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Many ideas have been proposed to explain the origin of bipedalism in hominins and suspension in great apes (hominids); however, fossil evidence has been lacking. It has been suggested that bipedalism in hominins evolved from an ancestor that was a palmigrade quadruped (which would have moved similarly to living monkeys), or from a more suspensory quadruped (most similar to extant chimpanzees)1. Here we describe the fossil ape Danuvius guggenmosi (from the Allgau region of Bavaria) for which complete limb bones are preserved, which provides evidence of a newly identified form of positional behaviour-extended limb clambering. The 11.62-million-year-old Danuvius is a great ape that is dentally most similar to Dryopithecus and other European late Miocene apes. With a broad thorax, long lumbar spine and extended hips and knees, as in bipeds, and elongated and fully extended forelimbs, as in all apes (hominoids), Danuvius combines the adaptations of bipeds and suspensory apes, and provides a model for the common ancestor of great apes and humans.

Bipedal trackways discovered in 1978 at Laetoli site G, Tanzania and dated to 3.66 million years ago are widely accepted as the oldest unequivocal evidence of obligate bipedalism in the human lineage1–3. Another trackway discovered two years earlier at nearby site A was partially excavated and attributed to a hominin, but curious affinities with bears (ursids) marginalized its importance to the paleoanthropological community, and the location of these footprints fell into obscurity3–5. In 2019, we located, excavated and cleaned the site A trackway, producing a digital archive using 3D photogrammetry and laser scanning. Here we compare the footprints at this site with those of American black bears, chimpanzees and humans, and we show that they resemble those of hominins more than ursids. In fact, the narrow step width corroborates the original interpretation of a small, cross-stepping bipedal hominin. However, the inferred foot proportions, gait parameters and 3D morphologies of footprints at site A are readily distinguished from those at site G, indicating that a minimum of two hominin taxa with different feet and gaits coexisted at Laetoli., Reanalysis of bipedal trackways from Laetoli site A in Tanzania suggest that the footprints were made by a hominin that coexisted with at least one other hominin species.

Many ideas have been proposed to explain the origin of bipedalism in hominins and suspension in great apes (hominids); however, fossil evidence has been lacking. It has been suggested that bipedalism in hominins evolved from an ancestor that was a palmigrade quadruped (which would have moved similarly to living monkeys), or from a more suspensory quadruped (most similar to extant chimpanzees)

The mandibular nerve is a sensory and motor nerve that innervates the muscles of mastication, the lower dentition, and the lower lip and surrounding structures. Although this nerve contains both efferent and afferent fibers, the mental nerve, a terminal branch of the mandibular nerve, is a strictly sensory nerve that exits the mental foramen and innervates the lower lip, the skin overlaying the mandible, and the oral mucosa around the mandible. Osteological foramina are often used as proxies for nerve cross section area and they often correlate well with some aspect of a primate's ecology (e.g., optic foramen and visual acuity). The primary objective of this study is to explore the correlation between the mental foramen and dietary preference among primates. The mental foramen of 40 primate species (n = 180) was measured from 3-D surface models of the mandible. Both conventional and phylogenetic tests indicate that although frugivores have larger mental foramina than folivores, the differences were not significant. These results show that while structures like the infraorbital foramen correlate well with diet and touch sensitivity, the mental foramen does not. Based on these findings, the mental foramen is not a suggested morphological character for interpreting of the fossil record. J. Morphol. 277:978-985, 2016. © 2016 Wiley Periodicals, Inc.

Anthropoid incisors are large relative to the postcanine dentition and function in the preprocessing of food items. Previous analyses of anthropoid incisor allometry and shape demonstrate that incisor morphology is correlated with preferred foods and that more frugivorous anthropoids have larger and more curved incisors. Although the relationship between incisal crown curvature and preferred foods has been well documented in extant and fossil anthropoids, the functional significance of curvature variation has yet to be conclusively established. Given that an increase in crown curvature will increase maximum linear crown dimensions, and bending resistance is a function of linear crown dimensions, it is hypothesized that incisor crown curvature functons to increase incisor crown resistance to bending forces. This study uses beam theory to calculate the mesiodistal and labiolingual bending strengths of the maxillary and mandibular incisors of hominoid and platyrrhine taxa with differing diets and variable degrees of incisal curvature. Results indicate that bending strength correlates with incisal curvature and that frugivores have elevated incisor bending resistance relative to folivores. Maxillary central incisor bending strengths further discriminate platyrrhine and hominoid hard- and soft-object frugivores suggesting this crown is subjected to elevated occlusal loading relative to other incisors. These results are consistent with the hypothesis that incisor crown curvature functions to increase incisor crown resistance to bending forces but does not preclude the possibility that incisor bending strength is a composite function of multiple dentognathic variables including, but not limited to, incisor crown curvature. Anat Rec, 298:463–478, 2015. © 2014 Wiley Periodicals, Inc.

The infraorbital foramen (IOF) is located below the orbit and transmits the sensory infraorbital nerve (ION) to mechanoreceptors located throughout the maxillary region. The size of the IOF correlates with the size of the ION; thus, the IOF appears to indicate relative touch sensitivity of maxillary region. In primates, IOF size correlates well with diet. Frugivores have relatively larger IOFs than folivores or insectivores because fruit handling/processing requires increased touch sensitivity. However, it is unknown if the IOF can be used to detect subtle dietary differences among closely related hominoid species. Hominoids are traditionally grouped into broad dietary categories, despite the fact that hominoid diets are remarkably diverse. This study examines whether relative IOF size is capable of differentiating among the dietary preferences of closely related species with overlapping, yet divergent diets. We measured IOF area in Hylobates lar, Symphalangus syndactulus, Pongo pygmaeus spp., Pan troglodytes, Gorilla gorilla, Gorilla beringei graueri, and Gorilla beringei beringei. We classified each species as a dedicated folivore, mixed folivore/frugivore, soft object frugivore, or hard object frugivore. The IOF is documented to be larger in more frugivorous species and smaller in more folivorous taxa. Interestingly, G.b. beringei, had the largest relative IOF of any gorilla, despite being a dedicated folivore. G.b. beringei does have unique food processing behavior that relies heavily on maxillary mechanoreception, thus this finding is not entirely unsupported behaviorally. The results of this study provide evidence that the IOF is an informative feature in interpretations of fossil apes. Anat Rec, 297:1377–1384, 2014. © 2014 Wiley Periodicals, Inc.

Background: The advocacy for operative fixation of midshaft clavicle fractures has prompted a reemergence of interest in clavicle anatomy. Three-dimensional (3D) anatomical studies provide more information than 2-dimensional studies, but are currently rare. Material and methods: Twenty-five skeletonized clavicles were digitized using a laser scanner. Threedimensional computer software was used to analyze the data. Clavicles were divided into medial, middle, and lateral segments based on the medial and lateral apices of curvature and their lengths and midpoint cortical diameter measured. The angles of medial and lateral curvatures were measured in standardized axial and coronal planes. The medial and lateral curvatures were fitted with circles and the radii of curvature measured. Correlations between the intrinsic dimensions of the clavicle were assessed. Results: The mean length was 136.7 mm. The medial, middle, and lateral segments had mean lengths of 48, 56, and 32.7 mm, respectively. In the axial plane, the mean medial and lateral angles were 149.5 � and 145.8 � , respectively. In the coronal plane, the mean medial and lateral angles were 178.2 � and 174.2 � , respectively. The mean midpoint cortical diameter was 10.9 mm. The mean medial and lateral radii of curvature were 66.4 and 33.5 mm, respectively. The length and cortical diameter and length and medial radius of curvature were found to positively correlate, R 2 ¼ .355 and .184, respectively. Conclusion: Using standardized measurements, we were able to accurately characterize the dimensions of the clavicle. We found that the length of the clavicle correlates with the midpoint cortical diameter and with the radius of medial curvature. Level of evidence: Basic Science Study, Anatomic Study. 2013 Journal of Shoulder and Elbow Surgery Board of Trustees.

AIM To provide a “patient-normalized” parameter in the proximal forearm. METHODS Sixty-three cadaveric upper extremities from thirty-five cadavers were studied. A muscle splitting approach was utilized to locate the posterior interosseous nerve (PIN) at the point where it emerges from beneath the supinator. The supinator was carefully incised to expose the midpoint length of the nerve as it passes into the forearm while preserving the associated fascial connections, thereby preserving the relationship of the nerve with the muscle. We measured the transepicondylar distance (TED), PIN distance in the forearm’s neutral rotation position, pronation position, supination position, and the nerve width. Two individuals performed measurements using a digital caliper with inter-observer and intra-observer blinding. The results were analyzed with the Wilcoxon-Mann-Whitney test for paired samples. RESULTS In pronation, the PIN was within two confidence intervals of 1.0 TED in 95% of cases (range 0.7-1.3 TED); in neutral, within two confidence intervals of 0.84 TED in 95% of cases (range 0.5-1.1 TED); in supination, within two confidence intervals of 0.72 TED in 95% of cases (range 0.5-0.9 TED). The mean PIN distance from the lateral epicondyle was 100% of TED in a pronated forearm, 84% in neutral, and 72% in supination. Predictive accuracy was highest in supination; in all cases the majority of specimens (90.47%-95.23%) are within 2 cm of the forearm position-specific percentage of TED. When comparing right to left sides for TEDs with the signed Wilcoxon-Mann-Whitney test for paired samples as well as a significance test (with normal distribution), the P-value was 0.0357 (significance - 0.05) indicating a significant difference between the two sides. CONCLUSION This “patient normalized” parameter localizes the PIN crossing a line drawn between the lateral epicondyle and the radial styloid. Accurate PIN localization will aid in diagnosis, injections, and surgical approaches.

Despite considerable post-cranial and cranial morphological overlap with Proconsul, Afropithecus turkanensis is distinguished from that taxon by a suite of anterior dental and gnathic characters shared in common with extant pitheciin monkeys (i.e. low crowned, robust and laterally splayed canines, procumbent incisors, prognathic premaxilla, powerful temporalis muscles, reduced or absent maxillary sinuses, and deep mandibular corpora). Pitheciins are unique among living anthropoids because their canines serve a habitual dietary function and are not strictly influenced by inter-male competition. Given the functional association between pitheciin canine morphological specializations and sclerocarp foraging, a feeding strategy where the hard pericarps of unripe fruit are mechanically deformed by the canines, it has been suggested that Afropithecus may also have used its canines in a dietary context. This is confirmed by quantitative morphometric analyses of Afropithecus canine curvature and basal dimensions demonstrating that Afropithecus and extant pitheciins (Chiropotes, Cacajao) are distinguished from all other anthropoids by pronounced and evenly distributed mesial canine crown contours as well as greater resistance to canine bending in both the mesiodistal and labiolingual axes. In addition, Afropithecus, Chiropotes and Cacajao are also shown to have significantly longer and more curved premaxillae with greater incisor procumbency that effectively isolates the incisor and canine functional complexes. These morphological similarities are a result of convergence and not a shared derived ancestry. Despite their considerable morphological overlap, it is unlikely that Afropithecus and extant pitheciin diets are identical given significant dissimilarities in their post-canine morphology, maximum angular gape and body size. Nevertheless, Afropithecus canine dietary function is unique among hominoids and may have been a key component for the expansion of hominoids into Eurasia at the end of the early Miocene.

Department of Anatomy and Neurobiology, College of Medicine, University of Kentucky, MN 224 UK Medical Center,Lexington, KY 40536-0298KEY WORDS platyrrhine; HRPCF; incisor; curvature; dietABSTRACT Despite the relatively large size ofanthropoid incisors in relation to the remainder of thedental arcade, and their prominent role in the preprocess-ing of food prior to ingestion, comparatively little isknown about the functional morphology of anthropoid in-cisor shape and crown curvature. The relationshipbetween incisor allometry and diet is well documented forboth platyrrhines and catarrhines; however, similar rela-tionships between incisor shape and crown curvaturehave to date only been reported for living and fossil mem-bers of the superfamily Hominoidea. Given the limitedtaxonomic diversity among the extant members of thatgroup, it is difficult to firmly establish the relative influ-ence of phylogeny and dietary function in the governanceof incisor crown curvature. Unlike hominoids, which arerepresented by only five living genera, extant platyr-rhines are a more varied group that includes 16 ecologi-cally diverse genera. In an effort to clarify the functionalrelationship between maxillary and mandibular incisorcrown curvature and diet, this study uses high resolutionpolynomial curve fitting to quantify mesiodistal and cervi-coincisal curvature for a taxonomically diverse platyr-rhine sample (n 5 133 individuals representing 18 taxa)with well documented dietary behavior. Results were con-sistent with prior analyses of hominoid incisor curvatureand identify a significant and positive correlation betweenincisor crown curvature and diet such that increasing cur-vature is associated with a proportionate increase in fru-givory. These results are independent confirmation of theresults reported from a previous analysis of hominoid in-cisor curvature and provide new evidence to suggest thatdiet is the primary governing factor influencing anthro-poid incisor curvature. Am J Phys Anthropol 148:249–261, 2012.

Prehensile tails evolved independently twice in primates: once in the ateline subfamily of platyrrhine primates and once in the genus Cebus. Structurally, the prehensile tails of atelines and Cebus share morphological features distinguishing them from nonprehensile tails (e.g., robust and strong caudal vertebrae, well developed lateral tail musculature, etc.). However, because of their independent evolutionary histories, the prehensile tails of atelines exhibit some differences from the Cebus prehensile tail. Ateline tails are relatively longer than those of Cebus, and they have less well-developed extensor compartment musculature. However, perhaps the most obvious difference is the distinctive hairless friction pad on the ventrodistal surface of the ateline tail; the tail of Cebus is completely covered in hair. This study documents the presence of four epicritic histologic mechanoreceptors in the friction pad of atelines: Meissner's corpuscles, Pacinian corpuscles, Ruffini corpuscles, and Merkel discs. Ruffini corpuscles and Merkel cells were also identified in the ventrodistal skin of the Cebus tail. However, Meissner's and Pacinian corpuscles (not typically associated with hairy skin) were not found in Cebus. Cebus was also compared to its closest living sister taxon, nonprehensile-tailed Saimiri, in which genus only Ruffini corpuscles are observed (no Merkel discs). The differences in mechanoreceptor type and morphology are attributed to the contrasting behavioral and tactile demands of the tail as it is used in posture and locomotion, which also distinguishes atelines from Cebus. Anat Rec,, 2011. © 2011 Wiley Periodicals, Inc.

In 1943, Weidenreich described the squamosal suture of Homo erectus as long, low, and simian in character and suggested that this morphology was dependent upon the correlation between the size of the calvarium and the face. Many researchers now consider this character to be diagnostic of H. erectus. The relationship between cranial size and shape and temporal squama morphology, however, is unclear, and several authors have called for detailed measurements of squamosal variation to be collected before any conclusions are drawn regarding the nature of the morphology observed in H. erectus. Thirteen fossil and extant taxa were examined to address two questions: 1) Are size and shape of the temporal squama correlated with cranial vault morphology? and 2) Is the H. erectus condition plesiomorphic? To answer these questions, measurements were collected and indices were calculated for squamosal suture height, length, and area in relation to metric variables describing cranial size and shape. A two-dimensional morphometric study was also completed using High Resolution-Polynomial Curve Fitting (HR-PCF) to investigate correlations between curvature of the squamosal suture and curvature of the cranial vault. Results of both analyses indicate that squamosal suture form is related to cranial size and shape. Furthermore, the plesiomorphic condition of the squamosal suture for hominins was identified as high and moderately arched; this condition is retained in H. erectus and is distinct from the great ape condition. It is suggested that this similarity is the result of increased cranial length without a corresponding increase in cranial height. Am J Phys Anthropol, 2008. © 2008 Wiley-Liss, Inc.

The mandibular nerve is a sensory and motor nerve that innervates the muscles of mastication, the lower dentition, and the lower lip and surrounding structures. Although this nerve contains both efferent and afferent fibers, the mental nerve, a terminal branch of the mandibular nerve, is a strictly sensory nerve that exits the mental foramen and innervates the lower lip, the skin overlaying the mandible, and the oral mucosa around the mandible. Osteological foramina are often used as proxies for nerve cross section area and they often correlate well with some aspect of a primate's ecology (e.g., optic foramen and visual acuity). The primary objective of this study is to explore the correlation between the mental foramen and dietary preference among primates. The mental foramen of 40 primate species (n = 180) was measured from 3-D surface models of the mandible. Both conventional and phylogenetic tests indicate that although frugivores have larger mental foramina than folivores, the differences were not significant. These results show that while structures like the infraorbital foramen correlate well with diet and touch sensitivity, the mental foramen does not. Based on these findings, the mental foramen is not a suggested morphological character for interpreting of the fossil record. J. Morphol. 277:978-985, 2016. © 2016 Wiley Periodicals, Inc.

Homo rudolfensis Samples from Olduvai Gorge, East Lake Turkana, and Lake Malawi were included in this study. The East Lake Turkana fossils available prior to 2010 were examined first-hand, while for the Olduvai and Lake Malawi fossils and KNM-ER 60000, 62000, and 62003 we relied on original observations on fossils and casts as well as published reports (Schrenk et al., 1993; Blumenschine et al., 2003; Leakey et al., 2012). We include the following fossils in the hypodigm of H. rudolfensis: KNM-ER 819, KNM-ER 1470, KNM-ER 1482, KNM-ER 1483, KNM-ER 1590, KNM-ER 1801, KNM-ER 1802, KNM-ER 3732, KNM-ER 3891, KNM-ER 60000, KNM-ER 62000, KNM-ER 62003, OH 65, and UR 501. We do recognize that KNM-ER 60000 and KNM-ER 1802 present some conflicting anatomy that some authors have argued precludes them as conspecific specimens (Leakey et al., 2012); by considering both, we aim to be conservative as they encompass more variation within H. rudolfensis., Published as part of Lee R Berger, John Hawks, Darryl J de Ruiter, Steven E Churchill, Peter Schmid, Lucas K Delezene, Tracy L Kivell, Heather M Garvin, Scott A Williams, Jeremy M DeSilva, Matthew M Skinner, Charles M Musiba, Noel Cameron, Trenton W Holliday, William Harcourt-Smith, Rebecca R Ackermann, Markus Bastir, Barry Bogin, Debra Bolter, Juliet Brophy, Zachary D Cofran, Kimberly A Congdon, Andrew S Deane, Mana Dembo, Michelle Drapeau, Marina C Elliott, , Elen M Feuerriegel, Daniel Garcia-Martinez, David J Green, Alia Gurtov, Joel D Irish, Ashley Kruger, Myra F Laird, Damiano Marchi, Marc R Meyer, Shahed Nalla, Enquye W Negash, Caley M Orr, Davorka Radovcic, Lauren Schroeder, Jill E Scott, Zachary Throckmorton, Matthew W Tocheri, Caroline VanSickle, Christopher S Walker, Pianpian Wei & Bernhard Zipfel, 2015, Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa, pp. 1-35 in eLife e 09560 4 on page 26, DOI: 10.7554/eLife.09560

Australopithecus africanus The samples attributed to Au. africanus from Taung, Sterkfontein and Makapansgat were employed. Original specimens were examined first-hand by the authors., Published as part of Lee R Berger, John Hawks, Darryl J de Ruiter, Steven E Churchill, Peter Schmid, Lucas K Delezene, Tracy L Kivell, Heather M Garvin, Scott A Williams, Jeremy M DeSilva, Matthew M Skinner, Charles M Musiba, Noel Cameron, Trenton W Holliday, William Harcourt-Smith, Rebecca R Ackermann, Markus Bastir, Barry Bogin, Debra Bolter, Juliet Brophy, Zachary D Cofran, Kimberly A Congdon, Andrew S Deane, Mana Dembo, Michelle Drapeau, Marina C Elliott, , Elen M Feuerriegel, Daniel Garcia-Martinez, David J Green, Alia Gurtov, Joel D Irish, Ashley Kruger, Myra F Laird, Damiano Marchi, Marc R Meyer, Shahed Nalla, Enquye W Negash, Caley M Orr, Davorka Radovcic, Lauren Schroeder, Jill E Scott, Zachary Throckmorton, Matthew W Tocheri, Caroline VanSickle, Christopher S Walker, Pianpian Wei & Bernhard Zipfel, 2015, Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa, pp. 1-35 in eLife e 09560 4 on page 26, DOI: 10.7554/eLife.09560

Paranthropus boisei Samples from the Omo Shungura sequence, East Lake Turkana, Olduvai Gorge and Konso were included in this study. Original specimens from Olduvai Gorge and East Lake Turkana were examined first-hand, while casts and published reports (Tobias, 1967; Suwa et al., 1996, 1997; Do ḿınguez- Rodrigo et al., 2013) were used to study the Omo and Konso materials. Our postcranial considerations of P. boisei are very limited and we did not rely upon the association of KNM-ER 1500 (Grausz et al., 1988) to derive information about the postcranial skeleton of P. boisei. Paranthropus robustus The samples from Kromdraai, Swartkrans, Sterkfontein, Drimolen, Gondolin, and Coopers were included in this study. First-hand observations of original specimens from all localities were used with the exception of Drimolen fossils, which were compared using published reports (Keyser, 2000; Keyser et al., 2000)., Published as part of Lee R Berger, John Hawks, Darryl J de Ruiter, Steven E Churchill, Peter Schmid, Lucas K Delezene, Tracy L Kivell, Heather M Garvin, Scott A Williams, Jeremy M DeSilva, Matthew M Skinner, Charles M Musiba, Noel Cameron, Trenton W Holliday, William Harcourt-Smith, Rebecca R Ackermann, Markus Bastir, Barry Bogin, Debra Bolter, Juliet Brophy, Zachary D Cofran, Kimberly A Congdon, Andrew S Deane, Mana Dembo, Michelle Drapeau, Marina C Elliott, , Elen M Feuerriegel, Daniel Garcia-Martinez, David J Green, Alia Gurtov, Joel D Irish, Ashley Kruger, Myra F Laird, Damiano Marchi, Marc R Meyer, Shahed Nalla, Enquye W Negash, Caley M Orr, Davorka Radovcic, Lauren Schroeder, Jill E Scott, Zachary Throckmorton, Matthew W Tocheri, Caroline VanSickle, Christopher S Walker, Pianpian Wei & Bernhard Zipfel, 2015, Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa, pp. 1-35 in eLife e 09560 4 on page 26, DOI: 10.7554/eLife.09560

Paranthropus aethiopicus The cranium KNM-WT 17000 was examined first-hand for this study., Published as part of Lee R Berger, John Hawks, Darryl J de Ruiter, Steven E Churchill, Peter Schmid, Lucas K Delezene, Tracy L Kivell, Heather M Garvin, Scott A Williams, Jeremy M DeSilva, Matthew M Skinner, Charles M Musiba, Noel Cameron, Trenton W Holliday, William Harcourt-Smith, Rebecca R Ackermann, Markus Bastir, Barry Bogin, Debra Bolter, Juliet Brophy, Zachary D Cofran, Kimberly A Congdon, Andrew S Deane, Mana Dembo, Michelle Drapeau, Marina C Elliott, , Elen M Feuerriegel, Daniel Garcia-Martinez, David J Green, Alia Gurtov, Joel D Irish, Ashley Kruger, Myra F Laird, Damiano Marchi, Marc R Meyer, Shahed Nalla, Enquye W Negash, Caley M Orr, Davorka Radovcic, Lauren Schroeder, Jill E Scott, Zachary Throckmorton, Matthew W Tocheri, Caroline VanSickle, Christopher S Walker, Pianpian Wei & Bernhard Zipfel, 2015, Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa, pp. 1-35 in eLife e 09560 4 on page 26, DOI: 10.7554/eLife.09560

Homo erectus Samples from Buia, Chemeron, Daka, Dmanisi, East and West Lake Turkana, Gona, Hexian, Konso, Mojokerto, Olduvai Gorge, Sangiran, Swartkrans, Trinil, and Zhoukoudian were included in this study. South African material is of special interest in this comparison because of the geographic proximity, and because of the difficulty of clearly identifying Homo specimens within the large fossil sample from Swartkrans. In particular, the following specimens from Swartkrans are considered to represent H. erectus: SK 15, SK 18a, SK 27, SK 43, SK 45, SK 68, SK 847, SK 878, SK 2635, SKW 3114, SKX 257/258, SKX 267/ 2671, SKX 268, SKX 269, SKX 334, SKX 339, SKX 610, SKX 1756, SKX 2354, SKX 2355, SKX 2356, and SKX 21204. It has been suggested (Grine et al., 1993, 1996) that SK 847 and Stw 53 might represent the same taxon, and that this taxon is a currently undiagnosed species of Homo in South Africa. However, we agree with Clarke (1977; 2008) that SK 847 can be attributed to H. erectus, and that Stw 53 cannot. Because there is no clear indication that more than one species of Homo is represented in the Swartkrans sample, we consider all this material to belong to H. erectus. We considered ‘ Homo ergaster ’ (and also ‘ Homo aff. erectus ’ from Wood, 1991) to be synonyms of H. erectus for this study; Turkana Basin specimens that are attributed to H. erectus thus include KNM-ER 730, KNM-ER 820, KNM-ER 992, KNM- ER 1808, KNM-ER 3733, KNM-ER 3883, KNM-ER 42700, KNM-WT 15000. Olduvai specimens include OH 9, OH 12 and OH 28. Original fossil materials from Chemeron, Lake Turkana, Swartkrans, Trinil, and Dmanisi were examined first-hand by the authors, while the remainder were based on casts and published reports (Weidenreich, 1943; Wood, 1991; Anton´, 2003; Rightmire et al., 2006; Suwa et al., 2007). A large number of postcranial specimens have been collected from the Turkana Basin and appear consistent with the anatomical range otherwise found in Homo, and inconsistent with known samples of Australopithecus and Paranthropus from elsewhere. These include KNM-ER 1472, KNM-ER 1481, KNM- ER 3228, KNM-ER 737, and others. We may add other fossils from other sites lacking association with craniodental material, such as the partial BOU-VP 12/1 skeleton and even the Gona pelvis. These specimens attributable to Homo but not necessarily to a particular species did inform our understanding of variability within the genus, but for the most part these specimens do not inform our differential diagnosis of H. naledi relative to particular species. For example, the key element of femoral morphology of H. naledi in contrast to other species is the presence of two well-defined mediolaterally running pillars in the femoral neck; the isolated specimens of early Homo do not contradict this apparent autapomorphy. Likewise, no isolated specimens inform us about the humanlike aspects of foot morphology in H. naledi. In these cases, the lack of associations for this evidence actually is less important than the lack of specimens that replicate the distinctive features of the H. naledi morphology., Published as part of Lee R Berger, John Hawks, Darryl J de Ruiter, Steven E Churchill, Peter Schmid, Lucas K Delezene, Tracy L Kivell, Heather M Garvin, Scott A Williams, Jeremy M DeSilva, Matthew M Skinner, Charles M Musiba, Noel Cameron, Trenton W Holliday, William Harcourt-Smith, Rebecca R Ackermann, Markus Bastir, Barry Bogin, Debra Bolter, Juliet Brophy, Zachary D Cofran, Kimberly A Congdon, Andrew S Deane, Mana Dembo, Michelle Drapeau, Marina C Elliott, , Elen M Feuerriegel, Daniel Garcia-Martinez, David J Green, Alia Gurtov, Joel D Irish, Ashley Kruger, Myra F Laird, Damiano Marchi, Marc R Meyer, Shahed Nalla, Enquye W Negash, Caley M Orr, Davorka Radovcic, Lauren Schroeder, Jill E Scott, Zachary Throckmorton, Matthew W Tocheri, Caroline VanSickle, Christopher S Walker, Pianpian Wei & Bernhard Zipfel, 2015, Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa, pp. 1-35 in eLife e 09560 4 on page 27, DOI: 10.7554/eLife.09560

Australopithecus garhi The cranium BOU-VP-12/130 from Bouri was included, with data taken from a published report (Asfaw et al., 1999)., Published as part of Lee R Berger, John Hawks, Darryl J de Ruiter, Steven E Churchill, Peter Schmid, Lucas K Delezene, Tracy L Kivell, Heather M Garvin, Scott A Williams, Jeremy M DeSilva, Matthew M Skinner, Charles M Musiba, Noel Cameron, Trenton W Holliday, William Harcourt-Smith, Rebecca R Ackermann, Markus Bastir, Barry Bogin, Debra Bolter, Juliet Brophy, Zachary D Cofran, Kimberly A Congdon, Andrew S Deane, Mana Dembo, Michelle Drapeau, Marina C Elliott, , Elen M Feuerriegel, Daniel Garcia-Martinez, David J Green, Alia Gurtov, Joel D Irish, Ashley Kruger, Myra F Laird, Damiano Marchi, Marc R Meyer, Shahed Nalla, Enquye W Negash, Caley M Orr, Davorka Radovcic, Lauren Schroeder, Jill E Scott, Zachary Throckmorton, Matthew W Tocheri, Caroline VanSickle, Christopher S Walker, Pianpian Wei & Bernhard Zipfel, 2015, Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa, pp. 1-35 in eLife e 09560 4 on page 26, DOI: 10.7554/eLife.09560

Australopithecus sediba The partial skeletons MH1 and MH2 from Malapa, South Africa were included in this study, based on examination of the original specimens by the authors., Published as part of Lee R Berger, John Hawks, Darryl J de Ruiter, Steven E Churchill, Peter Schmid, Lucas K Delezene, Tracy L Kivell, Heather M Garvin, Scott A Williams, Jeremy M DeSilva, Matthew M Skinner, Charles M Musiba, Noel Cameron, Trenton W Holliday, William Harcourt-Smith, Rebecca R Ackermann, Markus Bastir, Barry Bogin, Debra Bolter, Juliet Brophy, Zachary D Cofran, Kimberly A Congdon, Andrew S Deane, Mana Dembo, Michelle Drapeau, Marina C Elliott, , Elen M Feuerriegel, Daniel Garcia-Martinez, David J Green, Alia Gurtov, Joel D Irish, Ashley Kruger, Myra F Laird, Damiano Marchi, Marc R Meyer, Shahed Nalla, Enquye W Negash, Caley M Orr, Davorka Radovcic, Lauren Schroeder, Jill E Scott, Zachary Throckmorton, Matthew W Tocheri, Caroline VanSickle, Christopher S Walker, Pianpian Wei & Bernhard Zipfel, 2015, Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa, pp. 1-35 in eLife e 09560 4 on page 26, DOI: 10.7554/eLife.09560

Middle Pleistocene Homo Specimens from the latest Lower Pleistocene and MP of Europe and Africa that cannot be attributed to H. erectus were included in our comparisons. These include fossils that have been attributed to H. heidelbergensis, H. rhodesiensis, ‘archaic H. sapiens ’, or ‘evolved H. erectus ’ by a variety of other authors. Specimens attributed to MP Homo include materials from Eliye Springs, Arago, Atapuerca Sima de los Huesos, Bodo, Broken Hill, Cave of Hearths, Ceprano, Dali, Elandsfontein, Jinniushan, Kapthurin, Mauer, Narmada, Ndutu, Petralona, Reilingen-Schwetzingen, Solo, Steinheim, Swanscombe. This grouping includes the following specimens: KNM-ES 11693, Arago 2, Arago 13, Arago 21, Atapuerca 1, Atapuerca 2, Atapuerca 4, Atapuerca 5, Atapuerca 6, Cave of Hearths, SAM-PQ- EH1, Kabwe, Mauer, Ndutu, Sale´, Petralona, Reilingen-Schwetzingen, Steinheim.

Afropithecus turkanensis (17–17.5 Ma; Kalodirr, Buluk, Locherangan, Moruorot, Nabwal Hills; Kenya) and Morotopithecus bishopi (20.6 Ma; Moroto II; Uganda) are both large-bodied catarrhines from the early Miocene of eastern Africa with relatively primitive cranial and postcanine dental morphology. They are primarily differentiated by a temporal separation of ∼3.6 million years and by postcranial samples suggesting that M. bishopi was capable of orthograde postures and below-branch arboreality, while A. turkanensis was most likely a pronograde quadruped. Several researchers dispute the validity of the postcranial and dating evidence and argue that M. bishopi and A. turkanensis may be congeneric or even conspecific. Although A. turkanensis possesses a derived suite of specialized anterior dentognathic characters that are functionally convergent with extant pitheciins and associated with sclerocarp foraging and maxillary canine dietary function, a similar analysis of M. bishopi anterior dentognathic anatomy is presently lacking. The current study addresses this shortcoming via a detailed morphometric analysis of relevant A. turkanensis and M. bishopi specimens preserving the anterior palate, maxillary canines and incisors. Results indicate that the anterior dentognathic morphologies of A. turkanensis and M. bishopi are distinct and represent significantly dissimilar feeding adaptations. Specifically, M. bishopi lacks the elongated and anteriorly narrow premaxilla, lateral incisors that are more posterior and mesially positioned relative to the central incisors, and pronounced yet evenly distributed mesial curvature of the maxillary canine that are shared by A. turkanensis and extant pitheciins. Given that A. turkanensis anterior dentognathic morphology is functionally convergent with extant pitheciins to the exclusion of M. bishopi, it is likely that M. bishopi and A. turkanensis have dissimilar feeding adaptations. Although a systematic analysis is required to verify these species at the generic and species level, the absence of any substantial morphological similarity in their anterior dentognathic anatomy is most consistent with the interpretation that M. bishopi and A. turkanensis represent, at the least, different species.

Anthropoid incisors are large relative to the postcanine dentition and function in the preprocessing of food items. Previous analyses of anthropoid incisor allometry and shape demonstrate that incisor morphology is correlated with preferred foods and that more frugivorous anthropoids have larger and more curved incisors. Although the relationship between incisal crown curvature and preferred foods has been well documented in extant and fossil anthropoids, the functional significance of curvature variation has yet to be conclusively established. Given that an increase in crown curvature will increase maximum linear crown dimensions, and bending resistance is a function of linear crown dimensions, it is hypothesized that incisor crown curvature functons to increase incisor crown resistance to bending forces. This study uses beam theory to calculate the mesiodistal and labiolingual bending strengths of the maxillary and mandibular incisors of hominoid and platyrrhine taxa with differing diets and variable degrees of incisal curvature. Results indicate that bending strength correlates with incisal curvature and that frugivores have elevated incisor bending resistance relative to folivores. Maxillary central incisor bending strengths further discriminate platyrrhine and hominoid hard- and soft-object frugivores suggesting this crown is subjected to elevated occlusal loading relative to other incisors. These results are consistent with the hypothesis that incisor crown curvature functions to increase incisor crown resistance to bending forces but does not preclude the possibility that incisor bending strength is a composite function of multiple dentognathic variables including, but not limited to, incisor crown curvature.

The infraorbital foramen (IOF) is located below the orbit and transmits the sensory infraorbital nerve (ION) to mechanoreceptors located throughout the maxillary region. The size of the IOF correlates with the size of the ION; thus, the IOF appears to indicate relative touch sensitivity of maxillary region. In primates, IOF size correlates well with diet. Frugivores have relatively larger IOFs than folivores or insectivores because fruit handling/processing requires increased touch sensitivity. However, it is unknown if the IOF can be used to detect subtle dietary differences among closely related hominoid species. Hominoids are traditionally grouped into broad dietary categories, despite the fact that hominoid diets are remarkably diverse. This study examines whether relative IOF size is capable of differentiating among the dietary preferences of closely related species with overlapping, yet divergent diets. We measured IOF area in Hylobates lar, Symphalangus syndactulus, Pongo pygmaeus spp., Pan troglodytes, Gorilla gorilla, Gorilla beringei graueri, and Gorilla beringei beringei. We classified each species as a dedicated folivore, mixed folivore/frugivore, soft object frugivore, or hard object frugivore. The IOF is documented to be larger in more frugivorous species and smaller in more folivorous taxa. Interestingly, G.b. beringei, had the largest relative IOF of any gorilla, despite being a dedicated folivore. G.b. beringei does have unique food processing behavior that relies heavily on maxillary mechanoreception, thus this finding is not entirely unsupported behaviorally. The results of this study provide evidence that the IOF is an informative feature in interpretations of fossil apes.

Prehensile tails, capable of suspending the entire body weight of an animal, have evolved in parallel in New World monkeys (Platyrrhini): once in the Atelinae (Alouatta, Ateles, Brachyteles, Lagothrix), and once in the Cebinae (Cebus, Sapajus). Structur- ally, the prehensile tails of atelines and cebines share morphological features that distinguish them from nonprehensile tails, including longer proximal tail regions, well-developed hemal processes, robust cau- dal vertebrae resistant to higher torsional and bend- ing stresses, and caudal musculature capable of producing higher contractile forces. The functional significance of shape variation in the articular surfa- ces of caudal vertebral bodies, however, is relatively less well understood. Given that tail use differs con- siderably among prehensile and nonprehensile anthropoids, it is reasonable to predict that caudal vertebral body articular surface area and shape will respond to use-specific patterns of mechanical load- ing. We examine the potential for intervertebral articular surface contour curvature and relative sur- face area to discriminate between prehensile-tailed and nonprehensile-tailed platyrrhines and cercopithe- coids. The proximal and distal intervertebral articular surfaces of the first (Ca1), transitional and longest caudal vertebrae were examined for individuals rep- resenting 10 anthropoid taxa with differential pat- terns of tail-use. Study results reveal significant morphological differences consistent with the func- tional demands of unique patterns of tail use for all vertebral elements sampled. Prehensile-tailed platyr- rhines that more frequently use their tails in suspen- sion (atelines) had significantly larger and more convex intervertebral articular surfaces than all nonprehensile-tailed anthropoids examined here, although the intervertebral articular surface contour curvatures of large, terrestrial cercopithecoids (i.e., Papio sp.) converge on the ateline condition. Prehensile-tailed platyrrhines that more often use their tails in tripodal bracing postures (cebines) are morphologically intermediate between atelines and nonprehensile tailed anthropoids. J. Morphol. 000:000-000, 2014. V C 2014 Wiley Periodicals, Inc.

Rudabanya is rare among Eurasian Miocene fossil primate localities in preserving both a hominid and pliopithecoid, and as such provides the unique opportunity to reconstruct the nature of sympatry and niche partitioning in these taxa. Rudapithecus and Anapithecus have similar locomotor and positional behavior and overlapping body mass ranges. While prior analyses of molar occlusal anatomy and microwear identify Rudapithecus as a soft-object frugivore, reconstructing the dietary behavior of Anapithecus has been more problematic. This taxon has been interpreted to be more folivorous by some, and more frugivorous by others. Here, we use high-resolution polynomial curve fitting (HR-PCF) to quantify and evaluate the mesiodistal and cervico-incisal curvatures of the incisor crowns of Rudapithecus and Anapithecus to identify diet-specific morphological variation in these taxa. Results are consistent with the interpretation that Anapithecus and Rudapithecus were primarily frugivorous and had diets that included similar resource types. However, Anapithecus may have consumed greater amounts of foliage, similar to extant mixed folivore–frugivores (i.e., Gorilla gorilla gorilla , Symphalangus syndactylus ), while Rudapithecus generated elevated compressive loads in the incisor region consistent with a specialized role for the anterior dentition in food processing (i.e., removal of tough protective fruit pericarps). We interpret these findings in light of the paleoecology at Rudabanya and conclude that, if these taxa were indeed sympatric, Anapithecus may have used additional leaf consumption as a seasonal fallback resource to avoid direct competition with Rudapithecus . Conversely, Rudapithecus may have relied on less preferred and harder fruiting resources as a seasonal fallback resource during periods of fruit scarcity.

The early Miocene catarrhine fossil record of East Africa represents a diverse and extensive adaptive radiation. It is well accepted that these taxa encompass a dietary range similar to extant hominoids, in addition to some potentially novel dietary behaviour. There have been numerous attempts to infer diet for these taxa from patterns of dental allometry and incisor and molar microwear, however, morphometric analyses until now have been restricted to the post-canine dentition. It has already been demonstrated that given the key functional role of the incisors in pre-processing food items prior to mastication, there is a positive correlation between diet and incisal curvature (Deane, A.S., Kremer, E.P., Begun, D.R., 2005. A new approach to quantifying anatomical curvatures using High Resolution Polynomial Curve Fitting (HR-PCF). Am. J. Phys. Anthropol. 128(3), 630-638.; Deane, A.S., 2007. Inferring dietary behaviour for Miocene hominoids: A high-resolution morphometric approach to incisal crown curvature. Ph.D. Dissertation. The University of Toronto.). This study seeks to re-examine existing dietary hypotheses for large-bodied early Miocene fossil catarrhines by contrasting the incisal curvature for these taxa with comparative models derived from prior studies of the correlation between extant hominoid incisor curvature and feeding behaviour. Incisor curvature was quantified for 78 fossil incisors representing seven genera, and the results confirm that early Miocene fossil catarrhines represent a dietary continuum ranging from more folivorous (i.e., Rangwapithecus) to more frugivorous (i.e., Proconsul) diets, as well as novel dietary behaviours that are potentially similar to extant ceboids (i.e., Afropithecus). Additionally, early Miocene fossil catarrhine incisors are less curved than extant hominoid incisors, indicating a general pattern of increasing mesio-distal and labial curvature through time. This pattern of morphological shifting is consistent with the Red Queen Effect (Van Valen, L., 1973. A new evolutionary law. Evol. Theory 1, 1-30), which predicts that taxa that are removed from one another by geological time, although potentially having similar diets, may exhibit differing degrees of a similar dietary adaptation (i.e., differing degrees of incisal curvature).

Phalangeal curvature has frequently been used as a proxy indicator of fossil hominoid and hominin positional behavior and locomotor adaptations, both independently and within the context of broader discussions of the postcranium as a whole. This study used high-resolution polynomial curve fitting (HR-PCF) to measure the shaft curvature of fragmentary proximal phalanges that have previously been excluded from analyses of phalangeal curvature owing to design limitations of existing methods. In doing so, the available sample of fossil specimens was increased substantially, making it possible to test prevailing locomotor hypotheses for many taxa with new specimens. The results generated from the HR-PCF analysis of extant primate manual and pedal phalangeal samples suggest that, although capable of identifying suspensory hominoids with some degree of accuracy, phalangeal curvature values reported for extant terrestrial and arboreal quadrupeds overlap considerably. Consequently, it is difficult to reliably predict the locomotor adaptations for fossil taxa with phalangeal curvatures similar to these groups, although the curvature values reported for most taxa were broadly consistent with existing locomotor hypotheses. Only the curvature values reported for Pierolapithecus, which are most similar to those of suspensory hominoids, are inconsistent with previously published locomotor hypotheses. Likewise, although not inconsistent with bipedality, curvature values reported for Australopithecus confirm earlier conclusions that, despite a general reduction in phalangeal length relative to Pan, these taxa have similar and overlapping ranges of phalangeal curvature.

Accurately interpreting fossil primate dietary behaviour is necessary to fully understand a species' ecology and connection to its environment. Traditional methods developed to infer diet from hominoid teeth successfully group taxa into broad dietary categories (i.e., folivore, frugivore) but often fail to represent the range of dietary variability characteristic of living apes. This oversimplification is not only a consequence of poor resolution, but may also reflect the use of similar fallback resources by closely related taxa with dissimilar diets. This study demonstrates that additional dietary specificity can be achieved using a morphometric approach to hominoid incisor curvature. High-resolution polynomial curve fitting (HR-PCF) was used to quantify the incisor curvatures of closely related hominoid taxa that have dissimilar diets but similar morphological adaptations to specific keystone resources (e.g., Gorilla gorilla beringei vs. G. g. gorilla). Given the key role of incisors in food processing, it is reasonable to assume that these teeth will be at least partially influenced by the unique selective pressures imposed by the mechanical loading specific to individual diets. Results from this study identify a strong correlation between hominoid dietary proportions and incisor linear dimensions and curvature, indicating that more pronounced incisor curvature is positively correlated with higher levels of frugivory. Hard-object frugivores have the greatest mesiodistal and cervico-incisal curvature and dedicated folivores have the least curved incisors. Mixed folivore/frugivores are morphological intermediates between dedicated folivores and hard- and soft-object frugivores. Mesiodistal curvature varied only in the degree of curvature; however, cervico-incisal curvature was shown to differ qualitatively between more frugivorous and more folivorous taxa. In addition to identifying a greater range of dietary variability among hominoids, this study also demonstrates that HR-PCF is capable of identifying morphological distinctions between closely related taxa with overlapping diets that rely on similar fallback foods (e.g., Pan paniscus vs. P. troglodytes).