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Pelvic sexual dimorphism in primates is typically seen as the result of female-specific adaptations to obstetric constraints, which arise from the tight fit between the neonate head and the maternal pelvis. However, it remains debated to which extent pelvic dimorphism is a correlate of obstetric constraints, of body size dimorphism, and/or of other factors. Also, little is known on how pelvic dimorphism develops. Here we use methods of biomedical imaging and geometric morphometrics to address these questions in two hylobatid species, Hylobates lar and Symphalangus syndactylus. These species differ markedly in body size, but within each species, there is only little body size dimorphism. Results show that the neonates of H. lar are large compared to the maternal pelvis, resulting in high cephalopelvic proportions and substantial obstetric constraints. Pelvic sexual dimorphism is moderate but significant: During puberty, females develop a more capacious pelvic inlet than males, while overall pelvic size is similar in both sexes. S. syndactylus has substantially larger pelves than H. lar, but neonates are similar in size to those of H. lar. Cephalopelvic proportions are thus low, and there are no obstetric constraints. Pelvic sexual dimorphism is absent. Overall, these data indicate that pelvic sexual dimorphism in hylobatids reflects obstetric constraints. Anat Rec, 300:859-869, 2017. © 2017 Wiley Periodicals, Inc.

The bony pelvis of primates is a composite structure serving a variety of functions, and exhibiting a complex pattern of modularity and integration. Still little is known, however, about how patterns of modularity and integration arise, and how they change throughout ontogeny. Here we study the ontogeny of modularity and integration in developmental and functional units of the pelvis of our closest living relatives, the chimpanzees. We use methods of biomedical imaging and geometric morphometrics to quantify pelvic shape change from late fetal stages to adulthood, and to track changes in patterns of covariation within and among pelvic regions. Our results show that both developmental and functional units of the pelvis exhibit significant levels of modularity throughout ontogeny. Modularity of developmental units (ilium, ischium, and pubis) decreases with increasing age, whereas modularity of functional units tends to increase. We suggest that the decreasing modularity and increasing integration of developmental units reflects their gradual fusion. In contrast, increasing modularity of functional pelvic units likely reflects changing functional demands during an individual's lifetime. Overall, ontogenetic changes in patterns of modularity and integration imply that natural selection could act differently on each module, either developmental or functional, at different stages of ontogeny. This further implies that adult patterns of covariation in the pelvis provide only limited information about its evolvability. Anat Rec, 300:675-686, 2017. © 2017 Wiley Periodicals, Inc.

Survey studies of osteoarchaeological collections occasionally yield specimens exhibiting rare skeletal developmental disorders. Beyond paleopathological diagnosis, however, it is often difficult to gain insight into the processes, mechanisms, and consequences of the pathology, notably because archaeological specimens are often fragmentary. Here, we propose a combination of virtual reconstruction (VR) and geometric morphometrics (GM) to address these issues. As an example, we use VR to reconstruct the only known archaeological specimen exhibiting persistence of the pelvic triradiate cartilage and compare it via GM with a set of healthy pelvises representing both sexes and different ontogenetic stages. Our results evidence (i) a marked deviation of the pathological pelvis from the adult mean shape, (ii) the retention of typical male features, and (iii) the retention of a paedomorphic ratio between iliac and ischiopubic size. Altogether, such data offer new insights into the modularity and integration of pelvic ontogeny, while at the same time demonstrating the usefulness of a combined VR/GM approach as complement to classical methods of paleopathology.

MultiMedia Laboratorium, Institut fu¨r Informatik, Universita¨tZu¨rich-Irchel,Zu¨rich, SwitzerlandABSTRACTIn this study, we present a new computerized reconstruction of the LeMoustier 1 Neanderthal skull and discuss its significance for Neanderthalgrowth and variability. Because of the precarious state of preservation of theoriginal material, we applied entirely noninvasive methods of fossil recon-struction and morphometry, using a combination of computed tomography,computer graphics, and stereolithography.After electronic restoration, the isolated original pieces were recom-posed on the computer screen using external and internal anatomical cluesto position the bone fragments and mirror images to complete missing parts.The inferred effects of general compressive deformation that occurredduring fossilization were corrected by virtual decompression of the skull.The resulting new reconstruction of the Le Moustier 1 skull shows morpho-logicfeaturesclosetothetypicalNeanderthaladultstate.Residualasymme-try of skeletal parts can be traced to in vivo skeletal modification: the leftmandibularjointshowssignsofahealedcondylarfracture,andtheanatomyof the occipital region suggests mild plagiocephaly.Using micro-CT analysis, the left incus could be recovered from thematrix filling of the middle ear cavity. Its morphometric dimensions aresimilar to those of the La Ferrassie III incus. The morphometric characteris-tics of the inner ear deviate substantially from the condition reported astypical for Neanderthals and fall within the range of modern humanvariability. Anat Rec 254:474–489, 1999.