyzed pliopithecoids is virtually identical to those of crown anthropoids and crown 452 platyrrhines, and broadly similar to the dendropithecid Simiolus and the crown catarrhine 453 LCA. However, note that the LCA of anthropoids was left unrooted so that its position could 454 shift to some extent if stem anthropoids were incorporated into the analysis. Similarly, the 455 position of the LCAs of pliopithecoids and of Simiolus + crown catarrhines might slightly 456 vary depending on the divergence time arbitrarily chosen for computing their estimation. 457 Barberapithecus is most similar to Cebus, whereas Epipliopithecus and Dendropithecus 458 appear more divergent and convergent with Lagothrix by showing extremely positive bgPC1 459 scores. In turn, the LCA of crown cercopithecoids appears slightly derived toward more 460 positive bgPC2 scores than platyrrhines, whereas that of crown hominoids is markedly more 461 derived toward the modern ape condition (characterized by more negative scores along 462 bgPC1). The stem hominoid Ekembo is closely situated to the hominoid LCA and occupies an 463 intermediate position between platyrrhines and living apes along bgPC1. Ateles shows a 464 displacement toward negative values (i.e., toward the hominoids) in bgPC1 alongside 465 Mandrillus, even though they are clearly differentiated in bgPC2. Remarkably, among the 466 fossil taxa, Dendropithecus shows the most extreme negative scores for bgPC2 (followed 467 closely by Epipliopithecus). 468 469 4. Discussion 470 4.1. The catarrhine elbow complex 471 Our results indicate that the overall shape of the proximal radius is only partially 472 explained by the phylogenetic relationships among taxa because locomotor adaptation has 473 played a significant role in shaping elbow joint morphology and, specifically, the proximal 474 radius (Harrison 1987; Rose, 1993a). In particular, we found no significant phylogenetic 475 signal in bgPC2 (probably because the hominoid scatter encompasses entirely that of 476 monkeys; Fig. 4), while bgPC1 embedded significant phylogenetic signal but with low values 477 of K and λ (denoting homoplasy). To further explore these results, alternative evolutionary 478 models should be tested in the future under different phylogenetic assumptions, as our model 479 is based on the most simplistic approach. 480 Of the few analyses devoted to the proximal radius published to date, Patel (2005) did 481 not detect a functional signal in the proximal radius of extant hominoids, as they display 482 entirely similar and distinctly derived humeroantebrachial articular complexes (e.g., 483 Sarmiento et al., 2002: Fig. 4). However, Patel (2005) relied on linear measurements and did 484 not explore the evolutionary implications of proximal radial shape in fossil apes or other 485 catarrhines except hominins, which are essentially like other extant hominoids. Tallman 486 (2010) also found poor separation between taxa in her 3DGM analysis, and attributed it to 487 intraobserver error due to reliance on type II and III landmarks around the radial head. This 488 study, however, used only four landmarks on the radial head and one on the deepest point of 489 the fovea to explore proximal radial shape, and, similarly to Patel (2005), did not include non- 490 hominoid primates in the comparative extant taxa. In contrast, our results, based on a wider 491 sample of anthropoids, have been able to identify an important role of function in the 492 proximal radius shape variation—best illustrated by the convergence in proximal radius 493 morphology between Ateles and hominoids, with the former overlapping the hominoid 494 morphospace in the bgPCA despite being placed in different a priori groups (see below for 495 further discussion). In the same vein, in the phylomorphospace analysis we detected a 496 considerable amount of homoplasy, which might have been at least partly brought about by 497 the morphological convergence between Ateles and hominoids (especially hylobatids), 498 although the results also indicate some degree of convergence between Hylobates agilis and 499 Mandrillus sphinx. Additional analyses based on a landmark protocol for the full proximal 500 radial shape would be needed to confirm and better characterize the latter apparent 501 convergence. In contrast, Ateles shares with hominoids a more rounded outline and deeper 502 fovea than in cercopithecoids and quadrupedal platyrrhines, as well as a less tilted head and 503 the presence of a bevel (albeit better developed in hominoids, where it encompasses the whole 504 circumference of the head) beyond the lateral lip of the radial head. Our quantitative shape 505 analyses thus agree with previous reports, based on linear measurements, that found 506 convergence between Ateles and hominoids in the elbow in general (Ashton et al., 1971) and 507 more specifically for proximal radial morphology, among other elements of the forelimb 508 (Takahashi, 1990; Larson 1998). The traits shared with Ateles are part of the derived elbow 509 joint complex characteristic of modern hominoids, which has been described extensively in 510 the literature (Rose 1988; Sarmiento et al., 2002; Patel, 2005). . The derived condition of 511 hominoids (and Ateles) in the proximal radius is readily reflected in our 3DGM analyses— 512 especially bgPC1, because shape differences along bgPC2 are more difficult to interpret (both 513 from a functional and a phylogenetic viewpoint). Such characteristics are functionally related 514 to wide pronation/supination ranges and, together with multiple derived features of the 515 humeroulnar joint enabling a wide range of flexion/(hyper)extension, they allow hominoids to 516 maintain considerable joint stability in a variety of elbow postures (Morbeck, 1976; Harrison, 517 1982; Sarmiento, 1987, 1988; Rose, 1988, 1993b; Begun, 1992; Kelley, 1997; Alba et al., 518 2011). 519 An essentially primitive elbow morphology more closely representing the ancestral 520 anthropoid morphotype (Rose, 1988, 1993a, 1994, 1997; Senut, 1989) is reflected in both the 521 Miocene dendropithecids from Africa (Dendropithecus and Simiolus; Le Gros Clark and 522 Thomas, 1951; Harrison, 1982; Fleagle, 1983; Rose, 1988, 1993a, 1994, 1997; Senut, 1989; 523 Rose et al., 1992) and the pliopithecoids from Eurasia (Zapfe, 1958, 1961; Fleagle, 1983; 524 Rose, 1993a, 1994). The primitive catarrhine elbow complex is characterized, regarding the 525 radius, by (1) a relatively small and flat fovea, (2) a broad peripheral lateral surface, resulting 526 in an asymmetrical (oval) proximal outline of the radial head, and (3) an articular surface that 527 extends distally and involves the anteromedial side of the radial head, being most suited to 528 stability maintenance in a flexed-elbow and pronated hand posture (i.e., the load-bearing 529 phase of quadrupedal progression; Rose, 1988). 530 Regarding the above, our results further support the notion that, in terms of proximal 531 radial head, hominoids and cercopithecoids diverged in opposite directions from the ancestral 532 anthropoid morphotype (Rose, 1988). However, paleontological evidence indicates that the 533 hominoid elbow complex evolved in a mosaic-like, stepwise fashion (Rose, 1983, 1988, 534 1993a; Alba et al., 2011, 2012b, 2015). Our results highlight that the proximal radius 535 morphology of stem hominoids such as Ekembo, Turkanapithecus and Equatorius is 536 intermediate between extant hominoids and cercopithecoids (Napier and Davis, 1959; 537 Morbeck, 1975, 1976; Harrison, 1982; Fleagle, 1983; Walker and Pickford, 1983; Rose, 1983, 538 1993a, 1997; Leakey et al., 1988; Sherwood et al., 2002; Begun, 2015). This intermediate 539 morphology suggests the use of more varied elbow postures than in non-hominoid taxa, but 540 still indicates a higher stability in full pronation (Rose, 1988, 1997; Alba et al., 2011). The 541 radial morphology of Ekembo and Turkanapithecus, with a rounder outline of the head with 542 less tilting and more extensive bevel, but not yet as developed as in extant hominoids, is thus 543 consistent with a locomotor repertoire basically relying on flexed-elbow stable positions 544 (albeit with an enhanced stability in wide-ranging pronosupination), concordant with the slow 545 and powerful-grasping cautious climbing/clambering and above-branch quadrupedalism 546 typically inferred for these taxa (Fleagle, 1983; Walker and Pickford, 1983; Rose, 1983, 1988, 547 1993a, 1997; Leakey et al., 1988; Sarmiento, 1988, 1995; Ward, 1993, 1998, 2015; Ward et 548 al., 1993; Rein et al., 2011). While Equatorius might have displayed some form of 549 semiterrestrial locomotion (McCrossin et al., 1998; Patel et al., 2009), its radial morphology 550 appears overall similar to that of Ekembo and Turkanapithecus (Rose, 1993a). In contrast, the 551 elbow morphology of fossil great apes such as Rudapithecus, Hispanopithecus, 552 Ankarapithecus and Lufengpithecus (Morbeck, 1983; Lin et al., 1987; Begun, 1992; Moyà- 553 Solà and Köhler, 1996; Kappelman, 2003; Alba et al., 2011, 2012b) indicates the possession 554 of a quite modern humeroantebrachial complex preserving stability through broad ranges of 555 flexion/extension and pronation/supination postures. The modern elbow complex of these 556 taxa would be suitable for both vertical climbing and suspensory behaviors (Begun, 1992, 557 1994; Rose, 1993a; Moyà-Solà and Köhler, 1996; Kappleman et al., 2003; Ward, 2015; Alba 558 et al., 2012b), as in extant hylobatids and great apes, although still retaining some features 559 functionally related to above-branch quadrupedalism (Alba et al., 2012b). 560 561 4.2. Locomotor inferences for Barberapithecus and other stem catarrhines 562 As noted in the original description of the species (Alba and Moyà-Solà, 2012), B. 563 huerzeleri is a small-sized pliopithecoid, similar in size to Dionysopithecus and several 564 Pliopithecus species, such as P. canmatensis. The BM estimated here for IPS66267 is entirely 565 compatible with an attribution to a female individual of B. huerzeleri. IPS66267 shows 566 morphological affinities with monkeys (particularly cebids and colobines) as well as the 567 dendropithecid Simiolus (particularly the specimen KNM-MO 17022B), instead of 568 hominoids, Ateles and stem apes, and also fits quite well the primitive catarrhine morphotype 569 (Rose, 1988, 1994; Rose et al., 1992). The morphological differences between the two 570 Simiolus specimens (particularly in bgPC2) do not exceed the variability range of most extant 571 genera included in the analysis. Therefore, they might simply reflect intraspecific variation, 572 maybe related to sexual dimorphism, with IPS66267 more closely resembling the smaller 573 radius (KNM-MO 17022B). In fact, the radial head size differences between KNM-MO 574 17022B and KNM-MO 63 are similar to those between male and female average values for 575 extant taxa such as Cebus (Rose et al., 1992: Table 4). On the other hand, it should be taken 576 into account that the attribution of these radii to Simiolus is tentative (Rose et al., 1992), so 577 that one of them might potentially belong to a different small catarrhine genus. 578 Qualitatively, the proximal radius of Barberapithecus essentially resembles the 579 morphology of most non-hominoid anthropoids (i.e., extant monkeys other than atelines, as 580 well as putative stem catarrhines), in the following features: (1) relatively short and robust 581 neck; (2) markedly compressed neck anteroposteriorly; (3) proximodistally very expanded 582 proximal radioulnar joint on the anteromedial portion of the head; (4) pronounced lateral lip; 583 (5) restricted beveled articular surface for the humeral capitulum; and (6) tilted radial head 584 with an oval outline. This is also quantitatively supported by our morphometric analyses, in 585 which the shape of radial head outline, the expanded proximal radioulnar joint on the 586 anteromedial portion of the head, and the tilting of the head appeared as the major drivers of 587 shape change and group separation. The proximal radius of Barberapithecus also displays 588 some deviations from the primitive catarrhine elbow pattern. In particular, the radial head of 589 Barberapithecus displays a deeper capitular fovea than Dendropithecus, Epipliopithecus and 590 Simiolus from Moruorot, which suggests that the humeral capitulum in Barberapithecus 591 might have been more globular. Similarly, Barberapithecus displays slightly less tilting of the 592 radial head relative to the neck with respect to the aforementioned fossil taxa—but more 593 markedly so than extant hominoids and stem apes. Nevertheless, Barberapithecus seems to 594 possess a more intermediate condition (with respect to the other fossil catarrhines 595 Epipliopithecus and Simiolus) between the primitive catarrhine morphotype and the derived 596 condition of hominoids and stem apes. 597 From a morphofunctional viewpoint, the extensive morphological similarities between 598 the proximal radius of Barberapithecus and the inferred primitive condition for catarrhines 599 and even anthropoids suggest extensive humeroradial contact only when the forearm was in a 600 fully pronated position (Rose, 1988, 1994; Rose et al., 1992). Moreover, the presence of a 601 mediolaterally restricted but proximodistally extensive ulnar notch of the radius in 602 Barberapithecus—resembling the primitive catarrhine condition—further indicates a 603 particularly stable radioulnar articulation. These features, together with the oval and tilted 604 radial head without extensive beveling, are suitable for quadrupedal locomotion, with limb 605 movements preferentially limited along the parasagittal plane, and with restricted forearm 606 pronation/supination capabilities (Harrison, 1982; Rose, 1988, 1994; Rose et al., 1992). 607 Barberapithecus also displays some morphological features in the proximal radius—an 608 anteroposteriorly less compressed radial neck (based on our qualitative assessment), as well 609 as a relatively deeper capitular fovea and a less tilted head (observed both qualitatively and 610 quantitatively—that might be related to improved mobility at the elbow joint, thus suggesting 611 enhanced climbing as compared with the primitive anthropoid pattern. 612 The other investigated fossil catarrhines (Simiolus, Dendropithecus and 613 Epipliopithecus) appear morphologically close to the crown anthropoid and platyrrhine 614 ancestral morphotypes (Rose, 1988, 1993a, 1994, 1997; Senut, 1989). Simiolus has been 615 interpreted as an arboreal quadruped most similar to platyrrhines (Rose et al., 1992; Rose, 616 1993a, 1994, 1997; Harrison, 2010), and our analyses indicate closer similarities specifically 617 with Alouatta (characterized by a slow and deliberate pronograde locomotion with a high 618 percentage of climbing; Cant, 1986; Youlatos, 1993), suggesting that Simiolus might have 619 relied on a slower form of locomotion than other, more agile platyrrhines such as cebids. 620 Fleagle (1983) put forward similarities between Dendropithecus and Ateles as well, inferring 621 quadrupedalism and suspension and/or climbing for this taxon, while Rose (1988) and Rose et 622 al (1992) described the radius of Dendropithecus as sharing with other small fossil 623 catarrhines, such as Simiolus, the generalized anthropoid morphotype more suited to 624 quadrupedal locomotion and without the extensive pronosupination ranges of suspensory 625 and/or climbing of hominoids and Ateles. Similarly, arboreal quadrupedalism has generally 626 been inferred for Epipliopithecus (e.g., Bacon, 1994); however, inferences of below-branch 627 suspensory behaviors have also been made based on forelimb morphological similarities with 628 Lagothrix and Ateles (Fleagle, 1983; Conroy and Rose, 1983; Rose, 1988; Rose et al., 1992; 629 Rein et al., 2011, 2015; Arias-Martorell et al., 2015). Our analyses of proximal radial shape 630 should be contrasted with analyses on other remains preserved for these taxa. However, both 631 Dendropithecus and Epipliopithecus appear similar to each other in proximal radial 632 morphology, and derived toward the morphology of the semisuspensory Lagothrix, thus 633 supporting the notion these fossil catarrhines might have displayed some suspensory 634 capabilities (Fleagle, 1983: Rein et al., 2011, 2015; Arias-Martorell et al., 2015) 635 superimposed on a generalized quadrupedal locomotor repertoire. 636 Additionally, some morphological differences between Epipliopithecus and 637 Pliopithecus have been noted by previous authors (Senut, 2012; Alba and Moyà-Solà, 2014; 638 Arias-Martorell et al., 2015), although their implications in terms of positional behavior are 639 uncertain due to the scarce material available for the latter genus. Based on the Sansan 640 material, Senut (2012) concluded that both Pliopithecus and Crouzelia were semiarboreal (or 641 semiterrestrial) animals that displayed a marked quadrupedal component—with the former 642 probably showing more slow-climbing abilities, and the latter displaying more rapid arboreal 643 and/or terrestrial running. The latter behavior (most likely arboreal) cannot be discounted 644 either for Barberapithecus, given its morphological similarities in proximal radial shape with 645 the smaller and more agile arboreal monkeys (particularly Cebus). Other crouzeliid 646 postcranial remains are scarce and include phalanges and pedal elements of Anapithecus 647 hernyaki (Begun, 1988, 1993) as well as a manual proximal phalanx of Laccopithecus 648 robustus (Meldrum and Pan, 1988). The phalanges of Anapithecus are generally similar to 649 those of Epipliopithecus, but further display some features (e.g., a more marked curvature) 650 indicative of climbing and/or suspensory postures (Begun, 1993). The phalangeal morphology 651 of Laccopithecus is more hylobatid-like, thus suggesting even more marked suspensory 652 adaptations than in Anapithecus (Meldrum and Pan, 1988). Postcranial elements from other 653 anatomical regions would be necessary for Barberapithecus and other pliopithecoids to better 654 reconstruct their locomotor repertoires. However, based on currently available data, 655 pliopithecoids overall appear to have been remarkably diverse in terms of positional behavior. 656 657 5. Summary and conclusions 658 We describe a proximal radial fragment (IPS66267) from the late Miocene of Castell 659 de Barberà (11.2 Ma; Vallès-Penedès Basin, NE Iberian Peninsula) that constitutes the first 660 known postcranial of the pliopithecoid B. huerzeleri (Crouzeliidae, Anapithecinae). The 661 postcranial anatomy of crouzeliines (and hence their positional behavior) are poorly known, 662 as is the case of other pliopithecoids with the exception of Epipliopithecus. IPS66267 663 generally resembles the proximal radius of extant anthropoids other than hominoids and 664 Ateles, as well as those of dendropithecids (especially Simiolus). On the other hand, IPS66267 665 displays some features indicative of enhanced mobility at the elbow joint, suggesting that 666 Barberapithecus might have displayed better climbing abilities than Epipliopithecus and 667 dendropithecids. We conclude that Barberapithecus might thus have been a pronograde 668 arboreal quadruped, which, like other crouzeliids, might have displayed better climbing 669 abilities than pliopithecids. In this regard, pliopithecoids as a whole (and crouzeliids in 670 particular) display a diversity of positional behaviors, including semiterrestrial 671 quadrupedalism (in Pliopithecus, and, possibly Crouzelia), arboreal quadrupedalism (in 672 Barberapithecus), and arboreal quadrupedalism with occasional suspensory behaviors (in 673 Epipliopithecus, Anapithecus and, probably to an even greater extent, Laccopithecus), thus 674 highlighting the locomotor diversity attained by these Eurasian stem catarrhines. 675 676 Acknowledgments 677 This work has been funded by the by the Agencia Estatal de Investigación (CGL2016-76431- 678 P and CGL2017-82654-P, AEI/FEDER EU; and BES-2015-071318 to A.U.), the Generalitat 679 de Catalunya/CERCA Programme, and the Agència de Gestió d’Ajust Universitaris i de 680 Recerca of the Generalitat de Catalunya (2017 SGR 86 and 2017 SGR 116 GR, and Beatriu de 681 Pinós Programme-H2020 MSCA-Cofund Grant No 801370 to J.A.M). We thank Lars van den 682 Hoek Ostende and Isaac Casanovas-Vilar for drawing our attention to the proximal radius 683 fragment described in this paper, and Marta Palmero for the artwork. We are also thankful to 684 the Editor (Clément Zanolli), the Associate Editor (Terry Harrison), and three anonymous 685 reviewers for useful comments and suggestions that helped to improve this paper. 686 687 References 688 Adams, D.C., 2014. A method for assessing phylogenetic least squares models for shape and 689 other high-dimensional multivariate data. Evolution 68, 2675–2688. 690 Adams, D. C., Collyer, M.L., Kaliontzopoulou, A., 2020. Geomorph: Software for geometric 691 morphometric analyses. R package version 3.2.1. https://cran.r- 692 project.org/package=geomorph. 693 Alba, D.M., 2012. Fossil apes from the Vallès-Penedès Basin. Evol. Anthropol. 21, 254–269. 694 Alba, D.M., Berning, B., 2013. On the holotype and original description of the pliopithecid 695 Plesiopliopithecus lockeri (Zapfe, 1960). J. Hum. Evol. 65, 338–340. 696 Alba, D.M., Moyà-Solà, S., 2012. A new pliopithecid genus (Primates: Pliopithecoidea) from 697 Castell de Barberà (Vallès-Penedès Basin, Catalonia, Spain). Am. J. Phys. Anthropol. 147, 698 88–112. 699 Alba, D.M., Moyà-Solà, S., 2014. New fossil remains of Pliopithecus canmatensis from 700 Abocador de Can Mata, and their implications for the taxonomic validity and phylogenetic 701 position of Epipliopithecus (Primates, Pliopithecidae). Am. J. Phys. Anthropol. 153 (S58), 702 64. 703 Alba, D.M., Almécija, S., Casanovas-Vilar, I., Méndez, J.M., Moyà-Solà, S., 2012b. A partial 704 skeleton of Hispanopithecus laietanus from Can Feu and the mosaic evolution of crown- 705 hominoid positional behaviors. PLoS One 7, e39617. 706 Alba, D.M., Almécija, S., DeMiguel, D., Fortuny, J., Perez de los Rios, M., Pina, M., Robles, 707 J.M., Moyà-Solà, S., 2015. Miocene small-bodied ape from Eurasia sheds light on 708 hominoid evolution. Science 350, aab2625. 709 Alba, D.M., Casanovas-Vilar, I., Garcés, M., Robles, J.M., 2017. Ten years in the dump: An 710 updated review of the Miocene primate-bearing localities from Abocador de Can Mata (NE 711 Iberian Peninsula). J. Hum. Evol. 102, 12–20. 712 Alba, D.M., Garcés, M., Casanovas-Vilar, I., Robles, J.M., Pina, M., Moyà-Solà, S., 713 Almécija, S., 2019. Bio- and magnetostratigraphic correlation of the Miocene primate- 714 bearing site of Castell de Barberà to the earliest Vallesian. J. Hum. Evol. 132, 32–46. 715 Alba, D.M., Moyà-Solà, S., Almécija, S., 2011. A partial hominoid humerus from the middle 716 Miocene of Castell de Barberà (Vallès-Penedès Basin, Catalonia, Spain). Am. J. Phys. 717 Anthropol. 144, 365–381. 718 Alba, D.M., Moyà-Solà, S., Malgosa, A., Casanovas-Vilar, I., Robles, J.M., Almécija, S., 719 Galindo, J., Rotgers, C., Bertó Mengual, J.V., 2010. A new species of Pliopithecus 720 Gervais, 1849 (Primates: Pliopithecidae) from the Middle Miocene (MN8) of Abocador de 721 Can Mata (els Hostalets de Pierola, Catalonia, Spain). Am. J. Phys. Anthropol. 141, 52–75. 722 Alba, D.M., Moyà-Solà, S., Robles, J.M., Galindo, J., 2012a. Brief Communication: The 723 oldest pliopithecid record in the Iberian Peninsula based on new material from the Vallès- 724 Penedès Basin. Am. J. Phys. Anthropol. 147, 135–140. 725 Almécija, S., Alba, D.M., Moyà-Solà, S., 2011. Large-hominoid remains from the Middle 726 Miocene locality of Castell de Barberà (Vallès-Penedès Basin, Catalonia, Spain). Am. J. 727 Phys. Anthropol. 144 (S52), 74. 728 Almécija, S., Alba, D.M., Moyà-Solà, S., 2012. The thumb of Miocene apes: new insights 729 from Castell de Barberà (Catalonia, Spain). Am. J. Phys. Anthropol. 148, 436–450. 730 Almécija, S., Tallman, M., Sallam, H.M., Fleagle, J.G., Hammond, A.S., 2019. Early 731 anthropoid femora reveal divergent adaptive trajectories in catarrhine hind-limb evolution. 732 Nat. Commun. 10, 4778. 733 Andrews, P., Harrison, T., Delson, E., Bernor, R.L., Martin, L., 1996. Distribution and 734 biochronology of European and Southwest Asian Miocene catarrhines. In: Bernor, R.L., 735 Fahlbusch, V., Mittmann, H.-W. (Eds.), The Evolution of Western Eurasian Neogene 736 Mammal Faunas. Columbia University Press, New York, pp. 168–207. 737 Arias-Martorell, J., Alba, D.M., Potau, J.M., Bello-Hellegouarch, G., Pérez-Pérez, A., 2015. 738 Morphological affinities of the proximal humerus of Epipliopithecus vindobonensis and 739 Pliopithecus antiquus: suspensory inferences based on a 3D geometric morphometrics 740 approach. J. Hum. Evol. 80, 83–95. 741 Arnold, C., Matthews, L.J., Nunn, C.L., 2010. The 10kTrees website: A new online resource 742 for primate phylogeny. Evol. Anthropol. 19, 114–118. 743 Bacon, A.-M., 1994. Nouvelles perspectives sur la locomotion de Pliopithecus vindobonensis 744 (Zapfe et Hüerzeler, 1957). C. R. Acad. Sci. Paris 318, 259–266. 745 Begun, D.R., 1988. Catarrhine phalanges from the Late Miocene (Vallesian) or Rudabánya, 746 Hungary. J. Hum. Evol. 17, 413–438. 747 Begun, D.R., 1992. Phyletic diversity and locomotion in primitive European hominids. Am. J. 748 Phys. Anthropol. 87, 311–340. 749 Begun, D.R., 1993. New catarrhine phalanges from Rudabánya (Northeastern Hungary) and 750 the problem of parallelism and convergence in hominoid postcranial morphology. J. Hum. 751 Evol. 24, 373–402. 752 Begun, D.R., 1994. Relations among the great apes and humans: new interpretations based on 753 the fossil great ape Dryopithecus. Yrbk. Phys. Anthropol. 37, 11–63. 754 Begun, D.R., 2002. The Pliopithecoidea. In: Hartwig, W.C. (Ed.), The Primate Fossil Record. 755 Cambridge University Press, Cambridge, pp. 221–240. 756 Begun, D.R., 2015. Fossil record of Miocene hominoids. In: Henke, W., Tattersall, I. (Eds.), 757 Handbook of Paleoanthropology, 2nd ed. Springer, Heidelberg, pp. 1261–1332. 758 Begun, D.R., 2017. Evolution of the Pliopithecoidea. In: Fuentes, A. (Ed.), The International 759 Encyclopedia of Primatology. John Wiley & Sons, 760 https://doi.org/10.1002/9781119179313.wbprim0165. 761 Benefit, B.R., McCrossin, M.L., 2015. A window into ape evolution. Science 350, 515–516. 762 Blomberg, S.P., Garland, T., Ives, A.R., 2003. Testing for phylogenetic signal in comparative 763 data: behavioral traits are more labile. Evolution 57, 717–745. 764 Bookstein, F. L., 2014. Measuring and Reasoning: Numerical Inference in the Sciences. 765 Cambridge University Press, Cambridge. 766 Bookstein, F.L., 2019. Pathologies of between-groups principal components analysis in 767 geometric morphometrics. Evol. Biol. 46, 271–302. 768 Bookstein, F.L., Schaefer, K., Prossinger, H., Seidler, H., Fieder, M., Stringer, C., Weber, 769 G.W., Arsuaga, J.-L., Slice, D., Rohlf, J.F., Recheis, W., Mariam, A.J., Marcus, L.F., 1999. 770 Comparing frontal cranial profiles in archaic and modern Homo by morphometric analysis. 771 Anat. Rec. 257, 217–224. 772 Cant, J. G. H., 1986. Locomotion and feeding postures of spider and howling monkeys: Field 773 study and evolutionary interpretation. Folia Primatol. 46, 1–14. 774 Cardini, A., Polly, P.D., 2020. Cross-validated between group PCA scatterplots: A solution to 775 spurious group separation? Evol. Biol. 47, 85–95. 776 Cardini, A., O'Higgins, P., Rohlf, F.J., 2019. Seeing distinct groups where there are none: 777 Spurious patterns from between‑group PCA. Evol. Biol. 46, 303–316. 778 Casanovas-Vilar, I., Alba, D.M., Garcés, M., Robles, J.M., Moyà-Solà, S., 2011. Updated 779 chronology for the Miocene hominoid radiation in Western Eurasia. Proc. Natl. Acad. Sci. 780 USA 108, 5554-5559. 781 Casanovas-Vilar, I., Garcés, M., Van Dam, J., García-Paredes, I., Robles, J.M., Alba, D.M., 782 2016b. An updated biostratigraphy for the late Aragonian and the Vallesian of the Vallès- 783 Penedès Basin (Catalonia). Geol. Acta 14, 195–217. 784 Casanovas-Vilar, I., Madern, A., Alba, D.M., Cabrera, L., García-Paredes, I., Van den Hoek 785 Ostende, L.W., DeMiguel, D., Robles, J.M., Furió, M., Van Dam, J., Garcés, M., 786 Angelone, C., Moyà-Solà, S., 2016a. The Miocene mammal record of the Vallès-Penedès 787 Basin (Catalonia). C. R. Palevol 15, 791–812. 788 Conroy, G.C., Rose, M.D., 1983. The evolution of the primate foot from the earliest primates 789 to the Miocene hominoids. Foot Ankle 3, 342–363. 790 Crusafont-Pairó, M., Golpe-Posse, J.M., 1981. Estudio de la dentición inferior del primer 791 pliopitécido hallado en España (Vindoboniense terminal de Castell de Barberà, Cataluña, 792 España). Butll. Inf. Inst. Paleontol. Sabadell 13, 25–38. 793 Crusafont Pairó, M., Hürzeler, J., 1969. Catálogo comentado de los póngidos fósiles de 794 España. Acta Geol. Hisp. 4(2), 44–48. 795 DeMiguel, D., Domingo, L., Sánchez, I.M., Casanovas-Vilar, I., Robles, J.M., Alba, D.M., 796 2021. Palaeoecological differences underlie rare co-occurrence of Miocene European 797 primates. BMC Biology 9, 6. 798 Depéret, C., 1887. Recherches sur la succession des faunes de Vertébrés Miocènes de la 799 Vallée du Rhone. Arch. Mus. Hist. Nat. Lyon 4, 46–313. 800 Egi, N., Takai, M., Shigehara, N., Tsubamoto, T., 2004. Body mass estimates for Eocene 801 eosimiid and amphipithecid primates using prosimian and anthropoid scaling models. Int. 802 J. Primatol. 25, 211–236. 803 Fleagle, J.G., 1983. Locomotor adaptations of Oligocene and Miocene hominoids and their 804 phyletic implications. In: Ciochon, R.L., Corruccini, R.S. (Eds.), New Interpretations of 805 Ape and Human Ancestry. Plenum Press, New York, pp. 301–324. 806 Freckleton, R.P., Harvey, P.H., Pagel, M., 2002. Phylogenetic analysis and comparative data: 807 a test and review of evidence. Am. Nat. 160, 712–726. 808 Gilbert, C.C., Ortiz, A., Pugh, K.D., Campisano, C.J., Patel, B.A., Singh, N.P., Fleage, J.G., 809 Patnaik, R., 2020b. New middle Miocene ape (Primates: Hylobatidae) from Ramnagar, 810 India fills major gaps in the hominoid fossil record. Proc. R. Soc. B 287, 20201655. 811 Gilbert, C.C., Pugh, K.D., Fleagle, J.G., 2020a. Dispersal of Miocene hominoids (and 812 pliopithecoids) from Africa to Eurasia in light of changing tectonics and climate. In: 813 Prasad, G.V., Patnaik, R. (Eds.), Biological Consequences of Plate Tectonics. New 814 Perspectives on Post-Gondwana Break-Up—A Tribute to Ashok Sahni. Springer, Cham, 815 pp. 393–412. 816 Ginsburg, L., Mein, P., 1980. Crouzelia rhodanica, nouvelle espèce de Primate catarhinien, et 817 essai sur la position systématique des Pliopithecidae. Bull. Mus. Natl. Hist. Nat. Paris 4, 818 57–85. 819 Harrison, T., 1982. Small-bodied apes from the Miocene of East Africa. Ph.D. Dissertation, 820 University College London, London. 821 Harrison, T., 1987. The phylogenetic relationships of the early catarrhine primates: a review 822 of the current evidence. J. Hum. Evol. 16, 41–80. 823 Harrison, T., 2005. The zoogeographic and phylogenetic relationships of early catarrhine 824 primates in Asia. Anthropol. Sci. 113, 43–51. 825 Harrison, T., 2010. Dendropithecoidea, Proconsuloidea, and Hominoidea (Catarrhini, 826 Primates). In: Werdelin, L., Sanders, W.J. (Eds.), Cenozoic Mammals of Africa. University 827 of California Press, Berkeley, pp. 429–469. 828 Harrison, T., 2013. Catarrhine origins. In: Begun, D.R. (Ed.), A Companion to 829 Paleoanthropology. Blackwell Publishing, Chichester, pp. 377–396. 830 Harrison, T., Gu, Y., 1999. Taxonomy and phylogenetic relationships of early Miocene 831 catarrhines from Sihong, China. J. Hum. Evol. 37, 225–277. 832 Harrison, T., van der Made, J. Ribot, F., 2002a. A new middle Miocene pliopithecid from 833 Sant Quirze, northern Spain. J. Hum. Evol. 42, 371–377. 834 Harrison, T., Ji, X., Su, D., 2002b. On the systematic status of the late Neogene hominoids 835 from Yunnan Province, China. J. Hum. Evol. 43, 207–227. 836 Harrison, T., Zhang, Y., Wei, G., Sun, C., Wang, Y., Liu, J., Tong, H., Huang, B., Xu, F., 837 2020. A new genus of pliopithecoid from the late Early Miocene of China and its 838 implications for understanding the paleozoogeography of the Pliopithecoidea. J. Hum. 839 Evol. 145, 102838. 840 Heizmann, E.P.J., Begun, D.R., 2001. The oldest Eurasian hominoid. J. Hum. Evol. 41, 463– 841 481. 842 Kappelman, J., Richmond, B.G., Seiffert, E.R., Maga, A.M., Ryan, T.M., 2003. Hominoidea 843 (Primates). In: Fortelius, M., Kappelman, J., Sen, S., Bernor, R.L. (Eds.), Geology and 844 Paleontology of the Miocene Sinap Formation, Turkey. Columbia University Press, New 845 York, pp. 90–124. 846 Kaup, J.J., 1861. Beiträge zur näheren Kenntniss der urweltlichen Säugethiere. Fuenftes Heft. 847 Eduard Zernin, Darmstadt. 848 Kelley, J., 1997. Paleobiological and phylogenetic significance of life history in Miocene 849 hominoids. In: Begun, D.R., Ward, C.V., Rose, M.D. (Eds.), Function, Phylogeny and 850 Fossils: Miocene Hominoid Evolution and Adaptation. Plenum Press, New York, pp. 173– 851 208. 852 Köhler, M., Alba, D.M., Moyà-Solà, S., MacLatchy, L., 2002. Taxonomic affinities of the 853 Eppelsheim femur. Am. J. Phys. Anthropol. 119, 297–304. 854 Kordos, L., Begun, D.R., 1999. Femora of Anapithecus from Rudabánya. Am. J. Phys. 855 Anthropol. 108 (S28), 173. 856 Kordos, L., Begun, D.R., 2001. Primates from Rudabánya: allocation of specimens to 857 individuals, sex and age categories. J. Hum. Evol. 40, 17–39. 858 Larson, S.G., 1998. Parallel evolution in the hominoid trunk and forelimb. Evol. Anthropol. 6, 859 87–99. 860 Le Gros Clark, W.E., Thomas, D.P., 1951. Associated jaws and limb bones of Limnopithecus 861 macinnesi. Foss. Mamm. Afr. 3, 1–27. 862 Leakey, R.E., Leakey, M.G., 1986. A second new hominoid from Kenya. Nature 324, 143– 863 146. 864 Leakey, R.E., Leakey, M.G., Walker, A.C., 1988. Morphology of Turkanapithecus 865 kalakolensis from Kenya. Am. J. Phys. Anthropol. 76, 277–288 866 Lin, Y., Wang, S., Guo, Z., Zhang, L., 1987. The first discovery of the radius of Sivapithecus 867 lufengensis in China. Geol. Rev. 33, 1–4. 868 Marigó, J., Susanna, I., Minwer-Barakat, R., Madurell-Malapeira, J., Moyà-Solà, S., 869 Casanovas-Vilar, I., Robles, J.M., Alba, D.M., 2014. The primate fossil record in the 870 Iberian Peninsula. J. Iber. Geol. 40, 179–211. 871 McCrossin, L.M., Benefit, B.R., Giteu, S.N., Palmer, A.K., Blue, K.T., 1998. Fossil evidence 872 for the origins of terrestriality among Old World higher primates. In: Strasser, E., Fleagle, 873 J., Rosenberger, A., McHenry, H. (Eds.), Primate Locomotion: Recent Advances. Plenum 874 Press, New York, pp. 353–396. 875 McNulty, K.P., Begun, D.R., Kelley, J., Manthi, F.K., Mbua, E.N., 2015. A systematic 876 revision of Proconsul with the description of a new genus of early Miocene hominoid. J. 877 Hum. Evol. 84, 42–61. 878 Meldrum, D.J., Pan, Y., 1988. Manual proximal phalanx of Laccopithecus robustus from the 879 Latest Miocene site of Lufeng. J. Hum. Evol. 17, 719–731. 880 Mitteroecker, P., Bookstein, F., 2011. Linear discrimination, ordination, and the visualization 881 of selection gradients in modern morphometrics. Evol. Biol. 38, 100–114. 882 Morbeck, M.E., 1975. Dryopithecus africanus forelimb. J. Hum. Evol. 4, 39–46. 883 Morbeck, M.E., 1976. Problems in reconstruction of fossil anatomy and locomotor behavior: 884 the Dryopithecus elbow complex. J. Hum. Evol. 5, 223–233. 885 Morbeck, M.E., 1983. Miocene hominoid discoveries from Rudabánya. Implications from the 886 postcranial skeleton. In: Ciochon, R.L., Corruccini, R.S. (Eds.), New Interpretations of 887 Ape and Human Ancestry. Plenum Publishing Corporation, New York, pp. 369–404. 888 Moyà-Solà, S., Köhler, M., 1996. A Dryopithecus skeleton and the origins of great-ape 889 locomotion. Nature 379, 156–159. 890 Moyà-Solà, S., Köhler, M., Alba, D.M., 2001. Egarapithecus narcisoi, a new genus of 891 Pliopithecidae (Primates, Catarrhini) from the Late Miocene of Spain. Am. J. Phys. 892 Anthropol. 114, 312–324. 893 Moyà-Solà, S., Köhler, M., Rook, L., 2005. The Oreopithecus thumb: a strange case in 894 hominoid evolution. J. Hum. Evol. 49, 395–404. 895 Napier, J.R., Davis, P.R., 1959. The fore-limb skeleton and associated remains of Proconsul 896 africanus. Foss. Mamm. Afr. 16, 1–69. 897 Nengo, I., Tafforeau, P., Gilbert, C.C., Fleagle, J.G., Miller, E.R., Feibel, C., Fox, D.L., 898 Feinberg, J., Pugh, K.D., Berruyer, C., Mana, S., Engle, Z., Spoor, F., 2017. New infant 899 cranium from the African Miocene sheds light on ape evolution. Nature 548, 169–174. 900 O’Higgins, P., 2000. The study of morphological variation in the hominid fossil record: 901 biology, landmarks and geometry. J. Anat. 197, 103–120. 902 Oksanen, J., Blanchet, F.G., Friendly, M., Kindt, R., Legendre, P., McGlinn, D., Minchin, 903 P.R., O'Hara, R. B., Simpson, G.L., Solymos, P., Stevens, M.H.H., Szoecs, E., Wagner. H., 904 2020. Package “Vegan”: Community Ecology Package. R package version 2.5-7. 905 https://CRAN.R-project.org/package=vegan. 906 Pagel, M., 1999. Inferring the historical patterns of biological evolution. Nature 401, 877– 907 884. 908 Patel, B.A., 2005. The hominoid proximal radius: re-interpreting locomotor behaviors in early 909 hominins. J. Hum. Evol. 48, 415–432. 910 Peppe, D.J., McNulty, K., Cote, S.M., Harcourt-Smith, W.E.H., Dunsworth, H.M., Van 911 Couvering, J.A., 2009. Stratigraphic interpretation of the Kulu Formation (Early Miocene, 912 Rusinga Island, Kenya) and its implications for primate evolution. J. Hum. Evol. 56, 447– 913 461. 914 Pohlig, H., 1895. Paidopithex rhenanus, n.g.n.s., le singe anthropomorphe du Pliocene 915 rhenan. Bull. Soc. Belge Géol. 9, 149–151. 916 R Core Team, 2019. R: A language and environment for statistical computing. R Foundation 917 for Statistical Computing, Vienna. 918 Rein, T.R., Harrison, T., Zollikofer, C.P.E., 2011. Skeletal correlates of quadrupedalism and 919 climbing in the anthropoid forelimb: implications for inferring locomotion in Miocene 920 catarrhines. J. Hum. Evol. 61, 564–574. 921 Rein, T.R., Harvati, K., Harrison, T., 2015. Inferring use of forelimb suspensory locomotion 922 by extinct primate species via shape exploration of the ulna. J. Hum. Evol. 78, 70–79. 923 Revell, L.J., 2012. Phytools: an R package for phylogenetic comparative biology (and other 924 things). Methods Ecol. Evol. 3, 217–223. 925 Roos, C., Kothe, M., Alba, D.M., Delson, E., Zinner, D., 2019. The radiation of macaques out 926 of Africa: Evidence from mitogenome divergence times and the fossil record. J. Hum. 927 Evol. 133, 114–132. 928 Rose, M.D., 1983. Miocene hominoid postcranial morphology monkey-like, ape-like, neither, 929 or both? In: Ciochon, R.L., Corruccini, R.S. (Eds.), New Interpretations of Ape and Human 930 Ancestry. Plenum Publishing Corporation, New York, pp. 405–417. 931 Rose, M.D., 1988. Another look at the anthropoid elbow. J. Hum. Evol. 17, 193–224. 932 Rose M.D., 1993b. Functional anatomy of the elbow and forearm in primates. In: Gebo, D.L. 933 (Ed.), Postcranial Adaptation in Nonhuman Primates. Northern Illinois University, 934 DeKalb, pp. 70–95. 935 Rose, M.D., 1993a. Locomotor anatomy of Miocene hominoids. In: Gebo, D.L. (Ed.), 936 Postcranial Adaptation in Nonhuman Primates. Northern Illinois University Press, 937 DeKalb, pp. 252–272. 938 Rose, M.D., 1994. Quadrupedalism in some Miocene catarrhines. J. Hum. Evol. 26, 387–411. 939 Rose, M.D., 1997. Functional and phylogenetic features of the forelimb in Miocene 940 hominoids. In: Begun, D.R., Ward, C.V., Rose, M.D. (Eds.), Function, Phylogeny and 941 Fossils: Miocene Hominoid Evolution and Adaptation. Plenum Press, New York, pp. 79– 942 100. 943 Rose, M.D., Leakey, M.G., Leakey, R.E.F., Walker, A.C., 1992. Postcranial specimens of 944 Simiolus enjiessi and other primitive catarrhines from the early Miocene of Lake Turkana, 945 Kenya. J. Hum. Evol. 22, 171–237. 946 Rossie, J.B., Gutierrez, M., Goble, E., 2012. Fossil forelimbs of Simiolus from Moruorot, 947 Kenya. Am. J. Phys. Anthropol. 147 (S54), 252. 948 Rossie, J.B., MacLatchy, L., 2006. A new pliopithecoid genus from the early Miocene of 949 Uganda. J. Hum. Evol. 50, 568–586. 950 Ruff, C.B., 2002. Long bone articular and diaphyseal structure in Old World monkeys and 951 apes. I: Locomotor effects. Am. J. Phys. Anthropol. 119, 305–342. 952 Ruff, C.B., 2003. Long bone articular and diaphyseal structure in Old World monkeys and 953 apes. II: Estimation of body mass. Am. J. Phys. Anthropol. 120, 16–37. 954 Sankhyan, A.R., Kelley, J., Harrison, T., 2017. A highly derived pliopithecoid from the Late 955 Miocene of Haritalyangar, India. J. Hum. Evol. 105, 1–12. 956 Sarmiento, E.E., 1987. The phylogenetic position of Oreopithecus and its significance in the 957 origin of the Hominoidea. Am. Mus. Nov. 2881, 1–44. 958 Sarmiento, E.E., 1988. Anatomy of the hominoid wrist joint: its evolutionary and functional 959 implications. Int. J. Primatol. 9, 281–345. 960 Sarmiento, E.E., 1995. Cautious climbing and folivory: a model of hominoid differentiation. 961 Hum. Evol. 10, 289–321. 962 Sarmiento E.E., Stiner, E., Mowbray, K., 2002. Morphology-based systematics (MBS) and 963 problems with fossil hominoid and hominid systematics. Anat. Rec. 269, 50–66. 964 Schlager, S., 2017. Morpho and Rvcg – shape analysis in R: R-packages for geometric 965 morphometrics, shape analysis and surface manipulations. In: Zheng, G., Li, S., Székely, 966 G. (Eds.), Statistical Shape and Deformation Analysis. Methods, Implementation and 967 Applications. Academic Press, London, pp. 217–256. 968 Senut, B., 1989. Le Coude des Primates Hominoïdes. Anatomie, Fonction, Taxonomie, 969 Évolution. Éditions du Centre National de la Recerche Scientifique, Paris. 970 Senut, B., 2012. Les restes post-crâniens des Pliopithecidae (Primates) de Sansan. Mém. Mus. 971 Hist. Nat. Paris 203, 535–558. 972 Shearer, B.M., Cooke, S.B., Halenar, L.B., Reber, S.L., Plummer, J.E., Delson, E., Tallman, 973 M., 2017. Evaluating causes of error in landmark-based data collection using scanners. 974 PLoS One 12, e0187452. 975 Sherwood, R.J., Ward, R.J., Hill, A., Duren, D.L., Brown, B., Downs, W., 2002. Preliminary 976 description of the Equatorius africanus partial skeleton KNM-TH 28860 from 977 Kipsaramon, Tugen Hills, Baringo District, Kenya. J. Hum. Evol. 42, 63–73. 978 Sidlauskas, B., 2008. Continuous and arrested morphological diversification in sister clades of 979 characiform fishes: a phylomorphospace approach. Evolution 62, 3135–3156. 980 Smith, R.J., 1993. Bias in equations used to estimate fossil primate body mass. J. Hum. Evol. 981 25, 31–41. 982 Sukselainen, L., Fortelius, M., Harrison, T., 2015. Co-occurrence of pliopithecoid and 983 hominoid primates in the fossil record: An ecometric analysis. J. Hum. Evol. 84, 25–41. 984 Takahashi, L., K., 1990. Morphological basis of arm-swinging: multivariate analyses of the 985 forelimbs of Hylobates and Ateles. Folia Primatol. 54, 70–85. 986 Tallman, M., 2010. Postcranial variation in Plio-Pleistocene hominins of Africa. Ph.D. 987 Dissertation, The City University of New York. 988 Tallman, M., 2013. Forelimb to hindlimb shape covariation in extant hominoids and fossil 989 hominins. Anat. Rec. 296, 290–304. 990 Tocheri, M.W., Solhan, C. R., Orr, C. M., Femiani, J., Frohlich, B., Groves, C.P., Harcourt- 991 Smith, W.E., Richmond, B.G., Shoelson, B., Jungers, W.L., 2011. Ecological divergence 992 and medial cuneiform morphology in gorillas. J. Hum. Evol. 60, 171–184. 993 Urciuoli, A., Zanolli, C., Beaudet, A., Pina, M., Almécija, S., Moyà-Solà, S., Alba, D.M., 994 2021. A comparative analysis of the vestibular apparatus in Epipliopithecus 995 vindobonensis: Phylogenetic implications. J. Hum. Evol. 151, 102930. 996 van der Meulen, A.J., García-Paredes, I., Álvarez-Sierra, M.Á., van den Hoek Ostende, L.W., 997 Hordijk, K., Oliver, A., López-Guerrero, P., Hernández-Ballarín, V., Peláez- 998 Campomanes, P., 2011. Biostratigraphy or biochronology? Lessons from the Early and 999 Middle Miocene small Mammal Events in Europe. Geobios 44, 309–321. 1000 Walker, A.C., Pickford, M., 1983. New postcranial fossils of Proconsul africanus and 1001 Proconsul nyanzae. In: Ciochon, R.L., Corruccini, R.S. (Eds.), New Interpretations of Ape 1002 and Human Ancestry. Plenum Press, New York, pp. 325–351. 1003 Ward, C.V., 1993. Torso morphology and locomotion in Proconsul nyanzae. Am. J. Phys. 1004 Anthropol. 92, 291–328. 1005 Ward, C.V., 1998. Afropithecus, Proconsul, and the primitive hominoid skeleton. In: Strasser, 1006 E., Fleagle, J., Rosenberger, A., McHenry, H. (Eds.), Primate Locomotion: Recent 1007 Advances. Plenum Press, New York, pp. 337–352. 1008 Ward, C.V., 2015. Postcranial and locomotor adaptations of hominoids. In: Henke, W., 1009 Tattersall, I. (Eds.), Handbook of Paleoanthropology, 2nd ed. Springer, Heidelberg, pp. 1010 1363–1386. 1011 Ward, C.V., Walker, A., Teaford, M.F., Odhiambo, L., 1993. Partial skeleton of Proconsul 1012 nyanzae from Mfangano Island, Kenya. Am. J. Phys. Anthropol. 90, 77–111. 1013 Ward, S., Brown, B., Hill, A., Kelley, J., Downs, W., 1999. Equatorius: a new hominoid 1014 genus from the middle Miocene of Kenya. Science 285, 1382–1386. 1015 Wiley, D.F., Amenta, N., Alcantara, D.A., Ghosh, D., Kil, Y.J., Delson, E., Harcourt-Smith, 1016 W., Rohlf, F.J., St John, K., Hamann, B., 2005. Evolutionary morphing. In: Silva, T.C., 1017 Gorller, E., Rushmeier, H. (Eds.), VIS 05 IEEE Visualization. IEEE, Minneapolis, pp. 1018 431–438. 1019 Youlatos, D., 1993. Passages within a discontinuous canopy: Bridging in the red howler 1020 monkey (Alouatta seniculus). Folia Primatol. 66, 144–147. 1021 Zapfe, H., 1958. The skeleton of Pliopithecus (Epipliopithecus) vindobonensis Zapfe and 1022 Hürzeler. Am. J. Phys. Anthropol. 16, 441–457. 1023 Zapfe, H., 1961. Die Primatenfunde aus der miozänen Spaltenfüllung von Neudorf an der 1024 March (Děvínská Nová Ves), Tschechoslowakei. Schweizer. Palaeontol. Abh. 78, 1–293. 1025 Zapfe, H., Hürzeler, J., 1957. Die Fauna der miozänen Spaltenfüllung von Neudorf an der 1026 March (ČSR.). Primates. Sitz.-ber. Österr. Akad. Wiss. Math.-natur. Kl. Abt. I 166, 113– 1027 123. 1028 1029 Figure captions 1030 1031 Figure 1. Right proximal radius (IPS66267) of Barberapithecus huerzeleri from Castell de 1032 Barberà, in anterior (a), lateral (b), posterior (c), medial (d) and proximal (e) views. See 3D 1033 model in SOM File S1. 1034 1035 Figure 2. Landmark protocol illustrated on 3D model renderings of the Barberapithecus 1036 huerzeleri left proximal radial fragment (IPS66267, mirrored), in superior (a), anterior (b), 1037 lateral (c), medial (d) and posterior (e) views. Landmarks (L) are described in Table 2. 1038 1039 Figure 3. The right proximal radius (IPS66267) of Barberapithecus huerzeleri from Castell 1040 de Barberà, in anterior (a) and proximal (b) views, compared with selected fossil and extant 1041 catarrhines, including: Simiolus enjiessi KNM-MO 63 from Moruorot (right), in anterior (c) 1042 and proximal (d) views; Epipliopithecus vindobonensis from Děvínská Nová Ves (individual 1043 I, right), in anterior (e) and proximal (f) views; and Hylobates sp. (right), in anterior (g) and 1044 proximal (h) views. Artwork by Marta Palmero. 1045 1046 Figure 4. Results of the between-group principal component analysis as depicted by a 1047 bivariate plot of bgPC2 vs. bgPC1. Groups distinguished a priori are denoted with different 1048 colors: violet = hominids; green = hylobatids; dark yellow = cercopithecines; blue = 1049 colobines; pink = platyrrhines. Fossil specimens (scores projected a posteriori) are denoted by 1050 stars. Abbreviation: bgPC = between-group principal component. 1051 1052 Figure 5. Phylomorphospace of proximal radius shape in anthropoid primates. The 1053 phylogenetic tree on the left is projected onto the tangent space defined by the bgPCs as 1054 shown in Figure 4. Ancestral states inferred for the LCAs of main anthropoid clades based on 1055 maximum likelihood (assuming Brownian motion) are denoted by colored pentagons. The 1056 branches are colored according to the phylogeny of the groups in both the phylogenetic tree 1057 and the phylomorphospace. The fossils are denoted with colored stars as shown in Figure 4 1058 (except for Simiolus, which is an average of the two specimens analyzed). The inset to the 1059 right is a close-up of the dashed area in the phylomorphospace. Abbreviations: bgPC = 1060 between-group principal component; LCA = last common ancestor. L2 L6 L6 L7 L7 L8 L7 L8 L5 L9 L10 L10 L9 L10 L8 L2 L1 L11 L12 L13 L13 L14 L11 L4 L7 L14 L12 L13 L14 L11 L12 L3 L6 a b c d e Gorilla Pongo Pan Homo 0.1 Nomascus g h Hylobates Symphalangus Hoolock Mandrillus Macaca Papio bgPC2 (18.7% of variance) Colobus Nasalis 0.0 Alouatta Cebus Ateles Lagothrix Ekembo heseloni Simiolus enjiessi (KNM-MO 63) Simiolus enjiessi (KNM-MO 17022B) Epipliopithecus vindobonensis Dendropithecus macinnesi −0.1 Barberapithecus huerzeleri −0.2 e f −0.1 0.0 0.1 bgPC1 (69% of variance) a b c d Table 1 Summary of the extant primate sample used in this study.a Taxon n Sex (M/F/?) Side Repositories (L/R) Gorilla 15 7/5/3 11/4 AMNH, USNM, RMCA, CMNH, PCM, MS Pan 20 10/8/2 16/4 AMNH, USNM, RMCA, TC MPI-EVA, SBU, MS Homo 5 2/2/1 5/0 AMNH, USNM, MS Pongo 19 6/7/6 16/3 AMNH, USNM, ZMB, ZMS, MS Hylobates 4 2/2/0 3/1 AMNH, USNM Nomascus 1 0/1/0 1/0 AMNH Hoolock 2 1/1/0 0/2 AMNH Symphalangus 8 1/2/5 6/2 AMNH, USNM, ZMB, MS Macaca 8 2/2/4 6/2 AMNH, USNM, ZMB, MS Papio 6 2/2/2 5/1 AMNH, USNM, ZMB Mandrillus 2 2/0/0 0/2 MS Colobus 5 2/3/0 5/0 AMNH, USNM Nasalis 3 2/1/0 3/0 AMNH, USNM Cebus 6 5/1/0 2/4 AMNH, USNM Ateles 6 2/2/2 3/3 USNM, ZMB Lagothrix 1 0/0/1 0/1 MS Alouatta 6 3/2/1 5/1 AMNH, USNM, ZMB, ZMS Abbreviations: M = male; F = female; ? = unknown sex; L = left; R = right; AMNH = American Museum of Natural History, New York, USA; USNM = Smithsonian National Museum of Natural History, Washington D.C., USA; RMCA = Royal Museum for Central Africa, Tervuren, Belgium; CMNH = Cleveland Museum of Natural History, Cleveland, USA; PCM = Powell-Cotton Museum, Birchington, UK; TC MPI-EVA = Tai Forest Collection, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; ZMB = Museum für Naturkunde – Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany; ZMS = Zoologische Staatssammlung Munchen, Munich, Germany; SBU = Stony Brook University; MS = MorphoSource. a See SOM Table S1 for the collection numbers of all the specimens included. Table 2 Landmark protocol used in this study.a Landmark No. Description Fovea capitis: L1 Deepest point of the fovea capitis L2 Most medial point on fovea capitis outline L3 Most anterior point on fovea capitis outline L4 Most lateral point on fovea capitis outline L5 Most posterior point on fovea capitis outline Radial head: L6 Most anterior point on radial head outline L7 Most lateral point on radial head outline L8 Most medial point on distal articular expansion of the radial head L9 Most anterior point on distal articular expansion of the radial head L10 Most lateral point on distal articular expansion of the radial head Radial neck: L11 Most medial point on radial neck L12 Most anterior point on radial neck L13 Most lateral point on radial neck L14 Most posterior point on radial neck a All landmarks used are type II/III (sensu Bookstein et al., 1999; O’Higgins, 2000). Table 3 Body mass estimates for Barberapithecus huerzeleri.a Molar Catalog No. MD BL A BM 95% CI M1 IPS1724c 5.3 6.5 34.45 5.20 4.22, 6.17 M2 IPS1724d,e 5.6 7 39.20 5.74 4.79, 6.70 M1 IPS1724m 5.7 4.6 26.22 4.73 4.02, 5.44 M2 IPS1724n 6.4 5.1 32.64 5.40 4.62, 6.17 Averageb IPS1724 — — — 5.27 4.02, 6.70 Radius Catalog No. RHML RHAP RHSA BM 95% CI Radial head IPS66267 11.27 9.61 85.02 4.85 4.40, 5.30 Abbreviations: MD = mesiodistal length (mm); BL = buccolingual breadth (mm); A = occlusal area (mm2), computed as MD × BL; BM = estimated body mass (kg); RHML = radial head mediolateral breadth (mm); RHAP = radial head anteroposterior breadth (mm); RHSA = radial head surface area (mm2), computed as 0.785 × RHML × RHAP. a Dental BM estimates were derived using the anthropoid equations of Egi et al. (2004), while the postcranial estimate was derived using Ruff’s (2003: Table 7) ‘total sample’ (hominoids + cercopithecoids) equation for the proximal radius. The CIs were computed based on the standard error of estimate reported by these authors and an inverse Student’s t distribution with degrees of freedom = n – 2 (Ruff, 2003) or effective n (Egi et al., 2004). b Average BM is the mean of the estimates derived for the four molars of IPS1724 (holotype), but average CI is based on the minimum and maximum values for all these molars considered together. Supplementary Online Material (SOM): A proximal radius of Barberapithecus huerzeleri from Castell de Barberà: Implications for locomotor diversity among pliopithecoids Julia Arias-Martorell a,b,*, Sergio Almécija c,d,a, Alessandro Urciuoli a, Masato Nakatsukasae, Salvador Moyà-Solà a,f,g, David M. Albaa,* 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 School of Anthropology and Conservation, Marlowe Building University of Kent, Canterbury, UK CT2 7NR, UK c Division of Anthropology, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024, USA d New York Consortium in Evolutionary Primatology, New York, NY 10024, USA e Laboratory of Physical Anthropology, Graduate School of Science, Kyoto University, 606- 8502 Kyoto, Japan; f Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig de Lluís Companys 23, 08010 Barcelona, Spain g Unitat d’Antropologia Biològica (Departament de Biologia Animal, Biologia Vegetal i Ecologia), Universitat Autònoma de Barcelona, 08193 Cerdanyola del Vallès, Barcelona, Spain * Corresponding authors. E-mail addresses: julia.arias@icp.cat (J. Arias-Martorell); david.alba@icp.cat (D.M. Alba). 1 Gorilla 0.1 Pongo Pan Homo Nomascus Hylobates Symphalangus Hoolock Mandrillus Macaca 0.0 Papio Colobus bgPC2 Nasalis Alouatta Cebus Ateles Lagothrix Ekembo heseloni Simiolus enjiessi (KNM-MO 63) −0.1 Simiolus enjiessi (KNM-MO 17022B) Epipliopithecus vindobonensis Dendropithecus macinnesi Barberapithecus huerzeleri Barberapithecus huerzeleri cast −0.2 −0.1 0.0 0.1 bgPC1 SOM Figure S1. Results of the between-group principal component analysis depicted as a bivariate plot of bgPC2 vs. bgPC1 of proximal radius shape among extant anthropoid primates, the fossils included in the analysis and the high-resolution cast of Barberapithecus showing little deviation from the original specimen. Abbreviation: bgPC = between-group principal component. 2 Gorilla 0.1 Pongo Pan Homo Nomascus Hylobates Shymphalangus Hoolock bgPC2 Mandrillus Macaca 0.0 Papio Colobus Nasalis Alouatta Cebus Ateles Lagothrix −0.1 a −0.2 −0.1 0.0 0.1 bgPC1 0.1 bgPC2 0.0 −0.1 b −0.2 −0.1 0.0 0.1 bgPC1 SOM Figure S2. Results of the between-group principal component analysis of proximal radius shape among extant anthropoid primates as depicted by bivariate plots of bgPC2 vs. bgPC1 before (a) and after (b) cross-validation. Abbreviation: bgPC = between-group principal component. 3 SOM Table S1 Details of the extant primate sample used in the study. Media and identifier (when available) are listed for specimens downloaded from Morphosource.org. Species Catalog No. Sex Side Source Media Identifier Scanner Alouatta palliata aequatorialis USNM 338107 M L USNM — — NextEngine Alouatta palliata palliata USNM 282798 F L USNM — — NextEngine Alouatta seniculus AMNH 42316 F L AMNH — — NextEngine Alouatta seniculus AMNH 23333 M L AMNH — — NextEngine Alouatta sp ZMB 35764 M L ZMB — — μCT (BIR ACTIS) Alouatta sp ZMS 1973-0330 ? R ZMS — — μCT (BIR ACTIS) Ateles fusciceps robustus USNM 338111 F L USNM — — NextEngine Ateles fusciceps robustus USNM 338112 M L USNM — — NextEngine Ateles sp ZMB 45255 F R ZMB — — μCT (BIR ACTIS) Ateles sp ZMB 44814 M R ZMB — — μCT (BIR ACTIS) Ateles sp ZMB 38734 ? R ZMB — — μCT (BIR ACTIS) Ateles sp ZMB 44079 ? L ZMB — — μCT (BIR ACTIS) Cebus apella apella USNM 361020 M L USNM — — NextEngine Cebus apella USNM 397940 F R USNM — — NextEngine Cebus apella AMNH 133606 M L AMNH — — NextEngine Cebus apella paraguanayanus AMNH 133631 M R MS M12099-19605 urn:catalog:AMNH:Mammals:M-133631 — Cebus apella paraguayanus AMNH 133623 M R MS M12095-19594 urn:catalog:AMNH:Mammals:M-133623 — Cebus apella paraguayanus AMNH 133628 M R MS M12093-19588 urn:catalog:AMNH:Mammals:M-133628 — Colobus guereza AMNH 52223 F L AMNH — — NextEngine Colobus guereza AMNH 52241 F L AMNH — — NextEngine Colobus guereza kikuyuensis USNM 452621 M L USNM — — NextEngine Colobus guereza AMNH 52248 M L AMNH — — NextEngine Colobus guereza USNM 452632 F L USNM — — NextEngine Gorilla beringei beringei AMNH 54091 F L AMNH — — NextEngine 4 Gorilla beringei beringei RMCA 2263 F L RMCA — — NextEngine Gorilla beringei beringei USNM 395636 M L USNM — — NextEngine Gorilla beringei beringei USNM 396934 ? L Morphosource M56720-102006 http://n2t.net/ark:/65665/313444cf4-f1e7-4bbc-ba69-039e4d4557e4 — Gorilla beringei beringei USNM 396937 ? L Morphosource M57009-102295 http://n2t.net/ark:/65665/32f41b8f5-9a15-4f88-af7e-8218ebf0b616 — Gorilla beringei beringei USNM 397351 ? L Morphosource M56268-101554 http://n2t.net/ark:/65665/3db306794-3c8e-4930-bb20-e514ac62bac6 — Gorilla beringei graueri AMNH 202932 M R AMNH — — NextEngine Gorilla beringei graueri RMCA 8187 M L RMCA — — NextEngine Gorilla beringei USNM 239883 M L USNM — — NextEngine Gorilla gorilla USNM 586541 F R USNM — — NextEngine Gorilla gorilla gorilla AMNH 1673390 F L AMNH — — NextEngine Gorilla gorilla CMNH 2767 M L CMNH — — NextEngine Gorilla gorilla USNM 174722 M R USNM — — NextEngine Gorilla gorilla USNM 176225 M L USNM — — NextEngine Gorilla gorilla MER 300 F R PCM — — μCT (Nikon) Homo sapiens AMNH 99-8376 F L AMNH — — NextEngine Homo sapiens USNM 1512 F L USNM — — NextEngine Homo sapiens AMNH 20-3501 M L AMNH — — NextEngine Homo sapiens USNM 942 M L USNM — — NextEngine Homo sapiens PSU 105-1793 ? L MS M45359-82651 — — Hoolock hoolock AMNH 83425 F R AMNH — — NextEngine Hoolock hoolock AMNH 83420 M R AMNH — — NextEngine Hylobates agilis AMNH 106575 F L AMNH — — NextEngine Hylobates klossii AMNH 103344 M R AMNH — — NextEngine Hylobates klossii AMNH 103347 M L AMNH — — NextEngine Hylobates lar vestitus NMNH 271047 F L USNM — — NextEngine Lagothrix lagotricha DU-BAA 90 ? R MS M12471-20497 — — Macaca arctoides AMNH 112727 F L AMNH — — NextEngine Macaca fascicularis USNM 271168 M R USNM — — NextEngine Macaca fascicularis ZMB 48496 ? L ZMB — — μCT (BIR ACTIS) 5 Macaca fascicularis ZMB 49090 ? L ZMB — — μCT (BIR ACTIS) Macaca fascicularis ZMB 49092 ? L ZMB — — μCT (BIR ACTIS) Macaca mulatta DU-BAA 142 ? R MS M12472-20500 — — Macaca mulatta USNM 537241 F L USNM — — NextEngine Macaca mulatta USNM 537253 M L USNM — — NextEngine Mandrillus sphinx AMNH 89361 M R MS M10169-14599 urn:catalog:AMNH:Mammals:M-89361 — Mandrillus sphinx AMNH 89365 M R MS M10176-14633 urn:catalog:AMNH:Mammals:M-89365 — Nasalis larvatus USNM 536050 F L USNM — — NextEngine Nasalis larvatus AMNH 106275 M L AMNH — — NextEngine Nasalis larvatus AMNH 198276 M L USNM — — NextEngine Nomascus gabriellae AMNH 87253 F L AMNH — — NextEngine Pan paniscus AMNH 86857 F L AMNH — — NextEngine Pan paniscus RMCA 29045 F L RMCA — — NextEngine Pan paniscus RMCA 27696 M R RMCA — — NextEngine Pan paniscus SBU 87-1 M L SBU — — NextEngine Pan troglodytes USNM 176226 F L USNM — — NextEngine Pan troglodytes USNM 176229 F L USNM — — NextEngine Pan troglodytes USNM 176227 M L USNM — — NextEngine Pan troglodytes USNM 220327 M L USNM — — NextEngine Pan troglodytes USNM 395820 M L USNM — — NextEngine Pan troglodytes UNSM 481804 M R USNM — — NextEngine Pan troglodytes schweinfurthii AMNH 51376 M R MS M10175-14630 urn:catalog:AMNH:Mammals:M-51376 — Pan troglodytes schweinfurthii AMNH 51393 M R MS M10242-14814 urn:catalog:AMNH:Mammals:M-51393 — Pan troglodytes troglodytes AMNH 54330 M L MS M10240-14808 urn:catalog:AMNH:Mammals:M-54330 — Pan troglodytes troglodytes USNM 220064 F L USNM — — NextEngine Pan troglodytes troglodytes USNM 220062 ? L MS M56889-102175 http://n2t.net/ark:/65665/3dcfb7753-f4d7-4334-9b52-6f9f1b9ea03e — Pan troglodytes troglodytes USNM 220063 ? L MS M56483-101769 http://n2t.net/ark:/65665/386ed1f25-2f34-459d-91e5-d0111c2e0dc6 — Pan troglodytes verus MPI-EVA 11778 F L MPI — — μCT (BIR ACTIS) Pan troglodytes verus MPI-EVA 13429 F L MPI — — μCT (BIR ACTIS) 6 Pan troglodytes verus MPI-EVA 15001 F L MPI — — μCT (BIR ACTIS) Pan troglodytes verus AMNH 89406 M L AMNH — — NextEngine Papio anubis AMNH 52668 F L AMNH — — NextEngine Papio anubis AMNH 120388 M L AMNH — — NextEngine Papio anubis neumanni USNM 384235 F L USNM — — NextEngine Papio anubis neumanni USNM 384229 M L USNM — — NextEngine Papio hamadryas ZMB 105450 ? R ZMB — — μCT (BIR ACTIS) Papio hamadryas ZMB 65265 ? L ZMB — — μCT (BIR ACTIS) Pongo abelii USNM 588109 F L USNM — — NextEngine Pongo abelii UNSM 143588 M L USNM — — NextEngine Pongo abelii USNM 143587 ? L MS M56592-101878 http://n2t.net/ark:/65665/33bd6f2f4-8b1a-4ffd-966f-06506fd24428 — Pongo abelii USNM 143590 ? L MS M56324-101610 http://n2t.net/ark:/65665/389dc210f-f5b3-4910-ae87-a26700227801 — Pongo abelii USNM 143593 ? L MS M56494-101780 http://n2t.net/ark:/65665/329ae2628-4c93-4da7-8e52-5f0c1e7bcc9e — Pongo abelii USNM 143594 ? L MS M56426-101712 http://n2t.net/ark:/65665/3a893123e-021c-4f9b-ab42-4b4050332c24 — Pongo abelii USNM 143596 ? L MS M56423-101709 http://n2t.net/ark:/65665/3c26ea641-6662-42df-9b0d-a288ade0d69c — Pongo pygmaeus AMNH 200900 F L AMNH — — NextEngine Pongo pygmaeus USNM 142169 F L USNM — — NextEngine Pongo pygmaeus USNM 145302 F L USNM — — NextEngine Pongo pygmaeus USNM 153805 F R USNM — — NextEngine Pongo pygmaeus USNM 153822 F L USNM — — NextEngine Pongo pygmaeus ZMS 1982-0092 F R ZMS — — μCT (BIR ACTIS) Pongo pygmaeus USNM 145301 M L USNM — — NextEngine Pongo pygmaeus USNM 145305 M L USNM — — NextEngine Pongo pygmaeus USNM 153823 M L USNM — — NextEngine Pongo pygmaeus ZMS 1909-0801 M L ZMS — — μCT (BIR ACTIS) Pongo pygmaeus ZMS 1966-0203 M R ZMS — — μCT (BIR ACTIS) Pongo pygmaeus ZMB 87092 ? L ZMB — — μCT (BIR ACTIS) Symphalangus syndactylus AMNH 106583 F L AMNH — — NextEngine Symphalangus syndactylus NMNH 271048 F L USNM — — NextEngine 7 Symphalangus syndactylus AMNH 106581 M L AMNH — — NextEngine Symphalangus syndactylus PSU 105-1841 ? L MS M45351-82643 — — Symphalangus syndactylus UWBM 58721-1 ? R MS M69298-125011 — — Symphalangus syndactylus UWBM 82801-1 ? L MS M69299-125019 — — Symphalangus syndactylus ZMB 38573 ? R ZMB — — μCT (BIR ACTIS) Symphalangus syndactylus ZMB 38587 ? L ZMB — — μCT (BIR ACTIS) Abbreviations: F = female; M = male; ? = unknown sex; L = left; R = right; AMNH = American Museum of Natural History, New York, USA; CMNH = Cleveland Museum of Natural History, Cleveland, USA; MPI-EVA = Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany; MS = MorphoSource.org; PCM = Powell-Cotton Museum, Birchington, UK; RMCA = Royal Museum for Central Africa, Tervuren, Belgium; SBU = Stony Brook University, New York, USA; USNM = Smithsonian National Museum of Natural History, Washington D.C., USA; ZMB = Museum für Naturkunde – Leibniz Institute for Evolution and Biodiversity Science, Berlin, Germany; ZMS = Zoologische Staatssammlung Munchen, Munich, Germany. 8 SOM Table S2 The meaningful between-group principal component (bgPC1 and bgPC2) scores for the original fossil and a high-quality cast of the proximal radius of Barberapithecus (IPS66267). See also SOM Figure S2. Specimen bgPC1 scores bgPC2 scores IPS66267 (original) 0.10657264 -0.01297840 IPS66267 (cast) 0.10881666 -0.00938558 9 SOM File S1. 3D model of the right proximal radius (IPS66267) of Barberapithecus huerzeleri from Castell de Barberà, available as a PLY file from MorphoSource.org (https://doi.org/10.17602/M2/M349186). 10