American Journal of Physical Anthropology

Dunn, Rachel H.; Sybalsky, Julia M.; Conroy, Glenn C.; Rasmussen, D. Tab

doi: 10.1002/ajpa.20407pmid: 16617428

North American omomyids represent a tremendous Eocene radiation of primates exhibiting a wide range of body sizes and dietary patterns. Despite this adaptive diversity, relatively little is known of the postcranial specializations of the group. Here we describe hindlimb and foot bones of Ourayia uintensis and Chipetaia lamporea that were recovered from the Uinta B member (early Uintan Land Mammal Age), Uinta Formation, Utah. These specimens provide insights into the evolution of postcranial adaptations across different body sizes and dietary guilds within the Eocene primate radiation. Body mass estimates based on talar measurements indicate that Ourayia uintensis and Chipetaia lamporea weighed about 1,500–2,000 g and 500–700 g, respectively. Skeletal elements recovered for Ourayia include the talus, navicular, entocuneiform, first metatarsal, and proximal tibia; bones of Chipetaia include the talus, navicular, entocuneiform, and proximal femur. Both genera had opposable grasping big toes, as indicated by the saddle‐shaped joint between the entocuneiform and first metatarsal. Both taxa were arboreal leapers, as indicated by a consistent assemblage of characters in all represented bones, most notably the somewhat elongated naviculars, the high and distinct trochlear crests of the talus, the posteriorly oriented tibial plateau (Ourayia), and the cylindrical head of the femur (Chipetaia). The closest resemblances to Ourayia and Chipetaia are found among the Bridger omomyines, Omomys and Hemiacodon. The results of our comparisons suggest that the later, larger, more herbivorous omomyines from Utah retained a skeletal structure characteristic of earlier, smaller North American omomyids. Am J Phys Anthropol, 2006. © 2006 Wiley‐Liss, Inc.

Chaimanee, Yaowalak; Yamee, Chotima; Tian, Pannipa; Khaowiset, Kitti; Marandat, Bernard; Tafforeau, Paul; Nemoz, Christian; Jaeger, Jean‐Jacques

doi: 10.1002/ajpa.20437pmid: 16617433

A Khoratpithecus piriyai lower jaw corresponds to a well‐preserved Late Miocene hominoid fossil from northeastern Thailand. Its morphology and internal structure, using a microcomputed tomography scan, are described and compared to those of other known Miocene hominoids. It originated from fluviatile sand and gravel deposits of a large river, and was associated with many fossil tree trunks, wood fragments, and large vertebrate remains. A biochronological analysis by using associated mammal fauna gives an estimated geological age between 9–6 Ma. The flora indicates the occurrence of a riverine tropical forest and wide areas of grassland. K. piriyai displays many original characters, such as the great breadth of its anterior dentition, suggesting large incisors, large lower M3, a canine with a flat lingual wall, and symphysis structure. Several of its morphological derived characters are shared with the orangutan, indicating sister‐group relationship with that extant ape. This relationship is additionally strongly supported by the absence of anterior digastric muscle scars. These shared derived characters are not present in Sivapithecus, Ankarapithecus, and Lufengpithecus, which are therefore considered more distant relatives to the orangutan than Khoratpithecus. The Middle Miocene K. chiangmuanensis is older, displays more primitive dental characters, and shares several dental characters with the Late Miocene form. It is therefore interpreted as its probable ancestor. But its less enlarged M3 and more wrinkled enamel may suggest an even closer phylogenetic position to orangutan ancestors, which cannot yet be supported because of the incomplete fossil record. Thus Khoratpithecus represents a new lineage of Southeast Asian hominoids, closely related to extant great ape ancestors. Am J Phys Anthropol 2006. © 2006 Wiley‐Liss, Inc.

Judd, Margaret A.

doi: 10.1002/ajpa.20401pmid: 16596602

Modern communities affiliated with the same culture have been shown to experience comparable levels of interpersonal violence, no matter what their size. It was hypothesized that a similar relationship would exist among ancient rural and urban people, but that accident‐related trauma may be more prominent among rural dwellers due to their activity base. Through an analysis of antemortem trauma, this investigation contrasted the injury profile of Nubian adult villagers (N = 55) from the Kerma period (2500–1750 BC) to that of their urban neighbors (N = 223) at Kerma (2050–1500 BC). The injury pattern associated with interpersonal violence (cranial injury, direct‐force ulna fractures, and multiple injuries) was similar between the two samples, as hypothesized. The rural group sustained significantly more nonviolence‐related injuries that suggested occupational or environmental influences. The more severe cranial injuries observed among urban people are attributed to a preference for more lethal hand‐wielded objects that may have accompanied increasing local tensions and incursions into Egypt during the 17th Dynasty. Am J Phys Anthropol, 2006. © 2006 Wiley‐Liss, Inc.

Nystrom, Kenneth C.

doi: 10.1002/ajpa.20431pmid: 16617430

Archaeological and ethnohistorical documents suggest that the Chachapoya region was inhabited by a number of distinct sociopolitical groups that only united in the face of their common enemy, the Inka. The purpose of this research is to quantify the amount of internal genetic differentiation and levels of extraregional gene flow during the Late Chachapoya period, in order to obtain a better understanding of the genetic relationship between these presumed ethnic groups. Craniometric data were collected from three Late Chachapoya samples (Laguna Huayabamba, Kuelap, and Laguna de los Cóndores), in order to understand the genetic relationships between the groups and facilitate our understanding of Late Chachapoya population structure. Genetic differentiation among these series ranged from 0.047 (heritability = 1.0) to 0.090 (heritability = 0.55). The Relethford‐Blangero residuals indicate that the Laguna Huayabamba and Laguna de los Cóndores populations were receiving greater than average external gene flow, while Kuelap was receiving less than average external gene flow. The correspondence between biological and archaeological data in the investigation of prehistoric ethnic identity is discussed. Am J Phys Anthropol, 2006. © 2006 Wiley‐Liss, Inc.

Mays, S.; Turner‐Walker, G.; Syversen, U.

doi: 10.1002/ajpa.20445pmid: 16634046

Modern populations from Norway and England differ in their experience of osteoporosis, the former showing lower bone mineral density (BMD) and a higher fragility fracture rate. The aim of the present work was to investigate whether this was also the case during the Middle Ages. Age‐dependent loss of BMD in the proximal femur was assessed using dual X‐ray absorptiometry (DXA) in male and female adult skeletons from a cemetery in the medieval town of Trondheim, Norway. Fracture prevalence was also investigated. Results were compared with those previously reported for a skeletal series from Wharram Percy, a deserted medieval village in England. Results indicate that peak BMD and patterns of age‐related loss of BMD in the Norwegian and the English group were similar. Among females, the prevalence of osteoporotic fractures was greater in the Norwegian than in the English population. The BMD results suggest that differences in BMD between English and Norwegians are of recent origin, although given the fairly modest sample sizes, further work is needed to confirm this. Reasons for the greater prevalence of osteoporotic fractures in women in the Norwegian skeletal series are unclear, but the colder climate and greater frequency of hard surfaces may have meant that falls were more frequent, and when they occurred, were more likely to result in fractures than in the rural English group. Am J Phys Anthropol, 2006. © 2006 Wiley‐Liss, Inc.

Mays, S.

doi: 10.1002/ajpa.20447pmid: 16634047

The prevalence of spondylolysis and spondylolisthesis was studied in an adult skeletal series from a rural English medieval archaeological site. Attempts were made to evaluate the association of three aspects of lumbo‐sacral skeletal morphology (pelvic incidence (a measure of the anterior inclination of the sacral table), lumbar transverse process width, and the presence of lumbo‐sacral spina bifida occulta) with spondylolysis and spondylolisthesis. Results indicated a high prevalence of spondylolysis compared with a modern reference population, but few cases of spondylolisthesis were identified. Analysis of prevalence with respect to age suggests that in the study population, pars interarticularis defects generally formed late in the growth period or early in adult life. The study group showed a high mean pelvic incidence compared with modern Western Europeans, indicating a more steeply inclined sacral table, which may have elevated the risk of developing pars interarticularis defects. However, no statistically valid association could be demonstrated between the presence/absence of spondylolysis and pelvic incidence in the study material. There was no evidence for a link between lumbar transverse process index or lumbo‐sacral spina bifida occulta and spondylolysis/spondylolisthesis. It is concluded that the potential role of lumbo‐sacral morphology, as well as of activity regimes, should be considered when interpreting spondylolysis in paleopathological studies. If the frequency of spondylolysis is to some extent an indicator of past activity regimes, it may reflect lifestyle in younger individuals rather than in mature adults. Further work investigating the link between spondylolysis and lumbo‐sacral morphological variables in premodern populations would be of value. Am J Phys Anthropol, 2006. © 2006 Wiley‐Liss, Inc.

Megyesi, Mary S.; Ubelaker, Douglas H.; Sauer, Norman J.

doi: 10.1002/ajpa.20446pmid: 16617435

The Lamendin aging method involves the quantification of root translucency and the attachment position of the periodontal membrane. It was developed using recent medical‐examiner specimens, and was tested on modern skeletal samples such as the Terry Collection (Lamendin et al. [1992] J. Forensic Sci. 37:1373–1379; Prince and Ubelaker [2002] J. Forensic Sci. 47:107–116). The method may be one of the most useful for estimating age after the mid‐30s. The current study is an evaluation of the Lamendin criteria on two historic skeletal samples from Britain. Both the Christ's Church Spitalfields and St. Bride's Church collections represent documented skeletal samples that were interred in the 18th and 19th centuries. In total, 1,188 teeth from 220 adult individuals were examined from these two collections. The Lamendin method requires measuring total root length (cementoenamel junction to apex), gingival regression (cementoenamel junction to periodontal ligament attachment), and root translucency (root apex to maximum level of root translucency) on the labial surface of single‐rooted teeth. Our results indicate that postmortem factors affect the applicability of the Lamendin technique to archaeological and historical samples. In particular, root translucency disappears with time, or is obscured by unknown postmortem taphonomic effects related to the length of interment or postmortem environment. Thirty‐five percent of our sample showed no root translucency, indicating that caution is required when applying this method to archaeological or historical remains. The mean error of age estimates for Spitalfields and St. Bride's was higher than in the original study of Lamendin et al. ([1992] J. Forensic Sci. 37: 1373–1379), and higher than in the test by Prince and Ubelaker ([2002] J. Forensic Sci. 47:107–116) of the Lamendin method on the Terry Collection. Am J Phys Anthropol 2006. © 2006 Wiley‐Liss, Inc.

Nicholson, Elisabeth; Harvati, Katerina

doi: 10.1002/ajpa.20425pmid: 16617436

Human mandibular morphology is often thought to reflect mainly function, and to be of lesser value in studies of population history. Previous descriptions of human mandibles showed variation in ramal height and breadth to be the strongest difference among recent human groups. Several mandibular traits that differentiate Neanderthals from modern humans include greater robusticity, a receding symphysis, a large retromolar space, a rounder gonial area, an asymmetric mandibular notch, and a posteriorly positioned mental foramen in Neanderthals. Nevertheless, the degree to which these differences are part of modern human variation and/or are related to size and function remains unclear. The aim of this study was to document geographic and functional patterning in the mandibular shape of recent humans, to assess the effects of allometry on mandibular form, and to quantitatively evaluate proposed “Neanderthal” mandibular traits through comparison with samples of geographically diverse recent humans. Data were collected in the form of three‐dimensional coordinates of 28 landmarks. Unlike previous studies, this analysis found that modern human mandibular shape exhibits considerable geographic patterning, with some aspects of mandibular morphology reflecting a climatic gradient, and others, a functional specialization. Population history is also reflected in mandibular form, albeit relatively weakly. Proposed “Neanderthal” traits were found to separate Neanderthal from modern human mandibles successfully in the statistical analysis. Of these, the retromolar gap was found to be related to increased mandibular size in modern humans. The status of this trait as a Neanderthal autapomorphy should therefore be treated with caution. Am J Phys Anthropol, 2006. © 2006 Wiley‐Liss, Inc.

Thorpe, Susannah K.S.; Crompton, Robin H.

doi: 10.1002/ajpa.20422pmid: 16617429

The Asian apes, more than any other, are restricted to an arboreal habitat. They are consequently an important model in the interpretation of the morphological commonalities of the apes, which are locomotor features associated with arboreal living. This paper presents a detailed analysis of orangutan positional behavior for all age‐sex categories and during a complete range of behavioral contexts, following standardized positional mode descriptions proposed by Hunt et al. ([1996] Primates 37:363–387). This paper shows that orangutan positional behavior is highly complex, representing a diverse spectrum of positional modes. Overall, all orthograde and pronograde suspensory postures are exhibited less frequently in the present study than previously reported. Orthograde suspensory locomotion is also exhibited less often, whereas pronograde and orthograde compressive locomotor modes are observed more frequently. Given the complexity of orangutan positional behavior demonstrated by this study, it is likely that differences in positional behavior between studies reflect differences in the interplay between the complex array of variables, which were shown to influence orangutan positional behavior (Thorpe and Crompton 2005 Am. J. Phys. Anthropol. 127:58–78). With the exception of pronograde suspensory posture and locomotion, orangutan positional behavior is similar to that of the African apes, and in particular, lowland gorillas. This study suggests that it is orthogrady in general, rather than forelimb suspend specifically, that characterizes the positional behavior of hominoids. Am J Phys Anthropol 2006. © 2006 Wiley‐Liss, Inc.

Wang, Qian; Dechow, Paul C.

doi: 10.1002/ajpa.20438pmid: 16617434

Knowledge of elastic properties and of their variation in the cortical bone of the craniofacial skeleton is indispensable for creating accurate finite‐element models to explore the biomechanics and adaptation of the skull in primates. In this study, we measured elastic properties of the external cortex of the rhesus monkey craniofacial skeleton, using an ultrasonic technique. Twenty‐eight cylindrical cortical specimens were removed from each of six craniofacial skeletons of adult Macaca mulatta. Thickness, density, and a set of longitudinal and transverse ultrasonic velocities were measured on each specimen to allow calculation of the elastic properties in three dimensions, according to equations derived from Newton's second law and Hooke's law. The axes of maximum stiffness were determined by fitting longitudinal velocities measured along the perimeter of each cortical specimen to a sinusoidal function. Results showed significant differences in elastic properties between different functional areas of the rhesus cranium, and that many sites have a consistent orientation of maximum stiffness among specimens. Overall, the cortical bones of the rhesus monkey skull can be modeled as orthotropic in many regions, and as transversely isotropic in some regions, e.g., the supraorbital region. There are differences from human crania, suggesting that structural differences in skeletal form relate to differences in cortical material properties across species. These differences also suggest that we require more comparative data on elastic properties in primate craniofacial skeletons to explore effectively the functional significance of these differences, especially when these differences are elucidated through modeling approaches, such as finite‐element modeling. Am J Phys Anthropol 2006. © 2006 Wiley‐Liss, Inc.